Major objectives of this study are to determine the mechanisms of ecosystem recovery following eleven years of nutrient (ureaphosphate fertilizer and sewage sludge) enrichment. Three 0.1-ha plots received five monthly (May - September) applications of fertilizer annually. Three received an equivalent nutrient subsidy of sludge, and two plots served as untreated controls. Plots subjected to this eleven-year history of nutrient subsidy will be divided into experimental subplots and results analyzed annually for a five year period. One subplot within each plot will be treated with lime to restore pH to control conditions; one subplot will be tilled to reinitiate secondary succession, and one subplot will be both limed and tilled to evaluate treatment interactions. The remaining subplot will be undisturbed. The following will be examined: a) the mechanisms that best explain the recovery process, b) the effect of pH restoration on the rate of recovery, c) the effect of liming on the rate of heavy metal transfer between trophic levels, d) whether community disturbance i.e., tilling increases the rate of recovery, e) processes on abiotic (e.g., pH) versus biotic (e.g., seed banks) factors, f) the structural and functional parameters which better indicate community recovery, and g) whether succession in the disturbed subplots parellel those developmental processes (e.g., patterns of species composition) demonstrated during the past eleven years within the same plots.
