Lake Titicaca (Peru/Bolivia) phytoplankton: species composition and structural comparison with other tropical and temperate lakes
Mountain Wetlands Repository
Carney
Imported from marcos-custom-data

Macroinvertebrate community structure in an extreme altiplanic environment from Chile: The Ascotán salt pan
Mountain Wetlands Repository
Vila
et al.
Imported from marcos-custom-data

Abrupt Younger Dryas cooling in the northern tropics recorded in lake sediments from the Venezuelan Andes
Mountain Wetlands Repository
Stansell
et al.
Imported from marcos-custom-data

Palynological signal of the Younger Dryas in the tropical Venezuelan Andes
Rull
et al.

Re-evaluation of mid-Holocene deposits at Quebrada Puripica, northern Chile
Rech

Carbonate and organic matter sedimentation and isotopic signatures in Lake Chungará, Chilean Altiplano, during the last 12.3kyr
Pueyo
Putre, Provincia de Parinacota, Arica y Parinacota Region, Chile

Archaeological silence and ecorefuges: Arid events in the Puna of Atacama during the Middle Holocene
Nunez

Mid-Holocene Climate and Culture Change in the Atacama Desert, Northern Chile
Grosjean
AbstractTwenty archaeological campsites intercalated between more than 30 debris flows caused by heavy rainfall events between 6200 and 3100 14C yr B.P. have recently been discovered at Quebrada Puripica in the Atacama Desert of northern Chile. This record provides detailed information about extreme, short-lived climatic events during the hyperarid mid-Holocene period. For the first time, we found evidence of continuous human occupation in this area, filling the regional hiatus in the Atacama basin (“Silencio Arqueologico”) between 8000 and 4800 14C yr B.P. The transformation of Early Archaic hunters into the complex Late Archaic cultural tradition was an adaptive process. During this time, the site was a local ecological refuge with abundant resources in a generally hostile environment.

From proxy data to paleoclimate interpretation: the mid-Holocene paradox of the Atacama Desert, northern Chile
Grosjean
San Pedro de Atacama, Provincia de El Loa, Antofagasta Region, Chile

Palaeoindian occupation of the Atacama Desert, northern Chile
Grosjean
AbstractPalaeoindian occupation of the Atacama Desert in northern Chile has been found between 12 600 and 10 200 cal. yr BP. The new site at Salar Punta Negra (24°28′S/60°53′W/2976 m) includes about 1000 classifiable, mostly unifacial artefacts and, uniquely, three different diagnostic types of early projectile points. Two of the Lateglacial/early Holocene projectile types have wide distribution and are known from different geographical areas in South America: the Palaeoindian ‘Fell’ fish‐tail point mainly from the southern cone of South America, and the triangular ‘Tuina’ points typical of the Puna of the south‐central Andes in northern Chile and northwestern Argentina. In addition, we found a third type, a stemmed point typical for the Salar Punta Negra. Filling a large geographical gap of ‘Fell’ occupation, the site at Salar Punta Negra provides evidence for generally much higher mobility and diversity of early cultures, and supports an Andean‐Pacific route for early human exploration of South America to the south through the desert at intermediate altitudes. Contemporaneous high‐amplitude climatic changes were fundamental preconditions to provide adequate environments and habitats, and to make Palaeoindian hunting‐gathering occupation possible in the Atacama Desert. Copyright © 2005 John Wiley & Sons, Ltd.

Late-Quaternary lowstands of Lake Titicaca: evidence from high-resolution seismic data
D Agostino
Peru

Holocene tropical South American hydroclimate revealed from a decadally resolved lake sediment δ18O record
Bird

Water Availability, Protected Areas, and Natural Resources in the Andean Desert Altiplano
Messerli

Mid- and late-Holocene limnogeology of Laguna del Negro Francisco, northern Chile, and its palaeoclimatic implications
Lacustrine sediments from the high elevation, endorheic, saline lake Negro Francisco (27°28'S/69°14'W, 4125 m) provide a detailed mid- and late-Holocene environmental history of the Southern Chilean Altiplano. Mineralogy, chemical composition and sedimentary facies analyses of the deposits confirm the regional significance of mid-Holocene aridity between 6000 and 3800 BP. Precipitation rates were signifi cantly lower than the c. 250 mm yr-1 of today. Fully arid conditions were interrupted by short-term moist spells with an average return period of about 200 years. Effective moisture increased after 3800 BP and peaked between 3000 and 2600 BP and between 2200 and 1800 BP in two phases with conditions more humid than today. Comparison with regional palaeodata suggest that these two late-Holocene humid spells were most likely related to Pacific moisture sources. Salinity levels increased again in Laguna del Negro Francisco after 1800 BP. The onset of modern climatic conditions was a stepwise, nonlinear process. However, the functioning of modern climate in this remote part of the world is not understood well enough to explain fully possible mech anisms of climatic changes in the past.

Isotopic evidence for late Quaternary climatic change in tropical South America
Seltzer

The Amazon River headstream area in the Cordillera Chila, Peru: hydrographic, hydrological and glaciological conditions
Janský

Millennial-scale climate variability during the Last Glacial period in the tropical Andes
Fritz
Peru

Climatic Influence on Sedimentology and Geomorphology of the Rio Ramis Valley, Peru
Farabaugh
Rigsby

GIS-Based Detection of Gullies in Terrestrial LiDAR Data of the Cerro Llamoca Peatland (Peru)
Höfle
Cushion peatlands are typical features of the high altitude Andes in South America. Due to the adaptation to difficult environmental conditions, they are very fragile ecosystems and therefore vulnerable to environmental and climate changes. Peatland erosion has severe effects on their ecological functions, such as water storage capacity. Thus, erosion monitoring is highly advisable. Erosion quantification and monitoring can be supported by high-resolution terrestrial Light Detection and Ranging (LiDAR). In this study, a novel Geographic Information System (GIS)-based method for the automatic delineation and geomorphometric description of gullies in cushion peatlands is presented. The approach is a multi-step workflow based on a gully edge extraction and a sink filling algorithm applied to a conditioned digital terrain model. Our method enables the creation of GIS-ready polygons of the gullies and the derivation of geomorphometric parameters along the entire channel course. Automatically derived boundaries and gully area values correspond to a high degree (93%) with manually digitized reference polygons. The set of methods developed in this study offers a suitable tool for the monitoring and scientific analysis of fluvial morphology in cushion peatlands.

Structural control on geothermal circulation in the Cerro Tuzgle–Tocomar geothermal volcanic area (Puna plateau, Argentina)
Giordano
Municipio de Susques, Departamento Susques, Jujuy, 4641, Argentina
Municipio de Susques, Jujuy, Argentina

A late Holocene record of arid events from the Cuzco region, Peru
Chepstow-Lusty
AbstractThe small recently infilled lake basin of Marcacocha (13°13′S, 72°12′W, 3355 m) in the Cuzco region of Peru has a morphology and location that renders it extremely sensitive to environmental change. A record of vegetation, human impact and climatic change during the past 4200 yr has been obtained from a highly organic core taken from the centre of the basin. Sustained arid episodes that affected the Peruvian Andes may be detectable using the proxy indicator of sedge (Cyperaceae) pollen abundances. As the lake‐level was lowered during sustained drier conditions, the local catchment was colonised by Cyperaceae, whereas during lake floods, they retreated or were submerged and pollen production was correspondingly reduced. Drier episodes during prehistoric times occurred around 900 bc, 500 bc, ad 100 and ad 550, with a longer dry episode occurring from ad 900 to 1800. Evidence from the independently derived Quelccaya ice‐core record and the archaeological chronology for the Cuzco region appears to support the climatic inferences derived from the sedge data. Many of these aridity episodes appear to correspond with important cultural changes in the Cuzco region and elsewhere in the Central Andes. Copyright © 2003 John Wiley & Sons, Ltd.
Ollantaytambo, Province of Urubamba, Cusco, Peru

Ice-cores, sediments and civilisation collapse: a cautionary tale from Lake Titicaca
Calaway
The temptation to equate environmental change with archaeologically observed events is always with us, and matching a climatic downturn with civilisation collapse is perhaps more attractive then ever. The archaeologically observed collapse of the Tiwanaku civilisation in the twelfth century AD has been specifically related to a prolonged drought which would have affected the people’s ability to produce food. However, a careful scrutiny of the data from ice cores and lake sediments persuades the author that no such drought can be inferred: the evidence for climatic change is of quite a different scale and order to the archaeological changes and cannot be used as an explanation of social events.
Peru

The history of South American tropical precipitation for the past 25,000 years
Baker
Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much of the Amazon basin were wetter than today. The LGM in this part of the Andes is dated at 21,000 cal yr B.P., approximately coincident with the global LGM. Maximum aridity and lowest lake level occurred in the early and middle Holocene (8000 to 5500 cal yr B.P.) during a time of low summer insolation. Today, rising levels of Lake Titicaca and wet conditions in Amazonia are correlated with anomalously cold sea-surface temperatures in the northern equatorial Atlantic. Likewise, during the deglacial and Holocene periods, there were several millennial-scale wet phases on the Altiplano and in Amazonia that coincided with anomalously cold periods in the equatorial and high-latitude North Atlantic, such as the Younger Dryas.

Chilean geothermal resources and their possible utilization
Lahsen
Calama, Provincia de El Loa, Antofagasta Region, Chile
Putre, Provincia de Parinacota, Arica y Parinacota Region, Chile
Turco, Sajama, Oruro, Bolivia
Colchane, Provincia del Tamarugal, Tarapacа Region, Chile
Pica, Provincia del Tamarugal, Tarapacа Region, Chile
Santa María, Provincia de San Felipe de Aconcagua, Valparaiso Region, Chile
Colina, Provincia de Chacabuco, Santiago Metropolitan Region, Chile
Los Andes, Provincia de Los Andes, Valparaiso Region, 2100000, Chile
San Fernando, Provincia de Colchagua, O'Higgins Region, Chile
Chile

Late Pleistocene Climate and Water Budget of the South American Altiplano
Hastenrath
Geomorphic evidence from the Peruvian-Bolivian Altiplano indicates that during episodes prior to 28,000 and around 12,500-11,000 yr B.P., lakes covered an area about six and four times as large as at present, respectively. Within the constraints of the heat and water budget, model calculations are used to estimate the precipitation rate that would allow hydrologic equilibrium. On this basis it is suggested that rainfall on the Altiplano during the episodes of enlarged lakes was, respectively, some 300 and 200 mm annum−1 larger than at present, representing increases of about 75 and 50%, respectively. Field evidence suggests that the episodes of enlarged lakes on the Altiplano may have preceded or coincided with periods of maximum glaciation in the neigh-boring Andes. In this region with high elevation of the ice equilibrium line, increased precipitation is particularly conducive to glaciation.

Late-glacial and early Holocene lake sediments, ground-water formation and climate in the Atacama Altiplano 22-24S
Grosjean at al1995a

Radiocarbon Reservoir Effect and the Timing of the Late-Glacial/Early Holocene Humid Phase in the Atacama Desert (Northern Chile)
Geyh
We revise substantially the regional chronology of lake-level fluctuations from the late-glacial/early Holocene humid phase along a high altitude transect (3500 to 4500 m) between 18°S and 28°S in the Southwestern Altiplano of Northern Chile. Radiocarbon dates and210Pb profiles for limnic and terrestrial materials allow us to estimate and justify reservoir correction values for conventional14C dates. Our chronology suggests that the latest Pleistocene/early Holocene humid phase started between 13,000 and 12,00014C yr B.P., and that maximum lake levels were reached between 10,800 and 920014C yr B.P. This is significantly younger than what has been established so far for the Titicaca–Uyuni Basin in Bolivia. The paleolakes disappeared sometime between 8400 and 800014C yr B.P. Our revised chronology agrees with the regional history of human occupation, and is broadly synchronous with vegetation changes in subtropical continental South America, and with the onset of wetland expansion in the northern hemisphere tropics.
Putre, Provincia de Parinacota, Arica y Parinacota Region, Chile
San Pedro de Atacama, Provincia de El Loa, Antofagasta Region, Chile
Chile

Water Recycling in Arid Regions: Chilean Case
Caceres

Water chemistry of Lake Quilotoa (Ecuador) and assessment of natural hazards
Aguilera

Limnogeology of Laguna Miscanti: evidence for mid to late Holocene moisture changes in the Atacama Altiplano (Northern Chile)
Valero-Garces
San Pedro de Atacama, Provincia de El Loa, Antofagasta Region, Chile

Lake-Level Chronology on the Southern Bolivian Altiplano (18°–23°S) During Late-Glacial Time and the Early Holocene
Sylvestre
AbstractStratigraphic analyses of outcrops, shorelines, and diatoms from the southern Bolivian Altiplano (Uyuni-Coipasa basin) reveal two major lacustrine phases during the late-glacial period and the early Holocene, based on a chronology established by radiocarbon and U/Th control. A comparison of14C and230Th/234U ages shows that during times of high lake level, radiocarbon ages are valid. However, during low-water periods,14C ages must be corrected for a reservoir effect. The lacustrine Tauca phase started a little before 16,00014C yr B.P., and the lake level reached its maximum between 13,000 and 12,00014C yr B.P. A dry event (Ticaña) occurred after ca. 12,000 and before 950014C yr B.P. A moderate lacustrine oscillation (Coipasa event) occurred between ca. 9500 and 850014C yr B.P., using a reservoir-corrected conventional14C chronology. Comparisons between the lake-level chronology in the Uyuni-Coipasa basin and data from other southern tropical areas of South America suggest that the lacustrine evolution may reflect large-scale climatic changes.
Municipio Colcha K, Provincia Nor Lípez, Potosí, Bolivia

Non-conservative behavior of bromide in surface waters and brines of Central Andes: A release into the atmosphere?
Risacher
Municipio Colcha K, Provincia Nor Lípez, Potosí, Bolivia

Bromine geochemistry of salar de Uyuni and deeper salt crusts, Central Altiplano, Bolivia
Risacher
Fritz
Municipio Colcha K, Provincia Nor Lípez, Potosí, Bolivia

Geochemistry of Bolivian salars, Lipez, southern Altiplano: Origin of solutes and brine evolution
Risacher

Quaternary geochemical evolution of the salars of Uyuni and Coipasa, Central Altiplano, Bolivia

Geochemical evolution of brines in the Salar of Uyuni, Bolivia
Rettig

Miocene to Recent history of the western Altiplano in northern Chile revealed by lacustrine sediments of the Lauca Basin (18°15′–18°40′S/69°30′–69°05′W)
Kött

Chemical composition and distribution of lithium-rich brines in salar de Uyuni and nearby salars in southwestern Bolivia
Ericksen

New and past geochemical data on fresh to brine waters of the Salar de Atacama and Andean Altiplano, northern Chile
Boschetti

A 106 ka paleoclimate record from drill core of the Salar de Atacama, northern Chile
Bobst

Authigenic smectite on diatom frustules in Bolivian saline lakes
Badaut

Hydrogeochemistry and stable isotopes of ground and surface waters from two adjacent closed basins, Atacama Desert, northern Chile
Alpers
Whittemore

Effects of wind-driven spatial structure and environmental heterogeneity on high-altitude wetland macroinvertebrate assemblages with contrasting dispersal modes
Bertin

Invertebrate Metacommunity Structure and Dynamics in an Andean Glacial Stream Network Facing Climate
Cauvy-Fraunié

Glacial flood pulse effects on benthic fauna in equatorial high-Andean streams
Cauvy-Fraunié

Glacier recession and water resources in Peru’s Cordillera Blanca
Baraer
AbstractThe tropical glaciers of the Cordillera Blanca, Peru, are rapidly retreating, resulting in complex impacts on the hydrology of the upper Río Santa watershed. The effect of this retreat on water resources is evaluated by analyzing historical and recent time series of daily discharge at nine measurement points. Using the Mann-Kendall nonparametric statistical test, the significance of trends in three hydrograph parameters was studied. Results are interpreted using synthetic time series generated from a hydrologic model that calculates hydrographs based on glacier retreat sequences. The results suggest that seven of the nine study watersheds have probably crossed a critical transition point, and now exhibit decreasing dry-season discharge. Our results suggest also that once the glaciers completely melt, annual discharge will be lower than present by 2-30% depending on the watershed. The retreat influence on discharge will be more pronounced during the dry season than at other periods of the year. At La Balsa, which measures discharge from the upper Río Santa, the glacier retreat could lead to a decrease in dry-season average discharge of 30%.

Paleohydrology of Andean saline lakes from sedimentological and isotopic records, Northwestern Argentina
Valero-Garcés etal
Departamento Antofagasta de la Sierra, Catamarca, K4705, Argentina
Catamarca, Argentina

Foraging ecology of Vicuña, Vicugna vicugna, in dry Puna of Argentina
Borgnia

Soil chronosequence and geomorphology in a semi-arid valley in the Andes of southern Peru
Eash
Sandor

Chromohalobacter sarecensis sp. nov., a psychrotolerant moderate halophile isolated from the saline Andean region of Bolivia
Quillaguamán
A moderately halophilic, aerobic, motile, Gram-negative, rod-shaped bacterium (strain LV4T) was isolated from saline soil around the lake Laguna Verde in the Bolivian Andes. The organism is a heterotroph, able to utilize various carbohydrates as a carbon source. It showed tryptophan deaminase, oxidase and catalase activity, but was unable to produce indole or H2S; nitrate was not reduced. The G+C content of the genomic DNA was 56·1 mol%. The pH range for growth was 5–10, temperature range was 0–45 °C and the range of NaCl concentrations was 0–25 % (w/v). On the basis of 16S rRNA gene sequence analysis, strain LV4T was found to be closely related to Chromohalobacter canadensis DSM 6769T and Pseudomonas beijerinckii DSM 7218T; however, its DNA–DNA relatedness with these type strains was low. Strain LV4T resembled other Chromohalobacter species with respect to various physiological, biochemical and nutritional characteristics but also exhibited differences. Thus, a novel species, Chromohalobacter sarecensis sp. nov., is proposed, with LV4T (=CCUG 47987T=ATCC BAA-761T) as the type strain.

Carbon dioxide and methane fluxes in grazed and undisturbed mountain peatlands in the Ecuadorian Andes
Sanchez
Peatlands are widespread throughout the tropical Andean páramo. Despite the large carbon stocks in these ecosystems, carbon dioxide (CO2) and methane (CH4) flux data are lacking. In addition, cattle grazing is widespread in the páramo and could alter gas fluxes. Therefore, our objectives were to measure CO2 and CH4 fluxes with the static chamber technique in an undisturbed and in an intensively cattle grazed peatland in the mountains of Ecuador. We found that hummocks in the undisturbed site had higher net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (ER), and CH4 fluxes, compared to lawns. In contrast, microtopography at the grazed site did not predict CO2 fluxes, whereas vegetation cover was correlated for all three metrics (NEE, ER, and GPP). At low vegetation cover, NEE was positive (losing carbon). CH4 emissions in the undisturbed site were low (8.1 mg CH4 m-2 d-1). In contrast, CH4 emissions at the grazed site were much greater (132.3 mg CH4 m-2 d-1). This is probably attributable to trampling and nutrient inputs from cattle. In summary, the two peatlands differed greatly in CO2 and CH4 exchange rates, which could be due to the variation in climate and hydrology, or alternatively to intensive grazing by cattle.
Pifo, Quito Canton, Pichincha, 170175, Ecuador
Pintag, Quito Canton, Pichincha, 170811, Ecuador
Quito Canton, Ecuador

A documentation of glacier tongue variations and lake development in the Cordillera Blanca, Peru
Ames
Abstract
At Hualcán in the Cordillera Blanca is a high-altitude glacier lake dammed by a moraine. Local glaciers regularly produce ice avalanches. In 1988 it was confirmed that the moraine was ice-cored. The rate of melting of the ice was sufficiently fast that, unless mitigation measures had been undertaken rapidly, the moraine would have collapsed. This would have resulted in the inundation downstream of Carhuaz, a town with a population of 25000 people. Following the successful installation of siphons in 1988–89 to reduce the water level by 8 m, it was decided to undertake more permanent engineering works to ensure that the lake could never again pose a threat. It was proposed to construct a 2-m diameter tunnel, 155 m long beneath a rock bar below the moraine dam, to lower the lake level by a further 20 m. This would create sufficient freeboard to contain possible displacement waves.
Work on the tunnel was started in May 1993 using compressed air drilling and blasting with hand excavation. The initial tunnel design consisted of a single tunnel drive 135 m long plus a 20-m inclined drive under the lake. A second, near-vertical shaft was constructed for ventilation and access. Had the proposed method of breakthrough from the tunnel to the lake been carried out, it would have resulted in a rockburst leading to the catastrophic discharge of the lake. The tunnel design was changed on site to include three additional inclined drives from the main shaft, reaching the lake at vertical intervals of 5 m. Using this method, the lake level was lowered 20 m safely.
The objective of this paper is to describe in detail the geotechnical engineering aspects of the tunnel construction, the reasons for the change in its design, and the results of the mitigation work.

