Baas Pauline, van der Valk Tom, Vigilant Linda, Ngobobo Urbain, Binyinyi Escobar, Nishuli Radar, Caillaud Damien, Guschanski Katerina
Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
Primatology Department, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, Germany.
Am J Phys Anthropol. 2018 Mar;165(3):565-575. doi: 10.1002/ajpa.23393. Epub 2018 Jan 4.
The critically endangered Grauer's gorilla (Gorilla beringei graueri) has experienced an estimated 77% population decline within a single generation. Although crucial for informed conservation decisions, there is no clear understanding about population structure and distribution of genetic diversity across the species' highly fragmented range. We fill this gap by studying several core and peripheral Grauer's gorilla populations throughout their distribution range.
We generated genetic profiles for a sampling of an unstudied population of Grauer's gorillas from within the species' core range at 13 autosomal microsatellite loci and combined them with previously published and newly generated data from four other Grauer's gorilla populations, two mountain gorilla populations, and one western lowland gorilla population.
In agreement with previous studies, the genetic diversity of Grauer's gorillas is intermediate, falling between western lowland and mountain gorillas. Among Grauer's gorilla populations, we observe lower genetic diversity and high differentiation in peripheral compared with central populations, indicating a strong effect of genetic drift and limited gene flow among small, isolated forest fragments.
Although genetically less diverse, peripheral populations are frequently essential for the long-term persistence of a species and migration between peripheral and core populations may significantly enrich the overall species genetic diversity. Thus, in addition to central Grauer's gorilla populations from the core of the distribution range that clearly deserve conservation attention, we argue that conservation strategies aiming to ensure long-term species viability should include preserving peripheral populations and enhancing habitat connectivity.
极度濒危的东部大猩猩指名亚种（Gorilla beringei graueri）在短短一代时间内估计种群数量下降了77%。虽然这对于做出明智的保护决策至关重要，但对于该物种高度破碎化分布范围内的种群结构和遗传多样性分布，目前尚无清晰的认识。我们通过研究分布范围内的几个东部大猩猩指名亚种的核心和边缘种群来填补这一空白。
我们在13个常染色体微卫星位点上，对该物种核心分布范围内一个此前未被研究的东部大猩猩指名亚种种群进行抽样，生成了遗传图谱，并将其与之前发表的以及新生成的来自其他四个东部大猩猩指名亚种种群、两个山地大猩猩种群和一个西部低地大猩猩种群的数据相结合。
与之前的研究一致，东部大猩猩指名亚种的遗传多样性处于中等水平，介于西部低地大猩猩和山地大猩猩之间。在东部大猩猩指名亚种的各个种群中，我们观察到边缘种群的遗传多样性低于核心种群，且分化程度较高，这表明遗传漂变效应强烈，且在小而孤立的森林片段之间基因流动有限。
尽管边缘种群的遗传多样性较低，但它们对于一个物种的长期存续往往至关重要，边缘种群与核心种群之间的迁移可能会显著丰富整个物种的遗传多样性。因此，除了分布范围核心区域的东部大猩猩指名亚种核心种群显然值得保护关注外，我们认为旨在确保物种长期生存能力的保护策略应包括保护边缘种群并增强栖息地的连通性。
