The Gusum case: a brass mill and the distribution of soil Collembola

Abstract

The sensitivity towards metal pollution of some population and community characteristics in Collembola was demonstrated based on observations at eight field sites along a transect from a brass mill. Samples were collected in coniferous forest soils at Gusum, southeastern Sweden, where a local brass mill has created a metal gradient in the surrounding area, with Cu and Zn concentrations in the mor (Oa + Oe) layer close to the mill at levels 50 times above background. Cu concentrations in whole animals increased exponentially in the vicinity of the smelter, but accumulation in body tissues was only observed at background sites. Neither species number, density, nor species diversity were linearly correlated with metal concentrations but instead showed a bell-shaped distribution. The vertical distribution of Collembola was clearly dependent on soil metal concentrations, and their densities at 2 – 10 cm depth were positively correlated with metal concentrations at 0–2 cm depth. The most pertinent information was gained from observations on the species composition. Tullbergia spp. and Onychiurus armatus (Tullberg) became more abundant in the polluted soils, whereas Folsomia quadrioculata (Tullberg) and Frisea mirabilis (Tullberg) generally disappeared. Folsomia fimetarioides (Axelson) became the dominant species in the polluted soil and seemed to have a distribution that was inversely related to that of Isotomiella minor (Schäffer). The general persistence of a high abundance of Collembola in the polluted soils and the more specific changes in species abundances may be due to quantitative and qualitative changes in food supply, low bioavailability of the metals, and efficient avoidance and detoxification capabilities in the animals.