Although ecological studies have noted streams drying in the Interior Highlands, published measurements of streambed dryness are lacking. Clearly, stream drying has the potential to affect benthic macroinvertebrate and fish communities. In 2003, we initiated an assessment of streambed dryness for three streams in the Ouachita Mountains representative of the Central Hills, Ridges, and Valleys. In the following summer, we applied the approach to 15 similar size watersheds in three distinct ecoregions of the Interior Highlands: Ouachita Mountains-Athens Plateau, Ozark Highlands-Springfield Plateau, and Lower Boston Mountains. Repeated dryness measurements were recorded in each stream and correlated to nearby USGS stream gage records. Dryness reached as high as 86% for the Ouachita Mountains in 2003; whereas, flow was continuous in 2004. One stream in the Ozark Highlands dried completely in 2004, and dryness reached 84% in the Boston Mountains. Percent dry streambed was negatively correlated (Spearman rank) to discharge for the Ouachita Mountains in 2003 and in the Boston Mountains in 2004 (rs = -0.94 and -0.60, respectively; p ≤ 0.01). Lowest monthly mean daily discharge, corrected for watershed area, differed among ecoregions for May through October in 2004 (highest discharge in the Ouachita Mountains, p ≤ 0.05, Tukey-Kramer). Maximum dryness during these months was significantly lower for the Ouachita Mountains than the Boston Mountains and Ozark Highlands. Thus, discernable patterns of stream dryness exist among the different ecoregions of the Interior Highlands. Aquatic ecologists and resource managers in these ecoregions could employ such measures to further understand habitat limitations associated with these stream systems.
Journal of the Arkansas Academy of Science
Homan, Justin M.; Girondo, Nicholas M.; and Gagen, Charles J., "Quantification and Prediction of Stream Dryness in the Interior Highlands" (2005). Faculty Publications - Biological Sciences. 5.