Structure and diversity of stream invertebrate assemblages: the influence of temperature with altitude and latitude
Jacobsen
1. Structure and diversity of the macroinvertebrate fauna were studied in relation to altitude and latitude among three groups of streams from Ecuador (lowland: 100–600 m, Central Valley: 2600–3100 m, páramo: 3500–4000 m), and one group from the temperate lowland region of Denmark. The streams in the four regions were comparable with regard to physical characteristics such as size, current and substratum.2. In terms of faunal composition the Ecuadorian highland streams bore more resemblance to the Danish lowland streams than the Ecuadorian lowland streams. The greater similarity between the Ecuadorian highland and the Danish streams, however, was due to the large number of insect families in the Ecuadorian lowlands, many of which were not found in the other regions. Of ten physico‐chemical parameters measured, maximum stream temperature explained by far the most variability in faunal composition.3. The number of insect orders and families increased linearly with maximum stream temperature and therefore decreased with altitude and latitude. A compilation of literature data on insect richness and maximum water temperature from streams around the world confirmed this pattern, yielding a common linear relation for both temperate and tropical streams. This pattern may arise due to a direct temperature effect on speciation but is probably also related to geological history and the influence of climatic changes on stream ecosystems. We estimate that small, tropical, lowland streams have, on average, a two‐ to fourfold higher species richness than temperate lowland streams.

Are macroinvertebrates in high altitude streams affected by oxygen deficiency?
Jacobsen 2003b
Summary1. The solubility of oxygen in water increases with decreasing temperature. This has led to a general perception of cold, high mountain streams as more oxygen rich than warmer lowland streams, and that macroinvertebrates inhabiting high altitude streams have had no need to adapt to critical oxygen conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes.2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small streams from sea level to 4000 m a.s.l. in Ecuador, we determined predicted oxygen availability, oxygen demand and macroinvertebrate assemblage structure along this wide altitudinal gradient.3. We show that the predicted oxygen availability at 4000 m a.s.l. is only one fifth of that at sea level, whereas the mean weight‐specific respiratory rate of macroinvertebrates declined by only 50%, from 400 to 3800 m. We suggest that this disproportionately large gap between availability and demand of oxygen at high altitudes may imply a potential oxygen deficiency for the fauna, and we discuss how oxygen deficiency can be expected to affect macroinvertebrates in high altitude streams.4. Finally, we present preliminary data on the predicted response to oxygen deficiency of macroinvertebrate assemblages in high altitude streams. Compared with lowland streams, assemblages in natural high altitude streams include relatively few groups normally regarded as oxygen‐sensitive. Nevertheless, high altitude assemblages react more strongly to lowering of oxygen saturation, and are thus more sensitive to organic pollution.5. Oxygen deficiency has been overlooked completely in studies of the altitudinal distribution of species and aquatic communities. We argue that oxygen deficiency may be a potentially important factor, and that more focus on this topic is likely to produce significant new insights in aquatic community ecology.

Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates
Jacobsen
Abstract. Spatial variation in hydraulic conditions in streams often results in distinct water surface patterns, or surface flow types. Visual assessments of the distribution of surface flow types have been used to provide rapid assessment of habitat heterogeneity. The efficacy of this approach is predicated on the notion that surface flow types consistently represent a distinct suite of hydraulic conditions with biological relevance. This study tested this notion, asking three specific questions. First, do surface flow types provide a characterisation of physical habitat that is relevant to macroinvertebrates? Second, how well do near-bed hydraulic conditions explain macroinvertebrate distributions? Third, what components of near-bed hydraulic conditions exert the strongest influence on macroinvertebrate distributions? Results show that hydraulic conditions (incorporating direct measurements of near-bed velocity and turbulence in three dimensions) and substratum character (incorporating estimates of particle size distribution, and biofilm and macrophyte cover) within each surface flow type were largely distinct and that macroinvertebrate assemblages differed across flow types in taxon richness and assemblage composition, thus supporting the notion that rapid assessments of surface flow type distributions provide biologically relevant information. Macroinvertebrate assemblages were most strongly correlated with water depth, size of a flow type patch, near-bed velocity in the downstream direction, turbulence in the transverse direction, % pebble, % sand, % silt and clay and macrophyte cover. This study suggests that surface flow type mapping provides an assessment of physical habitat that is relevant to macroinvertebrates. The strong relationship detected between macroinvertebrate assemblages and transverse turbulence also highlights the value of directly measuring near-bed hydraulics. Further investigations are required to test the mechanisms underlying this relationship.

Altitudinal changes in diversity of macroinvertebrates from small streams in the Ecuadorian Andes
Jacobsen 2003a

A Null Model to Explain Zooplankton Species Associations in Saline Lakes of the South American Altiplano (14-27°S)
los Rios de
Gajardo

Patterns of regional hydrological variability in central-southern Altiplano (18°–26°S) lakes during the last 500 years
Valero-Garcés
Departamento Antofagasta de la Sierra, Catamarca, K4705, Argentina

Pronounced occurrence of long-chain alkenones and dinosterol in a 25,000-year lipid molecular fossil record from Lake Titicaca, South America
Theissen

Holocene precipitation and atmospheric changes inferred from river paleowetlands in the Bolivian Andes
Servant
Servant-Vildary
Tupiza, Sur Chichas, Potosí, Bolivia
Municipio Caripuyo, Provincia Alonso de Ibañez, Potosí, Bolivia
Potosí, Provincia Tomás Frías, Potosí, Bolivia
Municipio Charaña, Provincia Pacajes, La Paz, Bolivia
Municipio Comanche, Provincia Pacajes, La Paz, Bolivia
Pucarani, Provincia Los Andes, La Paz, Bolivia
Bolivia

Holocene environments from stable isotope stratigraphy of ostracods and authigenic carbonate in Chilean Altiplano Lakes
Schwalb

Lacustrine sedimentation in active volcanic settings: the Late Quaternary depositional evolution of Lake Chungará (northern Chile)
Sáez
AbstractLake Chungará (18°15′S, 69°09′W, 4520 m above sea‐level) is the largest (22·5 km2) and deepest (40 m) lacustrine ecosystem in the Chilean Altiplano and its location in an active volcanic setting, provides an opportunity to evaluate environmental (volcanic vs. climatic) controls on lacustrine sedimentation. The Late Quaternary depositional history of the lake is reconstructed by means of a multiproxy study of 15 Kullenberg cores and seismic data. The chronological framework is supported by 10 14C AMS dates and one 230Th/234U dates. Lake Chungará was formed prior to 12·8 cal kyr bp as a result of the partial collapse of the Parinacota volcano that impounded the Lauca river. The sedimentary architecture of the lacustrine succession has been controlled by (i) the strong inherited palaeo‐relief and (ii) changes in the accommodation space, caused by lake‐level fluctuations and tectonic subsidence. The first factor determined the location of the depocentre in the NW of the central plain. The second factor caused the area of deposition to extend towards the eastern and southern basin margins with accumulation of high‐stand sediments on the elevated marginal platforms. Synsedimentary normal faulting also increased accommodation and increased the rate of sedimentation in the northern part of the basin. Six sedimentary units were identified and correlated in the basin mainly using tephra keybeds. Unit 1 (Late Pleistocene–Early Holocene) is made up of laminated diatomite with some carbonate‐rich (calcite and aragonite) laminae. Unit 2 (Mid‐Holocene–Recent) is composed of massive to bedded diatomite with abundant tephra (lapilli and ash) layers. Some carbonate‐rich layers (calcite and aragonite) occur. Unit 3 consists of macrophyte‐rich diatomite deposited in nearshore environments. Unit 4 is composed of littoral sediments dominated by alternating charophyte‐rich and other aquatic macrophyte‐rich facies. Littoral carbonate productivity peaked when suitable shallow platforms were available for charophyte colonization. Clastic deposits in the lake are restricted to lake margins (Units 5 and 6). Diatom productivity peaked during a lowstand period (Unit 1 and subunit 2a), and was probably favoured by photic conditions affecting larger areas of the lake bottom. Offshore carbonate precipitation reached its maximum during the Early to Mid‐Holocene (ca 7·8 and 6·4 cal kyr bp). This may have been favoured by increases in lake solute concentrations resulting from evaporation and calcium input because of the compositional changes in pyroclastic supply. Diatom and pollen data from offshore cores suggest a number of lake‐level fluctuations: a Late Pleistocene deepening episode (ca 12·6 cal kyr BP), four shallowing episodes during the Early to Mid‐Holocene (ca 10·5, 9·8, 7·8 and 6·7 cal kyr BP) and higher lake levels since the Mid‐Holocene (ca 5·7 cal kyr BP) until the present. Explosive activity at Parinacota volcano was very limited between c. >12·8 and 7·8 cal kyr bp. Mafic‐rich explosive eruptions from the Ajata satellite cones increased after ca 5·7 cal kyr bp until the present.

A vegetation and fire history of Lake Titicaca since the Last Glacial Maximum
Paduano

Water quality and limnological features of a high altitude Andean lake, Chungará, in northern Chile
Mühlhauser

A 22,000 14C year BP sediment and pollen record of climate change from Laguna Miscanti (23°S), northern Chile

Dating of paleolakes in the central Altiplano of Bolivia
Fornari

A 22,000-Year Record of Monsoonal Precipitation from Northern Chile's Atacama Desert
Betancourt
Fossil rodent middens and wetland deposits from the central Atacama Desert (22° to 24°S) indicate increasing summer precipitation, grass cover, and groundwater levels from 16.2 to 10.5 calendar kiloyears before present (ky B.P.). Higher elevation shrubs and summer-flowering grasses expanded downslope across what is now the edge of Absolute Desert, a broad expanse now largely devoid of rainfall and vegetation. Paradoxically, this pluvial period coincided with the summer insolation minimum and reduced adiabatic heating over the central Andes. Summer precipitation over the central Andes and central Atacama may depend on remote teleconnections between seasonal insolation forcing in both hemispheres, the Asian monsoon, and Pacific sea surface temperature gradients. A less pronounced episode of higher groundwater levels in the central Atacama from 8 to 3 ky B.P. conflicts with an extreme lowstand of Lake Titicaca, indicating either different climatic forcing or different response times and sensitivities to climatic change.

Holocene paleohydrology and glacial history of the central Andes using multiproxy lake sediment studies
Abbott

Holocene Paleohydrology of the Tropical Andes from Lake Records
Abbott

A 2,300-year-long annually resolved record of the South American summer monsoon from the Peruvian Andes
Bird
Decadal and centennial mean state changes in South American summer monsoon (SASM) precipitation during the last 2,300 years are detailed using an annually resolved authigenic calcite record of precipitation
δ
18
O from a varved lake in the Central Peruvian Andes. This unique sediment record shows that
O peaked during the Medieval Climate Anomaly (MCA) from A.D. 900 to 1100, providing evidence that the SASM weakened considerably during this period. Minimum
O values occurred during the Little Ice Age (LIA) between A.D. 1400 and 1820, reflecting a prolonged intensification of the SASM that was regionally synchronous. After the LIA,
O increased rapidly, particularly during the current warm period (CWP; A.D. 1900 to present), indicating a return to reduced SASM precipitation that was more abrupt and sustained than the onset of the MCA. Diminished SASM precipitation during the MCA and CWP tracks reconstructed Northern Hemisphere and North Atlantic warming and a northward displacement of the Intertropical Convergence Zone (ITCZ) over the Atlantic, and likely the Pacific. Intensified SASM precipitation during the LIA follows reconstructed Northern Hemisphere and North Atlantic cooling, El Niño-like warming in the Pacific, and a southward displacement of the ITCZ over both oceans. These results suggest that SASM mean state changes are sensitive to ITCZ variability as mediated by Western Hemisphere tropical sea surface temperatures, particularly in the Atlantic. Continued Northern Hemisphere and North Atlantic warming may therefore help perpetuate the recent reductions in SASM precipitation that characterize the last 100 years, which would negatively impact Andean water resources.

Synchronous interhemispheric Holocene climate trends in the tropical Andes
Polissar etal
Holocene variations of tropical moisture balance have been ascribed to orbitally forced changes in solar insolation. If this model is correct, millennial-scale climate evolution should be antiphased between the northern and southern hemispheres, producing humid intervals in one hemisphere matched to aridity in the other. Here we show that Holocene climate trends were largely synchronous and in the same direction in the northern and southern hemisphere outer-tropical Andes, providing little support for the dominant role of insolation forcing in these regions. Today, sea-surface temperatures in the equatorial Pacific Ocean modulate rainfall variability in the outer tropical Andes of both hemispheres, and we suggest that this mechanism was pervasive throughout the Holocene. Our findings imply that oceanic forcing plays a larger role in regional South American climate than previously suspected, and that Pacific sea-surface temperatures have the capacity to induce abrupt and sustained shifts in Andean climate.

Late-glacial and Holocene vegetational history from two sites in the western Cordillera of southwestern Ecuador
Hansen

Upper quaternary vegetational and climatic sequence of the fuquene area (Eastern Cordillera, Colombia)
vanGeel
van der Hammern

Spatial and temporal variation of the vegetation of the semiarid Puna in a pastoral system in the Pozuelos Biosphere Reserve
Rojo

Salicola marasensis gen. nov., sp. nov., an extremely halophilic bacterium isolated from the Maras solar salterns in Peru
Maturrano
Six strains of extremely halophilic bacteria were isolated from several crystallizer ponds of the Maras solar salterns in the Peruvian Andes. On the basis of 16S rRNA gene sequence similarity, G+C contents and DNA–DNA hybridization results, the six isolates constituted a genomically homogeneous group affiliated with the Gammaproteobacteria. The closest relatives were members of the halophilic genera Halovibrio and Halospina, which showed 16S rRNA gene sequence similarities below 97 % and whole-genome hybridization levels below 33 % for the type strain, 7Sm5T. From the genomic and phenotypic properties of the six novel isolates and phylogenetic reconstruction based on 16S rRNA gene sequence analysis, they can be considered to represent a novel genus within the Gammaproteobacteria. On the basis of the taxonomic study, a novel genus, Salicola gen. nov., is proposed containing the single species Salicola marasensis sp. nov., which is the type species. The type strain of Salicola marasensis is 7Sm5T (=CECT 7107T=CIP 108835T).

Through the looking glass: re-assessing the role of agro-pastoralism in the north-central Andean highlands
Lane

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 2. Azonal vegetation
Cuello
Cleef
openalex
["Vegetation (pathology)", "Bog", "Sphagnum", "Peat", "Ecology", "Geography", "Floristics", "Biology", "Species richness"]
["Mediterranean and Iberian flora and fauna", "Plant Taxonomy and Phylogenetics", "Botanical Research and Applications"]

Multi-taxon patterns from high Andean peatlands: assessing climatic and landscape variables
Izquierdo

Integrating Farming and Páramo Conservation: A Case Study From Colombia
Robineau

Late Holocene environmental changes as recorded in the sediments of high Andean Laguna Chepical, Central Chile
Martel-Cea

Geomorphodynamics as recorded in a high-Andean cushion peatland of the western Chilean Central Andes (27° S) during the last 1800 cal. yr BP
Kock

Late Holocene summer temperatures in the central Andes reconstructed from the sediments of high-elevation Laguna Chepical, Chile (32° S)
Jong
Abstract. High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr-long austral summer (November to February) temperature reconstruction derived from the 210Pb- and 14C-dated organic sediments of Laguna Chepical (32°16' S, 70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3 yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC. The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca. AD 1400, long-term temperature patterns were generally similar at low and high altitudes in central Chile.

Greenhouse gas emissions in natural and managed peatlands of America: Case studies along a latitudinal gradient
Veber

Assessing groundwater recharge in an Andean closed basin using isotopic characterization and a rainfall-runoff model: Salar del Huasco basin, Chile
Uribe

Upward range extension of Andean anurans and chytridiomycosis to extreme elevations in response to tropical deglaciation
Seimon

Proglacial lake sediment records of Holocene climate change in the western Cordillera of Peru
Stansell

Delta progradation and Neoglaciation, Laguna Paron, Cordillera Blanca, Peru
Seltzer
Rodbell
AbstractThe history of Holocene glaciation serves as an important record of glacier mass balance and, therefore, of climatic change. The moraine record of Holocene glaciation in the tropical Andes, however, is fragmentary and poorly dated. In contrast, increases in the rate of accumulation of inorganic sediment in glacier‐fed lakes have been linked to periods of Neoglaciation in many mountain regions. The interpretation of such a record of Neoglaciation from sediment cores in glacier‐fed lakes in the tropical Andes can provide the continuity and chronologic control that is lacking in the existing moraine record. Unusual exposures of glacial lacustrine sediment in the Cordillera Blanca, Peru, provide a rare opportunity to assess the link between climatic change, glaciation, and lacustrine sedimentation.Intentional lowering of water levels in Laguna Parón (9°S, 77°44′ W, 4200 m a.s.l.) in 1985 resulted in the incision and exposure of at least 20 m of deltaic deposits at the eastern end of the lake. Three deltaic units can be identified: horizontal topset beds, steeply dipping and deformed foreset beds, and horizontally laminated fine‐grained sediment. Six radiocarbon ages ranging from 1800 ± 210 to 465 ± 95 14C yr BP on wood indicate that the average rate of delta progradation in the late Holocene has been approximately 290 m per 1000 yr. The lake formed during deglaciation at least 10 000 yr ago and if such a rate of progradation of the delta had prevailed over the entire Holocene, then the delta would be at least three times as extensive as it is today. Thus the rate of delta progradation has varied significantly over the Holocene. We suggest that the rate of delta progradation was at least three times greater when glaciers were in advanced positions. These positions are clearly delimited by Neoglacial moraines, which are within 1–2 km of the exposures studied and within 1 km of modern ice limits. The most recent increase in the rate of delta progradation is evidenced by an increase in sedimentation rate ca. 575 ± 90 14C yr BP, coincident with the onset of the Little Ice Age. Copyright © 2005 John Wiley & Sons, Ltd.

Clastic sediment flux to tropical Andean lakes: records of glaciation and soil erosion
Rodbell

The rainbow trout Salmo gairdneri (Rich.) fishery of Lake Titicaca
Everett
Rainbow trout were introduced to Lake Titicaca in 1942. A commercial trout canning operation started in 1961 but terminated in 1970. Data for this study were collected in 1966 and 1967, with the object of examining the life history, biology, and commercial fishery of Titicaca rainbow trout. Trout were caught commercially and experimentally by gillnets in different parts of the lake.Lake Titicaca lies across the border of Peru and Bolivia at 3212 m above sea level. The physico‐chemical characteristics of the lake appear ideal for self‐sustaining populations of rainbow trout. Growth was constant throughout the year, and was good in relation to growth rates of rainbow trout in other parts of the world. Spawning took place in the tributaries in the winter. Recruitment to the fishery occurs in 7.62 cm stretch mesh gillnets at about 27 cm fork length.The total annual commercial catch increased to 500 metric tons in 1965 before subsequently decreasing. The simplest explanation for the decline in total catch would be the increase in fishing mortality due to increased fishing effort, although it is possible that the decline in water level has had some effect. It appeared possible that the lake could sustain an annual catch of about 350 tons.

Notes on the Birds of Lake Junin, Central Peru
Morrison
After I had finished my work in the Department of Huancavelica, in January 1938, I made a lengthy stay on Lake Junin. This lake is the source of the Mantaro River, and lies about 50 miles north of Oroya, at an altitude of a little less than 14,000 feet. It is situated in a great plain, ringed by rather low rolling brown hills. It is, of course, in typical Puna zone.

