Sheep Grazing as a Grassland Management Tool: Lessons Learned on Nantucket Island, Massachusetts

On Nantucket Island, MA, the present range of coastal sandplain grasslands is primarily attributed to intense and prolonged historic sheep grazing following European settlement. The maintenance of this early successional habitat (ranked S-1 or "critically imperiled" in Massachusetts) relies on disturbance-based land-management tools. Habitat management efforts have focused primarily on mechanical and prescribed fire treatments, with limited emphasis on re-introducing sheep. This study examined and compared the impacts of repeated growing-season grazing, repeated growing-season mowing, and no management on vegetation community composition in a previously managed grassland. Sheep grazing effectively controlled and reduced clonal and vining woody plant coverage while increasing available bare ground for grassland species seed recruitment. However, grazing and mowing treatments resulted in an increase in weedy agricultural plant species, which may be an inherent side effect of management that results in soil disturbance. Given the long-term, variable nature of the ecological disturbances that created Nantucket's sand-plain grassland vegetation communities, one management technique alone will not likely result in successful habitat restoration over a short period of time. We recommend that sheep grazing be more widely considered as an addition to the existing sandplain grassland management "tool box".