Eelgrass meadows are both ecologically and economically valuable to coastal waters and have become the focus of many resource management initiatives in Massachusetts. On the Upper North Shore, Plum Island Sound historically harbored an abundance of eelgrass meadows. To investigate the potential for eelgrass restoration, the University of New Hampshire (UNH) developed an Eelgrass Habitat Suitability Model, funded by the Mass Bays 2012 Research and Planning Grant Program. The eelgrass habitat suitability model identified areas or Plum Island Sound most suitable for eelgrass restoration.
In 2013, Mass Bays funded UNH to continue to investigate eelgrass restoration in Plum Island Sound. Eelgrass shoots from multiple donor sources were test-transplanted at four of the most suitable sites in Plum Island Sound as determined by the previous year's work. Results were mixed. Shoots transplanted between June and August did not survive while those transplanted after September in the central and southern portions of Plum Island Sound are still thriving. The low success rate of the summer transplants was attributed to multiple stressors including warm waters, poor water clarity, and bioturbation from a hyper-abundant European green crab population.
Based on the results, this system needs further investigation before large-scale restoration is implemented. The report recommends additional test-transplanting in the southern part of Plum Island Sound where waters are well-flushed and where results from the fall transplants were more promising. The report also recommends studying the population structure of the European green crab to better inform eelgrass management in the future. Information on the population structure of this invasive species would inform management of the species and advise future eelgrass restoration and management initiatives in this system.
The 2013 project informs the ongoing effort by many agency partners to bring eelgrass back to Massachusetts waters, provides managers with vital information on donor populations for successful restoration efforts, and identifies several barriers to eelgrass restoration. The report, Novak, A. and Short, F. 2013. Creating the Basis for Successful Restoration: Test-transplanting Multiple Eelgrass Donor Populations in Plum Island Sound, MA. file size 3MB, provides a detailed description of the transplanting efforts and results as well as a set of recommendations for future work.