Trends and drivers of prairie stream fish community persistence: implications for climate refugia
Identifying the characteristics of climate refugia for multiple species is becoming increasingly urgent. We used repeated, fish community surveys in streams of the northern Great Plains, USA to characterize occupancy change between historical and contemporary surveys. We then identified variables correlated with community change. Across all sites, average community turnover was 56%, native species persistence was 60%, and contemporary surveys consisted of 37% colonizing species (native or introduced). Community turnover was driven about equally by species loss and colonization. Individual species showed highly variable trends in occupancy with native plains minnow (Hybognathus placitus), northern redbelly dace (Chrosomus eos), longnose sucker (Catostomus catostomus), and flathead chub (Platygobio gracilis), declining substantially, and introduced smallmouth bass (Micropterus dolomieu) and native channel catfish (Ictalurus punctatus) increased considerably. While factors associated with individual species persistence and colonization varied, warm temperatures and agriculture were most associated with community change. Importantly, cool water temperatures appear to buffer fish communities from turnover at sites moderately impacted by agriculture. Protection of cool-water refugia will thus be critical for persistence of fishes in agricultural regions.