Spider Assemblages of Hummocks and Hollows in a Primeval Alder Carr in the Białowieża National Park : Effect of Vegetation Structure and Soil Humidity

We studied the species richness, diversity, abundance and guild composition of spider assemblages on the hummocks and in the hollows of the alder carr in the Białowieża National Park. We also assessed the effect of vegetation structure and soil humidity on spiders settled in these two microhabitats. The spiders were collected from 10 May until 27 October 2001 by pitfall trapping. The main factor which differed between the hummocks and the hollows was soil humidity. In the case of vegetation cover we found some differences between the microhabitats but it was particularly evident in the case of litter, which was higher on the hummocks. Spider species diversity was significantly higher on the hummocks than in the hollows, but the number of individuals captured in both microhabitats was similar. The collected spiders belonged to six guilds and the proportion of spider individuals in particular guilds was significantly different between the hummocks and the hollows. The most abundant guild in both microhabitats was ‘ground hunters’ and the most numerous species was Piratula hygrophila. Our analyses showed that soil humidity positively affected the number of spider species and the number of individuals. Sampling date strongly influenced the number of collected species and spider individuals. Vegetation and litter cover did not have a significant impact on the spider assemblages. Our findings suggest that research conducted only on hummocks in the alder carr does not reveal the real structure of spider assemblages.

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Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.