An Expedition to the Laguna Colorada, Southern Bolivia: With a Note on the Recent Occurrence of "El Nino"
Walcott

Lago Verde and Lago Flaco: Gypsum-bound lakes of the Chilean altiplano
Hurlbert
Two small perennial salt lakes in a salar of the Chilean altiplano have indurated bottom sediments and are bordered by damlike ramparts composed of almost pure gypsum. The bottom of one lake is constituted of polygonal plates (5–15‐m diam) of gypsum buckled upward into pressure ridges and overthrust slabs. Overthrust slabs that have reached the lake surface have developed massive iceberglike accumulations of gypsum on their leading edges. Expansion of anhydrite (CaSO4) on alteration to gypsum (CaSO4 ·2H2O) is speculated to be involved in formation of the pressure ridges. The two lakes are about four times deeper (2 m) than any other lakes in the salar, and their surfaces are elevated as much as 1.2 m above the adjacent salar crust, only the gypsum ramparts intervening. The ramparts range to 2 m high. The buildup of these ramparts via evaporative precipitation of wave‐wash, spray, and capillary brine, elevation of the lip of the small outflow channels, and deflation of the salar crust probably account for the lakes’ depths and elevated positions.

Glaciological Problems Set by the Control of Dangerous Lakes in Cordillera Blanca, Peru. III. Study of Moraines and Mass Balances at Safuna
Lliboutry
Abstract
We explain how preliminary results concerning the internal constitution of the big push moraine at Safuna were obtained in 1967. Cross-sections which were obtained later through electrical and seismic exploration and arduous borings are given. Under the lake Safuna Alta there exists a layer of dead ice which is probably a remnant from an old glacier advance and over which the active glacier slides, but this dead ice does not extend into the push moraine. Since 1950 Safuna Alta has formed, the glacier tongue has lowered by 0.8 m per year on average, and the big push moraine has moved and settled.
The annual balance on the glacier tongue was measured in 1968. It increases by 3.9 m of ice per 100 m in altitude. The discharge of ice near the lake and the annual balance further up-valley allow an estimate of the mean annual balance in the accumulation zone (between 4850 and 6020 m) at 2.30 m of water per year. Until now no annual precipitation higher than 1 m/year had been measured in Cordillera Blanca, but this Cordillera includes many meso-climates.
Eight successive moraines are found at Safuna. They are tentatively correlated with the eight existing between Huaraz and Laguna Llaca. Clapperton's (1972) “group 4” was not formed during the 20th, but during the 17th century. His “group 3” is not from A.D. 1750-1800, but is rather 5 000 to 7 000 years old, according to the offset of Cordillera Blanca great fault.
Yuracmarca, Province of Huaylas, Ancash, Peru

A Late Quaternary diatom record of tropical climatic history from Lake Titicaca (Peru and Bolivia)
Tapia
openalex
["Diatom", "Holocene", "Pelagic zone", "Oceanography", "Benthic zone", "Geology", "Salinity", "Plankton", "Quaternary", "Chaetoceros", "Ecology", "Phytoplankton", "Paleontology", "Biology"]
["Geology and Paleoclimatology Research", "Pleistocene-Era Hominins and Archaeology", "Geological formations and processes"]

Palaeoclimates in Central and South America since 18,000 BP based on pollen and lake-level records
Markgraf

Morphological and genetic differentiation among Chilean populations of Bufo spinulosus (Anura: Bufonidae)
Mendez

Formation of silica oncoids around geysers and hot springs at El Tatio, northern Chile
Jones
Renaut
ABSTRACTSiliceous oncoids, up to 4 cm in diameter, are common on the laterally extensive sinter aprons that surround the spectacular geysers and hot springs at El Tatio in northern Chile. Many of these complex oncoids developed close to geyser and spring vents that discharge boiling water. Internally the oncoids, which are composed of precipitated amorphous silica, are formed of complex arrays of spicules and concentric laminae as well as detrital volcanic grains. Spicular growth is dominant in most examples. The formation and growth of the spicules and concentric laminae were mediated by a microbial community which included filamentous microbes, mucus, and possibly bacteria. The microbes and mucus were silicified by replacement and encrustation. In some laminae the filamentous microbes lay parallel to the growth surface; in other laminae most filaments forming the thin mats were suberect. Amorphous silica precipitated between the filaments occluded porosity and commonly disguised the microbial fabric.The oncoids grew on the proximal sinter aprons around the geyser vents and hot spring pools. Most growth took place subaerially with the silica delivered to the precipitation sites by splashing water from the geysers and/or periodic shallow flooding of the discharge aprons. Unlike silica oncoids at other geothermal sites, vertical growth of oncoids that formed in some rimstone pools was not limited by water depth.

Crystal fabrics and microbiota in large pisoliths from Laguna Pastos Grandes, Bolivia
Jones
Renaut
ABSTRACTLarge pisoliths from the Laguna Pastos Grandes playa in the Bolivian Altiplano have a wide diversity of cortical fabrics and variable mineralogical composition. The cortical laminae are composed of radial calcite bundles, spar calcite, micrite, amorphous silica, mixed micrite‐amorphous silica, quartz, gypsum and halite. Diatoms are common in the outer parts of some radial calcite laminae and amorphous silica laminae, but cyanobacterial filaments are rare. Although the organization of the cortical laminae is highly variable, some repetitive sequences of different laminae are present. Cavities in and between pisoliths contain micrite, detrital grains, calcite bundles and peloids morphologically similar to those found in marine reefs.The pisoliths grow in shallow ephemeral pools fed by hot springs. Radial bundles of calcite precipitate rapidly by degassing and photosynthetic removal of CO2 following spring snowmelt. Conditions for micrite precipitation are unclear, but there is evidence to suggest formation in partially stagnant waters, some of elevated salinity. Amorphous silica laminae precipitate mainly by evaporative concentration; quartz may precipitate from warm silica‐rich spring waters that remain below amorphous silica saturation. The evaporite minerals form during desiccation of the pools or from spray. The peloids in cavities are probably primary precipitates. Different types of laminae may form simultaneously in different pools because of the highly variable conditions across the playa.Lateral migration of spring locations through time has created a complex carbonate‐silica pavement. Large spherical pisoliths form in outflow channels near spring orifices and across discharge aprons where waters are several decimetres deep. With mineral precipitation, channels are filled and become shallow, producing discoid pisoliths and crusts. In shallow waters and on distal aprons only small pisolith gravels form. As spring pools fill with deposits, their locations shift laterally; new pisoliths form elsewhere or precipitation may recommence on older abandoned pisoliths.

Landscape evolution and the environmental context of human occupation of the southern pampa del tamarugal, Atacama Desert, Chile
Workman

Physicochemical Parameters Affecting the Distribution and Diversity of the Water Column Microbial Community in the High-Altitude Andean Lake System of La Brava and La Punta
Nunez Salazar
Due to the low incidence of precipitation attributed to climate change, many high-altitude Andean lakes (HAALs) and lagoons distributed along the central Andes in South America may soon disappear. This includes La Brava–La Punta, a brackish lake system located south of the Salar de Atacama within a hyper-arid and halophytic biome in the Atacama Desert. Variations in the physicochemical parameters of the water column can induce changes in microbial community composition, which we aimed to determine. Sixteen sampling points across La Brava–La Punta were studied to assess the influence of water physicochemical properties on the aquatic microbial community, determined via 16S rRNA gene analysis. Parameters such as pH and the concentrations of silica, magnesium, calcium, salinity, and dissolved oxygen showed a more homogenous pattern in La Punta samples, whereas those from La Brava had greater variability; pH and total silica were significantly different between La Brava and La Punta. The predominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia. The genera Psychroflexus (36.85%), Thiomicrospira (12.48%), and Pseudomonas (7.81%) were more abundant in La Brava, while Pseudospirillum (20.73%) and Roseovarius (17.20%) were more abundant in La Punta. Among the parameters, pH was the only statistically significant factor influencing the diversity within La Brava lake. These results complement the known microbial diversity and composition in the HAALs of the Atacama Desert.

Zooplankton of a mountain river and highland bogs in a wetlands complex in Atacama, an Altiplano desert, in northern Chile
Munoz Pedreros
Abstract
The Atacama is the world’s driest desert. It contains various types of wetlands. In general, the diversity and structure of the zooplankton in these wetlands have been very little studied. The object of the present study was to analyse the specific composition and structure of the zooplankton in a transect which included highland bogs and an endorheic mountain river in the Altiplano of northern Chile. In 2017, samples of zooplankton were collected for qualitative and quantitative analysis in two types of wetlands. Eight taxa of zooplanktonic crustaceans were recorded. The results of null models revealed the absence of regulator patterns for all sites in species co-occurrence. Cluster analysis generated two groups with low similarity between them. The results observed in the correlation matrix showed significant direct associations between some species and the level of dissolved oxygen, conductivity and salinity.

Fine scale approach to propose conservation areas for the endangered andean cat (Leopardus
Lagos

Virus and Potential Host Microbes from Viral-Enriched Metagenomic Characterization in the High-Altitude Wetland, Salar de Huasco, Chile
Eissler
Salar de Huasco is a wetland in the Andes mountains, located 3800 m above sea level at the Chilean Altiplano. Here we present a study aimed at characterizing the viral fraction and the microbial communities through metagenomic analysis. Two ponds (H0 and H3) were examined in November 2015. Water samples were processed using tangential flow filtration to obtain metagenomes from which the DNA fraction of the sample was amplified and sequenced (HiSeq system, Illumina). The ponds were characterized by freshwater and the viral-like particles to picoplankton ratio was 12.1 and 2.3 for H0 and H3, respectively. A great number of unassigned viral sequences were found in H0 (55.8%) and H3 (32.8%), followed by the family Fuselloviridae 20.8% (H0) and other less relatively abundant groups such as Microviridae (H0, 11.7% and H3, 3.3%) and Inoviridae (H3, 2.7%). The dominant viral sequences in both metagenomes belong to the order Caudovirales, with Siphoviridae being the most important family, especially in H3 (32.7%). The most important bacteria phyla were Proteobacteria, Bacteroidetes and Firmicutes in both sites, followed by Cyanobacteria (H0). Genes encoding lysogenic and lytic enzymes (i.e., recombinases and integrases) were found in H0 and H3, indicating a potential for active viral replication at the time of sampling; this was supported by the presence of viral metabolic auxiliary genes at both sites (e.g., cysteine hydrolase). In total, our study indicates a great novelty of viral groups, differences in taxonomic diversity and replication pathways between sites, which contribute to a better understanding of how viruses balance the cycling of energy and matter in this extreme environment.

Human occupations and climate change in the Puna de Atacama, Chile
Núñez
Widespread evidence for human occupation of the Atacama Desert, 20° to 25°S in northern Chile, has been found from 13,000 calibrated
14
C years before the present (cal yr B.P.) to 9500 cal yr B.P., and again after 4500 cal yr B.P. Initial human occupation coincided with a change from very dry environments to humid environments. More than 39 open early Archaic campsites at elevations above 3600 meters show that hunters lived around late glacial/early Holocene paleolakes on the Altiplano. Cessation of the use of the sites between 9500 and 4500 cal yr B.P. is associated with drying of the lakes. The mid-Holocene collapse of human occupation is also recorded in cave deposits. One cave contained Pleistocene fauna associated with human artifacts. Faunal diversity was highest during the humid early Holocene.

Meristic and morphological differentiation of Orestias species (Teleostei; Cyprinodontiformes) from the southern Altiplano
Scott

A limnological reconnaissance of Lake Tebenquiche, Salar de Atacama, Chile
Zuniga

Socio-ecological dimensions of Andean pastoral landscape change: Bridging traditional ecological knowledge and satellite image analysis in Sajama National Park, Bolivia
Yager etal
Estancia Junthuma
Near Rio Junthuma
On the slope
By the ditch
Near Estancia Tolahuata
Curahuara de Carangas, Sajama, Oruro, Bolivia

Low Holocene level (7700 to 3650 years ago) of lake Titicaca (Bolivia)
Wirrmann
Oliviera Almeida

Paleoclimatic and archaeological evidence from Lake Suches for highland Andean refugia during the arid middle-Holocene
Vining

Nitrate cycling in Lake Titicaca (Peru-Bolivia): the effects of high-altitude and tropicality
Vincent
SUMMARY.
The vertical distribution of dissolved oxygen and inorganic nitrogen differed considerably between three stratification cycles in Lake Titicaca, a tropical lake (latitude 16°S) in the high Andes (3800 m altitude). In 1980/81 an anoxic layer of water extended from 200 to 275 m and contained high levels of NH4 but zero NO3. During the annual deep mixing period in 1981 this layer was substantially eroded, and was completely eliminated during deep‐mixing in 1982.
Nitrapyrin assays of nitrification demonstrated highest activity in the surface mixed layer, lowest activity just beneath the thermocline, and then increasing nitrification rates with increasing depth towards the bottom anoxic zone. Denitrification rates were slow, but detectable, in the surficial sediments of Lake Titicaca during late 1982. Much faster rates were estimated for the periods of water column anoxia.
Lake Titicaca is a productive lake with low saturation levels of oxygen because of its high altitude. These features favour hypolimnetic anoxia, and thus denitrification which varies in magnitude from year to year.

Seasonal dynamics of nutrient limitation in a tropical high-altitude lake (Lake Titicaca, Peru-Bolivia): Application of physiological bioassays
Vincent
Five types of physiological assay were applied to samples from three sites in Lake Titicaca, Peru‐Bolivia (16°S), to assess the magnitude and seasonality of N or P limitation of algal growth. Phosphorus appeared to be in abundant supply relative to growth requirements throughout 1982. Alkaline phosphatase levels were low (<3 nmol substrate converted·µg‒1Chl a·liter‒1), 32PO43‒ turnover times were always long (> 103 min in the main body of the lake), and little or no phosphorus was accumulated by the seston during short term enrichments. Ammonium enhancement assays suggested a persistent cellular shortage of nitrogen throughout all seasons in the plankton of a large shallow bay, and in the main basin when the water was stratified. High ammonium uptake capacities, as measured with the NH4+ analogue [14C]methylammonium, and selective accumulation of nitrogen from N plus P enrichments provided supportive evidence of cellular N deficiency. Winter mixing brought large quantities of NO3‒ and SRP into the surface euphotic zone of the main basin, and throughout this period neither N nor P appeared to be limiting. Polymixis in the shallow bay resulted in large variations in nitrogen supply and deficiency, and these effects were modulated in part by changes in depth of the euphotic zone. Nitrogen was always in low abundance relative to phosphorus in Lake Titicaca, but the extent of nutrient control on algal growth varied considerably with site and time of year.

Local Management of Andean Wetlands in Sajama National Park, Bolivia
Villarroel
Estancia Junthuma
Near Rio Junthuma
Near Estancia Tolahuata
On the slope
By the ditch

Carbon sequestration and methane emissions along a microtopographic gradient in a tropical Andean peatland
Villa

Geomorphologic impacts of the glacial lake outburst ﬂood from lake no. 513 (Peru)
Vilímek

Influence of glacial retreat on natural hazards of the Palcacocha Lake area, Peru
Vilímek

The System Nobody Sees: Irrigated Wetland Management and Alpaca Herding in the Peruvian Andes
Verzijl
Quispe

Abundance and Distribution of the South American Altiplano Flamingos
Valqui

Simulated Small Scale Disturbances Increase Decomposition Rates and Facilitates Invasive Species Encroachment in a High Elevation Tropical Andean Peatland
Urbina
Benavides
AbstractTropical alpine peatlands are important carbon reservoirs and are a critical component of local hydrological cycles. In high elevation peatlands slow decomposition rates result from a nutrient‐poor substrate resistant to decay. The responses of páramo peatland ecosystems to increased nutrient additions and physical disturbance due to agricultural activities are unknown. Here, we conducted a two‐year fertilization and physical disturbance experiment in a Sphagnum—dominated peatland in the Central Andes of Colombia. We hypothesized that fertilization and physical disturbance will diminish the ability of the peat to store organic matter by increasing decomposition and that vascular plants will displace Sphagnum as the dominant plant group. We simulated cattle activity by adding manure as a fertilizer and physical disturbance as a proxy for cattle trampling. Species composition varied in proportion to the intensity of disturbance. Sphagnum cover was reduced under any disturbance treatment. Non‐native grasses usually found in cattle pastures invaded treatments with fertilizer additions or physical disturbance. Overall aboveground plant biomass doubled in fertilized treatments, suggesting that plant biomass production was nutrient limited. Decomposition rates tripled in disturbed treatments as compared to controls. This reduces the ability of the peatland to store organic matter. Andean peatlands are prized ecological assets; however, our results show that the El Morro páramo peatland experienced increased decomposition rates over short time periods after small‐scale disturbances. This created profound consequences for the ecological services offered by these peatlands.

In-stream wetland deposits, megadroughts, and cultural change in the northern Atacama Desert, Chile
Tully
AbstractA key concern regarding current and future climate change is the possibility of sustained droughts that can have profound impacts on societies. As such, multiple paleoclimatic proxies are needed to identify megadroughts, the synoptic climatology responsible for these droughts, and their impacts on past and future societies. In the hyperarid Atacama Desert of northern Chile, many streams are characterized by perennial flow and support dense in-stream wetlands. These streams possess sequences of wetland deposits as fluvial terraces that record past changes in the water table. We mapped and radiocarbon dated a well-preserved sequence of in-stream wetland deposits along a 4.3-km reach of the Río San Salvador in the Calama basin to determine the relationship between regional climate change and the incision of in-stream wetlands. The Río San Salvador supported dense wetlands from 11.1 to 9.8, 6.4 to 3.5, 2.8 to 1.3, and 1.0 to 0.5 ka and incised at the end of each of these intervals. Comparison with other in-stream wetland sequences in the Atacama Desert, and with regional paleoclimatic archives, indicates that in-stream wetlands responded similarly to climatic changes by incising during periods of extended drought at ~9.8, 3.5, 1.3, and 0.5 ka.

Conserving birdlife of peruvian highland bogs: Effects of patch-size and habitat quality on species richness and bird numbers
Telleria

Modelling the water balance in the glacierized Parón Lake basin
Suarez

A Model for Estimating the Vegetation Cover in the High-Altitude Wetlands of the Andes (HAWA)
Soto etal
The natural salt meadows of Tilopozo in the hyperarid, Atacama Desert of northern Chile, which are located at approximately 2800 m above sea level, are under pressure from industrial activity, and cultivation and grazing by local communities. In this research, the land surface covered by salt meadow vegetation was estimated from normalized difference vegetation indices (NDVI) derived from Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager (OLI) data from 1985 to 2016. The vegetated area of the Tilopozo salt meadows decreased by 34 ha over the 32-year period studied. Multiple regression models of the area covered by vegetation and climate data and groundwater depths were derived on an annual basis, as well as for both the dry and wet seasons and had R2 values of 83.0%, 72.8% and 92.4% respectively between the vegetated areas modeled and those estimated from remotely sensed data. These models are potentially useful tools for studies into the conservation of the Tilopozo salt meadows, as they provide relevant information on the state of vegetation and enable changes in vegetation in response to fluctuations in climate parameters and groundwater depths to be predicted.

Peatlands of the Peruvian Puna ecoregion: types, characteristics and disturbance
Salvador
Peatlands represent one of the most important water resources in the Puna grassland ecoregion, but this fact is not yet widely recognised. Puna peatlands also provide key environmental services such as increasing the regional biodiversity of the Andean Altiplano plateau and contributing to the wellbeing of high-altitude human populations by providing grazing land and cooking fuel. We conducted a study in the Peruvian Puna ecoregion to describe the current condition of peatlands in terms of their vegetation, physical and chemical characteristics and disturbance status. Our results suggest that peat thickness, organic matter and degree of humification are good indicators for identifying peatlands in the Puna ecoregion. In general, the peatland sites that we sampled were dominated by mixtures of cushion and acaulescent rosette forming plants such as Distichia muscoides Nees & Meyen and Plantago tubulosa Decne. These Distichia and Plantago peatland sites were characterised by a mean surface water pH of 6.3, corrected electrical conductivity (K corr.) in the range 300–1814 μS cm-1 and presented the following mean exchangeable cation values: Ca2+ 48 mg L-1, Mg2+ 9.6 mg L-1, Na+ 8.2 mg L-1 and K+ 2.1 mg L-1. The most common causes of disturbance we encountered were grazing, peat extraction and roads. Disturbance was most severe in mining sites, where peatlands are especially vulnerable because they are not under legal protection.

