Raised bog biodiversity loss: A case-study of ground beetles (Coleoptera, Carabidae) as indicators of ecosystem degradation after peat mining

Peatlands are unique ecosystems inhabited by highly specialized biota. Due to extraction and drainage, these valuable ecosystems decline or represent only fragmented habitat patches. The aim of this study was to compare the carabid species composition, diversity, and life history traits between bog habitat types: 20 and 40 year post-extraction sites and undisturbed one. We tried to determine whether populations of rare carabid bog specialists would persist in the post-extraction habitats. The study was conducted in the raised bog, where 30 sampling transects with a total of 90 pitfall traps were established. 1616 individuals belonging to 30 carabid species were collected. The results revealed the significance differences in carabid species composition between studied habitat types and increasing the abundance and species richness in post-extraction sites. According to spontaneous succession in post-mining sites, the shift in life history traits of carabids towards forest assemblages was observed. We observed decline of the most valuable bog species in post-mining sites. Agonum ericeti, Pterostichus rhaeticus and Bembidion humerale were present on the reference bog, with large covers of Sphagnum and shrubs, but sporadically at the 20 year post-extraction site (except for A. ericeti), or not at all at the 40 year post-extraction site overgrown by trees. Therefore measures should be undertaken in post-extraction areas to enable the restoration of such specific conditions and a properly functioning raised bog ecosystem. This mainly requires restoration of a suitable hydrological regime, which is the key factor for the preservation of groups of bog specialist plants and animals.