Qiao Maiju, Connor Thomas, Shi Xiaogang, Huang Jie, Huang Yan, Zhang Hemin, Ran Jianghong
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences Sichuan University Chengdu China.
China Conservation and Research Center for the Giant Panda Dujiangyan China.
Ecol Evol. 2019 Jan 28;9(4):1809-1819. doi: 10.1002/ece3.4869. eCollection 2019 Feb.
The giant panda is an example of a species that has faced extensive historical habitat fragmentation, and anthropogenic disturbance and is assumed to be isolated in numerous subpopulations with limited gene flow between them. To investigate the population size, health, and connectivity of pandas in a key habitat area, we noninvasively collected a total of 539 fresh wild giant panda fecal samples for DNA extraction within Wolong Nature Reserve, Sichuan, China. Seven validated tetra-microsatellite markers were used to analyze each sample, and a total of 142 unique genotypes were identified. Nonspatial and spatial capture-recapture models estimated the population size of the reserve at 164 and 137 individuals (95% confidence intervals 153-175 and 115-163), respectively. Relatively high levels of genetic variation and low levels of inbreeding were estimated, indicating adequate genetic diversity. Surprisingly, no significant genetic boundaries were found within the population despite the national road G350 that bisects the reserve, which is also bordered with patches of development and agricultural land. We attribute this to high rates of migration, with four giant panda road-crossing events confirmed within a year based on repeated captures of individuals. This likely means that giant panda populations within mountain ranges are better connected than previously thought. Increased development and tourism traffic in the area and throughout the current panda distribution pose a threat of increasing population isolation, however. Maintaining and restoring adequate habitat corridors for dispersal is thus a vital step for preserving the levels of gene flow seen in our analysis and the continued conservation of the giant panda meta-population in both Wolong and throughout their current range.
大熊猫是一个面临广泛历史栖息地破碎化和人为干扰的物种的例子，被认为隔离在众多亚种群中，它们之间的基因流动有限。为了调查关键栖息地内大熊猫的种群规模、健康状况和连通性，我们在中国四川卧龙自然保护区内非侵入性地收集了总共539份新鲜的野生大熊猫粪便样本用于DNA提取。使用七个经过验证的四微卫星标记分析每个样本，共鉴定出142个独特的基因型。非空间和空间捕获 - 重捕模型估计该保护区的种群规模分别为164只和137只个体（95%置信区间为153 - 175和115 - 163）。估计遗传变异水平相对较高，近亲繁殖水平较低，表明有足够的遗传多样性。令人惊讶的是，尽管国道G350将保护区一分为二，且周边还有开发区域和农田斑块，但在该种群内未发现明显的遗传边界。我们将此归因于高迁移率，基于对个体的重复捕获，一年内确认了四起大熊猫穿越道路的事件。这可能意味着山脉中的大熊猫种群之间的连通性比之前认为的更好。然而，该地区以及当前整个大熊猫分布区域内不断增加的开发和旅游交通对种群隔离加剧构成了威胁。因此，维护和恢复足够的扩散栖息地走廊是保持我们分析中所见的基因流动水平以及持续保护卧龙及整个当前分布范围内大熊猫复合种群的关键一步。
