Draper John P, Waits Lisette P, Adams Jennifer R, Seals Christopher L, Steury Todd D
School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, United States of America.
Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, United States of America.
PLoS One. 2017 Nov 8;12(11):e0186701. doi: 10.1371/journal.pone.0186701. eCollection 2017.
One of the major concerns in conservation today is the loss of genetic diversity which is a frequent consequence of population isolation and small population sizes. Fragmentation of populations and persecution of carnivores has posed a substantial threat to the persistence of free ranging carnivores in North America since the arrival of European settlers. Black bears have seen significant reductions in range size from their historic extent, which is most pronounced in the southeastern United States and even more starkly in Alabama where until recently bears were reduced to a single geographically isolated population in the Mobile River Basin. Recently a second population has naturally re-established itself in northeastern Alabama. We sought to determine size, genetic diversity and genetic connectivity for these two populations in relation to other regional populations. Both populations of black bears in Alabama had small population sizes and had moderate to low genetic diversity, but showed different levels of connectivity to surrounding populations of bears. The Mobile River Basin population had a small population size at only 86 individuals (76-124, 95% C.I.), the lowest genetic diversity of compared populations (richness = 2.33, Ho and He = 0.33), and showed near complete genetic isolation from surrounding populations across multiple tests. The newly recolonizing population in northeastern Alabama had a small but growing population doubling in 3 years (34 individuals 26-43, 95% C.I.), relatively moderate genetic diversity compared to surrounding populations (richness = 3.32, Ho = 0.53, He = 0.65), and showed a high level of genetic connectivity with surrounding populations.
当今保护工作的主要关注点之一是遗传多样性的丧失，这是种群隔离和种群规模较小经常导致的结果。自欧洲定居者抵达以来，种群碎片化和对食肉动物的迫害对北美自由放养食肉动物的存续构成了重大威胁。黑熊的活动范围与历史范围相比大幅缩小，在美国东南部最为明显，在阿拉巴马州更为突出，直到最近该州的黑熊在莫比尔河流域被缩减为一个地理上孤立的种群。最近，第二个种群在阿拉巴马州东北部自然重新建立。我们试图确定这两个种群的规模、遗传多样性以及与其他区域种群的遗传连通性。阿拉巴马州的两个黑熊种群规模都很小，遗传多样性处于中等至较低水平，但与周边熊种群的连通性程度不同。莫比尔河流域种群规模很小，仅有86只个体（76 - 124只，95%置信区间），在所比较种群中遗传多样性最低（丰富度 = 2.33，观察杂合度和期望杂合度 = 0.33），并且在多项测试中显示与周边种群几乎完全遗传隔离。阿拉巴马州东北部新重新定殖的种群规模较小但在增长，3年内数量翻倍（34只个体，26 - 43只，95%置信区间），与周边种群相比遗传多样性相对中等（丰富度 = 3.32，观察杂合度 = 0.53，期望杂合度 = 0.65），并且与周边种群显示出高度的遗传连通性。
