Monitoring a Chicago Area Re Re - - created Natural Environment created Natural Environment

Extensive monitoring was employed in an attempt to document some of the factors responsible for the changes taking place in Dixon Prairie. The increase and decrease of many species was quantified, and an inventory of the plant life was estimated. Elevations and soil bulk densities were also recorded. The presence of Pycnanthemum virginianum was associated with plots of low to medium diversity as well as higher elevation. Taxa native to the Skokie River floodplain were found predominantly at the lower elevations at the perimeter of the prairie area. Most importantly, the percentage of graminoids decreased from roughly 50% in 1983 to roughly 11%. on the data. Certain species (including Cornus drummondii, Phragmites sp., Fraxinus sp., and Salix interior) are associated with sample plots in proximity to the Skokie lagoons along the perimeter of the prairie. These plots are, in general, at lower elevations and on south-facing slopes. Many of these species are considered weeds within the prairie but do reflect the more natural surroundings along the Skokie River corridor. Another strong association that the software identified was the correlation between the presence of Pycnanthemum virginianum and low species diversity. Other trends seem to be apparent according to the ordination analysis; however the strength of the correlations is difficult to interpret due to a lack of significant variation in the variables.