Individual fitness, directional dispersal, and the dynamics of trailing-edge populations

生物多样性保护是21世纪的重大挑战之一，保护工作取决于环境变化如何影响野生动物的信息。对于许多物种来说，尚不清楚种群数量的下降是由于繁殖和生存减少，还是由于个体为了寻找更好的环境条件而迁移，当地种群发生了变化。繁殖和生存的减少将对遗传多样性产生负面影响，并增加灭绝风险，而向首选栖息地迁移可以使物种避免环境变化的负面影响。这项研究将开发一个新的框架，利用实地研究的数据来确定繁殖、生存和运动对物种分布变化的贡献。新的框架将应用于在阿巴拉契亚山脉南部收集的鸟类种群的长期数据，那里有许多物种仅限于高海拔地区，对最近的温度和降水变化很敏感。研究结果将提高人们对种群动态和灭绝风险的认识，同时提高社会对需要保护的物种和地区的优先排序能力。在自然种群中量化适合度是非常困难的，因为由于环境的空间差异和异质表型特征，个体之间的存活率和繁殖率会有很大差异。对于动物来说，由于个体在复杂的环境中移动，依赖于位置的生存和繁殖率会随着时间的推移不断变化，因此问题变得更加复杂。该项目将发展所需的理论和方法，以理解空间、时间和个体水平上的适应性异质性，即使在人口统计数据不完整且易受观察误差影响的情况下。新的框架将用于确定在其地理范围的南部边缘的鸟类种群是否会因气候变化而经历适应性降低，或者种群是否可以通过向凉爽气候的定向分散来保持适应性。标记-再捕获数据、计数数据和巢监测数据将提供在明显的海拔驱动的气候梯度下繁殖、生存和物种分布的时空变化信息。有关环境变化对散布距离和方向性的影响的信息将使用新的跟踪技术收集，这些技术可以为小型鸣禽提供精确的位置信息。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Biodiversity conservation is one of the great challenges of the 21st century, and conservation efforts depend on information about how environmental change will impact wildlife. For many species, it is unclear whether population declines are the result of reduced reproduction and survival, or if local populations are shifting as individuals move in search of better environmental conditions. Reduced reproduction and survival would negatively affect genetic diversity and increase extinction risk, whereas movement towards preferred habitat could allow species to avoid negative impacts of environmental change. This research will develop a new framework for using data from field studies to determine the contributions of reproduction, survival, and movement to changes in species distributions. The new framework will be applied to long-term data collected on bird populations in the southern Appalachian Mountains where numerous species are restricted to high elevations and are sensitive to recent changes in temperature and precipitation. Results will advance knowledge about population dynamics and extinction risk while enhancing society's ability to prioritize species and regions in need of conservation.Quantifying fitness in natural populations is notoriously difficult because survival and reproductive rates can vary greatly among individuals as a result of spatial variation in the environment and heterogeneous phenotypic traits. For animals, the problem is complicated by location-dependent survival and reproductive rates that can change continuously in time as individuals move through complex landscapes. This project will develop theory and methods needed to understand spatial, temporal, and individual-level heterogeneity in fitness of mobile organisms, even when demographic data are incomplete and subject to observation error. The new framework will be used to determine if trailing-edge populations of birds at the southern edge of their geographic range will experience fitness reductions in response to climate change, or if populations can preserve fitness via directional dispersal towards cooler climates. Mark-recapture data, count data, and nest monitoring data will provide information about spatio-temporal variation in reproduction, survival, and species distribution over a pronounced elevation-driven climate gradient. Information about the effects of environmental change on dispersal distance and directionality will be collected using novel tracking technologies that yield precise location information for small songbirds.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.