Benthic Macroinvertebrates and Fish Assemblages in Little and Middle Bywy Creeks, Natchez Trace Parkway

Jackson, Donald; Dibble, Eric; Hashim, Rohasliney

Benthic macroinvertebrate and fish assemblages, and corresponding stream habitat characteristics were studied in Little Bywy and Middle Bywy creeks along the Natchez Trace Parkway, Mississippi. Tills was the first year of a multiyear study designed to address influences, if any, of lignite mining in the watersheds of these two streams. Little if any differences were discerned between the two creeks with respect to water quality. However, physical habitat features rendered Middle Bywy Creek a more favorable environment for benthic macroinvertebrates and fishes compared to Little Bywy Creek. This can be attributed primarily to the fact that Little Bywy Creek has a more straightened channel, less large woody debris and a hydrological regime less prone to flooding of adjacent riparian zones and floodplains. Heterogeneous habitat features within stream channels (e.g., riffles, runs, pools), large woody debris as stable attachment sites for aquatic invertebrates and cover for fishes, and deep water environments of pools (that serve as refugia during minimal flow periods), andincorporation of allochthonous organic materials from riparian zones and floodplains during flood events, work in concert to make Middle Bywy Creek a more dynamic and faunisticaUy richer systeIIL As the study evolves, discernment of temporal variation in habitat characteristics as well as faunal assemblage dynamics will serve as a solid foundation for determining changes, if any, that may reflect anthropogenic activities in the respective watersheds.