Plant communities along elevational and temporal gradients at the GLORIA sites in the Dolomites

Climate warming can be regarded as the main factor for changes occurring in alpine ecosystems. As high elevation species in the Alps are considered to be particularly sensitive to climate change, long term monitoring projects are important to determine amount and direction of biodiversity changes. This study extended the monitoring of the GLORIA sites in the Dolomites, started in 2001. According to previous studies, eastern and southern aspects are those with the most notable changes. We focused, therefore, on the identification and distribution of plant communities and the phytosociological differences between the summits and their southern slopes from the treeline upward. Ecological differences should be unravelled by the analysis of LANDOLT indicator values temperature and soil nutrients as well as by the competitive and non-competitive species. Four plant communities were identified on the south-facing slopes. Three of them were alpine grassland communities, while scree vegetation was only found on the higher plots of the highest summit. At the summits, additionally, two pioneer grassland communities were identified. This study gives further evidences of the ongoing thermophilisation at the summits. From our results it seems that on one summit changes in the plant communities are more likely to happen in the near future, while on the other two summits topographical barriers should prevent imminent changes