CRB: Population Viability of Tropical Forest Vertebrates

热带森林栖息地的破坏和破碎化是对地球生物多样性的最大威胁。遗传和人口因素在破碎生境斑块中小种群灭绝中的作用在理论上得到了理解，但缺乏经验文献。为了检验现有的理论和改进生物多样性保护技术，研究人员将开发一种新的方法来监测最近分散的种群的种群生存能力。具体来说，他们将在隔离后的头六年里，对不同大小的小雨林斑块上的老鼠、树鼩和其他小型哺乳动物种群进行种群活力分析。1987年，当Chiew Larn水库的建立淹没了泰国Khlong Saeng野生动物保护区的一个森林山谷，并创造了165个岛屿时，这些栖息地都被隔离了。将通过季节性活捕来监测选定种群的人口变化，以及遗传变异、近亲繁殖和基因流动的水平。这项研究的新颖之处在于，将在DNA序列水平上监测遗传变化，并从拔下的头发中非侵入性地获得DNA。这项研究将在许多方面有助于我们对进化生物学和生态学的基本理解。它将提供在几个自由放养的哺乳动物物种的一些核和线粒体基因变异的第一个序列水平的数据。它还将提供在隔离后关键的头20代监测种群生存能力的遗传和生态方面的首批案例之一。此外，这项研究有望在三个重要方面为保护生物学做出贡献。首先，基于头发DNA非侵入性采样的遗传监测技术的发展将具有广泛的适用性。第二，可以监测普通小型哺乳动物种群生存能力的证明，应该导致对更稀有和更濒危物种的管理措施的改进。最后，从泰国森林碎片研究中获得的经验教训应该适用于热带其他地区的生物多样性保护。

Habitat destruction and fragmentation in tropical forests are the single largest threat to the planet's biodiversity. The roles of genetic and demographic factors in the extinction of small populations in fragmented habitat patches are understood in theory but poorly documented empirically. To test existing theory and to improve techniques of biodiversity conservation, the investigators will develop a new method of monitoring population viability in recently fragmented populations. Specifically, they will conduct population viability analyses of rat, tree shrew, and other small mammal populations in small rainforest patches of different sizes during the first six years following isolation. These habitat patches were all isolated in 1987 when the creation of the Chiew Larn reservoir flooded a forested valley in the Khlong Saeng Wildlife Sanctuary, Thailand, and created 165 islands. Demographic changes in selected populations will be monitored by seasonal live-trapping as will levels of genetic variation, inbreeding and gene flow. The study is novel in that the genetic changes will be monitored at the DNA sequence level with DNA obtained non-invasively from plucked hair. This study will contribute to our basic understanding of evolutionary biology and ecology in a number of ways. It will provide among the first sequence-level data on variation in a number of nuclear and mitochondrial genes in several free- ranging mammal species. It will also provide one of the first cases where both genetic and ecological aspects of population viability are monitored in the critical first 20 generations following insularization. In addition, the study promises to contribute to conservation biology in three significant ways. First, the development of the genetic monitoring technique based on non-invasive sampling of DNA from hair will have wide applicability. Second, the demonstration that population viability can be monitored in common small mammals should lead to improved management practices for rarer and more endangered species. Finally, the lessons learned from this study in Thai forest fragments should be applicable to biodiversity conservation elsewhere in the tropics.