Effect of spot burning of logging residues on the properties of mountain forest soils and the occurrence of ground beetles (Coleoptera, Carabidae)

Abstract

We investigated the relationships between dehydrogenase activity and the physicochemical properties of mountain soils over three and five years from Norway spruce (Picea abies L. Karst) logging residue spot burning and the occurrence of epigeic carabid beetles. Six study sites were utilised, including 18 study plots (nine plots in a mixed coniferous mountain forest site and nine plots in a mixed broadleaf mountain forest site), with five replicate pitfall traps at each site located in southern Poland. Soil samples from the organic horizon were taken for pH, organic carbon, nitrogen, base cation content, acidity and dehydrogenase activity determination. Carabid beetles were monitored in weekly intervals during the period of July to August 2016. The burning of logging residues led to modified soil properties, especially the dehydrogenase activity. In all the tested variants, the activity was higher in soil samples after the burning in comparison to the control variants. We show no positive correlation between dehydrogenase activity and the number of carabid specimens. The preferences of dominant predatory hygrophilous carabids to acid habitats with weakly decomposed organic matter were proven. Simultaneously, the soil organic matter content was positively related to the carabid abundance. The significant impact of forest site conditions and the date of logging residue burning on the number of caught specimens were confirmed. In contrast, no relationships between the species richness, species diversity, mean individual biomass and spot burning effect were found. This work supports the recommendation of spruce fine woody debris utilisation by spot burning on mountain regions with rich habitats presenting moderate wet conditions and small land falls.