Data from: Genetic and population monitoring of two small black bear (Ursus americanus) populations in Alabama, within a regional context.

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.

当前野生动物保护领域的核心关切之一，便是遗传多样性丧失——种群隔离与种群规模过小是引发该现象的常见诱因。自欧洲殖民者登陆北美大陆以来，种群碎片化与食肉动物遭人为猎杀，已对北美野外自由栖息的食肉动物的存续构成严重威胁。美洲黑熊的分布范围较其历史分布区已出现显著缩减，这一现象在美国东南部尤为突出，而阿拉巴马州的情况更为严峻：直至近年，当地黑熊种群已缩减至仅存的、地理隔离的莫比尔河盆地种群。近期，阿拉巴马州东北部又自然重建了第二个黑熊种群。本研究旨在明确上述两个阿拉巴马州黑熊种群的种群规模、遗传多样性与遗传连通性，并将其与其他区域黑熊种群开展对比分析。

阿拉巴马州的两个黑熊种群均为小型种群，遗传多样性处于中等至较低水平，但与周边黑熊种群的遗传连通性水平存在显著差异。莫比尔河盆地种群规模经估计仅为86只个体（95%置信区间：76-124），是所有对比种群中遗传多样性最低的种群（等位基因丰富度（richness）=2.33，观测杂合度（Ho）与期望杂合度（He）=0.33），且经多重检验证实，该种群与周边种群几乎完全遗传隔离。阿拉巴马州东北部的新重建种群规模较小但呈增长态势，三年内种群数量翻倍，经估计当前种群数量为34只个体（95%置信区间：26-43）；与周边种群相比，其遗传多样性处于中等水平（等位基因丰富度（richness）=3.32，观测杂合度（Ho）=0.53，期望杂合度（He）=0.65），且与周边种群展现出极高的遗传连通性。