Distichia peat - A new stable isotope paleoclimate proxy for the Andes
Skrzypek

The Effects of Area and Habitat Heterogeneity on Bird Richness and Composition in High Elevation Wetlands (“Bofedales”) of the Central Andes of Peru
Servat

Long-term monitoring of tropical alpine habitat change, Andean anurans, and chytrid fungus in the Cordillera Vilcanota, Peru: Results from a decade of study
Seimon
AbstractThe Cordillera Vilcanota in southern Peru is the second largest glacierized range in the tropics and home to one of the largest high‐alpine lakes, Sibinacocha (4,860 m). Here, Telmatobius marmoratus (marbled water frog), Rhinella spinulosa (Andean toad), and Pleurodema marmoratum (marbled four‐eyed frog) have expanded their range vertically within the past century to inhabit newly formed ponds created by ongoing deglaciation. These anuran populations, geographically among the highest (5,200–5,400 m) recorded globally, are being impacted by the chytrid fungus Batrachochytrium dendrobatidis (Bd), and the disease it causes, chytridiomycosis. In this study, we report results from over a decade of monitoring these three anuran species, their habitat, and Bd infection status. Our observations reveal dynamic changes in habitat including ongoing rapid deglaciation (18.4 m/year widening of a corridor between retreating glaciers from 2005 to 2015), new pond formation, changes in vegetation in amphibian habitat, and widespread occurrence of Bd in amphibians in seven sites. Three of these sites have tested positive for Bd over a 9‐ to 12‐year period. In addition, we observed a widespread reduction in T. marmoratus encounters in the Vilcanota in 2008, 2009, and 2012, while encounters increased in 2013 and 2015. Despite the rapid and dynamic changes in habitat under a warming climate, continued presence of Bd in the environment for over a decade, and a reduction in one of three anuran species, we document that these anurans continue to breed and survive in this high Andean environment. High variability in anuran encounters across sites and plasticity in these populations across habitats, sites, and years are all factors that could favor repopulation postdecline. Preserving the connectivity of wetlands in the Cordillera Vilcanota is therefore essential in ensuring that anurans continue to breed and adapt as climate change continues to reshape the environment.

Spectroscopic Assessment of Soil Organic Matter in Wetlands from the High Andes
Segnini
Wetlands are valuable for their function as C sinks, water conservation and filtering, flood control, and as a recreational landscape. In the Central and Southern Andes, peatlands (a.k.a., bofedales) are also a source of good quality pastures for wild and domestic South American camelids (
Vicugna pacos
,
Lama glama
, and
Vicugna vicugna
). In the present study, whole soil samples from seasonally and permanently flooded bofedales were analyzed using laser‐induced fluorescence spectroscopy (LIFS) and electron paramagnetic resonance (EPR) to assess soil organic matter (SOM) stability. The results obtained by both techniques were comparable (
R
2
= 0.88) and proven to be reliable indicators of increased or reduced SOM stability and thus suitable methods for assessing its humification index. The humification values determined in the permanently flooded bofedal were lower than for the seasonally flooded one. Deeper in the soil profiles of both bofedal types, the humification process of SOM attains more advanced stages, with a relative increase of more recalcitrant organic compounds. An important factor is the presence of water in permanently flooded bofedales, which slows down organic matter decomposition due to anaerobiosis. Results from a portable LIFS system also showed significant correlations when compared with both the bench LIFS system (
= 0.88) and the EPR (
= 0.62). The portable system constitutes an affordable option for the in situ characterization of SOM. This assessment is of outmost importance in agroecosystems acting as green house gases sink or sources under variable climatic conditions.

A Directory of Neotropical Wetlands.
Scott
Carbonell

Mapping hazards from glacier lake outburst floods based on modelling of process cascades at Lake 513, Carhuaz, Peru
Schneider
Abstract. Recent warming has had enormous impacts on glaciers and high-mountain environments. Hazards have changed or new ones have emerged, including those from glacier lakes that form as glaciers retreat. The Andes of Peru have repeatedly been severely impacted by glacier lake outburst floods in the past. An important recent event occurred in the Cordillera Blanca in 2010 when an ice avalanche impacted a glacier lake and triggered an outburst flood that affected the downstream communities and city of Carhuaz. In this study we evaluate how such complex cascades of mass movement processes can be simulated coupling different physically-based numerical models. We furthermore develop an approach that allows us to elaborate corresponding hazard maps according to existing guidelines for debris flows and based on modelling results and field work.

Last millennial environmental dynamics in the western Peruvian Andes inferred from the development of a cushion-plant peat hillock
Schittek

A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years
Schittek
Abstract. High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650–800 and AD  1000–1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

Late Holocene eruptive activity at Nevado Cayambe Volcano, Ecuador
Samaniego

Vegetation and ecology of the high Andean peatlands of Bolivia
Ruthsatz
Near Estancia Tolahuata
Estancia Junthuma
On the slope
By the ditch
River source
Imported from db
Near Rio Junthuma
Municipio Comanche, Provincia Pacajes, La Paz, Bolivia
Municipio Santiago de Machaca, Provincia General José Manuel Pando, La Paz, Bolivia
Municipio Catacora, Provincia General José Manuel Pando, La Paz, Bolivia
Municipio Charaña, Provincia Pacajes, La Paz, Bolivia
Municipio Calacoto, Provincia Pacajes, La Paz, Bolivia
La Paz, Bolivia

Predicting outflow induced by moraine failure in glacial lakes: the Lake Palcacocha case from an uncertainty perspective
Rivas etal
Abstract. Moraine dam collapse is one of the causes of glacial lake outburst floods. Available models seek to predict both moraine breach formation and lake outflow. The models depend on hydraulic, erosion, and geotechnical parameters that are mostly unknown or uncertain. This paper estimates the outflow hydrograph caused by a potential erosive collapse of the moraine dam of Lake Palcacocha in Peru and quantifies the uncertainty of the results. The overall aim is to provide a simple yet hydraulically robust approach for calculating the expected outflow hydrographs that is useful for risk assessment studies. To estimate the peak outflow and failure time of the hydrograph, we assessed several available empirical equations based on lake and moraine geometries; each equation has defined confidence intervals for peak flow predictions. Complete outflow hydrographs for each peak flow condition were modeled using a hydraulic simulation model calibrated to match the peak flows estimated with the empirical equations. Failure time and peak flow differences between the simulations, and the corresponding empirical equations were used as error parameters. Along with an expected hydrograph, lower and upper bound hydrographs were calculated for Lake Palcacocha, representing the confidence interval of the results. The approach has several advantages: first, it is simple and robust. Second, it evaluates the capability of empirical equations to reproduce the conditions of the lake and moraine dam. Third, this approach accounts for uncertainty in the hydrographs estimations, which makes it appropriate for risk management studies.

Biomineralization of carbonates by Marinococcus albus and Marinococcus halophilus isolated from the Salar de Atacama (Chile)
Rivadeneyra etal

The origin of brines and salts in Chilean salars: a hydrochemical review

Hydrochemistry of two adjacent acid saline lakes in the Andes of northern Chile

Origin of Salts and Brine Evolution of Bolivian and Chilean Salars
Fritz

Paleoindian settlement of the high-altitude Peruvian Andes
Rademaker
Mountain dwellers of the Pleistocene
Humans colonized the inhospitable high Andes at least 11.5 thousand years ago. Rademaker
unearthed evidence of hunter-gatherer occupation at heights of almost 4500 m in Peru in two open-air sites. The sites contained more than 750 tools, including likely spearheads and scrapers. A nearby rockshelter with sooted ceilings and floor detritus may have been a campsite. The sites were probably used seasonally for hunting vicuña and other high-altitude prey.
Science
, this issue p.

Direct and indirect effects of glaciers on aquatic biodiversity in high Andean peatlands
Quenta
AbstractThe rapid melting of glacier cover is one of the most obvious impacts of climate change on alpine ecosystems and biodiversity. Our understanding of the impact of a decrease in glacier runoff on aquatic biodiversity is currently based on the ‘glacier‐heterogeneity‐diversity’ paradigm, according to which there is high α‐diversity at intermediate levels of glacial influence due to the high degree of environmental heterogeneity caused by glacier water. This α‐diversity pattern generates high levels of between‐site aquatic community variation (high β diversity) and increases regional diversity (γ‐diversity). There is a rich conceptual background in favor of this paradigm, but empirical data supporting it are scarce. We investigated this paradigm by analyzing the different diversity patterns (α, β and γ‐diversity) of four aquatic groups (zooplankton, macroinvertebrates, algae and macrophytes) living in high‐elevation peatlands (>4500 m above sea level). We sampled 200 pools from 20 peatlands along a glacier gradient in the Cordillera Real of Bolivia. We performed structural equation modeling (SEM) to analyze the potential mechanisms underlying the observed diversity patterns. Intermediate levels of glacial influence (15–20% cover) resulted in high heterogeneity, but α‐diversity responded to glacial influence only for the zooplankton group (Cladocera). Our SEM analysis did not identify environmental heterogeneity as a significant variable explaining the relationship between glacier and α‐diversity. Peatland area had a strong positive effect on heterogeneity and diversity. β‐diversity was significantly associated with glacier gradient, and 12.9% of the total regional diversity (γ‐diversity) was restricted to peatlands with a high degree of glacial influence. These species might be lost in a context of glacial retreat. These findings provide new insight into the potential effects of glacial retreat on the aquatic environment and biodiversity in the peatlands of the tropical Andes.

Chromohalobacter nigrandesensis sp. nov., a moderately halophilic, Gram-negative bacterium isolated from Lake Tebenquiche on the Atacama Saltern, Chile.
Prado etal
A total of 52 strains of moderately halophilic bacteria isolated from hypersaline sediment of Lake Tebenquiche on the Atacama Saltern, Chile, were subjected to a taxonomic study. The morphological, physiological, biochemical and nutritional characteristics of the strains matched those described for the genus Chromohalobacter. Cells were Gram-negative, non-spore-forming, rod-shaped and motile. A black pigmentation was produced. One strain, designated LTS-4NT, grew optimally at 32 °C. Growth occurred in media containing 0·5–25 % (w/v) total salts; the optimum was 7·5 % (w/v) total salts. The pH range for growth was 5–10. The G+C content of the DNA of strain LTS-4NT was 59·8 mol%. Analysis of 16S rRNA gene sequence similarity revealed that strain LTS-4NT was closely related to Chromohalobacter species; however, DNA–DNA hybridization of representative strain LTS-4NT failed to associate the strain with any species of the genus Chromohalobacter with validly published names. Therefore, the name Chromohalobacter nigrandesensis sp. nov. is proposed. The type strain is LTS-4NT (=CECT 5315T=DSM 14323T).

The effect of water table levels and short-term ditch restoration on mountain peatland carbon cycling in the Cordillera Blanca, Peru
Planas-Clark

Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes
Pena

Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data
Otto
Abstract. High Altitude Wetlands of the Andes (HAWA) belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. We derived HAWA land cover from satellite data at regional scale and analysed changes in connection with precipitation over the last decade. Perennial and temporal HAWA subtypes can be distinguished by seasonal changes of photosynthetically active vegetation (PAV) indicating the perennial or temporal availability of water during the year. HAWA have been delineated within a region of 12 800 km2 situated in the Northwest of Lake Titicaca. The multi-temporal classification method used Normalized Differenced Vegetation Index (NDVI) and Normalized Differenced Infrared Index (NDII) data derived from two Landsat ETM+ scenes at the end of austral winter (September 2000) and at the end of austral summer (May 2001). The mapping result indicates an unexpected high abundance of HAWA covering about 800 km2 of the study region (6 %). Annual HAWA mapping was computed using NDVI 16-day composites of Moderate Resolution Imaging Spectroradiometer (MODIS). Analyses on the relation between HAWA and precipitation was based on monthly precipitation data of the Tropical Rain Measurement Mission (TRMM 3B43) and MODIS Eight Day Maximum Snow Extent data (MOD10A2) from 2000 to 2010. We found HAWA subtype specific dependencies on precipitation conditions. A strong relation exists between perennial HAWA and snow fall (r2: 0.82) in dry austral winter months (June to August) and between temporal HAWA and precipitation (r2: 0.75) during austral summer (March to May). Annual changes in spatial extend of perennial HAWA indicate alterations in annual water supply generated from snow melt.

Potential Effects of Projected Decrease in Annual Rainfall on Spatial Distribution of High Andean Wetlands in Southern Peru
Otto
Gibbons

Extremophile culture collection from Andean lakes: extreme pristine environments that host a wide diversity of microorganisms with tolerance to UV radiation
Ordonez

Modelling beta diversity of aquatic macroinvertebrates in High Andean wetlands
Nieto
Central Andean Highlands represent a singular environment characterized by various extreme conditions. Among them, peatbogs are exceptional marshy habitats scattered throughout this arid and harsh area. In an effort to understand the patterns of beta diversity, we sampled the benthic macroinvertebrates of thirteen peatbogs and related the biological distance with ecological distance using the GDM (Generalized Dissimilarity Modelling) approach. Variables analyzed were altitude, geographical distance, physical and chemical parameters of the water. A coefficient based on the ordering properties of count data, from the perspective of both sites and taxa, was used to measure the compositional similarity between samples. The most frequent taxa were: Hyallela, Simuliidae, Andesiops, Austrelmis, Podonominae, Protallagma, Trichocorixa, Orthocladiinae and Glossiphonidae. The highest altitudinal record ever for leeches is reported here. Altitude and conductivity contributed greatly to the single ecological predictor of beta diversity. Sampling points can be classified first by altitude (cutoff sets at 4,200 m), which can be considered a surrogate of a regional factor (distinction between Puna and High Andean ecoregions) and then by conductivity (cutoff sets at 135 µS cm-1), which can be considered a proxy of a local factor (distinction between hyperfresh and more mineralized habitats). These results suggest a system of ecological filters acting on them.

Zooplankton of a mountain river and highland bogs in a wetlands complex in Atacama, an Altiplano desert, in northern Chile
Munoz Pedreros
The Atacama “puna” (high-altitude plateau) is situated among the high peaks of the Andes at over 4000 m a.s.l. This ecosystem covers parts of north-eastern Chile, north-western Argentina, south-eastern Peru, and mid-western Bolivia. The puna brings together several types of wetlands, such as salt-flats, lakes, rivers, high marshes, and highland bogs. Highland bogs are peatlands associated with endorheic basins. The object of this study was to analyse the specific composition and structure of the zooplankton of the bogs of the Putana River, on the Altiplano of northern Chile. In 2012, zooplankton samples were taken for qualitative and quantitative analysis at nine stations of the bog. Nine taxa of zooplanktonic crustaceans were recorded. The species richness is higher than records in other high Andean wetland at a similar altitude, although the species found have been reported for other high Andean wetlands and Andean lakes in Chile and from neighbouring countries.

Runoff from tropical alpine grasslands increases with areal extent of wetlands
Mosquera

A 14 kyr record of the tropical Andes: The Lago Chungara sequence (18 degrees S, northern Chilean Altiplano)
Moreno etal

Multi-century lake area changes in the Southern Altiplano: a tree-ring-based reconstruction
Morales
Abstract. Size fluctuations in endorheic lakes in northwestern Argentina (NWA) and southwestern Bolivia (SWB) are very sensitive to basin hydrological balances, and consequently, very vulnerable to deleterious effects from climatic changes. The management of these water resources and their biodiversity requires a comprehensive knowledge of their natural variability over multiple timescales. In this study, we present a multi-century reconstruction of past lake-area fluctuations in NWA and SWB. The evidence used to develop and validate this reconstruction includes satellite images and a century-long tree-ring record from P. tarapacana. Inter-annual fluctuations in lake area of nine lakes were quantified based on Landsat satellite images over the period 1975 to 2009. A regional P. tarapacana tree-ring chronology, composite from two sampling sites, was used as predictors in a regression model to reconstruct the mean annual (January–December) lake area from the nine lakes. The reconstruction model captures 62 % of the total variance in lake-area fluctuations and shows adequate levels of cross-validation. This high-resolution reconstruction covers the past 601 years and characterizes the occurrence of annual to multi-decadal lake area fluctuations and its main oscillation modes of variability. Our reconstruction points out that the late 20th century decrease in lake area was exceptional over the period 1407–2007; a persistent negative trend in lake area is clear in the reconstruction and consistent with glacier retreat and other climate proxies from the Altiplano and the tropical Andes. Since the mid 1970s, the Vilama-Coruto lake system recorded an accelerated decrease in area consistent with an increasing recurrence of extremely small lake-area events. Throughout the 601 years, the reconstruction provides valuable information about spatial and temporal stabilities of the relationships between changes in lake area, ENSO, and PDO, highlighting the Pacific influence over most modes of lake area variability. Global and regional climate models for the Altiplano project a marked reduction in precipitation to the end of the 21st century, exacerbating presently dry conditions. These results provide a baseline for the historical range of variability in lake fluctuations and thus should be considered for the management of biodiversity and water resources in the Central Andes during the next decades.

Microbial diversity in Maras salterns, a hypersaline environment in the peruvian andes.
Maturrano etal2006a
ABSTRACTMaras salterns are located 3,380 m above sea level in the Peruvian Andes. These salterns consist of more than 3,000 little ponds which are not interconnected and act as crystallizers where salt precipitates. These ponds are fed by hypersaline spring water rich in sodium and chloride. The microbiota inhabiting these salterns was examined by fluorescence in situ hybridization (FISH), 16S rRNA gene clone library analysis, and cultivation techniques. The total counts per milliliter in the ponds were around 2 × 106to 3 × 106cells/ml, while the spring water contained less than 100 cells/ml and did not yield any detectable FISH signal. The microbiota inhabiting the ponds was dominated (80 to 86% of the total counts) byArchaea, whileBacteriaaccounted for 10 to 13% of the 4′,6′-diamidino-2-phenylindole (DAPI) counts. A total of 239 16S rRNA gene clones were analyzed (132Archaeaclones and 107Bacteriaclones). According to the clone libraries, the archaeal assemblage was dominated by microorganisms related to the cosmopolitan square archaeon “Haloquadra walsbyi,” although a substantial number of the sequences in the libraries (31% of the 16S rRNA gene archaeal clones) were related toHalobacteriumsp., which is not normally found in clone libraries from solar salterns. All the bacterial clones were closely related to each other and to the γ-proteobacterium “Pseudomonas halophila” DSM 3050. FISH analysis with a probe specific for this bacterial assemblage revealed that it accounted for 69 to 76% of the total bacterial counts detected with aBacteria-specific probe. When pond water was used to inoculate solid media containing 25% total salts, both extremely halophilicArchaeaandBacteriawere isolated. Archaeal isolates were not related to the isolates in clone libraries, although several bacterial isolates were very closely related to the “P. halophila” cluster found in the libraries. As observed for other hypersaline environments, extremely halophilic bacteria that had ecological relevance seemed to be easier to culture than their archaeal counterparts.

Habitat Changes in Laguna de Pozuelos, Jujuy, Argentina: Implications for South American Flamingo Populations
Mascitti

James Flamingo Foraging Behavior in Argentina
Mascitti

Halorubrum tebenquichense sp. nov., a novel halophilic archaeon isolated from the Atacama Saltern, Chile
Lizama

Taxonomic study of extreme halophilic archaea isolated from the "Salar de Atacama", Chile
Lizama

Farmers' Perceptions of and Adaptations to Water Scarcity in Colombian and Venezuelan Páramos in the Context of Climate Change
Leroy

Late Holocene environmental changes reconstructed from stable isotope and geochemical records from a cushion-plant peatland in the Chilean Central Andes (27◦S)
Kock
ABSTRACTA Late Holocene paleoenvironmental record was obtained from the Lagunillas cushion peatland (LP, 27°12′S, 69°17′W), located in the dry Puna of the western Central Andes. Ten radiocarbon dates build the chronology for the last 1800 cal a BP. Analyses of stable isotopes on cellulose (δ18Ocell, δ13Ccell) and geochemical proxies on organic matter (δ13COM, δ15Nbulk, TOC, TN, LOI, T535) were conducted to identify major paleoenvironmental changes in this record. Simultaneously, ambient water (δ18O, δ2H) and plant samples of the dominant species Oxychloe andina (δ18Ocell, δ13Ccell) reveal insights into modern conditions. The record reveals distinct multi‐centennial oscillations of peat layer thickness and δ18Ocell. Decomposition, changes in the dominating plant species as well as in plant parts (leaves/roots) can be excluded as driving factors for these oscillations. Thus, δ18Ocell seems to be externally forced and reflects humidity changes. Around 470 cal a BP a distinct change towards increased humidity occurred, lasting during the Little Ice Age until about 70 cal a BP. Humid conditions prevailed between 1530 and 1270 cal a BP. Increasing δ18Ocell values since 30 cal a BP mark a trend towards again increased aridity.

Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru)
Klimeš

The reconstruction of a glacial lake outburst flood using HEC-RAS and its significance for future hazard assessments: an example from Lake 513 in the Cordillera Blanca, Peru
Klimeš

Methane Emissions from a Grassland-Wetland Complex in the Southern Peruvian Andes
Jones
Abstract. A 58 hectare mixed upland and lowland boreal plains watershed called the Sandhill Fen Watershed was constructed between 2008 and 2012. In the years following wetting in 2013, methane emissions were measured using manual, static, non-steady state chambers. The presence of vegetation with aerenchymous tissues and saturated soils were important factors influencing the spatial variability of methane emissions across the constructed watershed. Nevertheless, median methane emissions were equal to or less than 0.51 mg CH4 m−2 h−1 even from the saturated organic soils in the lowlands. Although overall methane emissions remained low, observations of methane ebullition increased over the three study years. As a ratio to the total number of measurements, the number of ebullition events increased from 10 % in 2013 to 21 % and 27 % in 2014 and 2015, respectively at the plots with saturated soils. Increasing metal ion availability and decreasing sulphur availability was measured using buried ion exchange resins at both seasonal and annual timescales potentially as a result of microbial reduction of these ions. Methane fluxes significantly correlated with the leading Principal Component of ammonium, iron, manganese and sulphur availability (r = 0.31, p

Fish-flamingo-plankton interactions in the Peruvian Andes
Hurlbert
The zooplankton and flamingo populations of 20 high elevation (3,700–4,700 m) lakes in the Andes of southern Peru were assessed on one to three occasions each. Some of these lakes have cyprinodont fish (Orestias spp.), others do not. Lakes with fish usually have a sparse zooplankton dominated by cyclopoid copepods and chydorid cladocerans; the others tend to have an abundant zooplankton dominated by calanoid copepods and daphnids or by Artemia. Chilean flamingos (Phoenicopterus chilensis) are usually absent or scarce on lakes with fish and present in large numbers where fish are absent. We suggest that the distribution of this flamingo in the Central Andes, and in South America generally, is determined primarily by the distribution of fish, with which it competes for invertebrate prey. The patterns above are complicated by the impact on Orestias populations of man, of fish‐eating birds, and of introduced, non‐native fish (Salmo gairdneri, Basilichthys bonariensis).

Wilson's Phalarope in the Central Andes and its Interaction with the Chilean Flamingo
Hurlbert
The geological development of the basement of the Argentinian/Chilean Andes during the Palaeozoic is characterized by an almost continuous structural, metamorphic and plutonic mobility. Ultrabasic magmatism occurred only in a few regions; terrigenic psammopelitic sequences are widespread at all times. Metamorphism is mostly of low to intermediate pressure, but of variable temperature; late Palaeozoic high pressure metamorphism only took place near the present Pacific coast. There are about four culminations of orogenic activity, varying in space and time: from the mid-Cambrian to the mid-Ordovician, from the Silurian to the mid-Devonian, during the early Carboniferous, and at the Permian/Triassic boundary. Fold structures strike in variable directions at different times. On the whole, the Pacific margin of Gondwana consolidated continuously from the shield region in the E towards the Pacific during the Palaeozoic.

Distribution and Spatial Patterning of Flamingos in the Andean Altiplano
Keith

Impact of a rock avalanche on a moraine-dammed proglacial lake: Laguna Safuna Alta, Cordillera Blanca, Peru
Hubbard etal
AbstractMoraines that dam proglacial lakes pose an increasing hazard to communities in the Andes and other mountain ranges. The moraines are prone to failure through collapse, overtopping by lake waters or the effect of displacement waves resulting from ice and rock avalanches. Resulting floods have led to the loss of thousands of lives in the Cordillera Blanca mountains of Peru alone in the last 100 years. On 22 April 2002 a rock avalanche occurred immediately to the south‐west of Laguna Safuna Alta, in the Cordillera Blanca. The geomorphic evidence for the nature, magnitude and consequences of this event was investigated in August 2002. Field mapping indicated that the avalanche deposited 8–20 × 106 m3 of rock into the lake and onto the surface of the frontal region of Glaciar Pucajirca, which flows into the lake. Repeated bathymetric surveying indicated that ∼5 × 106 m3 of this material was deposited directly into the lake. The immediate effect of this event was to create a displacement wave that gained in height as it travelled along the lake basin, overtopping the impounding moraine at the lake's northern end. To achieve overtopping, the maximum wave height must have been greater than 100 m. This, and subsequent seiche waves, caused extensive erosion of both the proximal and distal faces of the impounding terminal moraine. Further deep gullying of the distal face of this moraine resulted from the supply of pressurized water to the face via a relief overflow tunnel constructed in 1978. Two‐dimensional, steady‐state analysis of the stability of the post‐avalanche moraine rampart indicates that its proximal face remains susceptible to major large‐scale rotational failure. Copyright © 2005 John Wiley & Sons, Ltd.
Yuracmarca, Province of Huaylas, Ancash, Peru

Multidate, multisensor remote sensing reveals high density of carbon-rich mountain peatlands in the páramo of Ecuador
Hribljan
AbstractTropical peatlands store a significant portion of the global soil carbon (C) pool. However, tropical mountain peatlands contain extensive peat soils that have yet to be mapped or included in global C estimates. This lack of data hinders our ability to inform policy and apply sustainable management practices to these peatlands that are experiencing unprecedented high rates of land use and land cover change. Rapid large‐scale mapping activities are urgently needed to quantify tropical wetland extent and rate of degradation. We tested a combination of multidate, multisensor radar and optical imagery (Landsat TM/PALSAR/RADARSAT‐1/TPI image stack) for detecting peatlands in a 2715 km2 area in the high elevation mountains of the Ecuadorian páramo. The map was combined with an extensive soil coring data set to produce the first estimate of regional peatland soil C storage in the páramo. Our map displayed a high coverage of peatlands (614 km2) containing an estimated 128.2 ± 9.1 Tg of peatland belowground soil C within the mapping area. Scaling‐up to the country level, páramo peatlands likely represent less than 1% of the total land area of Ecuador but could contain as much as ~23% of the above‐ and belowground vegetation C stocks in Ecuadorian forests. These mapping approaches provide an essential methodological improvement applicable to mountain peatlands across the globe, facilitating mapping efforts in support of effective policy and sustainable management, including national and global C accounting and C management efforts.
Archidona, Napo, Ecuador
Pintag, Quito Canton, Pichincha, 170811, Ecuador
Papallacta, Quijos, Napo, Ecuador
Pifo, Quito Canton, Pichincha, 170175, Ecuador
Oyacachi, El Chaco, Napo, 150206, Ecuador
Ecuador

Peatland carbon stocks and accumulation rates in the Ecuadorian páramo
Hribljan
openalex
["Peat", "Environmental science", "Soil carbon", "Soil water", "Altitude (triangle)", "Ecosystem", "Bulk density", "Physical geography", "Forestry", "Soil science", "Ecology", "Geography", "Biology"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Geology and Paleoclimatology Research"]

Carbon storage and long-term rate of accumulation in high-altitude Andean peatlands of Bolivia.
Hribljan
1. (1) The high-altitude (4,500+ m) Andean mountain range of north-western Bolivia contains many peatlands. Despite heavy grazing pressure and potential damage from climate change, little is known about these peatlands. Our objective was to quantify carbon pools, basal ages and long-term peat accumulation rates in peatlands in two areas of the arid puna ecoregion of Bolivia: near the village of Manasaya in the Sajama National Park (Cordillera Occidentale), and in the Tuni Condoriri National Park (Cordillera Real). 2. (2) We cored to 5 m depth in the Manasaya peatland, whose age at 5 m was ca. 3,675 yr. BP with a LARCA of 47 g m-2 yr-1. However, probing indicated that the maximum depth was 7–10 m with a total estimated (by extrapolation) carbon stock of 1,040 Mg ha-1. The Tuni peat body was 5.5 m thick and initiated ca. 2,560 cal. yr. BP. The peatland carbon stock was 572 Mg ha-1 with a long-term rate of carbon accumulation (LARCA) of 37 g m-2 yr-1. 3. (3) Despite the dry environment of the Bolivian puna, the region contains numerous peatlands with high carbon stocks and rapid carbon accumulation rates. These peatlands are heavily used for llama and alpaca grazing.
["Peat", "Environmental science", "Carbon sink", "Altitude (triangle)", "Carbon fibers", "Grazing", "Ecoregion", "Hydrology (agriculture)", "Climate change", "Forestry", "Physical geography", "Ecology", "Geography", "Geology", "Biology"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Geology and Paleoclimatology Research"]

Animal domestication and oscillating climates
Hesse
["Domestication", "Agonistic behaviour", "Aggression", "Juvenile", "Population", "Social behavior", "Psychology", "Demography", "Developmental psychology", "Biology", "Ecology", "Sociology"]
["Human-Animal Interaction Studies", "Wildlife Ecology and Conservation", "Neuroendocrine regulation and behavior"]

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano
Hernández
["Environmental science", "Ecology", "Biology"]

Middle and late quaternary vegetational and climatic history of the paramo de Agua Blanca (Eastern Cordillera, Colombia)
Helmens
Kuhry
["Palynology", "Quaternary", "Holocene", "Interglacial", "Geology", "Pleistocene", "Physical geography", "Glacial period", "Geography", "Humanities", "Paleontology", "Pollen", "Ecology", "Art"]
["Geological and Tectonic Studies in Latin America", "Environmental and Cultural Studies in Latin America and Beyond", "Environmental and Ecological Studies"]

The effects of check dams and other erosion control structures on the restoration of Andean bofedal ecosystems
Hartman
AbstractRestoring degraded lands in rural environments that are heavily managed to meet subsistence needs is a challenge due to high rates of disturbance and resource extraction. This study investigates the efficacy of erosion control structures (ECSs) as restoration tools in the context of a watershed rehabilitation and wet meadow (bofedal) restoration program in the Bolivian Andes. In an effort to enhance water security and increase grazing stability, Aymara indigenous communities built over 15,000 check dams, 9,100 terraces, 5,300 infiltration ditches, and 35 pasture improvement trials. Communities built ECSs at different rates, and we compared vegetation change in the highest restoration management intensity, lowest restoration management intensity, and nonproject control communities. We used line transects to measure changes in vegetation cover and standing water in gullies with check dams and without check dams, and related these ground measurements to a time series (1986–2009) of normalized difference vegetation index derived from Landsat TM5 images. Evidence suggests that check dams increase bofedal vegetation and standing water at a local scale, and lead to increased greenness at a basin scale when combined with other ECSs. Watershed rehabilitation enhances ecosystem services significant to local communities (grazing stability, water security), which creates important synergies when conducting land restoration in rural development settings.
["Environmental science", "Watershed", "Restoration ecology", "Vegetation (pathology)", "Erosion control", "Hydrology (agriculture)", "Ecosystem services", "Surface runoff", "Ecosystem", "Environmental resource management", "Geography", "Erosion", "Ecology", "Geology"]
["Soil erosion and sediment transport", "Hydrology and Sediment Transport Processes", "Conservation, Biodiversity, and Resource Management"]

Glacial areas, lake areas, and snow lines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru
Hanshaw
Bookhagen
Abstract. Glaciers in the tropical Andes of southern Peru have received limited attention compared to glaciers in other regions (both near and far), yet remain of vital importance to agriculture, fresh water, and hydropower supplies of downstream communities. Little is known about recent glacial-area changes and how the glaciers in this region respond to climate changes, and, ultimately, how these changes will affect lake and water supplies. To remedy this, we have used 158 multi-spectral satellite images spanning almost 4 decades, from 1975 to 2012, to obtain glacial- and lake-area outlines for the understudied Cordillera Vilcanota region, including the Quelccaya Ice Cap. Additionally, we have estimated the snow-line altitude of the Quelccaya Ice Cap using spectral unmixing methods. We have made the following four key observations: first, since 1988 glacial areas throughout the Cordillera Vilcanota (1988 glacial area: 361 km2) have been declining at a rate of 3.99 ± 1.15 km2 yr−1 (22 year average, 1988–2010, with 95% confidence interval (CI), n = 8 images). Since 1980, the Quelccaya Ice Cap (1980 glacial area: 63.1 km2) has been declining at a rate of 0.57 ± 0.10 km2 yr−1 (30 year average, 1980–2010, with 95% CI, n = 14). Second, decline rates for individual glacierized regions have been accelerating during the past decade (2000–2010) as compared to the preceding decade (1988–1999) with an average increase from 37.5 to 42.3 × 10−3 km2 yr−1 km−2 (13%). Third, glaciers with lower median elevations are declining at higher rates than those with higher median elevations. Specifically, glaciers with median elevations around 5200 m a.s.l. are retreating to higher elevations at a rate of ~1 m yr−1 faster than glaciers with median elevations around 5400 m a.s.l. Fourth, as glacial regions have decreased, 77% of lakes connected to glacial watersheds have either remained stable or shown a roughly synchronous increase in lake area, while 42% of lakes not connected to glacial watersheds have declined in area (58% have remained stable). Our new and detailed data on glacial and lake areas over 37 years provide an important spatiotemporal assessment of climate variability in this area. These data can be integrated into further studies to analyze inter-annual glacial and lake-area changes and assess hydrologic dependence and consequences for downstream populations.
["Glacier", "Glacial period", "Physical geography", "Snow", "Geology", "Climate change", "Altitude (triangle)", "Climatology", "Geography", "Oceanography", "Geomorphology"]
["Cryospheric studies and observations", "Climate change and permafrost", "Geology and Paleoclimatology Research"]

Pollen studies in the Junín area, central Peruvian Andes
Hansen
["Wright", "Icon", "Citation", "Library science", "Geography", "History", "Computer science", "Art history"]
["Environmental and Cultural Studies in Latin America and Beyond", "Geology and Paleoclimatology Research", "Lichen and fungal ecology"]

Paleohydrology of the Laguna Lejía (north Chilean Altiplano) and climatic implications for late-glacial times
["Glacial period", "Geology", "Precipitation", "Last Glacial Maximum", "Shore", "Physical geography", "Climate change", "Water level", "Drainage basin", "Hydrology (agriculture)", "Oceanography", "Geomorphology", "Geography"]
["Geology and Paleoclimatology Research", "Geological formations and processes", "Groundwater and Isotope Geochemistry"]

Palynological investigations of two post-glacial peat bogs near the boundary of Bolivia and Peru
Graf
["Bog", "Palynology", "Peat", "Glacial period", "Geology", "Physical geography", "Geography", "Boundary (topology)", "Archaeology", "Paleontology", "Pollen", "Ecology", "Biology"]
["Geology and Paleoclimatology Research", "Marine and coastal plant biology", "Peatlands and Wetlands Ecology"]

Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile
Ginocchio
["Las vegas", "Geography", "Humanities", "Forestry", "Archaeology", "Art"]
["Heavy metals in environment", "Lichen and fungal ecology", "Botany, Ecology, and Taxonomy Studies"]

Long-term limnological changes in the Ecuadorian páramo: Comparing the ecological responses to climate warming of shallow waterbodies versus deep lakes
Giles
AbstractPáramos are high‐altitude ecosystems of grasslands and shrubs that sustain high levels of biodiversity and contain numerous lakes, ponds and wetlands that are a crucial source of water for millions. In the Andes, limnological data are rare from páramos and particularly so from shallow waterbodies that are prominent features of the landscape.Here, we analyse fossil diatom assemblages using dated sediment cores from three shallow lakes in the páramo of southern Ecuador and document their response to recent climate changes. The two shallowest sites were <0.5 m deep and contained nearly identical diatom assemblages, dominated byAchnanthidium minutissimumand other benthic taxa. The deepest study site, at 4 m depth, differed notably from its shallower counterparts in that the dominant taxa were tychoplanktonicAulacoseiraspecies. All three study sites showed only minor assemblage shifts over the past ˜200 years. This contrasts sharply with paleolimnological data from nearby deep lakes (Zmax > 17 m) that recorded abrupt changes in diatom phytoplankton coincident with the onset of higher temperatures, reduced wind speeds and the onset of thermal stratification in recent decades.In temperate and high‐latitude regions, an overriding factor influencing freshwater ecosystems is the duration and extent of ice cover, which itself is closely linked to climate variables. In contrast, there is no winter ice cover and the growing season is continuous year round in our equatorial Andean sites. Instead, rising temperatures are affecting deep lakes primarily by altering the physical structure of the water column resulting in greater periods of thermal stratification, which in turn drives changes in biota and other lake processes. However, this mechanism of change only affects deep lakes because shallow waterbodies are easily mixed by wind.Our data demonstrate the differential response of large, deep lakes in the páramo compared to the relative complacency of changes in shallow waterbodies, which is in marked contrast to similar sites affected by seasonal ice cover.
["Diatom", "Ecology", "Paleolimnology", "Benthic zone", "Limnology", "Temperate climate", "Climate change", "Wetland", "Environmental science", "Freshwater ecosystem", "Lake ecosystem", "Ecosystem", "Oceanography", "Phytoplankton", "Physical geography", "Geography", "Geology", "Biology", "Nutrient"]
["Geology and Paleoclimatology Research", "Aquatic Ecosystems and Phytoplankton Dynamics", "Marine and coastal ecosystems"]

Mineralogical characterization of silica sinters from the El Tatio geothermal field, Chile
Garcia-Valles
["Cristobalite", "Quartz", "Mineralogy", "Differential thermal analysis", "Halite", "Geothermal gradient", "Fourier transform infrared spectroscopy", "Crystallization", "Mineral", "Phase (matter)", "Geology", "Analytical Chemistry (journal)", "Chemistry", "Chemical engineering", "Materials science", "Metallurgy", "Diffraction", "Environmental chemistry", "Gypsum"]
["Mineralogy and Gemology Studies", "Geological and Geochemical Analysis", "Glass properties and applications"]

Assessing the services of high mountain wetlands in tropical Andes: A case study of Caripe wetlands at Bolivian Altiplano
Gandarillas
["Wetland", "Livelihood", "Ecosystem services", "Geography", "Recreation", "Indigenous", "Biodiversity", "Human settlement", "Local community", "Environmental resource management", "Environmental planning", "Agroforestry", "Environmental protection", "Ecosystem", "Ecology", "Agriculture", "Environmental science"]
["Economic and Environmental Valuation", "Land Use and Ecosystem Services", "Conservation, Biodiversity, and Resource Management"]

Isolation of UV-B resistant bacteria from two high altitude Andean lakes (4,400 m) with saline and non saline conditions
Flores
["Salinity", "Bacteria", "Stenotrophomonas", "Extremophile", "Biology", "Saline water", "Altitude (triangle)", "Botany", "16S ribosomal RNA", "Food science", "Horticulture", "Microorganism", "Ecology"]
["Microbial Community Ecology and Physiology", "Protist diversity and phylogeny", "Biocrusts and Microbial Ecology"]

