Dispersal rates of Collembola in metal polluted soil.

摘要

The impact of heavy metals on dispersal rates of five collembolan species was estimated. The species differ in size, morphology and vertical distribution. Experiments were performed in plastic boxes filled with a 3 cm layer of mor soil with 1 cm oflitter on top. The soils were sampled at one copper and zinc polluted site and one unpolluted site with similar vegetation and soil. Approximately 55 animals were introduced at one end of each box. The experimental treatments were: (1) unpolluted soil; (2) polluted soil; and (3) unpolluted soil with a 'barrier' of polluted soil in the middle. Two boxes of each treatment were destructively sampled after 1, 2, 3 and 4 weeks. All tested Collembola species had a higher rate of dispersal in polluted than inunpolluted soil. Dispersal rates were correlated to mean adult body size of the species. The polluted barrier in unpolluted soil did not change dispersal rates or result in a distribution differing from that in unpolluted soil. More specimens were recovered after 2-4 weeks of incubation in unpolluted than in polluted soil. Dispersal tests using soil fauna inhabiting the topmost layers of the soil, and thus exposed to anthropogenic activities, could be an alternative to soil toxicity tests focusing on sublethal effects on survival and reproduction.