Macroinvertebrate Community Assemblages and Leaf Decomposition in Three River Basins of the Southeastern Coastal Plain

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River systems within the Southeastern Coastal Plain are characterized by low gradients, broad floodplain connections, and limited autochthonous production, and thus derive the majority of their energy from allochthonous sources. The decomposition rate of this organic matter is a function of physical and biological factors. To assess the effects of flow regime, particularly the magnitude of discharge, and colonizing invertebrates on leaf-litter decomposition rates, packs of senesced leaves from Quercus nigra were deployed at six sites across three river basins (Savannah, Ogeechee, Altamaha). A total of 96 leaf packs containing 20g (± 0.15g) were deployed in mid-September 2014 and retrieved at two-week intervals over an eight-week period. During the period of study, we observed average discharges of 150.8, 75.3, and 8.2 m3/s on the Savannah, Altamaha, and Ogeechee, respectively. We predict that decomposition rates will be positively correlated with river discharge, and thus the Savannah will yield the greatest leaf mass losses. Furthermore, we hypothesize that functional composition of colonizing invertebrate communities will also differ among river basins due to variation in physicochemical characteristics of each basin.


Society for Freshwater Science Annual Meeting (SFS)


Milwaukee, WI