University of New Hampshire Scholars\u27 Repository
Abstract
In response to eelgrass habitat losses associated with development and marine activities in and around Nantucket Harbor, a plan to restore a meadow by transplanting eelgrass to previously vegetated areas was developed in conjunction with the Nantucket Land Council. Over 6,000 eelgrass shoots were sustainably harvested from an extensive bed within the Harbor that was located just west of First Point and near the inlet to Nantucket Sound. Four weeks following collection, impacts from our collection were shown by a 24% decline in shoot density, but live eelgrass cover did not decline significantly. After 12 weeks, no effects of collecting could be measured at the donor site for shoot density or cover. Plants had difficulty establishing within the restoration area due in part to extensive phytoplankton and macroalgal blooms that dramatically shaded the transplants for the initial three months following transplanting. After the first growing season, few of the 6,000 plants had survived, but those plants that survived became well established and grew through the second growing season in 2011. The significance of the macroalgae was documented through estimates of percentage cover, whereas light measurements showed the decline in water clarity from phytoplankton blooms to less than 10% ambient. Combined with our planting and monitoring results, our observations suggest that reestablishment of eelgrass beds in Nantucket Harbor is not limited by the distribution of seedlings, but by shading from phytoplankton and macroalgal blooms that resulted in levels of light too low to support eelgrass establishment during the summer months in 2010