Comparing Influences of Natural and Artificial Woody Habitat on Benthic Macroinvertebrates in a North Temperate Lake

Abstract

Littoral habitat is an important organizing force in lacustrine food webs. Modification of littoral habitat directly impacts aquatic macroinvertebrates, which are important vectors between basal resources and higher trophic levels. Lakeshore residential development is a pervasive phenomenon often characterized by the loss of coarse woody habitat (CWH) from lakes, and the construction of artificial wooden structures (docks and ramps). To characterize the effects of artificial wooden structures on macroinvertebrate spatial distributions, we surveyed assemblages across a lightly developed lake in New York’s Adirondack Park. Using benthic sweeps and Hester-Dendy samplers, we sampled assemblages at both natural CWH and artificial wooden structures (boat ramps), and compared them to those in adjacent, non-woody areas. We found that both CWH and artificial wooden structures facilitated larger, more complex assemblages than non-woody areas. We additionally considered general shoreline characteristics, and found only compositional effects on assemblages. We suggest that impacts on aquatic macroinvertebrates arise at a fine spatial scale, and find evidence that development-associated CWH loss drives macroinvertebrate depletion. Although CWH and artificial wooden structures are unlikely to be equivalent at whole-lake scales, macroinvertebrate depletion may be functionally alleviated at fine scales by the construction of artificial wooden structures such as ramps.

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