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

The Ogeechee River is a fifth order blackwater river that flows through Georgia’s Southeastern Coastal Plain. The majority of the Ogeechee River basin (~95%) lies in the Outer Coastal Plain Mixed Forest Province and is comprised of secondary forest, agricultural lands, and wetlands. These differences in land use likely impact the biological communities that inhabit the river. Examining consumer assemblages along a longitudinal gradient of the Ogeechee River allows for an assessment of spatial patterns in community structure in this system. As part of a long-term study we used benthic macroinvertebrate and fish data collected across six sites along a ~200-km stretch of the Ogeechee River from 2014-2015 to assess for spatial patterns in consumer communities. Sampling sites were numbered (1-6) from the upstream-most to the downstream-most site to reflect a gradient in drainage area. Differences in community structure can be observed along the longitudinal gradient for both benthic macroinvertebrates and fish assemblages. Preliminary data for benthic macroinvertebrate assemblages grouped sites into two distinct groupings (sites 1-2 ‘i.e., upstream sites’ and sites 3-6 ‘i.e., downstream sites’). Chironomids were consistently the dominant contributors at the two sites furthest upstream (\u3e40% of total) and isopods as the most common contributors to at the downstream-most sites (16-79% of total). Preliminary data for fish assemblages grouped sites into three distinct groupings (sites 1-2 ‘upstream sites’, sites 4-6 ‘downstream sites’, and site 3 ‘mid-reach’). Despite differences in fish assemblages between sites, redbreast sunfish (Lepomis auritus) were usually the dominant contributor across all sites (\u3e25% of total). Continuous monitoring of fish and 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 between these major groups and their role in river ecosystem function