The effects of environmental factors and land use history on the long-term vegetation dynamics of the Bolleswood natural area, Connecticut College Arboretum

Research on vegetation dynamics has traditionally focussed on successional dynamics and environmental factors, often ignoring the role of anthropogenic historical factors. In southern New England, at least 80% of the now-forested land was cleared for agriculture, and later abandoned. Little is known about the magnitude and longevity of the effects of prior agricultural use and of other forms of disturbance on the current vegetation, although a better understanding of these effects could be important for ecologists, conservationists and land managers.; The Connecticut College Arboretum is located in the central hardwoods region of New England. Tree, shrub and herb species abundances have been recorded along permanent transects every 10 years since 1952. Ancillary data included disturbance history and six environmental variables. The objective of this study was to determine which factors were most strongly related to the vegetation of this site, and to examine how those relationships have changed over time. Non-metric multidimensional scaling was used to trace vegetation dynamics. Partial Mantel tests were used to evaluate the relationship of each variable to vegetation.; Several patterns of vegetation dynamics were seen. The forested areas showed vegetational changes related to recovery from disturbance and the introduction of the hemlock woolly adelgid. The old field areas showed two separate trajectories. One area became increasingly similar to hardwood forest, while an adjacent area has been overrun by Oriental bittersweet. Dense cover of this introduced vine has prevented the development of a forest overstory. The wetland areas were relatively stable over time.; A more detailed examination of the importance of known environmental and historical factors revealed that human land use and drainage were most strongly related to plant species composition. Severity of wind damage was related to vegetation at a lower level, as were soil depth, soil texture and slope. The magnitude of the relationship between vegetation and both environmental and historical factors tended to decrease over time. The relationship of vegetation to drainage remained constant. Presumably other physical factors such as light and nutrient availability have become more important. Actually testing these relationships has added a valuable component to our knowledge of vegetation dynamics.