CEE Seminar: Climate-Vegetation Interactions in Complex Terrain

The response of ecosystems to climate change depends on how changes in atmospheric conditions influence the conditions that organisms experience on the ground, which are in turn shaped by finer-scale processes of landscape form and vegetation structure. I describe two case studies that address this interaction of atmospheric and landscape processes and what it means for the future of terrestrial ecosystems. In a regional study of ground-level microclimates in the Southern Appalachians, we use a distributed sensor network along with hierarchical modeling approaches to downscale synoptic temperatures to the below-canopy conditions that most organisms experience. Results suggest that the steep climate gradients responsible for much of the diversity of the region may lengthen as the climate warms, in ways that influence bioclimatic variables to different degrees. In a long-term climate manipulation in a limestone grassland in northern England, we use a plant functional trait approach to demonstrate how fine-scale topographic heterogeneity drives vegetation responses to drought and warming, and show that warming is likely to shift the community to more productive species even in the presence of nutrient limitation in deeper soils. Together, these studies point to a complexity in terrestrial climate responses that can be profitably addressed in a topographic context.