[Carbon stable isotope composition (delta 13C) of lichen thalli in the forests in the vicinity of the Chernobyl atomic power station].

The stable isotope abundance of carbon in the lichens Cladina mitis, Cladonia crispata Hypogymnia physodes, Parmelia sulcata has been investigated in a study relating these values with known levels of 106Ru, 134Cs, 137Cs and 144Ce defined activity in their thalli in the pine forests of region within a 30-km radius of the Chernobyl atomic power station and beyond it (37 km). All 63 samples of the lichens were obtained from 7 different sites. Small effects on delta 13C values in the lichens Cladina mitis, Hypogymnia physodes were found to be associated with distance from CNPP, activity level of radionuclides in them thalli whereas at Cladonia crispata is observed weighting of carbon with increase in values of 134Cs and 137Cs activity in thalli. Values of delta 13C the investigated lichen species more depends on habitat conditions rather than from levels of thalli radioactivity. In our study we didn't reveal the isotope specificity of any one species as it was not possible to establish a correlation between values of delta 13C and a particular species.

[Spatial distribution of soil animals: a geostatistical approach].

Spatial distribution is one of the main parameters of populations of soil animals. Spatial soil ecology having been developing during last decades bases animal distribution estimates on the geostatistic approach. A simple principle underlying the latter's methodology is that samples placed close to each other have more similarity than those distantly placed, it is usually called autocorrelation. The principles of basic statistics cannot be applied to autocorrelated data. Apiplying variograms, Mantel test, Moran index, and SADIE statistics enables to reveal the size of clusters of both soil parameters and soil animal aggregations. This direction of investigations quite popular in the western literature is just rarely employed by Russian soil ecologists. Statistically correct procedures allow developing field sampling methodology that is vital in applied studies of soil ecology, namely, in bioindication and ecotoxicology of soils, in the assessment of biological resources in terms of abundance and biomass of soil animals. This methodology has a decisive importance in the development of soil biogeography.

[Forest fires as a factor of formation of soil animal communities].

Forest fires usually destroy the most of soil animals. However due to the heterogeneity of soil cover some animals can survive in the partially burned patches (refugia). These groups along with the inhabitants of deep soil layers are the first to colonize burned areas. Nevertheless, the leading role in colonization of the burned areas belongs to obligate pyrophilous groups, adapted to discover burned areas and inhabit them. These, mostly saprovorous, groups develop thanks to the plenty of easily available resources (fungi and other microorganisms developing on pyrogenic mineralized organic remains) and lack of competition during first two years after the fire. They are replaced later by the phytophagous and saprovorous groups (facultative pyrophils), which are more successful in competition and gaining burned areas. Once the litter layer reestablished, the groups of other animals not occurring on the newly burned areas colonize them. A large part of those are predators. Fire severity is the most important factor regulating recovery of soil-living animal communities on the burned areas.