Test-transplanting Genetically Differentiated Eelgrass Populations to Identify Those Most Suitable for Future Restoration in New Hampshire
|Amy Costa||Provincetown Center for Coastal Studies||Collaborator|
|Alyssa Novak||UNH - Department of Natural Resources & the Environment||Collaborator|
|Holly Bayley||Cape Cod National Seashore||Collaborator|
|Nancy Pau||U.S. Fish and Wildlife Service||Collaborator|
|Fred Short||UNH - Department of Natural Resources & the Environment||Principal Investigator|
|Anita Klein||UNH - Department of Biological Sciences||Collaborator|
|Prassede Vella||Massachusetts Bays Program||Collaborator|
|N. Tay Evans||Massachusetts Division of Marine Fisheries||Collaborator|
Eelgrass meadows are both ecologically and economically valuable to coastal waters and have become the focus of resource management initiatives in New England. Plum Island Sound, located in the Upper North Shore region of Massachusetts, presently lacks eelgrass although historically it grew there. We recently developed an Eelgrass Habitat Suitability Model that identified areas within the Sound with good potential for an eelgrass restoration. We are now performing test-transplants using genetically differentiated eelgrass donor populations from Massachusetts and New Hampshire to identify those best suited for a large-scale restoration in Plum Island Sound. The development funds acquired through N.H. Sea Grant will be used to pay for some of the supplies and materials needed to run genetic analyses and to evaluate genetic relatedness and diversity among donor populations (parameters linked to resistance and resilience of eelgrass systems to multiple stressors). Our results will provide further baseline genetic information on selected donor populations from New Hampshire and Massachusetts, as well as critical information on the characteristics of donor populations that increase transplant success for future eelgrass restorations throughout New England.
Four genetically eelgrass populations are being used for this study. The donor beds include:
1. Great Bay, N.H.: population has high genetic diversity and showed high resistance to multiple stressors in mesocosm studies (Short et al., 2012).
2. Nahant, Mass.: population frequently used as a donor source for restorations in Mass. (N. Tay Evans, DMF, pers. comm.);
3. Southway, Cape Cod, Mass.: population showed moderate resistance to multiple stressors in mesocosm studies (Short et al., 2012) and high survival rates during pilot field-studies in Cape Cod; and
4. West Island, Fairhaven Mass.: population showed moderate resistance to multiple stressors in mesocosm studies (Short et al., 2012) and high survival rates during pilot field-studies in Cape Cod;
Genetic analysis has been completed for Southway, West Island, and Great Bay (Short et al., 2012). Funds acquired through N.H. Sea Grant will be used to help pay for some of the materials and supplies for DNA extraction on new samples from Nahant (Mass.) and additional samples from Great Bay (N.H.; total samples 100). DNA extraction and genotyping will be performed at the University of New Hampshire. Genetic relatedness and diversity among donor populations will be evaluated using FSTAT (Goudet, 1995), GENEPOP (Raymond and Rousset, 1995) and STRUCTURE (Pritchard et al., 2002).
One round of test-transplanting was conducted in June 2013. During the Fall of 2013, approximately 500 shoots were haphazardly collected from a bed at each of four donor sites in N.H. and Mass. and planted at four test-transplant sites within the Sound. Fifty shoots (25 planting units) from each donor bed were planted using the horizontal rhizome method. Test-transplants will be monitored for 1 year and measurements will be conducted at 4 weeks, 16 weeks and 52 weeks. The area being restored by test-transplants at each location will be ~0.1 acre after 1 year.
All plant measurements will be done in-situ at test-transplant sites. To evaluate the survival and growth of the transplanted eelgrass, shoot density, leaf area, and canopy height for each population will be conducted. Measurements will be used to evaluate how each respective population is performing, and to predict shoot survival, expansion of the transplant plot, and restoration suitability.
Habitat quality measurements:
Water quality parameters at the test-transplant sites will be measured and assessed by the Provincetown Center for Coastal Studies (with donated matching funds). Temperature and light intensity are being monitored continuously using HOBO logging sensors (Onset Corporation, Bourne, Mass.).
RATIONALE FOR SEEKING N.H. SEA GRANT DEVELOPMENT FUNDS
Our project is an extension of our previously funded projects from The Nature Conservancy (Short et al., 2012), Massachusetts Bays Program (Novak and Short, 2012), and our ongoing eelgrass transplanting effort with TNC in the upper Piscataqua River. Our project will provide further baseline genetic information on selected donor populations in New Hampshire and Massachusetts, as well as address concerns about genetic erosion, inbreeding depression, fitness and recovery ability of eelgrass beds to environmental stressors. Moreover, our work will provide managers with information on the role of donor populations in restoration success. Our project is consistent with N.H. Sea Grant’s strategic plan for 2014-2017 and will help to inform decisions on how best to restore and maintain the health of our coastal ecosystems. Understanding of the genetics of eelgrass in northern New England will create the background information needed for us to produce a full-scale Sea Grant proposal directed at the restoration of eelgrass in New Hampshire waters. In order to maintain and reestablish eelgrass under current conditions in the Great Bay Estuary it is critical to identify existing eelgrass populations that are better adapted to grow under the current conditions of the estuary, so they can be used in proposed restoration efforts. We plan to share our results with government and state agencies upon completion to ensure the success of future eelgrass restoration in New England.
Bayley, H.K., 2012. The Role of Eelgrass (Zostera marina L.) Source population characteristics in resilience to stress and restoration success. Master's Thesis. University of New Hampshire.
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Short, F.T, D. M. Burdick, G.E. Moore. 2012. The Eelgrass Resource of Southern New England and New York: Science in Support of Management and Restoration Success. The Nature Conservancy. 93 pp.