Collaborative Research: Evolutionary responses to environmental change at range limits: adaptation, migration, and population size at the core, margin, and trailing edge

点击翻译按钮获取中文摘要

Biologists lack a general understanding of the interaction between changes in climate and variation in abundance, connectivity, and local adaptation from the center to the edge of species' ranges. By the end of the 21st century, temperatures are predicted to rise 3-5 degrees C across much of temperate and boreal North America, causing populations of many species to face climate conditions beyond their current tolerances. Mathematical models predict that evolution in response to environmental change can depend critically on how close populations are located to the edge of their range, yet little is known empirically about how responses to environmental change vary spatially across a species' distribution, especially near range limits. This research uses an ecologically and economically important forest tree in eastern North America, red spruce (Picea rubens), to study the effects of range limits on responses to environmental change. The project addresses the overarching question: how do shifting range limits driven by environmental change affect adaptation, migration, and population size across a species' distribution? Addressing this problem advances our scientific understanding of adaptation at range limits and the processes that constrain species distributions. In addition, this work addresses a pressing applied problem of how environmental change will affect the productivity of natural and human-managed ecosystems located in marginal environments. Additional broader impacts include assessing the conservation status of southern populations of a foundation tree species in eastern coniferous forests at risk of local extinction. The results will be shared with diverse stakeholders working on forest conservation and management, and will be integrated with assessments of local population vulnerability and the design of informed mitigation efforts. Local citizens in rural communities will be engaged through public science outreach. This award will also serve to train two postdoctoral researchers, one graduate student, and numerous undergraduate researchers in evolutionary ecology, plant physiology, and environmental change science.The experimental approach of the research will leverage species distribution modeling to track historical range movements in red spruce over the last 11,000 years, and predict proximity to the shifting range limit for different locales. These predictions will then be related to the changing size, connectivity, and ecophysiology of populations experiencing environmental change by sampling fossil spruce pollen preserved in sediment and using recent advances at the interface of paleoecology and population genetics to measure plant water use efficiency, effective population size, and connectivity through time. The research will also couple the latest techniques in ecological genomics with novel spatial modeling approaches to predict how local adaptation will vary with proximity to the range limit under scenarios of projected climate warming in North America.