Ozark Highland Fish Community Response to Hydrological Disturbance and Stream Discharge

During the summer of 2012, fifteen moderately stable, groundwater streams were sampled in the Ozark Highlands of Arkansas, Missouri, and Oklahoma to evaluate relations of hydrologic disturbance and stream discharge to species diversity, richness, and reproductive guild composition. Backpack electrofishing was used to collect fish within 2 km of stream gauges. Watershed size ranged from 21 to 617 km². Falcone’s landscape hydrological disturbance averaged 16 and ranged from 6 to 29 (0 = no disturbance and 30 = maximum disturbance). Species richness averaged 15 and ranged from 10 to 22. Shannon diversity, Simpson diversity, and evenness ranged from 0.81 to 2.1, 1.54 to 6.4, and 0.33 to 0.81, respectively. Species were represented by 7 reproductive guilds. Guarding nest spawning lithophils was the most common reproductive guild (39.8%) followed by non-guarding open substrate lithophils (26.3%) and guarding nest spawning speleophils (24.8%). Simpson’s diversity index, percent intolerant species, and percent substratum choosing lithophils were negatively correlated to Falcone’s disturbance index. Percent tolerant species and percent Cyprinidae species were positively correlated to the disturbance index. Percent Percidae species was negatively correlated to discharge variation during high discharge months. Percent substrate choosing lithophils was negatively correlated to high discharge variation during low discharge months.