Characterization of cyanobacterial communities from high ‐ elevation lakes in the Bolivian Andes
Fleming
Prufert Bebout
The Bolivian Altiplano is a harsh environment for life with high solar irradiation (visible and UVR), below freezing temperatures, and some of the lowest precipitation rates on the planet. However, microbial life is visibly abundant in small isolated refugia of spring or snowmelt‐fed lakes. In this study, we characterized the cyanobacterial composition of a variety of microbial mats present in three lake systems: Laguna Blanca, Laguna Verde (elevation 4300 m), and a summit lake in the Licancabur Volcano cone (elevation 5970 m). These lakes and their adjacent geothermal springs present an interesting diversity of environments within a geographically small region (5 km2). From these sites, 78 cyanobacterial cultures were isolated in addition to ∼400 cyanobacterial 16S rRNA gene sequences from environmental genomic DNA. Based on microscopy, cultivation, and molecular analyses, these communities contained many heterocytous, nitrogen‐fixing cyanobacteria (e.g., Calothrix, Nostoc, Nodularia) as well as a large number of cyanobacteria belonging to the form‐genus Leptolyngbya. More than a third (37%) of all taxa in this study were new species (≤96% 16S rRNA gene sequence identity), and 11% represented new and novel taxa distantly related (≤93% identity) to any known cyanobacteria. This is one of the few studies to characterize cyanobacterial communities based on both cultivation‐dependent and cultivation‐independent analyses.
["Cyanobacteria", "Biology", "Ecology", "Extreme environment", "Microbial mat", "Botany", "Heterocyst", "Nostoc", "Anabaena", "Bacteria"]
["Microbial Community Ecology and Physiology", "Biocrusts and Microbial Ecology", "Aquatic Ecosystems and Phytoplankton Dynamics"]

The hot spring and geyser sinters of El Tatio, Northern Chile
Fernandez-Turiel
["Microbial mat", "Hot spring", "Algal mat", "Geology", "Subaerial", "Cyanobacteria", "Sponge spicule", "Tufa", "Sedimentary depositional environment", "Geochemistry", "Mineralogy", "Algae", "Paleontology", "Ecology", "Biology", "Bacteria", "Chemistry", "Structural basin", "Carbonate"]
["Lichen and fungal ecology", "Diatoms and Algae Research", "Geology and Paleoclimatology Research"]

Diverse responses to UV-B radiation and repair mechanisms of bacteria isolated from high-altitude aquatic environments
Fernández Zenoff
ABSTRACT
Acinetobacter johnsonii
A2 isolated from the natural community of Laguna Azul (Andean Mountains at 4,560 m above sea level),
Serratia marcescens
MF42,
Pseudomonas
sp. strain MF8 isolated from the planktonic community, and
Cytophaga
sp. strain MF7 isolated from the benthic community from Laguna Pozuelos (Andean Puna at 3,600 m above sea level) were subjected to UV-B (3,931 J m
−2
) irradiation. In addition, a marine
Pseudomonas putida
strain, 2IDINH, and a second
strain, ATCC 17909, were used as external controls. Resistance to UV-B and kinetic rates of light-dependent (UV-A [315 to 400 nm] and cool white light [400 to 700 nm]) and -independent reactivation following exposure were determined by measuring the survival (expressed as CFU) and accumulation of cyclobutane pyrimidine dimers (CPD). Significant differences in survival after UV-B irradiation were observed:
A2, 48%;
sp. strain MF8, 40%; marine
strain 2IDINH, 12%;
sp. strain MF7, 20%; and
, 21%. Most bacteria exhibited little DNA damage (between 40 and 80 CPD/Mb), except for the benthic isolate
sp. strain MF7 (400 CPD/Mb) and
ATCC 17909 (160 CPD/Mb). The recovery strategies through dark and light repair were different in all strains. The most efficient in recovering were both
A2 and
sp. strain MF7;
MF42 showed intermediate recovery, and in both
strains, recovery was essentially zero. The UV-B responses and recovery abilities of the different bacteria were consistent with the irradiation levels in their native environment.
Municipio de Fiambalá, Departamento Tinogasta, Catamarca, K5340, Argentina
Municipio de Cieneguillas, Departamento Santa Catalina, Jujuy, Argentina
Argentina
["Serratia marcescens", "Microbiology", "Biology", "Acinetobacter", "Cytophaga", "Pseudomonas putida", "Pseudomonas", "Strain (injury)", "Pseudomonadaceae", "Bacteria", "Serratia", "Pseudomonadales", "Marine bacteriophage", "Escherichia coli", "Flavobacterium", "Biochemistry", "Antibiotics", "Gene"]
["Microbial Community Ecology and Physiology", "Protist diversity and phylogeny", "Marine and coastal ecosystems"]

Diverse UV-B resistance of culturable bacterial community from high-altitude wetland water
Fernández Zenoff
Municipio de Fiambalá, Departamento Tinogasta, Catamarca, K5340, Argentina
Municipio de Fiambalá, Catamarca, Argentina
["Biology", "Bacteria", "Microbiology", "Enterobacter", "Flavobacterium", "Bacillus (shape)", "Acinetobacter", "Extreme environment", "Pseudomonas", "Escherichia coli"]
["Microbial Community Ecology and Physiology", "Algal biology and biofuel production", "Protist diversity and phylogeny"]

Spiral vegetation patterns in high-altitude wetlands
Fernandes-Oto
["Grazing", "Arid", "Wetland", "Ecology", "Vegetation (pathology)", "Herbivore", "Biomass (ecology)", "Spiral (railway)", "Environmental science", "Habitat", "Geography", "Physical geography", "Biology", "Mathematics"]
["Ecosystem dynamics and resilience", "Animal Ecology and Behavior Studies", "Ecology and Vegetation Dynamics Studies"]

Impact of solar radiation on bacterioplankton in Laguna Vilama, a hypersaline Andean lake (4650 m)
Farías etal
Laguna Vilama is a hypersaline Lake located at 4660 m altitude in the northwest of Argentina high up in the Andean Puna. The impact of ultraviolet (UV) radiation on bacterioplankton was studied by collecting samples at different times of the day. Molecular analysis (DGGE) showed that the bacterioplankton community is characterized by Gamma‐proteobacteria (Halomonas sp., Marinobacter sp.), Alpha‐proteobacteria (Roseobacter sp.), HGC (Agrococcus jenensis and an uncultured bacterium), and CFB (uncultured Bacteroidetes). During the day, minor modifications in bacterial diversity such as intensification of Bacteroidetes' signal and an emergence of Gamma‐proteobacteria (Marinobacter flavimaris) were observed after solar exposure. DNA damage, measured as an accumulation of Cyclobutane Pyrimidine Dimers (CPDs), in bacterioplankton and naked DNA increased from 100 CPDs MB−1 at 1200 local time (LT) to 300 CPDs MB−1 at 1600 LT, and from 80 CPDs MB−1 at 1200 LT to 640 CPDs MB−1 at 1600 LT, respectively. In addition, pure cultures of Pseudomonas sp. V1 and Brachybacterium sp. V5, two bacteria previously isolated from this environment, were exposed simultaneously with the community, and viability of both strains diminished after solar exposure. No CPD accumulation was observed in either of the exposed cultures, but an increase in mutagenesis was detected in V5. Of both strains only Brachybacterium sp. V5 showed CPD accumulation in naked DNA. These results suggest that the bacterioplankton community is well adapted to this highly solar irradiated environment showing little accumulation of CPDs and few changes in the community composition. They also demonstrate that these microorganisms contain efficient mechanisms against UV damage.
Municipio de Cusi Cusi, Departamento Santa Catalina, Jujuy, Argentina
Municipio de Cusi Cusi, Jujuy, Argentina
["Bacterioplankton", "Bacteroidetes", "Proteobacteria", "Biology", "Halomonas", "Microbiology", "Botany", "Bacteria", "16S ribosomal RNA", "Ecology", "Phytoplankton", "Genetics"]
["Microbial Community Ecology and Physiology", "Protist diversity and phylogeny", "Marine and coastal ecosystems"]

The discovery of stromatolites developing at 3570 m above sea level in a high-altitude volcanic lake Socompa, Argentinean Andes
Farías
Municipio de Tolar Grande, Los Andes, Salta, Argentina
Municipio de Tolar Grande, Salta, Argentina
["Stromatolite", "Crater lake", "Microbial mat", "Phylum", "Geology", "Volcano", "Aragonite", "Cyanobacteria", "Ecology", "Biology", "Geochemistry", "Paleontology", "Carbonate", "Bacteria", "Chemistry"]
["Microbial Community Ecology and Physiology", "Diatoms and Algae Research", "Marine and coastal ecosystems"]

Hazard mitigation of glacial lake outburst floods in the Cordillera Blanca (Peru): the effectiveness of remedial works
Emmer
Yuracmarca, Province of Huaylas, Ancash, Peru
Santa Cruz, Province of Huaylas, Ancash, Peru
Caraz, Province of Huaylas, Ancash, Peru
Carhuaz, Province of Carhuaz, Ancash, Peru
Tarica, Province of Huaraz, Ancash, Peru
Independencia, Province of Huaraz, Ancash, Peru
Ancash, Peru
["Moraine", "Glacial period", "Glacier", "Glacial lake", "Flood myth", "Geology", "Physical geography", "Hazard", "Drainage basin", "Population", "Hydrology (agriculture)", "Hazard analysis", "Current (fluid)", "Geomorphology", "Geography", "Cartography", "Oceanography", "Archaeology"]
["Cryospheric studies and observations", "Landslides and related hazards", "Climate change and permafrost"]

882 lakes of the Cordillera Blanca: An inventory, classification, evolution and assessment of susceptibility to outburst floods
Emmer

Rapid development of an unusual peat-accumulating ecosystem in the Chilean Altiplano
Earle
AbstractStratigraphic relationships, radiocarbon dating, sediment and peat characteristics, and rates of peat and carbon accumulation from a soligenous peatland, or “bofedal,” in the Chilean Altiplano shows the peatland to be unusually young, dynamic, and sensitive to environmental changes. The site lies in the National Park Nevado de Tres Cruces in the puna desert grassland at an elevation of 4300 m a.s.l. Eight peat cores were extracted from a 1.75-km transect yielding a maximum of 3.6 m of organic sediment. Organic matter began to accumulate 1700–1100 cal yr B.P. under a progressively arid local climate, after a period when regional climate is believed to have been more humid than at present. Areas of greater relief and better drainage in the valley bottom eventually fostered the growth of a riparian cushion plant community after water flowing down the valley began to diminish. This led to rapid lateral expansion of the riparian peatland communities over open water in topographic depressions at a rate heretofore unprecedented in the peatland literature. It appears that development of the peatland has been encouraged by autoregulation of internal hydrology. The drainage impediment created by organic mass accumulation in lower-relief areas probably reduced the amount of water arriving at the lower reaches of the peatland. These areas have become progressively drier and have since died and oxidized. Through endogenous peat accumulation and a concomitant drainage impediment, the ecosystem has been migrating upstream over the past 50 years.
["Peat", "Geology", "Hydrology (agriculture)", "Radiocarbon dating", "Riparian zone", "Ecosystem", "Physical geography", "Drainage basin", "Water table", "Environmental science", "Ecology", "Groundwater", "Geography", "Paleontology"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Geology and Paleoclimatology Research"]

Unique clusters of Archaea in Salar de Huasco, an athalassohaline evaporitic basin of the Chilean Altiplano
Dorador
["Biology", "Archaea", "Library", "Halophile", "16S ribosomal RNA", "Ecology", "Benthic zone", "Bacteria", "Botany", "Zoology", "Genetics"]
["Microbial Community Ecology and Physiology", "Methane Hydrates and Related Phenomena", "Genomics and Phylogenetic Studies"]

Diversity of Bacteroidetes in high-altitude saline evaporitic basins in northern Chile
Dorador
The phylum Bacteroidetes represents one of the most abundant bacterial groups of marine and freshwater bacterioplankton. We investigated the diversity of Bacteroidetes in water and sediment samples from three evaporitic basins located in the highlands of northern Chile. We used both 16S rRNA gene clone libraries created with targeted Bacteroidetes‐specific primers and separation of specifically amplified gene fragments by denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed a reduced richness of these organisms in samples from Salar de Huasco (two to four DGGE bands) increasing in Salar de Ascotán (two to seven DGGE bands) and Laguna Tebenquiche at Salar de Atacama (four to eight DGGE bands). Cluster analysis (WPGMA) of DGGE bands showed that bands from Salar de Huasco and Salar de Ascotán grouped together and samples from Salar de Atacama formed separate clusters in water and sediment samples, reflecting different Bacteroidetes communities between sites. Most of the sequences analyzed belonged to the family Flavobacteriaceae and clustered with the genera Psychroflexus, Gillisia, Maribacter, Muricauda, Flavobacterium, and Salegentibacter. The most abundant phylotype was highly related to Psychroflexus spp. and was recovered from all three study sites. The similarity of the analyzed sequences with their closest relatives in GenBank was typically <97% and notably lower when compared with type strains, demonstrating the unique character of these sequences. Culture efforts will be necessary to get a better description of the diversity of this group in saline evaporitic basins of northern Chile.
["Evaporite", "Effects of high altitude on humans", "Diversity (politics)", "Geology", "Altitude (triangle)", "Oceanography", "Geography", "Structural basin", "Geomorphology", "Meteorology", "Anthropology"]
["Microbial Community Ecology and Physiology", "Genomics and Phylogenetic Studies", "Protist diversity and phylogeny"]

Cyanobacterial diversity in Salar de Huasco, a high altitude saline wetland in northern Chile: An example of geographical dispersion?
Dorador
["Biology", "Sediment", "Tributary", "Biota", "Ecology", "Altitude (triangle)", "Wetland", "Library", "Water column", "16S ribosomal RNA", "Paleontology"]
["Microbial Community Ecology and Physiology", "Polar Research and Ecology", "Marine and coastal ecosystems"]

Molecular analysis of enrichment cultures of ammonia oxidizers from the Salar de Huasco, a high altitude saline wetland in northern Chile
["Phylotype", "Biology", "Archaea", "16S ribosomal RNA", "Salinity", "Enrichment culture", "Library", "Bacteria", "Botany", "Ecology"]
["Wastewater Treatment and Nitrogen Removal", "Microbial Community Ecology and Physiology", "Microbial Fuel Cells and Bioremediation"]

Two Thousand Years of Land-Use and Vegetation Evolution in the Andean Highlands of Northern Chile Inferred from Pollen and Charcoal Analyses
Domic
The European conquest of the New World produced major socio-environmental reorganization in the Americas, but for many specific regions and ecosystems, we still do not understand how these changes occurred within a broader temporal framework. In this paper, we reconstruct the long-term environmental and vegetation changes experienced by high-altitude wetlands of the southcentral Andes over the last two millennia. Pollen and charcoal analyses of a 5.5-m-long core recovered from the semi-arid puna of northern Chile indicate that while climatic drivers influenced vegetation turnaround, human land use and management strategies significantly affected long-term changes. Our results indicate that the puna vegetation mostly dominated by grasslands and some peatland taxa stabilized during the late Holocene, xerophytic shrubs expanded during extremely dry events, and peatland vegetation persisted in relation to landscape-scale management strategies by Andean pastoralist societies. Environmental changes produced during the post-conquest period included the introduction of exotic taxa, such as clovers, associated with the translocation of exotic herding animals (sheep, cattle, and donkeys) and a deterioration in the management of highland wetlands.
["Vegetation (pathology)", "Geography", "Holocene", "Wetland", "Peat", "Ecology", "Charcoal", "Paleoecology", "Arid", "Ecosystem", "Period (music)", "Physical geography", "Agroforestry", "Archaeology", "Environmental science", "Biology"]
["Geology and Paleoclimatology Research", "Archaeology and ancient environmental studies", "Pleistocene-Era Hominins and Archaeology"]

Long-term declines in waterbirds abundance at Lake Junín, Andean Peru
Dinesen
["Flood myth", "Abundance (ecology)", "Flooding (psychology)", "Environmental science", "Ecology", "Extreme weather", "Geography", "Fishery", "Climate change", "Biology"]
["Flood Risk Assessment and Management", "Hydrology and Watershed Management Studies", "Hydrology and Sediment Transport Processes"]

Isolation of bacteria from remote high altitude Andean lakes able to grow in the presence of antibiotics
Dib
["Ampicillin", "Antibiotics", "Bacteria", "Biology", "Tetracycline", "Cefotaxime", "Colistin", "Microbiology", "Antibiotic resistance"]
["Pharmaceutical and Antibiotic Environmental Impacts", "Aquaculture disease management and microbiota", "Microbial Community Ecology and Physiology"]

Occurrence of resistance to antibiotics, UV-B, and arsenic in bacteria isolated from extreme environments in high-altitude (above 4400 m) Andean wetlands
Dib
["Biology", "Microbiology", "Firmicutes", "Tetracycline", "Kanamycin", "Bacteria", "Antibiotics", "16S ribosomal RNA"]
["Microbial Community Ecology and Physiology", "bioluminescence and chemiluminescence research", "Pharmaceutical and Antibiotic Environmental Impacts"]

Seasonal activity patterns and abundance of Andean flamingo (Phoenicoparrus Andinus) at two contrasting wetlands in Argentina
Derlindati
Flamingos are gregarious birds that live in brackish lakes. During winter, Andean Flamingo (Phoenicoparrus andinus) and Chilean Flamingo (Phoenicopterus chilensis) inhabit shallow lakes of southern Santa Fe Province, Argentina. Our objectives were to assess the behavioural patterns of these species during winter at Melincué Lagoon, and to evaluate the influence of weather conditions on these patterns. We selected adult individuals of each species and recorded simultaneously their behaviours and the values of five weather conditions (temperature, wind-chill factor, atmospheric pressure, relative humidity, wind speed). Main behaviours recorded for both species were resting, preening and feeding. There were significant differences between species in their behavioural patterns. Andean Flamingo spent more time walking and in alert, while the Chilean Flamingo spent more time resting. Individuals of both species spent more time feeding during periods of high atmospheric pressure, and resting during strong winds. The Andean Flamingo was more active, being less affected by strong winds. These results highlight the need to do long-term ecoethological studies of these species. Knowledge about flamingo biology should help the design and implementation of action plans for its conservation and the conservation of the wetlands they inhabit.
["Humanities", "Geography", "Art"]
["Fish biology, ecology, and behavior", "Fish Ecology and Management Studies", "Avian ecology and behavior"]

Prokaryotic diversity pattern in high-altitude ecosystems of the Chilean Altiplano
Demergasso etal
The Chilean Altiplano is the westernmost part of a large volcanic‐sedimentary plateau in the central Andes. High solar irradiance and rapid increase of temperature have contributed to make it a hot spot of global climatic change. In this study, we describe microbial diversity in the summit lake of the Simba volcano (5,870 m) and the evaporitic basins of Salar de Aguas Calientes (4,200 m) and Laguna Lejía (4,325 m) using both culture and culture‐independent methods. The results obtained were analyzed together with available information from related environments to describe the traits of the microbial community driven by main environmental factors. Isolated cultures exhibit high resistance to all three types of UV radiation, further supporting the adaptation of microorganisms to the high altitude environment. The microbial community structures at Salar de Aguas Calientes and Laguna Lejía are similar to those from other saline systems and cold environments where Bacteroidetes is the major bacterial group. The abundance of sequences related to alphaproteobacteria and methanogenic populations likely reflects the importance of aerobic anoxigenic phothosynthesis and the cycling of one‐carbon compounds in the high altitude lake ecosystems. Geochemistry and microbial communities at Simba as well as those reported in the Licancabur summit lake provide evidence for sulfur‐rich environments but under different conditions. Those differences between neighboring mountain lake ecosystems highlight the effect of volcanic activity on microbial communities. The hypothetical ecosystem model described in this work provides a clue to follow the microbial community responses to geophysical environment coupled with rapid climate change.
["Ecosystem", "Microbial mat", "Ecology", "Lake ecosystem", "Microbial population biology", "Volcano", "Environmental science", "Plateau (mathematics)", "Altitude (triangle)", "Earth science", "Physical geography", "Geology", "Geography", "Biology", "Geochemistry"]
["Microbial Community Ecology and Physiology", "Polar Research and Ecology", "Methane Hydrates and Related Phenomena"]

Microbial Precipitation of Arsenic Sulfides in Andean Salt Flats
Demergasso etal
["Arsenic", "Environmental chemistry", "Sulfide minerals", "Precipitation", "Abiotic component", "Chemistry", "Biogeochemical cycle", "Geology", "Geochemistry", "Mineralogy", "Pyrite"]
["Arsenic contamination and mitigation", "Mine drainage and remediation techniques", "Heavy metals in environment"]

