Dynamics of the Integral Measure of Competition in Plant Communities of Different Uniformity

摘要

The effect of non-monotony of the correlation coefficient between crown projection area and the Voronoi polygon area in 90-year spruce sites in the Moscow Region arranged in ascending order of the variation coefficient of stem diameter is analyzed using the original 2D model of the plant community dynamics. Theoretical integral (over the entire community) indices of competition demonstrating non-monotone competition in relatively uniform communities—the Clements' index (Clements et al., 1929) and the mean suppression of community plants—were analyzed. Direct computation demonstrated that the correlation coefficient can also be considered as an index of competition, and its dynamics is indeed non-monotone in uniform communities. This finding allows us to roughly evaluate the potential duration of biomass growth for free-growing spruce in the Moscow Region as 1000 years. Due to the limitations of the 2D resource model (nearly "symmetric" competition), certain model characteristics of communities (the variation coefficient and correlation characteristics of neighborhood) differed several times from natural ones although showing the correct trend of changes.