Spatiotemporal changes of beetle communities across a tree diversity gradient

Authors

  • Stephanie Sobek,

    Corresponding author
    1. Agroecology, Department of Crop Science, University of Göttingen, Waldweg 26, 37073 Göttingen, Germany
      *Stephanie Sobek, Department of Biology, University of Western Ontario, London, ON, Canada N6A 5B7.
      E-mail: ssobek@gwdg.de
    Search for more papers by this author
  • Ingolf Steffan-Dewenter,

    1. Population Ecology Group, Department of Animal Ecology I, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
    Search for more papers by this author
  • Christoph Scherber,

    1. Agroecology, Department of Crop Science, University of Göttingen, Waldweg 26, 37073 Göttingen, Germany
    Search for more papers by this author
  • Teja Tscharntke

    1. Agroecology, Department of Crop Science, University of Göttingen, Waldweg 26, 37073 Göttingen, Germany
    Search for more papers by this author

*Stephanie Sobek, Department of Biology, University of Western Ontario, London, ON, Canada N6A 5B7.
E-mail: ssobek@gwdg.de

Abstract

Aim  Plant and arthropod diversity are often related, but data on the role of mature tree diversity on canopy insect communities are fragmentary. We compare species richness of canopy beetles across a tree diversity gradient ranging from mono-dominant beech to mixed stands within a deciduous forest, and analyse community composition changes across space and time.

Location  Germany’s largest exclusively deciduous forest, the Hainich National Park (Thuringia).

Methods  We used flight interception traps to assess the beetle fauna of various tree species, and applied additive partitioning to examine spatiotemporal patterns of diversity.

Results  Species richness of beetle communities increased across the tree diversity gradient from 99 to 181 species per forest stand. Intra- and interspecific spatial turnover among trees contributed more than temporal turnover among months to the total γ-beetle diversity of the sampled stands. However, due to parallel increases in the number of habitat generalists and the number of species in each feeding guild (herbivores, predators and fungivores), no proportional changes in community composition could be observed. If only beech trees were analysed across the gradient, patterns were similar but temporal (monthly) species turnover was higher compared to spatial turnover among trees and not related to tree diversity.

Main conclusions  The changes in species richness and community composition across the gradient can be explained by habitat heterogeneity, which increased with the mix of tree species. We conclude that understanding temporal and spatial species turnover is the key to understanding biodiversity patterns. Mono-dominant beech stands are insufficient to conserve fully the regional species richness of the remaining semi-natural deciduous forest habitats in Central Europe, and analysing beech alone would have resulted in the misleading conclusion that temporal (monthly) turnover contributes more to beetle diversity than spatial turnover among different tree species or tree individuals.

Ancillary