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Harvard Forest REU Symposium Abstract 2005

  • Title: Comparison of Macroinvertebrate Communities in Two Headwater Streams of Differing Forest Type
  • Author: James J Willacker Jr. (State University of New York College of Environmental Science and Forestry)
  • Abstract:

    Eastern hemlock (Tsuga canadensis) is a common riparian species in the eastern United States that is being replaced across its range by deciduous species as a result of the invasion of Hemlock Woolly Adelgid, an exotic forest pathogen. The conversion of forests from hemlock to deciduous species may have serious implications for headwater streams flowing through these forests. In this study I examined the macroinvertebrate communities of two headwater streams, in central Massachusetts, with differing hemlock influences. Macroinvertebrates were sampled from riffle and soft-bottomed habitats in each stream using a ½ m2 quadrat and kicknets. Samples were live picked in the field and sorted by genus and functional feeding group. Total taxa richness and taxa unique to each stream were greater in the deciduous stream relative to the hemlock stream. The increased number of unique taxa in the deciduous stream was primarily a result of increased diversity of the orders Coleoptera and Diptera. Differences in the distribution of functional feeding groups between streams were only found among filterers. Differences were found in the distribution of dominant taxa (see Fig. 1), with the mayfly Eurylophella sp. predominating in the hemlock stream and the caddis fly Lepidostoma sp. dominating in the hardwood stream. Overall my findings suggest that there are differences in the macroinvertebrate communities of hemlock and deciduous streams, however a year round study is necessary to determine the extent of these differences.

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