21st century climate change threatens mountain flora unequally across Europe

Abstract

Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36–55% of alpine species, 31–51% of subalpine species and 19–46% of montane species lose more than 80% of their suitable habitat by 2070–2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.

The two workshops leading to this study were granted by the Herbette Foundation, the Faculty of Geosciences and Environment at the University of Lausanne and the Mountain Research Initiative (MRI). A. G. and R. E. received further support from the Swiss National Science Foundation (SNF grant 31003A- 125145/NCCR Plant Survival) and the European commission (MACIS and ECOCHANGE projects). S. D. was supported by the ECOCHANGE project and M. P. by CNCSIS-UEFISCSU, project PNII-Resurse Umane (PD_405/no. 123/29.07.2010). M. T. S. was supported by EU INTERREG I3A4147E and MICINN CARBOPAS/CARBOAGROPAS/MONTES. M. B. A. was supported by the FCT RangeShift project. P. B. P. acknowledges support by SNF grants CRSII3_125240 ‘SPEED’ and 31003A_122433 ‘ENNIS’. W. T. acknowledges support from the French ANR DIVERSITALP (ANR-2007-BDIV-014). D. N. B. thanks the Danish National Research Foundation for support to the Center for Macroecology, Evolution and Climate. F. H., J. A. G. and E. H. received financial support from the Norwegian Research Council. Herbarium JACA was supported by R. P.: CGL2010-21642. M. T. was supported by NERC.