Comparing Leaf Breakdown and Macroinvertebrate Assemblages Among Three Coastal Plain Rivers

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We compared leaf breakdown and macroinvertebrate assemblages in main-channel habitats of three Coastal Plain rivers in southeast Georgia. Over two seasons (fall 2014 and spring 2015), a total of 192 coarse-mesh packs of water oak (Quercus nigra) leaves were retrieved across six study sites (two per basin) to assess the effects of flow regime, particularly discharge, on breakdown rates and assemblage structure. Despite significant differences in discharge during the fall (p = 0.0013), each basin exhibited similar processing coefficients (avg. k = -0.013/d). Significant differences in discharge were also observed during the spring (p = 0.0015), but processing coefficients remained similar among basins (avg. k = -0.011/d). Fall assemblages were similar among basins based on abundance (p = 0.121) and biomass (p = 0.091). Spring assemblages were also similar among basins based on abundance (p = 0.056) and biomass (p = 0.071). These results suggest that discharge is not a determining factor in leaf breakdown rates and reinforce the usefulness of the ecoregion concept in delineating macroinvertebrate distributions in these systems.


Society for Freshwater Science Annual Meeting (SFS)


Raleigh, NC