Landscape-scale Influences on Stream Fish Assemblages in Eastern Oklahoma
Abstract
Ecoregions are commonly used as a starting point for regional management planning and conservation applications. The objective of this study was to relate watershed characteristics to stream fish assemblages among aquatic ecoregions and stream types in eastern Oklahoma. We compiled fish collection data from three studies in eastern Oklahoma, and filled data gaps by seining streams that were not represented in these collections. Watershed and stream characteristics were compiled and summarized using a GIS. Differences in stream and watershed characteristics and fish assemblage parameters among ecoregions were analyzed with analysis of variance and least significant difference multiple comparison test. Multivariate techniques were used to identify stream groups and relationships between species assemblages and watershed characteristics. The Ouachita Mountains had the highest mean annual precipitation and was dominated by forest. Shale dominated, they also had the greatest topographic relief and valley slopes. The Arkansas Valley and Central Irregular Plains were predominantly low relief, low slope sandstone basins dominated by prairie and agriculture. Limestone was dominant in the Ozark Highlands with the Boston Mountains containing limestone and shale. These ecoregions also had high topographic relief, woodlands and prairie. We identified four clusters: Ozark streams, plains streams, Ouachita streams, and low gradient streams. Only the Ouachita group coincided with aquatic ecoregional boundaries. This group organized along gradients of geology and land use. The Ozark streams, low gradient streams and plains streams, however, grouped together regardless of the ecoregion in which they occurred. Ecoregions, while having some relationship to stream fish assemblage structure, may serve as the best template for regional fish management. To adequately capture fish assemblage patterns and issues, one must delineate management regions specific to streams, with a clear understanding of landscape patterns, stream channel conditions, habitat features.
Collections
- OSU Theses [15752]