Do traditional land rehabilitation processes improve habitat quality and function? Life-history traits of ground beetles (Coleoptera, Carabidae) say no.

Abstract

Background and purpose: In the thermal power station industry, waste is deposited on various types of slag heaps, which should be rehabilitated in order to restore ecosystem functioning. Traditional restoration processes focus mainly on recreating a tree zone, while the function of the soil is neglected. The aim of the project was to estimate the influence of land restoration (traditional tree plantation without rehabilitation of the soil layer) on the life traits of ground beetles in slag deposition areas.

Materials and methods: In a habitat restoration experiment, five sites sampled using pitfall traps were established in a rehabilitated forest and an untreated meadow, with the same number of traps set up on reference forest and meadow sites. Carabid beetles were classified into five categories according to life-history traits: body size, feeding strategy, breeding type, wing development and habitat preferences.

Results and conclusions: Non-metric multidimensional scaling indicated that twenty years of rehabilitation processes had had no effect on the species composition of slag heap forest carabid assemblages. These forest assemblages consisted mainly of species having broad ecological requirements, which are characteristic of initial succession. The most notable feature of the distribution of carabid life-history traits on the slag heap is the reduction in abundances of such groups as large and small predatory specialists having an autumn breeding type of reproduction, with limited dispersal abilities, and preferring forests. The results showed that restoration involving only tree plantation does not guarantee the successful recreation of a functioning and stable ecosystem, as the ecosystem remains in the initial stage.