Historical Changes in Nebraska's Lotic Fish Assemblages: A Spatiotemporal Assessment

Title:  Historical changes in Nebraska’s lotic fish assemblages: a spatiotemporal assessment

Presenter:  Christopher D. Smith

Abstract:

Nebraska has undergone numerous anthropogenic alterations and land use changes since European settlement.  Correspondingly, fish assemblages in small streams have likely experienced changes in structure in response to these alterations.  Shifts in Nebraska’s lotic fish assemblages were examined with a comparison of site-specific, presence-absence data from historic (1939-1940) and contemporary surveys (2003-2005; N = 183).  Our research indicated some species have increased (e.g., shorthead redhorse Moxostoma macrolepidotum, bluegill Lepomis macrochirus), while others have decreased (e.g., plains topminnow Fundulus sciadicus, orangespotted sunfish Lepomis humilis) in overall proportion of occurrences from historic to contemporary surveys.  Additionally, it appears piscivore richness, number of introduced species, and sport fish richness have increased from historic to current times.  A permutational multivariate analysis of variance of taxonomic and functional metrics indicated a shift in assemblage structure had occurred from historic to contemporary surveys.  Overall, species richness in Nebraska’s lotic assemblages has not dramatically shifted over the last 65 years; however, some ecoregions have undergone changes in assemblage structure and species-specific temporal trends are apparent. 

Student presenter:  Yes

Best student presentation: Yes