Novelty and spatio-temporal heterogeneity in the bacterial diversity of hypersaline Lake Tebenquiche (Salar de Atacama)
Demergasso
["Bacteroidetes", "Temperature gradient gel electrophoresis", "Bacterioplankton", "Salinity", "Biology", "Ecology", "Species evenness", "Gammaproteobacteria", "16S ribosomal RNA", "Beta diversity", "Zoology", "Biodiversity", "Species diversity", "Bacteria", "Phytoplankton"]
["Microbial Community Ecology and Physiology", "Protist diversity and phylogeny", "Genomics and Phylogenetic Studies"]

Distribution of prokaryotic genetic diversity in athalassohaline lakes of the Atacama Desert, Northern Chile
Demergasso
["Biology", "Temperature gradient gel electrophoresis", "Archaea", "Ecology", "Desert climate", "Cytophaga", "Plateau (mathematics)", "Proteobacteria", "Altitude (triangle)", "Flavobacterium", "16S ribosomal RNA", "Zoology", "Bacteria", "Arid", "Paleontology"]
["Microbial Community Ecology and Physiology", "Genomics and Phylogenetic Studies", "Protist diversity and phylogeny"]

Nurse species and indirect facilitation through grazing drive plant community functional traits in tropical alpine peatlands
Danet
AbstractFacilitation among plants mediated by grazers occurs when an unpalatable plant extends its protection against grazing to another plant. This type of indirect facilitation impacts species coexistence and ecosystem functioning in a large array of ecosystems worldwide. It has nonetheless generally been understudied so far in comparison with the role played by direct facilitation among plants. We aimed at providing original data on indirect facilitation at the community scale to determine the extent to which indirect facilitation mediated by grazers can shape plant communities. Such experimental data are expected to contribute to refining the conceptual framework on plant–plant–herbivore interactions in stressful environments. We set up a 2‐year grazing exclusion experiment in tropical alpine peatlands in Bolivia. Those ecosystems depend entirely on a few, structuring cushion‐forming plants (hereafter referred to as “nurse” species), in which associated plant communities develop. Fences have been set over two nurse species with different strategies to cope with grazing (direct vs. indirect defenses), which are expected to lead to different intensities of indirect facilitation for the associated communities. We collected functional traits which are known to vary according to grazing pressure (LDMC, leaf thickness, and maximum height), on both the nurse and their associated plant communities in grazed (and therefore indirect facilitation as well) and ungrazed conditions. We found that the effect of indirectly facilitated on the associated plant communities depended on the functional trait considered. Indirect facilitation decreased the effects of grazing on species relative abundance, mean LDMC, and the convergence of the maximum height distribution of the associated communities, but did not affect mean height or cover. The identity of the nurse species and grazing jointly affected the structure of the associated plant community through indirect facilitation. Our results together with the existing literature suggest that the “grazer–nurse–beneficiary” interaction module can be more complex than expected when evaluated in the field.
["Facilitation", "Grazing", "Herbivore", "Ecology", "Ecosystem", "Plant community", "Biology", "Abundance (ecology)", "Trait", "Ecological succession"]
["Ecology and Vegetation Dynamics Studies", "Plant and animal studies", "Plant Parasitism and Resistance"]

New land in the Neotropics: a review of biotic community, ecosystem, and landscape transformations in the face of climate and glacier change
Cuesta
["Glacier", "Climate change", "Ecosystem", "Biota", "Wetland", "Geography", "Ecology", "Ecosystem services", "Physical geography", "Environmental resource management", "Environmental science"]
["Geology and Paleoclimatology Research", "Species Distribution and Climate Change", "Cryospheric studies and observations"]

Obsidian sources from the southern Andean highlands (Laguna del Diamante, Argentina and Chile): geochemical insights on geological complexity and human biogeography
Cortegoso
["Archaeology", "Homogeneous", "Geography", "Plateau (mathematics)", "Natural (archaeology)", "Geology", "Biogeography", "Spatial distribution", "Distribution (mathematics)", "Altitude (triangle)", "Physical geography", "Paleontology", "Remote sensing"]
["Pleistocene-Era Hominins and Archaeology", "Archaeology and ancient environmental studies", "Pacific and Southeast Asian Studies"]

Temporary shallow pools in high-Andes `bofedal' peatlands: a limnological characterization at different spatial scales
Coronel
["Cognitive psychology", "Working memory", "Psychology", "Space (punctuation)", "Computer science", "Neuroscience", "Cognition"]
["Spatial Cognition and Navigation", "Augmented Reality Applications", "Human-Automation Interaction and Safety"]

Drivers of Peatland Water Table Dynamics in the Central Andes, Bolivia and Peru
Cooper et al
AbstractCushion plant dominated peatlands are key ecosystems in tropical alpine regions of the Andes in South America. The cushion plants have formed peat bodies over thousands of years that fill many valley bottoms, and the forage produced by the plants is critical for native and nonnative domesticated mammals. The sources and flow paths of water supporting these peatlands remain largely unknown. Some studies have suggested that glacier meltwater streams support some peatlands, and that the ongoing loss of glaciers and their meltwaters could lead to the loss or diminishment of peatlands. We analysed the hydrologic regime of 10 peatlands in four mountain regions of Bolivia and Peru using groundwater monitoring. Groundwater levels in peatlands were relatively stable and within 20 cm of the ground surface during the rainy season, and many sites had water tables 40–90 cm below the ground surface in the dry season. Topographic and groundwater elevations in the peatlands demonstrated that the water source of all 10 peatlands was hillslope groundwater flowing from lateral moraines, talus, colluvium, or bedrock aquifers into the peatlands. There was little to no input from streams, whether derived from glacier melt or other sources, and glacier melt could not have recharged the hillslope aquifers supporting peatlands. We measured the stable water isotopes in water samples taken during different seasons, distributed throughout the catchments, and the values are consistent with this interpretation. Our findings indicate that peatlands in the study region are recharged by hillslope groundwater discharge rather than stream water and may not be as vulnerable to glacial decline as other studies have indicated. However, both glaciers and peatlands are susceptible to changing thermal and precipitation regimes that could affect the persistence of peatlands.
["Peat", "Water table", "Groundwater", "Hydrology (agriculture)", "Aquifer", "Geology", "Glacier", "STREAMS", "Environmental science", "Surface water", "Meltwater", "Geomorphology", "Ecology"]
["Peatlands and Wetlands Ecology", "Cryospheric studies and observations", "Climate change and permafrost"]

Growth and Organic Carbon Production in Peatlands Dominated by Distichia muscoides, Bolivia, South America
Cooper
["Peat", "Environmental science", "Biomass (ecology)", "Ecosystem", "Total organic carbon", "Carbon fibers", "Latitude", "Southern Hemisphere", "Physical geography", "Ecology", "Geography", "Oceanography", "Geology", "Biology"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Botany and Plant Ecology Studies"]

Alpine Peatlands of the Andes, Cajamarca, Peru
Cooper
["Peat", "Bryophyte", "Lichen", "Wetland", "Gradient analysis", "Sphagnum", "Mire", "Bedrock", "Ordination", "Canonical correspondence analysis", "Environmental science", "Groundwater", "Ecology", "Plant community", "Bog", "Moss", "Detrended correspondence analysis", "Tundra", "Geology", "Ecological succession", "Ecosystem", "Abundance (ecology)", "Geomorphology", "Biology"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Lichen and fungal ecology"]

Effects of grazing pressure on plant species composition and water presence on bofedales in the Andes mountain range of Bolivia
Cochi Machaca
Bofedales are high-Andean peatland plant communities with high capacity for water retention, which are regarded as oases of biodiversity. These areas have great social and economic value for livestock grazing, which plays an important role in their vegetation dynamics. However, the effects of increased livestock pressure on vegetation composition and surface water have not yet been clarified. The goal of this study was to assess the impact of current grazing practices on bofedal vegetation, species diversity and function. Specifically, the study aimed to (1) quantify carrying capacity and stocking rate in grazed bofedales and (2) quantify the effects of grazing pressure on plant composition and the extents of bare soil and surface water. Biomass and stocking rate estimates for 25 bofedales along the Cordillera Real (Tropical Andes, Bolivia) showed that all bofedales were overgrazed (carrying capacity/stocking rate (CC/SR) <1). Regression analyses showed significant decreases in number of plant species, species dominance, diversity and percent surface water as CC/SR declined (p < 0.05). Bofedales are negatively affected by increased grazing pressure and potentially affected by changes in livestock species. These pressures, combined with land use changes and climate change, could result in long-term negative effects for the ecological functioning and sustainability of bofedales.
["Grazing", "Grazing pressure", "Dominance (genetics)", "Biodiversity", "Stocking", "Vegetation (pathology)", "Livestock", "Rangeland", "Environmental science", "Ecology", "Geography", "Biomass (ecology)", "Agroforestry", "Biology", "Forestry"]
["Peatlands and Wetlands Ecology", "Rangeland and Wildlife Management", "Coastal wetland ecosystem dynamics"]

Long-term carbon accumulation in two tropical mountain peatlands, Andes Mountains, Ecuador
Chimner
Karberg
Tropical peatlands form in at least two distinct altitudinal zones, namely lowlands and high mountains. Unlike lowland tropical peatlands, which are typically forested, tropical mountain peatlands are dominated by cushion plants, bryophytes and herbaceous plants. Tropical mountain peatlands are poorly understood and little information is available on their ages, whether their peat bodies are relicts or actively accumulating carbon, the amount of carbon they contain, or the rate at which they can accumulate carbon. Our objective in this paper is to quantify carbon accumulation rates in two peatlands in the Andes Mountains of Ecuador, South America. At each site, we collected peat cores which were analysed for bulk density, mineral content and % C and we calculated the amount of carbon stored. Due to the high amount of mineral sediment in the Cotopaxi peatland, carbon dating was not done at this site. The Cayambre-Coca peat body was 4 m thick, ca. 3,000 years old, and had accumulated 140 kgC m
-2
. The approximate long-term rate of carbon accumulation (LARCA) is 46 gC m
yr
-1
. However, a significant part of the depth of accumulation is due to high levels of mineral sediment input from steep side slopes and volcanic ash input.
["Peat", "Carbon fibers", "Geology", "Environmental science", "Tropics", "Physical geography", "Earth science", "Ecology", "Geography", "Biology"]

A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery
Chavez
The high Andean peatlands, locally known as “bofedales”, are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has provided critical water and forage resources for the livestock of the indigenous Aymara communities for thousands of years. Nevertheless, little is known about the productivity dynamics of the high Andean peatlands, particularly in the drier western Altiplano region bordering the Atacama desert. Here, we provide the first digital peatland inventory and multiscale productivity assessment for the entire western Altiplano (63,705 km2) using 31 years of Landsat data (about 9000 scenes) and a non-parametric approach for estimating phenological metrics. We identified 5665 peatland units, covering an area of 510 km2, and evaluated the spatiotemporal productivity patterns at the regional, peatland polygon, and individual pixel scales. The regional assessment shows that the peatland areas and peatlands with higher productivity are concentrated towards the northern part of our study region, which is consistent with the Altiplano north–south aridity gradient. Regional patterns further reveal that the last seven years (2011–2017) have been the most productive period over the past three decades. While individual pixels show contrasting patterns of reductions and gains in local productivity during the most recent time period, most of the study area has experienced increases in annual productivity, supporting the regional results. Our novel database can be used not only to explore future research questions related to the social, biological, and hydrological influences on peatland productivity patterns, but also to provide technical support for the sustainable development of livestock practices and conservation and water management policy in the Altiplano region.
["Peat", "Physical geography", "Productivity", "Wetland", "Plateau (mathematics)", "Environmental science", "Geography", "Digital elevation model", "Ecology", "Remote sensing"]
["Peatlands and Wetlands Ecology", "Fire effects on ecosystems", "Coastal wetland ecosystem dynamics"]

Waterbird Richness in Altiplano Wetlands of Northwestern Argentina
Caziani
Municipio de Cusi Cusi, Departamento Santa Catalina, Jujuy, Argentina
Municipio de Mina Pirquitas, Departamento Rinconada, Jujuy, 4643, Argentina
Municipio de Cieneguillas, Departamento Santa Catalina, Jujuy, Argentina
Municipio de Puesto del Marqués, Departamento Cochinoca, Jujuy, Argentina
Municipio de Abdón Castro Tolay, Departamento Cochinoca, Jujuy, J4641, Argentina
Jujuy, Argentina
["Species richness", "Wetland", "Geography", "Ecology", "Grazing", "Biology"]
["Avian ecology and behavior", "Wildlife-Road Interactions and Conservation", "Wildlife Ecology and Conservation"]

Abundance and Habitat of High Andes Flamingos in Northwestern Argentina
Caziani and Derlindati
Three flamingo species occur in the High Andes wetlands of Argentina, Bolivia, Chile, and Peru: James (Phoenicoparrusjamesi), Andean (P. andinus), and Chilean, (Phoenicopterus chilensis). During summer, the Vilama Lakes concentrate 30% of the James and Andean Flamingo populations of Argentina. These 9 lakes differ in size, depth, water composition, plankton, and submergent vegetation. We studied flamingo populations and wetlands of the Vilama Lakes region from 1995 through 1998. Species abundance was related to habitat variables. Shallow and highly saline lakes, rich in diatoms and cyanophytes but poor in zooplankton, concentrated the James Flamingo. Deep lakes with macrophytes and dense zooplankton provided habitat for the Chilean Flamingo and had more diverse waterbird communities than the shallow lakes. The Andean Flamingo occurred in almost every lake but in generally low numbers; however, it was more abundant in intermediate-character lakes and shallow lakes. Overall, shallow lakes sustained great numbers of flamingos, but changes in lake size did not explain abundance variations. The Vilama Lakes are complementary habitat patches for these species of flamingo, and for other vulnerable species (e.g., Horned Coot [Fulica cornuta]). This biological information contributed to the design of Vilama National Reserve (160,000 ha) with its 9 lakes under the management category of Natural Monument. The planned Vilama Reserve would contribute to a 3-nation reserve proposal formed by the present Eduardo Avaroa National Wildlife Reserve in Bolivia and Flamingos National Reserve in Chile, thus protecting the whole area of highest conservation value for Andean andJames F
Municipio de Cusi Cusi, Departamento Santa Catalina, Jujuy, Argentina
Cabanillas, Province of San Román, Puno, Peru
["Abundance (ecology)", "Habitat", "Geography", "Ecology", "Biology"]
["Avian ecology and behavior", "Fish Ecology and Management Studies", "Wildlife Ecology and Conservation"]

Interannual lake fluctuations in the Argentine Puna: relationships with its associated peatlands and climate change
Casagranda
High elevation ecosystems are likely more sensitive to climate change. But, due to paucity of instrumental records, such effects are poorly studied, particularly in mountains outside Europe and North America. Here, we quantified water body area fluctuations for the last 32 years in 15 lakes spread over an area of 14.3 million ha in the Argentine Puna, through the classification of Landsat images; and we quantified peatlands NDVI (a proxy of vegetation productivity) from MODIS images. We evaluated the pairwise similarity between lakes interannual fluctuations and their relationship with climate models (TRMM 3B43 v7; CRU TS 4.10) and potential controls (ENSO index); and the correlations between water body area and the NDVI variation of its associated peatlands. Lakes were grouped in two clusters defined by their synchronic water body area variability and these clusters define two main geographic zones: NE and SW. Consistent with previous observations of an overall aridization trend, water body area generally decreased but showed large variability among lakes. Peatlands productivity was more correlated with lake variability than with modeled precipitation, and lake water body area was weakly related to indices of ENSO, providing an additional tool to relate local climate with continental and global climate models. The analysis shows that lake behavior is highly variable spatially and temporally, and that satellite-based monitoring is a valuable tool for assessing ecological conditions of wetlands in the region, characterized by the lack of climatic instrumental records; and to explore the vulnerability of wetlands to climate change.
["Peat", "Wetland", "Cru", "Environmental science", "Physical geography", "Climate change", "Normalized Difference Vegetation Index", "Precipitation", "Lake ecosystem", "Vegetation (pathology)", "Climatology", "Ecosystem", "Hydrology (agriculture)", "Geography", "Ecology", "Geology"]
["Peatlands and Wetlands Ecology", "Climate variability and models", "Hydrology and Watershed Management Studies"]

Solute inputs in the Salar de Atacama (N. Chile)
Carmona etal
The provenance of saline inputs to the Salar de Atacama has been studied by means of the isotopic composition of sulphates dispersed in drilling core samples and the analysis of the water of surface inflows. The pattern shown by the ratios of 87Sr/86Sr and the isotopic composition of sulphur and oxygen in sulphates, suggests a mixing of two water inputs: one coming from the north-east of the basin, higher in 87Sr/86Sr, d34S and d18O and the other from the south-west, lower in 87Sr/86Sr, d34S and d18O. Analysis of the recent inflows to the Salar have confirmed the existence of two solute sources: northern and eastern inputs show an enrichment in those elements related to hydrothermalism and volcanism, in relation to water present in the west of the basin.
["\u03b434S", "\u03b418O", "Provenance", "Geology", "Structural basin", "Sulfur", "Plateau (mathematics)", "Geochemistry", "Isotope analysis", "Stable isotope ratio", "Oceanography", "Geomorphology", "Paleontology", "Chemistry", "Fluid inclusions"]
["Geology and Paleoclimatology Research", "Geological and Geophysical Studies Worldwide", "Groundwater and Isotope Geochemistry"]

An integrated socio-environmental framework for glacier hazard management and climate change adaptation: lessons from Lake 513, Cordillera Blanca, Peru
Carey
Glacier hazards threaten societies in mountain regions worldwide. Glacial lake outburst floods (GLOFs) pose risks to exposed and vulnerable populations and can be linked in part to long-term post-Little Ice Age climate change because precariously dammed glacial lakes sometimes formed as glaciers generally retreated after the mid-1800s. This paper provides an interdisciplinary and historical analysis of 40 years of glacier hazard management on Mount Hualcán, at glacial Lake 513, and in the city of Carhuaz in Peru’s Cordillera Blanca mountain range. The case study examines attempted hazard zoning, glacial lake evolution and monitoring, and emergency engineering projects to drain Lake 513. It also analyzes the 11 April 2010 Hualcán rock-ice avalanche that triggered a Lake 513 GLOF; we offer both a scientific assessment of the possible role of temperature on slope stability and a GIS spatial analysis of human impacts. Qualitative historical analysis of glacier hazard management since 1970 allows us to identify and explain why certain actions and policies to reduce risk were implemented or omitted. We extrapolate these case-specific variables to generate a broader socio-environmental framework identifying factors that can facilitate or impede disaster risk reduction and climate change adaptation. Facilitating factors are technical capacity, disaster events with visible hazards, institutional support, committed individuals, and international involvement. Impediments include divergent risk perceptions, imposed government policies, institutional instability, knowledge disparities, and invisible hazards. This framework emerges from an empirical analysis of a coupled social-ecological system and offers a holistic approach for integrating disaster risk reduction and climate change adaptation.
["Adaptation (eye)", "Vulnerability (computing)", "Livelihood", "Supply chain", "Climate change", "Scale (ratio)", "Adaptive capacity", "Business", "Disaster risk reduction", "Environmental resource management", "Environmental economics", "Agriculture", "Risk analysis (engineering)", "Computer science", "Geography", "Economics", "Marketing", "Ecology"]
["Climate change impacts on agriculture", "Agricultural Innovations and Practices", "Agricultural risk and resilience"]

Living and dying with glaciers: people's historical vulnerability to avalanches and outburst floods in Peru
Carey
Human populations worldwide are vulnerable to natural disasters. Certain conditions—such as geographical location or people’s income level—can affect the degree to which natural disasters impact people’s homes and livelihoods. This paper suggests that vulnerability to natural disasters increases when local people, scientists, and policymakers do not communicate and trust each other. Additionally, a breakdown in interaction and confidence among these groups can disrupt the implementation of sound science or well-intentioned policies. This case study analyzes how local people, scientists, and government officials responded to glacier hazards in Peru’s Cordillera Blanca mountain range. Cordillera Blanca glacier retreat since the late-19th century has triggered some of the world’s most deadly avalanches and glacial lake outburst floods. Although a Peruvian glaciology and lakes security office has bcontrolledQ 35 Cordillera Blanca glacial lakes, 30 glacier disasters have killed nearly 30,000 people in this region since 1941. A lack of local faith in government officials and scientists as well as the State’s failure to follow scientists’ warnings about potential disasters have endangered or led to the death of thousands of local residents, many of which remain living in hazard zones today
["Glacier", "Vulnerability (computing)", "Glacial period", "Natural hazard", "Natural disaster", "Geography", "Glacial lake", "Livelihood", "Hazard", "Government (linguistics)", "Physical geography", "Geology", "Archaeology", "Computer security", "Meteorology"]
["Cryospheric studies and observations", "Environmental and Cultural Studies in Latin America and Beyond", "Landslides and related hazards"]

