Lost at high latitudes : Arctic and endemic plants under threat as climate warms

Aim: Species' biogeographical patterns are already being altered by climate change. Here, we provide predictions of the impacts of a changing climate on species' geographical ranges within high-latitude mountain flora on a sub-continental scale. We then examined the forecasted changes in relation to species' biogeographic histories. Location: Fennoscandia, Northern Europe (55-72 degrees N). Methods: We examined the sensitivity of 164 high-latitude mountain species to changing climate by modelling their distributions in regard to climate, local topography and geology at a 1 km(2) resolution. Using an ensemble of six statistical modelling techniques and data on current (1981-2010) and future (2070-2099) climate based on three Representative Concentration Pathways (RCPs 2.6, 4.5, 8.5), we developed projections of current and future ranges. Results: The average species richness of the mountain flora is predicted to decrease by 15%-47% per 1 km(2) cell, depending on the climate scenario considered. Arctic flora is projected to undergo severe range loss along with non-poleward range contractions, while alpine flora is forecasted to find suitable habitat in a warmer North. A substantial majority (71%-92%) of the studied species are projected to lose more than half of their present range by the year 2100. Species predicted to lose all suitable habitat had ranges centred in the northernmost (>68 degrees N) part of continental Europe. Main conclusions: Climate change is predicted to substantially diminish the extent and richness of Europe's high-latitude mountain flora. Interestingly, species' biogeographic histories affect their vulnerability to climate change. The vulnerability of true Arctic and endemic species marks them as highly important for conservation decisions.Peer reviewe

Drivers of high-latitude plant diversity hotspots and their congruence

Determining the drivers, patterns and hotspots of biodiversity can be of critical importance in supporting regional conservation planning. However, as biodiversity hotspots can be described with several different metrics, it is important to investigate their congruence as well as the spatial overlap of hotspots with protected areas. Here, by using extensive data on climate, topography, soil characteristics and vascular plants combined with boosted regression tree models, we determine the patterns and key drivers of plant diversity hotspots along broad environmental gradients in northernmost Europe spanning from taiga landscapes to treeless tundra. We assess plant diversity with four metrics – species richness, range-rarity richness, threatened species richness, and local contribution to beta diversity – and examine their congruence with each other as well as with contemporary conservation areas. We found that climate plays an important role in governing species diversity, though topo-edaphic are highlighted alongside climatic predictors in determining the diversity patterns of many threatened, nearthreatened, and range-restricted species. Importantly, the different diversity metrics have contrasting drivers and, overall, their hotspots have low congruence. Furthermore, existing protected areas appear to offer limited coverage for hotspots of vascular plant diversity. Modelling the various facets of diversity and their drivers, such as the topo-edaphic setting, may provide useful information to help conserve diversity in a changing climate. Projected patterns of different aspects of diversity and their congruency can provide insights into the processes underlying biodiversity and be employed to assess the representativeness of protected area networks.Peer reviewe