Closing the gap between science and management of cold-water refuges in rivers and streams
Citation:
Mejia, F., V. Ouellet, M. Briggs, S. Carlson, R. Casas-Mulet, M. Chapman, M. Collins, S. Dugdale, J. Ebersole, D. Frechette, A. Fullerton, C. Gillis, Z. Johnson, C. Kelleher, B. Kurylyk, R. Lave, B. Letcher, K. Myrvold, Tracie-Lynn Nadeau, H. Neville, H. Piegay, K. Smith, D. Tonolla, AND C. Torgerson. Closing the gap between science and management of cold-water refuges in rivers and streams. GLOBAL CHANGE BIOLOGY. Blackwell Publishing, Malden, MA, 29(19):5482-5508, (2023). https://doi.org/10.1111/gcb.16844
Impact/Purpose:
Climate change is warming the world’s rivers and streams, threatening ecologically, economically, and culturally important cold-water species such as salmon and trout. Climate change impacts on water temperature are being made even worse by human activities and water demands. But even as rivers and streams warm, small areas created by snowmelt, groundwater, or shaded tributary streams can remain cold enough to provide small, temporary refuges for fish and other species. This review, conducted by an international team of researchers, summarizes current knowledge and understanding about these cold water refuges (CWRs). This paper reviews the state of the biophysical and social sciences of CWRs, identifies gaps between scientific knowledge and management, and evaluate whether current policies protect CWRs, thermally sensitive species, and their habitats using five case studies in North America, Europe and Australia. From these summaries, the paper provides guidelines for identifying, protecting, and restoring CWRs, with a particular emphasis on conservation and management across social and geographic boundaries.
Description:
Human activities and climate change threaten coldwater organisms in freshwater ecosystems by causing rivers and streams to warm, increasing the intensity and frequency of warm temperature events, and reducing thermal heterogeneity. Cold-water refuges are discrete patches of relatively cool water that are used by coldwater organisms for thermal relief and short-term survival. Globally, cohesive management approaches are needed that consider interlinked physical, biological, and social factors of cold-water refuges. We review current understanding of cold-water refuges, identify gaps between science and management, and evaluate policies aimed at protecting thermally sensitive species. Existing policies include designating cold-water habitats, restricting fishing during warm periods, and implementing threshold temperature standards or guidelines. However, these policies are rare and uncoordinated across spatial scales and often do not consider input from Indigenous peoples. We propose that cold-water refuges be managed as distinct operational landscape units, which provide a social and ecological context that is relevant at the watershed scale. These operational landscape units provide the foundation for an integrated framework that links science and management by (1) mapping and characterizing cold-water refuges to prioritize management and conservation actions, (2) leveraging existing and new policies, (3) improving coordination across jurisdictions, and (4) implementing adaptive management practices across scales. Our findings show that while there are many opportunities for scientific advancement, the current state of the sciences is sufficient to inform policy and management. Our proposed framework provides a path forward for managing and protecting cold-water refuges using existing and new policies to protect coldwater organisms in the face of global change.
URLs/Downloads:
DOI: Closing the gap between science and management of cold-water refuges in rivers and streams