Evaluating the conservation effectiveness of Ammopiptanthus nanus (Fabaceae) under different ex situ strategies through multi-molecular marker analysis
Ammopiptanthus nanus (Fabaceae), a nationally protected endangered evergreen shrub endemic to Central Asian deserts, is severely threatened by habitat fragmentation. To conserve its genetic resources, multiple ex situ populations have been established across China. We evaluated conservation efficacy under distinct management strategies across four ex situ populations (n = 114), including a near-site protected area (J), a Forestry and Grassland Administration–managed zone (L), Tazhong Botanical Garden (T), and the Forestry Academy of Sciences (K), using integrated molecular markers: expressed sequence tag–simple sequence repeats (EST-SSRs), chloroplast DNA fragments (psbA–trnH, trnL–trnF, trnS–trnG), and nuclear ribosomal ITS (ITS1/ITS4) sequences. The results reveal significant strategy-dependent divergence in genetic conservation efficiency, primarily driven by founder genetic composition and reproductive management protocols. Strategy (J) retained moderate chloroplast diversity but exhibited reduced nuclear diversity and high inbreeding. Strategy (L) maintained moderate nuclear diversity yet limited chloroplast variation. Strategy (T) showed the highest nuclear diversity but minimal maternal lineage preservation. Strategy (K) preserved unique maternal haplotypes and phylogenetic distinctiveness despite constrained nuclear diversity. Critically, all populations displayed high inbreeding coefficients (F > 0.404), indicating genetic bottlenecks and restricted gene flow. To ensure long-term viability, we recommend: (1) diversifying genetic foundations through the introduction of founders from multiple wild sources and expansion of population sizes to mitigate drift; (2) enhancing gene flow via periodic interpopulation transplants and facilitated distant cross-pollination, integrated with long-term monitoring of nuclear and cytoplasmic diversity.
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