A comparison of management strategies and shrub encroachment at two pastures on Naushon Island

Schroeder, Narin
Jon Atwood, PhD
Department of Environmental Studies
2002
Management goals on Naushon Island, Massachusetts have shifted form sheep farming to summer recreation. As a result, abandoned pastures have been invaded by shrublands composed of Gaylussacia baccata, Smilax rotundifolia, and Myrica pensylvanica. This ecological succession is changing the character of the Island and threatens rare flora and fauna associated with northeastern coastal grasslands. In actively managed areas controlled burning, grazing and mowing have been used to halt the succession of shrubs while passively managed areas have been abandoned. I compared ecological succession, vegetation community composition and species diversity at actively and passively managed study sites on Naushon Island. Percent cover data from 20 plots in each of the actively and passively managed study sites was analyzed and grouped into 6 distinct vegetation communities. Grassland-dominated plots occurred more frequently at the actively managed site while shrublands dominated the passively managed site. The average number of species occurring within plots was also significantly greater at the actively managed site. Panicum virgatum, Rosa Carolina, and Toxicodendron radicans were significantly greater in both percent cover and percent frequency at the actively managed site. Using aerial photography and a Geographic Information System (GIS) I determined that during the 48-year interval from 1951 to 1999 there was a 5% loss of grasslands at the actively managed site and 33% loss of grasslands at the passively managed site.

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