Population and landscape genetic analysis of the Malayan sun bear Helarctos malayanus

Conservation genetics can provide data needed by conservation practitioners for their decisions regarding the management of vulnerable or endangered species, such as the sun bear Helarctos malayanus. Throughout its range, the sun bear is threatened by loss and fragmentation of its habitat and the illegal trade of both live bears and bear parts. Sharply declining population numbers and population sizes, and a lack of natural dispersal between populations all threaten the genetic diversity of the remaining populations of this species. In this first population genetics study of sun bears using microsatellite markers, we analyzed 68 sun bear samples from Cambodia to investigate population structure and genetic diversity. We found evidence for two genetically distinct populations in the West and East of Cambodia. Ongoing or recent gene flow between these populations does not appear sufficient to alleviate loss of diversity in these populations, one of which (West Cambodia) is characterized by significant inbreeding. We were able to assign 85% of sun bears of unknown origin to one of the two populations with high confidence (assignment probability ≥ 85%), providing valuable information for the release of bears. Further, our results suggest that developed land (mostly agricultural mosaics) acts as a barrier to gene flow for sun bears in Cambodia. We highlight that regional sun bear conservation action plans should consider promoting population connectivity and enforcing wildlife protection of this threatened species.

保护遗传学（Conservation genetics）可为保护从业者针对易危或濒危物种（如马来熊（Helarctos malayanus））的管理决策提供所需数据。在其整个分布范围内，马来熊均面临栖息地丧失与破碎化，以及活体熊只和熊制品非法贸易的双重威胁。种群数量与种群规模急剧下降、种群间缺乏自然扩散途径，均对该物种现存种群的遗传多样性构成严重威胁。本研究为首次利用微卫星标记（microsatellite markers）开展的马来熊种群遗传学研究，我们对采自柬埔寨的68份马来熊样本进行了分析，以探究其种群结构与遗传多样性水平。研究结果显示，柬埔寨境内存在两个遗传分化显著的种群，分别分布于柬埔寨西部与东部。目前或近期发生的种群间基因流（gene flow）似乎不足以缓解这两个种群的遗传多样性丧失问题；其中柬埔寨西部种群还表现出显著的近交特征。我们可将85%来源未知的马来熊样本以高置信度（归属概率≥85%）准确归属至上述两个种群之一，这为马来熊的放归工作提供了极具价值的参考信息。此外，研究结果表明，开发用地（多为农业镶嵌景观）对柬埔寨境内马来熊的基因流构成了显著屏障。我们呼吁区域马来熊保护行动计划应充分考虑促进种群间的连通性，并强化针对这一受胁物种的野生动物保护执法工作。

搜集汇总

背景与挑战

背景概述

该数据集提供了对马来太阳熊（Helarctos malayanus）的种群和景观遗传分析，基于来自柬埔寨的68个样本的微卫星标记数据。研究发现柬埔寨存在两个遗传上不同的太阳熊种群（西部和东部），其中西部种群表现出显著的近亲繁殖，并指出开发土地（如农业马赛克）阻碍了基因流动。这些结果为太阳熊的保护管理提供了关键信息，强调了促进种群连通性和加强野生动物保护的重要性。