Short- and long-term effects of fire on the Collembola communities of a sub-alpine dwarf pine ecosystem in the Austrian Alps

Abstract

We compared the Collembola communities of three sub-alpine sites in the Limestone Alps to evaluate the short- and long-term effects of natural forest fires. SITE 1 was burned in August 2003, SITE 2 was burned 50 years ago and sampled to assess the long-term effects of fire and the recovery of soil animals. A reference site (REF) was sampled to represent the undisturbed dwarf pine community. All sites are close to each other on a steep slope between 1 400 and 1 650 m above sea level. We found a total of 41 species of Collembola, as well as clear differences in the species composition and abundance between the sites. Most species (29) were found on the REF site. The highest abundance was found on SITE 1 (48 960 individuals*m-2, 22 species). We assume that some species survived the fire in deeper soil layers and others migrated or were passively dispersed from unburned patches and surrounding sites. The lowest abundance and species number (8 160 individuals*m-2, 18 species) were found on the 50-year-old site. This site was covered with a typical community for moving substratum, consisting mainly of alpine grasses, yet the dwarf pine vegetation had not yet recovered. The soil layer was still very thin and we therefore assume that a recovery of the Collembola community will take much longer than 50 years.