Avalanches keep habitats open and species-rich in the montane and subalpine belt

eco.mont 2/1:5357. From a conservation point of view, avalanches are a natural ecological process. However, they can also endanger people and cause serious damage to buildings and infrastructure. From an anthropocentric point of view, protective measures in the form of avalanche barriers are necessary. Avalanche barriers in the starting zone of avalanches can prevent avalanche events. Hence there is a conflict between nature conservation and protection against natural hazards. This study aims primarily at assessing the conservation value of active avalanche tracks. To this end we examined 16 plant stands on three different avalanche tracks in the Gesäuse National Park (Styria, Austria) and recorded butterfly species at the same time. On the investigated avalanche tracks, the soils are very shallow, stony, periodically dry, nutrient-poor, base-rich rendzinas developed over limestone debris. The sites are scree-covered, steep and mostly east-facing slopes located in the montane belt. The plant stands investigated belong mainly to the Origano-Calamagrostietum variae community. This study of biodiversity concludes that under these conditions the vegetation in active avalanche tracks is characterised by a high richness of vascular plant species. On average, a plot size of 20 m contains 71 vascular plant species and 5 bryophyte species. The species-rich plant stands, colorful when in bloom, are dominated by autumn, resulting in a high aesthetic value and an increased diversity of butterflies. The avalanche tracks investigated have a high conservation value because natural ecological processes continue to happen, leading to near-natural and species-rich disclimax communities.