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The structure of Enchytraeidae communities of Leucobryo-Pinetum and Peucedano-Pinetum pine forests was analysed. One community-type was registered. Differences in species composition and dominance structure related to regional phytosociological diversity and limiting influence of anthropogenous pressure on community density were observed.
The earthworms occurrence in pine forests was analyzed. The communities of earthworms in studied areas are characterized by poor species composition and low density. D. octaedra was the dominant.
Analysing possibilities of indicating threats of earthworms for protection demands, it was shown that at the current stage of faunistical work it is not possible to choose the most threatened species in the Polish fauna, which could qualify to one of the threat of the European categories. In the case of this group of animals it is not possible basing, on current knowledge, to determine the category of threat. Although, it is assumed that there are four endemic species (e.g. connected with Carpathian Mts) in this group. The criteria stated in the Polish Red Data Book do not apply to oligochaete. Nearly none of the species can be characterized with demanded precision for chosen criteria, because the lack of quantity and quality data. It is only possible to distinguish „groups of non-determined species”, which are treated as „rare species”, but the lack of enough data does not allow to determine to which group they really belong. The determining of factors affecting the habitation of particular species belongs to a group of the least known subjects. A group of factor affecting one particular earthworm species was not considered yet.
It was found that some insecticides and fungicides are highly toxic to earthworms. The most toxic of the tested insecticides were pyrethroides, and of fungicides it was carbendazim, All the tested herbicides proved to be lowly toxic to earthworms.
The structure of Enchytraeidae communities inhabiting the soil in pine forest stands of various ages situated in Puszcza Białowieska has been analysed. The greatest transformations in Enchytraeidae communities have been observed in younger stands. Older stages of the sere are characterized by stabilization of the communities, which is associated with the establishment of specific soil conditions resulting from humus formation.
The highest density of macrofauna was recorded in a muddy habitat, and the highest biomass (d.w.) in a stony one. Only Naididae, Hydracarina, young larvae of Trichoptera, and large specimens of Gammarus spp. preferred a transitional habitat (mud-covered stones). Of the 25 identified species of Oligochaeta especially three dominant species (Nais bretscheri, N. pardalis, and N. communis) were most numerous in the transitional habitat. Downstream the species diversity of Oligochaeta increased and the composition of the community changed.
Oligochaetes constituted 91-98% of the numbers and 78-97% of the biomass of the macrofauna, the remaining part were Chironomidae, while Chaoboridae, Sphaeridae, Ephemeroptera, and Coleoptera occurred sporadically. The highest density (14.5 thous. indiv. m-2) and biomass (13 g m-2) were observed near the dam. 14 species of the Oligochaetes (the most numerous being Potamothrix hammoniensis, Limnodrilus claparedeanus, and L. hoffmeisteri) and 5 taxa of Chironomidae were determined in the samples.
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