Fish Community and Habitat Relationships in the Buffalo National River and Ozark National Scenic Riverways

The National Park Service (NPS) established the Inventory and Monitoring Networks to provide information on ecosystem health and processes to better manage their natural resources.  In 2005, the Heartland Network initiated a long-term fish monitoring program at two parks located in the Ozark Plateaus: Buffalo National River, Arkansas (BUFF), and Ozark National Scenic Riverways, Missouri (OZAR).  Data on fish communities, water quality, and physical habitat were collected annually at six sites on the Buffalo River at BUFF, and nine sites at OZAR (six on the Current River and three on the Jacks Fork).  Nonmetric multidimensional scaling (NMS) was used to determine clustering of sample sites based on individual species abundances (catch). At BUFF, we found the upstream-most sample site differed distinctly in species abundance relationships from the remaining five sites.  This upstream site is located in a different physiographic region (Boston Mountains), resulting in lower conductivity and larger substrate sizes. Species abundance relationships in the remaining five sites at BUFF tended to cluster based on year sampled rather than location in the watershed.  When physical habitat and water quality variables were overlaid on a three dimensional NMS ordination, we found that angle of the bank, water temperature, percent of tree cover along the banks, and canopy cover had the highest correlations with the ordination axes.  At OZAR, species abundance relationships at sample sites clustered by location in the watershed with the downstream Current River sites clustering separately from the upper Current River sites and Jacks Fork sites. Overlaying the habitat variables on a two dimensional NMS ordination indicated discharge, river mile, percent moss, percent large woody debris, and dissolved oxygen had the highest correlations with the ordination axes.  Although both rivers are located in the Ozark Plateaus, this data suggests that different water quality and habitat parameters are influencing fish community composition. Data from this long-term monitoring program will assist resource managers in better assessing factors affecting fish assemblages within their parks and indicate problem areas where habitat restoration or conservation may be necessary.