Due to the rate and magnitude of environmental change decision makers need systematic vulnerability assessments of many taxa, including many freshwater species that rank among the most threatened taxa globally. Rarity and traits-based identification of vulnerable taxa provide useful metrics for multispecies analysis of sensitivity to climate change; our objective was to conduct a combined geographic rarity and traits-based approach to systematically evaluate the climate sensitivity of a wide range of freshwater fishes with variable data availability across a large geographic area (the U.S.). We evaluated climate sensitivity of 128 fishes using geographic range size, climate niche breadth, and life histories. Fish species were selected to represent the breadth of phylogeographic regions, geographic range sizes, traits, and level of understanding (e.g., available data; conservation status) exhibited by native U.S. freshwater fishes. Geographic rarity was evaluated by quantifying area-of-occupancy at multiple spatial scales using point-occurrence data from the Global Biodiversity Information Facility (GBIF, www.gbif.org). We estimated species’ climate niche breadth across the range of variability, seasonality, and magnitude of key climate factors experienced by each species. Species life history and ecological traits were evaluated using the FishBase traits database to analyze key traits associated with sensitivity.
Results/Conclusions
Overall, our results support the utility of point-occurrence data, even when opportunistically collected, in providing a more comprehensive and detailed understanding of species climate change sensitivity than metrics based on coarse-grain (e.g., whole range map) approaches alone. For instance, our work included data from across 48 different institutions via GBIF. The major strengths of this approach are twofold: first, species that may have highly variable data availability, from heavily studied to poorly understood, are placed on a similar scale for evaluation. The ability to quickly evaluate multiple species is a critically important factor for resource-limited managers charged with the protection of many species. Second, despite a predictable correlation between area-of-occupancy and climate niche breadth, climate niche breadth varied significantly among species with similar range sizes and across functional groups supporting the use of a multifaceted approach in understanding sensitivity. Moreover, point occurrence data allow more precise range size estimates compared to those estimated using coarser metrics (e.g., minimum convex polygons) that often incorporate large areas of unoccupied habitat, and thus bias estimates. Here we demonstrate that when species are considered relative to one another, GBIF data offers a reliable metric of area of occupancy of freshwater species in the US.