Experimental Studies about the Effects of Soil Compaction on the Structure of the Testacean and Ciliate Community, HELMUT BERGER, WILHELM FOISSNER and HANS ADAM, Zoologisches Institut der Universität Salzburg, Akademiestrasse 26, 5020 Salzburg, Austria.
The effect of soil compaction on the structure of the testacean and ciliate community were studied by means of a special compaction chamber. The upper 5 cm of soil of an alpine pasture were compacted at 10% (c), 30% (d) and 50% (e). The control (a) was the undisturbed alpine pasture. Sample (b) was used to determine the effect of the chamber. The chambers were exposed for 3 month at the same sites. The testacea react by a loss of the infrequent species and a continuous decrease of their abundance. Centropyxis aerophila var. sphagnicola is most abundant in (a) to (d), whereas Trinema lineare is most frequent in (e). Both species number and abundance are significantly negatively correlated with bulk density. The part of empty tests increases from (a) to (e). Trinema complanatum is significantly smaller in (e) than in (c). We conclude, that smaller species are less influenced by soil compaction than larger ones. Active ciliates are most abundant in (d). The qualitative investigations (culture method!) showed a significant effect of the chamber to the species number. But there are no differences from (b) to (e). Concerning the abundance the nematoda react similar as the testacea. The pH is significantly postive correlated with the bulk density. The loss of Nebela parvula and Plagiopyxis declivis in (b) to (e) is maybe mainly due to the increased pH, because both species prefere very acid environment. However, the reduced pore space and moisture content seem to be responsible for most changes of the communities. The results of the experiments are comparable with field studies at ski trails. Thus terrestrial protozoa are useful bioindicators. The ciliates appear to react more sensitively but less selectively than the testacea to the disturbance of their environment. (Supported by the Österreichischen Akademie der Wissenschaften, Projekt 2794).
Keywords: Bodenverdichtung, Bodenbiologie, Boden, Biologie, soil science, Protozoa, Protista, Schipiste, Schi Piste, ski trail, run, Alps, alpine, Alpen, Gastein, Bad Gastein, Bad Hofgastein, Salzburg, Austria, Europe, Zentralalpen, Hohe Tauern, testate Amoeba, Ciliophora, ciliates, biological indicator, ecology, Wiese, Weide, Humus, Poren, Gebirge, Ciliaten, Wimpertierchen, Schlossalm, Schloßalm, Gasteiner Tal, Alm, Zerstörung, slope
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