Long-term Dynamics of Small Mammal Communities in the Period of Reduction of Copper Smelter Emissions: 1. Composition, Abundance, and Diversity

Abstract

The long-term dynamics of the composition, total abundance, and diversity (α- and γ-diversity) of small mammal (SM) communities is analyzed in the vicinity of a large copper smelter during the periods of high (1990–1997), reduced (1998–2009), and almost terminated emissions (2010–2019). It is shown that the response of SM communities to pollution has not fundamentally changed over 30 observation years. An increase in pollution caused a significant reduction in the total abundance and α-diversity of communities and their dominance index in each of the three periods; at the same time, the γ-diversity remained similar in the background (13 species) and polluted zones (12 species). The reduction of emissions had no significant influence on the SM communities in the background (conditionally clean) zone: the species structure fluctuated insignificantly, the dominance structure did not change, and the increase in the animal abundance by the end of observations (owing to forest voles but not insectivores) was due to successional changes in the vegetation. The reduction of emissions led to a succession of dominants near the smelter and the trends of changes in abundance in this area differed from those observed in the buffer and impact zones (increase and no change, respectively). The increase in the abundance of species of different trophic groups (phytophages, granivores, and zoophages) in the moderately polluted (buffer) zone can be considered a symptom of the initial stages of recovery due to the improvement of habitat quality. Positive shifts in the SM community from the highly polluted (impact) zone are less distinct, being expressed only as an increase in the proportion of shrews.