Drivers of Distribution and its Changes in two Closely Related Species with Contrasting Elevational Distributions Over two Decades

Abstract

\n Climate change has an enormous impact on species and communities, especially those in the alpine and arctic environments. Even though the reactions of species to climate change have been widely studied, their responses are not straightforward, and it is necessary to focus on them in more detail. In this study, we assessed the distribution of two closely related grass species Anthoxanthum odoratum , an allotetraploid species of lower altitudes and A. alpinum , a diploid occurring in higher altitudes, in the Krkonoše Mts., the Czech Republic. We explored the drivers of their current distribution and its changes over the past two decades during the ongoing climate change. The results indicate that distribution of these two species has not considerably changed, as there is only a weak evidence of a wider distribution of A. odoratum compared to the past. Surprisingly, A. alpinum has newly appeared at some localities at lower altitudes. Changes in the distribution of the two species over time were significantly related to a range of local habitat characteristics such as vegetation or bryophyte cover, nutrient level, moisture, or species composition, but were largely independent of altitude, a variable expected to be a proxy of climatic conditions of the localities. This indicates that the environmental characteristics of the localities, play more important role in species distribution and its changes than global climate change.