Changes in Prairie Stream Fish Assemblages Restricted to Isolated Streambed Pools

Abstract

Abstract We examined fish assemblages in isolated streambed pools in an intermittent portion of the Brazos River drainage in Texas to determine whether communities were structured in a predictable fashion by changing environmental conditions. Specific conductance, pool volume, and turbidity were significant predictors of species presence in isolated pools. The presence of the Red River pupfish Cyprinodon rubrofluviatilis increased with specific conductance and decreased with turbidity. The presence of the western mosquitofish Gambusia affinis, red shiner Cyprinella lutrensis, plains minnow Hybognathus placitus, smalleye shiner Notropis buccula, and sharpnose shiner N. oxyrhynchus decreased as specific conductance increased and as volume and turbidity decreased. Pools sampled through time showed progressive, predictable changes in environmental conditions. As pools evaporated, specific conductance increased and volume and turbidity decreased. Decreases in cyprinid presence and abundance occurred concurrent...