Effects of fine-scale topographic variation on climatic connectivity in alpine landscapes

Abstract

As climate change renders current habitats unsuitable for plant species, dispersal to favourable locations is an essential strategy for their populations’ persistence. In mountainous regions, climate warming may force species to move upward along elevational gradients or, as a possible shortcut, to colonize cold(er) micro-sites in the topoclimatically rugged terrain. Here, we employed climate connectivity analyses to assess how apparent options for such movement in an alpine landscape vary with different degrees of depicted microclimatic variation. We used topographically informed spatial interpolations of soil temperature and calculated climatic connectivity at six different spatial resolutions (1, 5, 10, 20, 50, 100 m) therefrom via a directional movement from warmer to colder temperatures, for two future climatic scenarios. Under strong warming, climatic connectivity of the landscape was improved with higher degree of depicted microclimatic variation, but even at very fine resolution a substantial proportion of the study area, especially in higher elevations, failed to achieve connectivity. These findings partly support the idea that microclimatic variation of topographically complex landscapes can buffer alpine flora against the effects of climate change. However, this buffering becomes increasingly ineffective with magnitude of warming, particularly for cold-adapted species.