Effect of expanding clones of Gaylussacia baccata (black huckleberry) on species composition in sandplain grassland on Nantucket Island, Massachusetts

Abstract

community were investigated. Expansion rates of G. baccata clones were determined by measuring the diameters of clones on 1975 aerial photographs and in the field in 1990. Data were collected on the cover, maximum height and stem density of G. baccata, as well as the presence of other species, in 0.25 m2 quadrats placed along radial transects within and outside clones. G. baccata clones nearly doubled in area from 1975 to 1990. Clone expansion was accompanied by an increase in G. baccata cover, height and stem density, and a corresponding decrease in species richness. The frequencies of other plant species displayed three different patterns along a transect into G. baccata clones: no change, a gradual decrease, and a sharp decrease in frequency at the clone edge.