Guanacos in the Desert Puna: A trade-off between drinking and the risk of being predated
Cappa etal
Habitats vary not only in resource availability and quality but also in predation risk, among other factors. The Desert Puna of Argentina comprises two habitats: the shrub steppe and the vegas. The former, the most abundant habitat, is a topographically simple area with unavailable free water and poor food quality; the latter is a very scarce and topographically complex habitat and with water available year round and high quality food. Guanaco relies heavily on vision to detect predators and narrow and complex habitats would be risky. Hence, we expected that guanacos would use the vegas in lowest proportion and would increase the time devoted to vigilance. Guanacos spent more time in the shrubsteppe than in the vegas, where the highest percentage of vigilant guanacos was recorded. A positive and significant relationship between time devoted to foraging and number of animals per herd was observed in both habitats. In the shrub-steppe the opposite was observed for vigilance, whereas in the vegas, no relationship was observed. Despite the low availability of vegas and the high predation risk, they represent a critical habitat for guanacos in the Desert Puna, because they representing the only areas with free water available throughout year for wildlife.
["Habitat", "Wildlife", "Ecology", "Predation", "Foraging", "Geography", "Shrub", "Biology"]
["Wildlife Ecology and Conservation", "Primate Behavior and Ecology", "Animal Behavior and Reproduction"]

The High-Lakes Project
Cabrol etal
The High Lakes Project is a multidisciplinary astrobiological investigation studying high-altitude lakes between 4200 m and 6000 m elevation in the Central Andes of Bolivia and Chile. Its primary objective is to understand the impact of increased environmental stress on the modification of lake habitability potential during rapid climate change as an analogy to early Mars. Their unique geophysical environment and mostly uncharted ecosystems have added new objectives to the project, including the assessment of the impact of low-ozone/high solar irradiance in nonpolar aquatic environments, the documentation of poorly known ecosystems, and the quantification of the impact of climate change on lake environment and ecosystem. Data from 2003 to 2007 show that UV flux is 165% that of sea level with maximum averaged UVB reaching 4 W/m2. Short UV wavelengths (260–270 nm) were recorded and peaked at 14.6 mW/m2. High solar irradiance occurs in an atmosphere permanently depleted in ozone falling below ozone hole definition for 33–36 days and between 30 and 35% depletion the rest of the year. The impact of strong UVB and UV erythemally weighted daily dose on life is compounded by broad daily temperature variations with sudden and sharp fluctuations. Lake habitat chemistry is highly dynamical with notable changes in yearly ion concentrations and pH resulting from low and variable yearly precipitation. The year-round combination of environmental variables define these lakes as end-members. In such an environment, they host ecosystems that include a significant fraction of previously undescribed species of zooplankton, cyanobacterial, and bacterial populations.
["Cloud computing", "Environmental science", "Geography", "Computer science", "Operating system"]
["Atmospheric and Environmental Gas Dynamics", "Water Quality and Resources Studies"]

Models as multiple working hypotheses: hydrological simulation of tropical alpine wetlands
Buytaert
Beven
Tropical alpine grasslands, locally known as p ́ aramos, are the water towers of the northern Andes. They are an essential water source for drinking water, irrigation schemes and hydropower plants. But despite their high socio-economic relevance, their hydrological processes are very poorly understood. Since environmental change, ranging from small scale land-use changes to global climate change, is expected to have a strong impact on the hydrological behaviour, a better understanding and hydrological prediction are urgently needed. In this paper, we apply a set of nine hydrological models of different complexity to a small, well monitored upland catchment in the Ecuadorian Andes. The models represent different hypotheses on the hydrological functioning of the p ́ aramo ecosystem at catchment scale. Interpretation of the results of the model prediction and uncertainty analysis of the model parameters reveals important insights in the evapotranspiration, surface runoff generation and base flow in the p ́ aramo. However, problems with boundary conditions, particularly spatial variability of precipitation, pose serious constraints on the differentiation between model representations.
["Conceptualization", "Flexibility (engineering)", "Computer science", "Process (computing)", "Representation (politics)", "Fidelity", "Management science", "Scale (ratio)", "Component (thermodynamics)", "Data science", "Temporal scales", "Risk analysis (engineering)", "Artificial intelligence", "Ecology", "Mathematics", "Geography", "Engineering"]
["Hydrology and Watershed Management Studies", "Flood Risk Assessment and Management", "Hydrological Forecasting Using AI"]

Ecology of a paramo cushion mire
Bosman
A pollen diagram of a 225 cm long core from a small Plantago rigida cushion mire (Turbera de Calostros) in the grassparamo belt at 3730m altitude in the Paramo de Chingaza, Eastern Cordillera of Colombia, records the last 8500 years of Holocene vegetational history. Three radiocarbon dates (8410 ± 160 BP, 7230 ± 1340 BP and 5980 ± 75 BP) provide a time frame. Pollen of taxa of zonal grassparamo and subparamo vegetation are dominant and pollen of subandean (lower montane) forest elements are overrepresented due to upslope aeolian pollen supply to this high-elevation site. Eight pollen zones were recognized and reflect, on a regional scale, a sequence of altitudinal shifts of the upper forest line (oscillating between 3000-3100 and 3500m) and synchronous changes in the composition of the Andean (upper montane) forest. Based on the radiocarbon dates and using the pollen density record, dates of changes in environmental conditions are estimated c. 8700, 8600, 7800, 7500, 6650, 5200, 300 and 100BP. Correlation with other palaeoecological records from this part of the Eastern Cordillera is discussed. Each pollen zone represents a characteristic phase in the local development of the Plantago rigida mire.
["Mire", "Sphagnum", "Peat", "Bog", "Vegetation (pathology)", "Canonical correspondence analysis", "Ecology", "Environmental science", "Vegetation type", "Biology", "Habitat"]
["Peatlands and Wetlands Ecology", "Geology and Paleoclimatology Research", "Botany and Plant Ecology Studies"]

Holocene mire development and climatic change from a high Andean Plantago rigida cushion mire
Bosman
A pollen diagram of a 225 cm long core from a small Plantago rigida cushion mire (Turbera de Calostros) in the grassparamo belt at 3730m altitude in the Paramo de Chingaza, Eastern Cordillera of Colombia, records the last 8500 years of Holocene vegetational history. Three radiocarbon dates (8410 ± 160 BP, 7230 ± 1340 BP and 5980 ± 75 BP) provide a time frame. Pollen of taxa of zonal grassparamo and subparamo vegetation are dominant and pollen of subandean (lower montane) forest elements are overrepresented due to upslope aeolian pollen supply to this high-elevation site. Eight pollen zones were recognized and reflect, on a regional scale, a sequence of altitudinal shifts of the upper forest line (oscillating between 3000-3100 and 3500m) and synchronous changes in the composition of the Andean (upper montane) forest. Based on the radiocarbon dates and using the pollen density record, dates of changes in environmental conditions are estimated c. 8700, 8600, 7800, 7500, 6650, 5200, 300 and 100BP. Correlation with other palaeoecological records from this part of the Eastern Cordillera is discussed. Each pollen zone represents a characteristic phase in the local development of the Plantago rigida mire.
["Mire", "Pollen", "Holocene", "Geology", "Radiocarbon dating", "Palynology", "Physical geography", "Peat", "Paleontology", "Ecology", "Geography", "Archaeology"]
["Geological and Tectonic Studies in Latin America", "Environmental and Ecological Studies"]

A phytoremediation approach using Calamagrostis ligulata and Juncus imbricatus in Andean wetlands of Peru
Bobadilla
Emergent plant species growing in Andean natural wetlands have shown efficient phytoremediation capabilities in wetlands polluted by acid mine drainage. However, the types and amounts of heavy metals accumulated by native plant species are not well understood. In this study, we focused on determining heavy metal concentrations and bioaccumulation factors in Calamagrostis ligulata and Juncus imbricatus. Two acid wetlands located above 3,500 m a.s.l. in Ancash, Peru were assessed. Physico-chemical parameters and heavy metals concentrations in control and experimental plant samples were measured in dry and rainy seasons. Results indicated that C. ligulata and J. imbricatus aerial parts accumulated higher amounts of Fe, Zn, As and Al. Also, bioaccumulation factors revealed notable increases in As, Pb and Al, but less so in Cd, Fe and Zn. On the other hand, physico-chemical parameters of water quality (pH, temperature, dissolved oxygen, sulphides) between inflow and outflow of wetlands indicated significant differences in the presence of metals in comparison with their maximum permissible limits. Both emergent plant species showed an accumulation of heavy metals and thus the ability to recovery of water quality in wetland outflows.
["Topsoil", "Subsoil", "Soil carbon", "Chemistry", "Litter", "Agronomy", "Sanjiang Plain", "Soil organic matter", "Environmental chemistry", "Marsh", "Animal science", "Environmental science", "Soil water", "Wetland", "Ecology", "Biology", "Soil science"]
["Peatlands and Wetlands Ecology", "Soil Carbon and Nitrogen Dynamics", "Agriculture, Soil, Plant Science"]

Using Foresight to Gain a Local Perspective on the Future of Ecosystem Services in a Mountain Protected Area in Peru
Blancas
Ecosystem services in the mountainous Salinas and Aguada Blanca National Reserve in Peru are under pressure, and perspectives on possible solutions depend on the different stakeholders’ understanding of these services and their interests in them. We describe the application of the foresight approach to integrate various stakeholders’ perspectives on the future of ecosystem services in the reserve. Ultimately, the purpose of this approach is to achieve an inclusive and viable plan for conservation and management of existing resources. The participatory analysis provided local people’s perceptions of bofedal (wetland) and tolar (shrubland) ecosystem services, as well as their assessment of likely scenarios for the future. We identified 2 important factors in the hypotheses the local people provided: extreme events such as water scarcity and drought, and participation of the private sector in water distribution. Participants estimated that water storage and fuel for cooking were likely to have the strongest effects on current and future ecosystem services. Based on this, we jointly developed hypotheses using a stepwise approach and used software to calculate probabilities in a systematic way and produce a series of scenarios. The likelihood of these scenarios was also assessed by groups of stakeholders, yielding 5 scenarios for consideration in designing management plans. Future scenarios are highly dependent on proper management of the bofedal. We conclude that foresight helps to involve local people better in the process of developing viable strategies for the future of the reserve and for the conservation of the natural resources that it harbors.
["Ecosystem services", "Futures studies", "Environmental resource management", "Business", "Ecosystem", "Scenario analysis", "Environmental planning", "Environmental economics", "Environmental science", "Ecology", "Computer science", "Economics"]
["Land Use and Ecosystem Services", "Conservation, Biodiversity, and Resource Management", "Economic and Environmental Valuation"]

The influence of climate change on recent peat accumulation patterns of Distichia muscoides cushion bogs in the high-elevation tropical Andes of Colombia
Benavides
extensive cushions of Distichia muscoides found at high elevations in the Andes form deep deposits of peat and function as peatland. The location of Distichia peatlands at the highest elevations makes them susceptible to the effects of global change including global warming. Accumulation rates of organic matter are the key function of peatland ecosystems and are highly susceptible to changes in climate. This study used 210Pb chronologies to infer the recent dynamics of three Distichia muscoides peatlands located above 4000 m in elevation. Chronological markers from dated volcanic eruptions were correlated to the 210Pb chronologies of Distichia peat and validated the 210Pb chronologies. Changes in 210Pb activity with depth indicated rapid accumulation in recent times. Organic matter had a mean accumulation rate of 1400 g m_x0001_2 yr_x0001_1 during the past 10 years, with values well above the observed regional accumulation rate of 300–400 g m_x0001_2 yr_x0001_1. The same pattern was observed in peat accretion rates, with growth rates of 1–2 cm per year during the last 10 years. Cushion plants engineer their own environment, allowing the system to be less susceptible to direct changes in climate. However, the high rates of peat accretion in recent times may be originated from increasing temperatures and excess water from nearby glacier melt. However, glaciers are predicted to disappear during the next 20 years in the northern Andes, reducing water inputs in tropical high-elevation ecosystems.
["Peat", "Glacier", "Climate change", "Physical geography", "Geology", "Ecosystem", "Bog", "Global warming", "Water table", "Elevation (ballistics)", "Accretion (finance)", "Environmental science", "Organic matter", "Hydrology (agriculture)", "Ecology", "Geomorphology", "Oceanography", "Geography", "Groundwater"]
["Peatlands and Wetlands Ecology", "Geology and Paleoclimatology Research", "Coastal wetland ecosystem dynamics"]

Response curves and the environmental limits for peat-forming species in the northern Andes
Benavides
Vitt
Peatlands, with organic soils, are usually dominated by one or a few species. Above and belowground ecological processes are regulated by the characteristics of the dominant species in the peat. Understanding how these species relate to climatic or water chemistry gradients will help to predict the fate of those ecosystems under current climate change. The patterns of abundance and occurrence of 12 major peat-forming species from different structural plant groups were quantified along gradients of elevation, precipitation, and water chemistry. The species were distributed in four major structural groups: cushion plants, true mosses, sedges, and Sphagnum mosses. A response curve for each species was built with Generalized Additive Models. Niche breadths, species tolerances, and species optima were estimated using bootstrap resampling. Our results showed that species were limited in their elevational ranges; Sphagnum species were biased toward low to intermediate elevations, sedges, and true mosses to intermediate elevations and cushion plants to very high elevations. Sphagnum species were more likely to occur in sites with low precipitation, while sedges preferred wet sites. Sphagnum species preferred habitats with acidic pH. The species tolerances and optimum distributions are an indication to the vulnerability of the species to changes in their environment. Species with limited tolerances are more vulnerable, such as the narrow elevational distribution of cushion plants or the low pH and narrow tolerances observed for Sphagnum species. Climate and hydrological changes will very possibly affect the distribution of those species forcing changes on ecosystem functioning.
["Sphagnum", "Peat", "Ecology", "Ombrotrophic", "Species distribution", "Abundance (ecology)", "Ecosystem", "Indicator species", "Environmental science", "Bog", "Biology", "Habitat"]
["Peatlands and Wetlands Ecology", "Coastal wetland ecosystem dynamics", "Botany and Plant Ecology Studies"]

The effect of drainage on organic matter accumulation and plant communities of high-altitude peatlands in the Colombian tropical Andes
The tropical Andes store and regulate water outflow that serves nearly 60 million people. Most of the water is for un-managed agricultural irrigation. In this work I report how the drainage of peatlands has adversely affected the development of plant communities and recent carbon accumulation in a páramo massif at 2500 to 3800 m altitude in the northern Andes. I surveyed vegetation and water chemistry in 26 peatlands with differing intensities of drainage. Peat cores to 50 cm from two sites with contrasting drainage histories were dated using 210Pb, and used to compare historical vegetation changes and carbon accumulation rates. (A) Species composition was much affected by drainage, which resulted in a reduction in cover of Sphagnum and other peat-forming species, and the encroachment of sedges and Juncus effusus. The ability of peat to store water and carbon was also reduced in drained peatlands. Vegetation records show a shift towards sedge-Juncus communities around 50 years ago when agricultural use of water increased. (B) Peat and carbon accumulation rates were lower in drained sites, indicating either greater decomposition rates of the upper peat column or lower production by the changed plant communities. The ecological services offered by peatlands to agrarian communities downstream are important. Measures to prevent peatland destruction are needed urgently.
["Peat", "Altitude (triangle)", "Drainage", "Environmental science", "Organic matter", "Hydrology (agriculture)", "Physical geography", "Geography", "Agroforestry", "Geology", "Ecology", "Biology", "Archaeology"]

Short-Term Effects of Pack Animal Grazing Exclusion from Andean Alpine Meadows
Barros
Grazing by livestock can have positive, neutral, and/or negative effects on vegetation depending on the intensity and type of grazing. This includes grazing by pack animals used for tourism in mountain protected areas. We assessed the response of vegetation to the exclusion of grazing by pack animals over one growing season in the highest park in the Southern Hemisphere, Aconcagua Provincial Park, dry Central Andes. Twenty pairs of exclosures and unfenced quadrats were established in three high-altitude Andean alpine meadows that are intensively grazed by horses and mules used by commercial operators to transport equipment for tourists. Vegetation parameters, including height, cover, and composition were measured in late spring when exclosures were established and ~120 days later at the end of the growing season along with above-ground biomass. Data was analyzed using mixed models and ordinations. Vegetation responded rapidly to the removal of grazing. Vegetation in exclosures was more than twice as tall, had 30% more above-ground biomass, a greater cover of grasses including the dominant Deyeuxia eminens, and less litter than grazed quadrats. These changes in the vegetation from short-term exclusion of grazing are likely to increase the habitat quality of the meadows for native wildlife.
["Grazing", "Vegetation (pathology)", "Quadrat", "Exclosure", "Biomass (ecology)", "Grazing pressure", "Ecology", "Geography", "Environmental science", "Livestock", "Grassland", "Forestry", "Biology", "Shrub"]
["Wildlife Ecology and Conservation", "Ecology and Vegetation Dynamics Studies", "Rangeland and Wildlife Management"]

Evolution of High Andean Puna Ecosystems: Environment, Climate, and Culture Change over the Last 12,000 Years in the Central Andes
Baied
Wheeler
In the High Andes, much of the traditional knowledge related to natural resource utilization and agricultural practices was lost with the arrival of the Spaniards. That which has survived has been transformed, together with the landscape. Based upon ongoing research on the paleoecology and archaeology of the central High Andes, this paper presents the first results of pollen analysis from late-Pleistocene/early Holocene Laguna Seca (latitude 18'11' South, longitude 69"14'30" West) in the ChungaraCotacotani lake district of Lauca National Park. The Laguna Seca record covers two crucial events in the evolution of high Andean puna ecosystems: (1) the period preceding the earliest human occupation, and (2) the period of change from a food-gathering to a food-producing economy. The results, though preliminary, indicate the contribution that these studies can make to the management and preservation of fragile mountain ecosystems.
["Ecosystem", "Geography", "Climate change", "Physical geography", "Ecology", "Biology"]
["Environmental and Cultural Studies in Latin America and Beyond", "Archaeology and ancient environmental studies", "Pleistocene-Era Hominins and Archaeology"]

Monitoring Andean high altitude wetlands in central Chile with seasonal optical data: A comparison between Worldview-2 and Sentinel-2 imagery
Araya Lopez
In the Maipo watershed, situated in central Chile, mining activities are impacting high altitude Andean wetlands through the consumption and exploitation of water and land. As wetlands are vulnerable and particularly susceptible to changes of water supply, alterations and modifications in the hydrological regime have direct effects on their ecophysiological condition and vegetation cover. The aim of this study was to evaluate the potential of Worldview-2 and Sentinel-2 sensors to identify and map Andean wetlands through the use of the one-class classifier Bias support vector machines (BSVM), and then to estimate soil moisture content of the identified wetlands during snow-free summer using partial least square regression.
The results obtained in this research showed that the combination of remote sensing data and a small sample of ground reference measurements enables to map Andean high altitude wetlands with high accuracies. BSVM was capable to classify the meadow areas with an overall accuracy of over ∼78% for both sensors. Our results also indicate that it is feasible to map surface soil moisture with optical remote sensing data and simple regression approaches in the examined environment. Surface soil moisture estimates reached r2 values of up to 0.58, and normalized mean square errors of 19% using Sentinel-2 data, while Worldview-2 estimates resulted in non-satisfying results. The presented approach is particularly valuable for monitoring high-mountain wetland areas with limited accessibility such as in the Andes.
["Wetland", "Environmental science", "Altitude (triangle)", "Watershed", "Remote sensing", "Hydrology (agriculture)", "Vegetation (pathology)", "Land cover", "Water content", "Physical geography", "Land use", "Geography", "Ecology", "Geology"]
["Soil Moisture and Remote Sensing", "Remote Sensing in Agriculture", "Soil erosion and sediment transport"]