Fish assemblage shifts in an Ozark river over 80 years amidst a mosaic of forest regeneration and persistent pasture

Abstract

AbstractFish assemblages are useful in evaluating the health of aquatic ecosystems. Over time, fish assemblages will respond to anthropogenic disturbances but may also simultaneously respond to conservation efforts in a watershed, shifting the taxonomic and functional structure of the assemblage. We quantified temporal changes in taxonomic and functional structure of fish assemblages in the Current River, Missouri, over an 80‐year time span and related these changes to forest regeneration and persistent pasture land use within the watershed. We found shifts in taxonomic and functional assemblage structure in two time‐steps from the 1940s to 2020 related to land use within the watershed. Reforested reaches exhibited increases in benthic species, rheophilic species and invertivorous feeding guilds. Higher pasture reaches exhibited decreases in benthic species and native centrarchid species while generalist centrarchid species increased. Ultimately, fish assemblage structure in the Current River appears to be shifting to an alternative state (i.e. increased presence/abundance of benthic species) in response to forest regeneration and persistent pasture land use.