The ABCs of Dispersal: Developing an Approximate Bayesian Computation Approach for Estimating Migration Rates from the Distribution of Related Individuals

估计种群和栖息地中个体动物的移动速率是保护生物学中的一个关键问题，对于确定高质量的栖息地和确定是否可以通过从其他种群移民来拯救下降的种群是必要的。 该项目的目标是开发一种新的统计和遗传框架，以改善对种群或栖息地之间生物扩散率的估计。 所提出的方法涉及翻译的空间分布的相关个人确定的遗传方法到估计的迁移率。 例如，如果一个亲本和它的后代出现在两个不同的种群或栖息地，那么一定发生了一个运动事件。 这种新方法将通过对生活在哥斯达黎加阴生农业生态系统中的霍夫曼二趾树懒和棕喉三趾树懒的运动和人口统计学进行研究来进行测试。 这两个物种的几百个个体将被捕获在阴凉生长的可可树，完整的森林和牛牧场;雄性将被无线电标记，雌性将被彩色标记，以估计这三种栖息地类型的出生率和死亡率。 将收集小的组织样本进行遗传分析，以提供有关相对远亲个体的信息和对移动速率的精确估计。 三种栖息地类型之间的相关性模式将被用来确定运动的幅度和方向，并最终确定这些敏感和魅力的热带哺乳动物的阴生农业的价值。 人们越来越多地指出，阴生农业是保护热带生物多样性的一种手段，但尚未就这种农业做法对敏感物种的好处进行详细的生态研究。 由于它们的定居和专性的树栖生活方式，树懒是一个有用的保护伞物种的保护工作;如果阴生农业可以保持可行的树懒种群在破碎的景观，然后农业实践可以受益于一系列其他热带物种。 该项目开发的统计和遗传方法将适用于一系列物种，并将通过免费下载的软件包提供给用户。 该项目将加强与哥斯达黎加研究人员的研究和培训合作，并将为两名博士后学者提供研究培训和指导。

Estimating rates of movements of individual animals among populations and habitats is a critical issue in conservation biology, necessary for identifying high quality habitats and determining if declining populations can be rescued by immigration from other populations. The goal of this project is to develop a novel statistical and genetic framework that would improve estimation of dispersal rates for organisms among populations or habitats. The proposed approach involves translating the spatial distribution of related individuals identified with genetic methods into estimates of migration rates. If, for example, a parent and its offspring occur in two different populations or habitats, a movement event must have occurred. This new methodology will be tested through a study of the movements and demographics of Hoffmann's two-toed sloths and brown-throated three-toed sloths living in a shade-grown agricultural ecosystem in Costa Rica. Several hundred individuals of both species will be captured in shade-grown cacao, intact forest, and cattle pastures; males will be radio-tagged and females will be color-marked in order to estimate birth and death rates in the three habitat types. Small tissue samples will be collected for genetic analyses that will provide information about relatively distantly related individuals and precise estimates of movement rates. Patterns of relatedness among the three habitat types will be used to determine the magnitude and direction of movements, and ultimately determine the value of shade-grown agriculture to these sensitive and charismatic tropical mammals. Shade-grown agriculture is increasingly pointed to as a means for protecting tropical biodiversity, but detailed ecological studies of the benefits of such agricultural practices to sensitive species have not been conducted. Because of their sedentary and obligate arboreal life style, sloths are a useful umbrella species for conservation efforts; if shade-grown agriculture can maintain viable sloth populations within fragmented landscapes then agricultural practices could benefit a range of additional tropical species. The statistical and genetic approach developed in this project will be applicable to a range of species and will be made publically accessible via a freely downloadable software package. This project will strengthen research and training collaborations with Costa Rican researchers and will provide research training and mentoring for two postdoctoral scholars.