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SFS Annual Meeting

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PRECIPITATION RESTRICTS FISH AND MACROINVERTEBRATE ASSEMBLAGES

Mean annual precipitation is expected to change in regions across the globe throughout the next century. In the American Southwest, conditions are expected to become more arid. Using a space-for-time approach, we predict fish composition shifts in responses to altered precipitation regimes based on existing patterns in streams spanning sub-humid to semi-arid climates along the Texas Coastal Prairie. In the Fall of 2016, we conducted surveys of 5 USGS gauged, wadeable streams spanning the central precipitation gradient; we measured stream metabolism, nutrients, water chemistry, habitat characteristics, benthic invertebrates, and fish community composition data. These sites plus 8 additional gauged streams were re-surveyed in Spring of 2017. The data were analyzed for existing correlations between environmental factors and the biodiversity and composition of fish and macroinvertebrate communities. Precipitation-mediated effects, flow regime, evapotranspiration, and land-usage were significantly correlated with fish and macroinvertebrate community structure. The compositional changes of fish and invertebrate communities along the gradient occur non-linearly, suggesting a climate threshold for these communities. The results indicate that small future changes in precipitation regime in this region may result in abrupt conversion to new community states.

Fernando Carvallo (Co-Presenter/Co-Author), Texas A&M University–Corpus Christi, fcarvallo@islander.tamucc.edu ;


Christopher Patrick (Co-Presenter/Co-Author), Texas A&M University–Corpus Ch, christopher.patrick@tamucc.edu;


Sean Kinard (Primary Presenter/Author), Texas A&M University–Corpus Christi, s2kinard@gmail.com;