Climate change threats to plant diversity in Europe

Abstract

Climate change has already triggered species distribution shifts in many parts of the world. Increasing impacts are expected for the future, yet few studies have aimed for a general understanding of the regional basis for species vulnerability. We projected late 21st century distributions for 1,350 European plants species under seven climate change scenarios. Application of the International Union for Conservation of Nature and Natural Resources Red List criteria to our projections shows that many European plant species could become severely threatened. More than half of the species we studied could be vulnerable or threatened by 2080. Expected species loss and turnover per pixel proved to be highly variable across scenarios (27-42% and 45-63% respectively, averaged over Europe) and across regions (2.5-86% and 17-86%, averaged over scenarios). Modeled species loss and turnover were found to depend strongly on the degree of change in just two climate variables describing temperature and moisture conditions. Despite the coarse scale of the analysis, species from mountains could be seen to be disproportionably sensitive to climate change (approximately 60% species loss). The boreal region was projected to lose few species, although gaining many others from immigration. The greatest changes are expected in the transition between the Mediterranean and Euro-Siberian regions. We found that risks of extinction for European plants may be large, even in moderate scenarios of climate change and despite inter-model variability.

Fig. 1.

Proportion of species classified according to the IUCN Red List assessment under two extremes assumptions about species migration. EX, extinct; CR, critically endangered; EN, endangered; VU, vulnerable; LR, lower risk.

Fig. 2.

Estimated percentage of species loss and turnover. Upper extreme, upper quartile, median, lower quartile, and lower extreme are represented for each box.

Fig. 3.

Relationships between the percentage of species loss and anomalies of moisture availability and growing-degree days. The colors correspond to different climate change scenarios.

Fig. 4.

Regional projections of the residuals from the multiple regression of species loss against growing-degree days and moisture availability. Red colors indicate an excess of species loss; gray colors indicate a deficit.

Fig. 5.

Spatial sensitivity of plant diversity in Europe ranked by biogeographic regions. Mean percentage of current species richness (Left) and species loss (Center) and turnover (Right) by environmental zones under the A1-HadCM3 scenario.