In July 2010, several catastrophic mudflows occurred in the nature park Sölktäler (Styria, Austria). From a nature conservation point of view, mudflows are a natural geomorphic process which creates pioneer habitats. Hence in protected areas mudflows can be regarded as a natural disturbance and therefore restoration measures should be avoided. On the other hand, mudflows are a natural hazard. They lead, among others, also to a devastation of agricultural used areas. From an agricultural point of view, rapid revegetation measures are necessary in order to produce new forage acreages. Thus, in protected areas there are conflicting interests concerning re-establishment of the vegetation following mudslides. This study aimed primarily at assessing the initial vegetation development on freshly sown and on unaltered erosional and depositional zones of mudflows both from a nature conservation and an agricultural point of view. For this purpose 59 permanent plots on unaltered sites and 52 permanent plots on freshly sown sites were established in 2011 and 2012. Our results show that the natural revegetation on humus-free bare surfaces is a slow and long-term process due to the lack of diaspores and the inherently extreme abiotic site conditions. In an early stage of primary succession, the pioneer vegetation is, with few exceptions, characterized by a low vascular plant species richness. Artificial revegetation measures using commercial seed mixtures accelerate grassland re-establishment, leading to a plant community of low nature conservation value which is dominated by a few sown grass species and legumes. The effects of different restoration measures (liming, application of straw or farmyard manure) on vegetation will be discussed.
Bohner, A., Winter, S., Kraml, B., Holzner, W. (2013): Destructive and constructive effects of mudflows - primary succession and success of pasture regeneration in the nature park Sölktäler (Styria, Austria). 5th Symposium for Research in Protected Areas, 71-74