Long-term effects of sheep grazing on coastal sandplain vegetation

In 1990, vegetation cover and frequency in thirty-one 0.2-m(2) quadrats in an ungrazed coastal sandplain in Massacussetts (USA) were compared with cover and frequency in matched quadrats in an adjacent grassland that had been used as a sheep pasture until 1948. Species that had significantly higher values of cover or frequency in the former pasture included Schizachyrium scoparium, Comptonia peregrina, Cladina spp., and Helianthemum dumosum. Four shrubs and a grass-Myrica pensylvanica, Quercus ilicifolia, Rosa carolina, Vaccinium angustifolium, and Festuca ovina-were more abundant in the ungrazed vegetation. Two dominant species that showed no differences in either abundance measure between the grazed and ungrazed sites were Gaylussacia baccata and Carer pensylvanica. These results suggest that sheep grazing may be a valuable tool for arresting shrub encroachment into native coastal sandplain grasslands.