Historic land use effects on forest composition at the post wildlife sanctuary, McDonough County, Illinois.

摘要

Current forest structure and composition are associated with historic land use, disturbances, and physical characteristics of the land such as slope and aspect. These relationships were studied at the Post Wildlife Sanctuary, a 140-acre tract of land that contained the historic town of Vishnu Springs, but has been relatively undisturbed for 80 years. The goal of this study was to determine the degree to which historic land use affects current forest cover types. Current forest cover types were determined for twenty-five .06 ha circular plots at the site in 2008 and plotted on a 2005 aerial photo. Historic land use types were determined by interpreting 1941 aerial photography. Patch metrics were used to identify characteristics of ArcGIS polygons outlining historic forested areas. These were percentage of forest cover, mean polygon size, core area, edge density, area weighted mean patch index, area weighted mean patch fractal dimension, and mean shape index. Patch metrics, land use type, slope and aspect were used as historic predictor variables in AIC ecological modeling for current species, percentage of forest cover (of each polygon), and current forest cover type. Results indicated that sugar maple (Acer saccharum), black locust (Robinia pseudoacacia ) and the current percentage of forest cover were significantly associated with edge density (the linear distance of edge of a habitat per unit area of landscape in m/ha), mean patch size and historic land use. The results of this study show that historic land use can be used as a predictor of particular species (such as sugar maple and black locust) and also the percent of forest coverage, which can affect the structure, composition and regeneration of the forest.