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The distribution of purse-web Atypus spiders (Araneae: Mygalomorphae) in central Europe is constrained by microclimatic continentality and soil compactness

Authors

  • Milan Řezáč,

    Corresponding author
    1. Research Institute of Crop Production, Drnovská 507, 161 06 Prague 6-Ruzyně, Czech Republic
    2. Department of Zoology, Faculty of Sciences, Charles University, Viničná 7, 128 44 Prague 2, Czech Republic
      *Milan Řezáč, Research Institute of Crop Production, Drnovská 507, 161 06 Prague 6-Ruzyně, Czech Republic.
      E-mail: rezac@vurv.cz
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  • Veronika Řezáčová,

    1. Microbiological Institute CAS, Vídeňská 1083, 142 20 Prague 4, Czech Republic
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  • Stano Pekár

    1. Institute of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
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*Milan Řezáč, Research Institute of Crop Production, Drnovská 507, 161 06 Prague 6-Ruzyně, Czech Republic.
E-mail: rezac@vurv.cz

Abstract

Aim  Three species of primitive spiders of the genus Atypus occur in European xerothermic habitats, where they live in burrows. The aim of this study is to explain their distribution by investigating environmental variables at sites where they occur in central Europe.

Location  Over 50 sites in central Europe, Czech Republic.

Methods  Data on climatic, edaphic and vegetational parameters were collected from more than 50 sites. Phytocenological data were processed using Ellenberg's indicator values.

Results Atypus muralis was found to occur almost exclusively in dry grassland (Festucion valesiacae), exposed to a continental microclimate. Atypus affinis usually occurred in dry sparse forests (Genisto germanicae–Quercion) that provide an Atlantic microclimate. Atypus piceus occurred in dry grassland (Bromion erecti) or forest fringes (Geranion sanguinei) characterized by an intermediate microclimate. Atypus piceus and A. muralis were restricted to agglutinate calcareous soils.

Main conclusions  Our results show that Atypus species colonized sites with different continentality in central Europe. These differences correspond to differences among their probable glacial refugia. Atypus muralis and A. piceus occur in habitats with a markedly continental climate, and are restricted to calcareous agglutinate soils that more efficiently buffer temperature and humidity extremes. Habitats of A. muralis and A. piceus are threatened by overgrowth of vegetation after a recent decline in grazing and by the decalcification of the landscape. However, habitats of A. affinis are stable in the present central European climate.

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