Macroinvertebrate Community Structure Along a ~200-km Stretch of the Ogeechee River

Examining consumer assemblages along a longitudinal gradient allows for an assessment of spatial patterns in community structure in river systems. As part of a long-term study we used benthic macroinvertebrate data collected from the Ogeechee River to assess for spatial patterns in consumer communities. Sampling sites were selected to reflect a gradient in drainage area and differences in community structure can be observed along the gradient for benthic macroinvertebrate assemblages. Non-metric multidimensional scaling based on square root transformed relative abundance data grouped sites by season (winter vs. spring) or spatially (by sampling site). Chironomidae were consistently the dominant contributors at the two upstream sites (>21%) while Amphipods (one site in winter) and Asellidae were the most common contributors at the two downstream sites (14-68% of total). Collector-Gatherers and Predators made up the greatest percentage of taxa in both winter and spring (>29%). Continuous monitoring of benthic macroinvertebrates in the Ogeechee River will further detail the structure of consumer communities in this river and ultimately allow for more thorough assessments of trophic relationships and aid in the construction of food webs.