Trout and salmon living in coldwater habitats are naturally vulnerable to a warming climate and related impacts such as increased wildfires and floods. Trout Unlimited scientists have studied how climate changes may influence native salmonid distributions, which trout and salmon populations are most vulnerable, and how we can help them adapt to a warmer and more uncertain future.
This study drew from a large agency database to characterize environmental influences on the current patterns of cutthroat trout in the interior West and predict how the climate change may impact the distribution of this native trout. Unlike previous studies, we included information not only about increasing stream temperature, but also changing flows and interactions with non-native species. Our models predicted a mean 47 percent decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. Native cutthroat trout, already at-risk, are predicted to lose a further 58 percent of habitat while brook, brown and rainbow trout are likely to decline to varying degrees depending on their specific tolerance of warming and impacts from other trout. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of restoration and management efforts.
Predicting how climate change will impact trout requires understanding the environmental factors which influence where they they are able to live currently. We drew from a large agency database to determine the relative role of climate (temperature and flow regime), geomorphology and land use in determining the observed distributions of native cutthroat and bull trout, and non-native brook trout in the interior Columbia River Basin. While the distribution of cutthroat trout is influenced by climate it is strongly related to the presence of non-native brook trout, which might be an important factor in shaping its response to climate change in the future. Bull trout are estimated to be comparably more sensitive climate warming.
The continuing bad news about climate change can be daunting, but there are things we can do to improve the likelihood trout and salmon will be able to persist in the future. We profiled three case studies which address existing and climate-driven causes of degradation through habitat restoration. We summarized elements of successful projects and discussed solutions to common challenges in conducting climate change adaptation restoration work.