Macroinvertebrates Associated with Beaver Dams in a Southeastern Coastal Plain River System

Beaver dams are known to produce changes in stream physical habitat that result in changes in water flow, organic matter standing stocks, and consumer diversity. We sampled benthic macroinvertebrate communities and organic matter standing stocks in three sites along the Ohoopee River (2 impacted with dams and 1 control) to assess the effects of beaver dams on consumer community structure. At impacted sites (i.e., with beaver dams), two separate habitats were studied; the sedentary slough immediately upstream of the dam, and the flowing area immediately downstream of the dam. Four benthic core samples were retrieved, and water parameters measured at each site seasonally (i.e., Summer, Fall, Winter). Organic matter standing stocks were found to be consistently higher above beaver impoundments suggesting that restricted water flow influences rates of material transport. Based on abundance and biomass shredders were determined to be the dominant feeding group in upstream habitats, while collector/gatherers dominated the downstream habitat. Differences in macroinvertebrate feeding group biomass and abundance suggest that influences of water flow on material transport may also influence consumer functional composition.