Traditionally managed mountain grasslands are declining as a result of abandonment or intensification of management. Based on a common chronosequence approach we investigated species compositions of 16 taxonomic groups on traditionally managed dry pastures, fertilized and irrigated hay meadows, and abandoned grasslands (larch forests). We included faunal above- and below-ground biodiversity as well as species traits (mainly rarity and habitat specificity) in our analyses. The larch forests showed the highest species number (345 species), with slightly less species in pastures (290 species) and much less in hay meadows (163 species). The proportion of rare species was highest in the pastures and lowest in hay meadows. Similar patterns were found for specialist species, i.e. species with a high habitat specificity. After abandonment, larch forests harbor a higher number of pasture species than hay meadows. These overall trends were mainly supported by spiders and vascular plants. Lichens, bryophytes and carabid beetles showed partly contrasting trends. These findings stress the importance to include a wide range of taxonomic groups in conservation studies. All in all, both abandonment and intensification had similar negative impacts on biodiversity in our study, underlining the high conservation value of Inner- Alpine dry pastures.

In the Central Alps the treeline is formed by the European larch (Larix decidua Mill.) and the Swiss pine (Pinus cembra L.), shaping the alpine plant community Larici-Cembretum. Currently, alpine pastures, which are increasingly abandoned in the European Alps, are colonised, after a phase of shrub encroachment, by the European larch, while a Swiss pine forest will establish once the undergrowth becomes too dense for larch trees. Former studies on tree growth rates indicate that the European larch will react positively to increasing temperatures at the treeline and will grow faster in the future. The Swiss pine has in general slower growth rates and will likely be less affected by higher temperatures. Thus, there might be a change from Swiss pine to European larch forests. This change in the dominating tree species might have profound impacts on the soil macro-invertebrate community, particularly due to differing chemical and physical compositions of larch and pine needle litter. To investigate potential effects of this change, we took soil core and litter samples and further installed pitfall traps in pure European larch and Swiss pine forests, as well as in mixed forests. We found no explicit differences in species composition between forests, presumably due to highly variable site and environmental parameters between and within forest types. The larch forests showed the highest number of taxa in general and the highest number of taxa found exclusively in this habitat. The pine forests were inhabited by the highest number of characteristic taxa while mixed forests harboured the most stable and consistent soil macro-invertebrate community.