Aboveground phytomass and rate of plant debris decomposition in herbaceous communities exposed to soil pollution with heavy metals

Abstract

Consideration is given to production and decomposition processes in herbaceous communities exposed to chemical pollution with heavy metals in the Middle Urals. High variation in the aboveground phytomass of agrobotanical groups (legumes, forbs, grasses) is due to spatial heterogeneity of soil pollution levels and consequent changes in the species composition of plant communities in the areas studied. Therefore, nonparametric statistical methods have been used (Kruskal–Wallis test with subsequent pairwise comparisons by Wilcoxon–Mann–Whitney with Bonferroni correction for multiple comparisons). The phytomass of legumes remains unchanged in the increasing pollution gradient, while the contribution of forbs to the total phytomass decreases and that of grasses increases. Soils rich in nutrient elements can maintain a high rate of plant debris decomposition, counterbalancing the adverse effect of increased heavy metal concentrations on relevant processes. The balance between production and mineralization processes provides for the sustainable, long-term existence of herbaceous communities under conditions of intense pollution of the natural environment.