Climate change impacts on global alpine plant diversity

The destruction of the Planets intact terrestrial biosphere is progressing rapidly as a result of human land use and exploitation. Mountain habitats were considered to be the most important refuges of threatened species due to their difficult accessibility, topographic diversity and their global distribution. Climate change, however, especially in the form of an unabated rise in temperature caused by human activities is also affecting the wilderness areas of remote high mountain regions. For species living above the forest zone in the alpine and nival elevation belts, this creates a new component of threat that can lead to their extinction for the following reasons: (1) Typical high mountain species are adapted to cold conditions and lose their habitats due to direct warming effects or competitive displacement by species from lower elevations. (2) Mountain species generally have much smaller distribution areas than species from lower altitudes and we expect that sufficiently cold refugial areas are often inadequate in terms of their surface area or the soil conditions required for colonization. (3) In mountains with isolated and small alpine areas, the proportion of local endemics (i.e. species that only occur within a small area) is often particularly high, which means that a very high risk of extinction can be assumed. Against this background, an international research network, the Global Observation Research Initiative in Alpine Environments (GLORIA), was established 25 years ago for the purpose of long-term monitoring of plant species in high mountain regions. The network of mountain summit observatories with permanent vegetation plots was initiated in Austria and is now active on all populated continents. The data collected with the participation of more than hundred research institutions is now available for the first time for a worldwide data analysis to answer the following research questions: (I) Are changes in species numbers and their composition related to the regional rate of climate change? (II) Did the simultaneous occurrence of warming and increased drought stress lead to an increased loss of plant diversity? (III) Are small-ranged species of high mountains overrepresented among the disappearing species and large-ranged ones among the increasing species? In the GLORIAGLO project, vegetation data and time series of soil temperature from over a hundred study areas distributed over the Earth`s mountains are combined with remote sensing data on topography and seasonal changes in green vegetation and snow cover, as well as with gridded climate data series and the global distribution and ecological niche of species. The aim is to compare the magnitude and velocity of biodiversity changes in alpine vegetation worldwide for the first time and to analyse and evaluate them in relation to the most important influencing ecological drivers.