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Harvard Forest REU Symposium Abstract 2008

  • Title: Influence of wetlands on stream chemistry and macroinvertebrate communities along a river continuum
  • Author: Israel DelToro (University of Massachusetts - Amherst )
  • Abstract:

    The River Continuum Concept (RCC) predicts changes in organic carbon dynamics and macroinvertebrate community structure along streams draining forested watersheds, but does not explicitly consider the role of stream wetlands or impoundments. We examined the chemistry and macroinvertebrate communities upstream and downstream of wetlands along the East Branch of the Swift River in North Central Massachusetts, (a major tributary to the Quabbin Reservoir). We hypothesized that wetlands cause changes in biogeochemical and hydrogeomorphic stream attributes and consequently affect macroinvertebrate community structure regardless of stream order or size. Macroinvertebrates were quantitatively sampled before and after three major wetlands (ranging in size from 330m2 to 1380 m2), identified to genus and sorted into functional feeding groups. Water chemistry grab samples were collected at each site and analyzed for biochemical oxygen demand and nutrients. Our results show that wetlands along this river continuum significantly reduce diversity (p<0.05) and homogenize functional feeding groups. However macroinvertebrates in second order intermediate reaches show approximately the same structure as predicted by the RCC. These findings can help explain variation in macroinvertebrate communities along stream ecosystems with wetlands or impoundments. Additionally these findings can be used to better understand how landscape changes may alter macroinvertebrate communities, food webs, organic matter dynamics and water quality. Future research should emphasize the importance of wetlands and impoundments on stream continuums and their impacts on macroinvertebrate community structure.

  • Research Category: Watershed Ecology