Influence of Land Use and Site Characteristics on Invasive Plant Abundance in the Quinebaug Highlands of Southern New England

Invasive exotic plants have been identified as one of the major threats to ecosystem function and biodiversity. This study examined the distribution and abundance (cover and frequency) of invasive plants in natural habitats of the Quinebaug Highlands forest block (13,760 ha) of northern Connecticut and southern Massachusetts in relation to current and historical land use and site conditions. Multiple regression and GIS analyses were used to identify areas of high infestation and factors most useful in predicting invasions. Celastrus orbiculatus, Rosa multiflora, and Berberis thunbergii were the most frequent invasives. Past land use was the strongest predictor of invasive cover (r2 = 0.219) and richness (r2 = 0.303; p < 0.001 both regressions). Current land development and physical soil characteristics were also strongly correlated. These results add to our understanding of factors promoting plant invasions. Because invasive species control in natural areas is time- and resource-intensive, this information may enhance conservation efforts by increasing efficiency in predicting and managing biological invasions.