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Effects of land use on summer thermal regimes in critical salmonid habitats of the Pacific Northwest

July 16, 2018

The effect of climate change on stream temperature regimes is of significant concern to natural resource managers focused on protecting cold-water-dependent species. Nevertheless, understanding of how human land-use activities may act to exacerbate the effects of climate change on stream temperature regimes is limited. Using extensive stream temperature data with high-resolution climate and habitat data, we quantified how land management activities are related to summer stream temperatures across the Pacific Northwest, USA. We then described the distribution of land management practices influencing summer thermal regimes relative to the distribution of salmonid fish species of conservation concern. After accounting for climatic and geophysical variation, we detected a strong relationship between livestock grazing and summer thermal regimes. Maximum, average, and diel variation in water temperature was greater where livestock grazing was present. Livestock grazing was widespread, occurring in 43%–100% of sites supporting salmonid species of conservation concern. Thus, current land management practices may be intensifying the effects of ongoing climate change in freshwater habitats, acting to further threaten cold-water fishes of conservation concern.

Publication Year 2018
Title Effects of land use on summer thermal regimes in critical salmonid habitats of the Pacific Northwest
DOI 10.1139/cjfas-2018-0165
Authors Ryan Kovach, Clint C. Muhlfeld, Robert Al-Chokhachy, Jeffrey V. Ojala, Eric Archer
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Journal of Fisheries and Aquatic Sciences
Index ID 70210222
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center