Effects of global warming on the alpine vegetation of four peaks in the Texel Group, South Tyrol, as part of the GLORIA project

Friederike Westrich ¹, Martin Mallaun ¹, Brigitta Erschbamer ¹, Pau Carnicero ¹

University of Innsbruck ¹

Climate change has a particularly strong impact on alpine vegetation, its distribution and its phenology, as these ecosystems are determined by cold temperatures. Global warming has triggered an increase in species richness at higher elevations, due to upwards migration of less cold-tolerant species. However, this is predicted to set local cryophilic species under extinction debt, due to an increase of competition. To track this trend, the GLORIA monitoring program (Global Observation Research Initiative in Alpine Environments) operates permanent observation plots in 130 study areas worldwide. The study presented here focuses on the GLORIA study area Texel Group (South Tyrol, Central Alps). The study area consists of four monitored summits, ranging from the subalpine to the nival elevation belts. In each summit, four permanent plots and eight sections of the summit area were monitored since 2003, following the standardized protocol of GLORIA. The soil temperature in the four summit aspects is also recorded. Recent comparisons of the monitoring data from 2003, 2011 and 2017 showed that the species number on the three lower summits increased significantly, while the highest summit showed no changes. The data of 2024 revealed a different pattern. The increase in species numbers continues on the two lower summits, but stagnated on the third highest. On the highest summit, Kasererwartl, a rapid increase in species number from eight to 15 occurred over the last seven years. The observed increase in species numbers is significantly correlated with higher annual mean temperatures and warmer winter temperatures. A significant increase of species number was found in all expositions except the northern plots. Kasererwartl showed a significant increase of thermophilic species, and the second highest summit lost the most cryophilic species. In the latter, the new and lost species have a significant difference in the upper elevational distribution range — new species show mostly lower distribution ranges. The significant increase in species with a higher indicator value for temperature and nutrients was found on this summit and also on the highest summit. This data indicates that high summits which have been weakly affected by climate change so far are now experiencing a rapid change in species richness and composition. At the lower summits, a stagnation of species richness or an extinction debt in cryophilic species has not been observed yet.

Main author career stage: Master student

Contribution type: Talk

First choice session: 3. Biodiversity and global change

Second choice session: 2. Ecology