Habitat diversity analysis along an altitudinal sequence of alpine habitats: the Carabid beetle assemblages as a study model

Abstract

Background and purpose. Species traits have been extensively used by botanists to describe, group and rank species according to their functions. Recently, the multi-trait approach has been extended also to the animal assemblages. There is now growing evidence that interspecific traits-variability can have significant effects on community dynamics and ecosystem functioning. The aim of our study was to describe how the carabid species traits change in relation to an altitudinal sequence of habitat types.

Materials and methods. In this paper we weighted the species traits (dispersal power, diet, reproductive rhythm, chorology) of the Carabid beetles assemblages in nineteen sites in the Dolomites along an altitudinal sequence of habitat types (1000-2250 m a.s.l.). Carabids have been sampled by means of pitfall traps.

Results. Species richness, activity density and species traits were not, or weakly, correlated with elevation, while they showed to be linked to the habitat type. Species traits, as taxa, showed to be not uniformly distributed along the sequence, with brachypterous species concentrated in high-altitude or climax environments mainly, and regional endemic species prevailing in high-altitude environments. Macropterous species with zoospermophagous species were found to increase with anthropogenic environmental disturbance.

Conclusions. The species traits analysis enabled us to shift the research focus from the taxonomic level to a biological more comprehensive level, opening the way for drawing more general ecologic models. Moreover it was possible to make inferences about the most successful carabid strategies in order to advance hypotheses on the historical colonization processes in the Alps.

Keywords: Alps, Carabidae, ecological succession, mountain ecosystems, species traits.