Four decades of old field vegetation development and the role of Celastrusorbiculatus in the northeastern United States

This paper describes four decades of in situ vegetation change in a post-ag ricultural site in southern New England where the role of the introduced vi ne, Celastrus orbiculatus, has drastically modified the course of vegetatio n development. An initial perennial forb-grassland community was replaced b y two strikingly different physiognomic vegetation types-an early hardwood forest and a vine community occupying the same site 40 yr later. This ecolo gical phenomenon was unpredictable since Celastrus was not recorded at the site until the 1970s. Within the young hardwood forest dominated by Prunus serotina and Acer rubrum, a few old field species (five) persist, whereas 1 7 forest herbs have become established. Typical forest shrubs are rare or a bsent. The Celastrus-dominated vine community has suppressed or eliminated pre-existing growth to form a relatively stable community where a forest ve getation is the regional vegetation type. Celastrus also appears to be faci litating a native vine (Vitis labrusca) by forming a 'ladder' for its advan ce. Although A.. rubrum and Quercus spp. could ultimately dominate the fore st community, the contiguous and aggressive nature of Celastrus makes predi ctions questionable. This long-term study highlights the unpredictable natu re of old field succession and the role of an exotic species in threatening the natural vegetation development.