Reaction of mollusk population to emissions from the Middle Ural Copper Smelter

A quantitative study of the mollusk population of the herbaceous layer has been carried out in the secondary upland meadows in a gradient of pollution with emissions from the Middle Ural Copper Smelter (MUCS) (city of Revda, Sverdlovsk oblast). The total abundance of mollusks is 1.3 times lower in a moderately polluted area than in reference areas. The mollusks disappear entirely from the grass cover in close proximity to the smelter. The reasons for the change in the mollusk population structure may be as follows: a heavy-metal toxic effect under conditions of environmental acidification, a lack of available Ca due to its depletion from the upper soil horizons, a reduction in species diversity, and a simplification of meadow grasscover architecture (which modifies the hydrothermal regime in the herbaceous layer). Apparently, a combination of these effects eliminates mollusks from the herbaceous layer, a trend which is not observed in the case of environmental pollution with only heavy metals.