CAREER: Resolving multi-scale ecological consequences of thermal refuges amidst climate warming

Reed College, Portland OR

Investigators

Abstract

Most life on Earth experiences changes in environmental conditions over time and exists in environments that vary across space. One grand challenge the field of ecology seeks to address is understanding the resulting biological consequences of this variation. This project will address the significance of one important type of spatial variation in the environment, thermal refuges. Thermal refuges are locations organisms may find beneficial during periods of extreme weather in that they are not as extreme as surrounding locations, and may maintain biodiversity amidst periods of extreme heat. Using both experiments and observations in freshwater ecosystems to document how common thermal refuges are, the project will investigate how organisms use thermal refuges, and how the presence or absence of refuges can alter the composition of organisms and their traits. Additionally, this research will perform experiments to understand the conditions over which thermal refuges may allow individual organisms to persist during periods of thermal stress. The project will be conducted at a primarily-undergraduate institution, and will help inform, and be completed as part of, an undergraduate inquiry-based ecology course focused on the consequences of environmental variation. While often lauded for their capacity to promote taxonomic diversity by minimizing exposure to lethal conditions, the demographic benefits of thermal refuges are more often assumed than empirically measured, as are the population-level costs of refuge utilization, and spatial scales and domains of environmental variation over which refuges may influence ecological outcomes. This research will develop a mechanistic understanding of the role of thermal refuges for the persistence of populations amidst climate warming, as well their limitations. It aims to 1) document the extent of, utilization of, and patterns of diversity associated with, thermal refuges; 2) assess and generalize population-level costs and benefits of thermal refuges amidst thermal stress, and 3) understand how thermal refuges alter population persistence and dynamics in response to extreme temperature events. Such information is valuable for refining estimates of extinction risk as it focuses on elucidating the impact of environmental conditions at the spatially relevant scales over which population and community dynamics unfold. In particular, this research has the potential to help identify early warning indicators amidst rising mean temperatures and episodic events. The proposed activities will address the pressing societal concern regarding the fate of biodiversity amidst climate warming, and represents an important initial step in a path towards disaster mitigation by maintaining, preserving, or engineering features of thermal refuges that promote desired ecological consequences. 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.