the Department of Biology, Stanford University, Stanford, CA 94305.
J Hered. 2014 May-Jun;105(3):295-302. doi: 10.1093/jhered/est086. Epub 2013 Dec 11.
Tigers (Panthera tigris), like many large carnivores, are threatened by anthropogenic impacts, primarily habitat loss and poaching. Current conservation plans for tigers focus on population expansion, with the goal of doubling census size in the next 10 years. Previous studies have shown that because the demographic decline was recent, tiger populations still retain a large amount of genetic diversity. Although maintaining this diversity is extremely important to avoid deleterious effects of inbreeding, management plans have yet to consider predictive genetic models. We used coalescent simulations based on previously sequenced mitochondrial fragments (n = 125) from 5 of 6 extant subspecies to predict the population growth needed to maintain current genetic diversity over the next 150 years. We found that the level of gene flow between populations has a large effect on the local population growth necessary to maintain genetic diversity, without which tigers may face decreases in fitness. In the absence of gene flow, we demonstrate that maintaining genetic diversity is impossible based on known demographic parameters for the species. Thus, managing for the genetic diversity of the species should be prioritized over the riskier preservation of distinct subspecies. These predictive simulations provide unique management insights, hitherto not possible using existing analytical methods.
老虎（Panthera tigris）与许多大型食肉动物一样，受到人为影响的威胁，主要是栖息地丧失和偷猎。目前老虎的保护计划侧重于种群扩张，目标是在未来 10 年内将普查规模翻一番。先前的研究表明，由于人口下降是最近的，老虎种群仍然保留了大量的遗传多样性。尽管保持这种多样性对于避免近交的有害影响极为重要，但管理计划尚未考虑预测遗传模型。我们使用基于先前从 6 个现存亚种中的 5 个测序的线粒体片段（n = 125）的合并模拟来预测未来 150 年内维持当前遗传多样性所需的种群增长。我们发现，种群之间的基因流动水平对维持遗传多样性所需的局部种群增长有很大影响，如果没有这种基因流动，老虎的适应性可能会下降。在没有基因流动的情况下，我们证明，根据该物种已知的人口参数，维持遗传多样性是不可能的。因此，管理物种的遗传多样性应该优先于保护独特亚种的风险。这些预测性模拟提供了独特的管理见解，以前使用现有的分析方法是不可能实现的。
