The cold-water climate shield: delineating refugia for preserving salmonid fishes through the 21st century.
The distribution and future fate of ectothermic organisms in a warming world will be dictated by thermalscapes across landscapes. That is particularly true for stream fishes and cold-water species like trout, salmon, and char that are already constrained to high elevations and latitudes. The extreme climates in those environments also preclude invasions by most non-native species, so identifying especially cold habitats capable of absorbing future climate change while still supporting native populations would highlight important refugia. By coupling crowd-sourced biological datasets with high-resolution stream temperature scenarios, we delineate network refugia across >250 000 stream km in the Northern Rocky Mountains for two native salmonids-bull trout (BT) and cutthroat trout (CT). Under both moderate and extreme climate change scenarios, refugia with high probabilities of trout population occupancy (>0.9) were predicted to exist (33-68 BT refugia; 917-1425 CT refugia). Most refugia are on public lands (>90%) where few currently have protected status in National Parks or Wilderness Areas (<15%). Forecasts of refuge locations could enable protection of key watersheds and provide a foundation for climate smart planning of conservation networks. Using cold water as a 'climate shield' is generalizable to other species and geographic areas because it has a strong physiological basis, relies on nationally available geospatial data, and mines existing biological datasets. Importantly, the approach creates a framework to integrate data contributed by many individuals and resource agencies, and a process that strengthens the collaborative and social networks needed to preserve many cold-water fish populations through the 21st century.
Rocky Mountain Research Station, U.S. Forest Service, 322 E. Front St. Suite 401, Boise, ID, 83702, USA.
Daniel J
DJ
Isaak
Rocky Mountain Research Station, U.S. Forest Service, 800 East Beckwith Avenue, Missoula, MT, 59801, USA.
Michael K
MK
Young
Rocky Mountain Research Station, U.S. Forest Service, 322 E. Front St. Suite 401, Boise, ID, 83702, USA.
David E
DE
Nagel
Rocky Mountain Research Station, U.S. Forest Service, 322 E. Front St. Suite 401, Boise, ID, 83702, USA.
Dona L
DL
Horan
Rocky Mountain Research Station, U.S. Forest Service, 322 E. Front St. Suite 401, Boise, ID, 83702, USA.
Matthew C
MC
Groce
bull trout; climate change; cutthroat trout; invasive species; refugia; salmonid; species distribution; stream temperature