Data from: Anticipated climate warming effects on bull trout habitats and populations across the interior Columbia River basin

A warming climate could profoundly affect the distribution and abundance
of many fishes. Bull trout Salvelinus confluentus may be especially
vulnerable to climate change given that spawning and early rearing are
constrained by cold water temperatures creating a patchwork of natal
headwater habitats across river networks. Because the size and
connectivity of patches also appear to influence the persistence of local
populations, climate warming could lead to increasing fragmentation of
remaining habitats and accelerated decline of this species. We modeled the
relationships between (1) the lower elevation limits of small bull trout
and mean annual air temperature and (2) latitude and longitude across the
species’ potential range within the interior Columbia River basin of the
USA. We used our results to explore the implications of the climate
warming expected in the next 50 or more years. We found a strong
association between the lower elevation limits of bull trout distributions
and longitude and latitude; this association was consistent with the
patterns in mean annual air temperature. We concluded that climate does
strongly influence regional and local bull trout distributions, and we
estimated bull trout habitat response to a range of predicted climate
warming effects. Warming over the range predicted could result in losses
of 18–92% of thermally suitable natal habitat area and 27–99% of large
(.10,000-ha) habitat patches, which suggests that population impacts may
be disproportionate to the simple loss of habitat area. The predicted
changes were not uniform across the species’ range, and some populations
appear to face higher risks than others. These results could provide a
foundation for regional prioritization in conservation management,
although more detailed models are needed to prioritize actions at local
scales.