Models of Arcticalpine refugia highlight importan

Authors: Annina Niskanen Miska Luoto Henry Väre Risto K Heikkinen

Publish Date: 2016/05/31

Volume: 40, Issue: 3, Pages: 489-502

PDF Link

Abstract

Projected climatic warming calls for increased attention to the identification of suitable refugia for the preservation of biota and ecosystems in changing highlatitude environments One such way is the development of models for drivers of refugia Here we investigate the distribution and species richness of Arcticalpine vascular plant species’ refugia The study is carried out in an environmentally variable area in N Europe encompassing the northern boreal to the Arcticalpine zone We defined refugia as isolated 1 km × 1 km grid cells with multiple Arcticalpine plant species occurrences outside their main distribution area and assessed the main environmental factors underlying their distribution and richness using crossvalidated boosted regression tree modelling In the modelling we examined the effects of climatic topographic and geologic factors and the connectivity of sites with refugia incrementally ie first modelling climatic impact alone then with separate additions of topographic geologic and connectivity variables concluding with a model including all predictor variables The inclusion of slope and connectivity significantly improved model performance Although climate has a central role in controlling the occurrence of refugia topography provides important clues for recognizing heterogeneous locations that harbour refugia with suitable local thermal and moisture conditions Results suggest considering refugia as on the one hand isolated pockets of suitable habitat but on the other hand as potentially interconnected habitat networks In general our study demonstrates that the spatial patterns of refugia can be successfully modelled but emphasizes a need for highquality data sampled at resolutions reflecting significant environmental gradientsA Niskanen was funded by the Doctoral school of Geosciences and Nordenskiöld samfundet We acknowledge funding from the Academy of Finland The Finnish Research Programme on Climate Change Project Number 1140873 We would like to thank the Finnish Museum of Natural History as one of the main contributors of the vegetation data and Juha Aalto for helping in gathering the environmental data and data analysis

Keywords: