Potential effects of climate change on the distribution of the common frog Rana temporaria at its northern range margin

Abstract

Climate change is projected to be particularly strong in northern latitudes, and subarctic species are thus likely to be especially susceptible to the effects of climate warming. We forecast potential effects of climate change on the extent of the suitable habitat of the common frog,Rana temporaria,at the margin of its northern range. We investigated 179 potential breeding sites in subarctic Finland and subjected the data to detailed bioclimate envelope modelling using three state-of-the-art techniques: generalized additive models, maximum entropy and generalized boosting methods. Moreover, we included local environmental factors in the models to investigate whether they improve model performance. Under all tested climate change projections and irrespective of the modelling method, the suitable habitat forR. temporariaincreased in warming climate. The inclusion of local abiotic variables significantly improved the performance of the models. However, June temperature appeared to be the most informative variable in all modelling approaches: a major increase in the extent of suitable habitat occurred when it increased by 1°C. Overall, the modelling results indicate that the distribution of northernR. temporariais likely to be very sensitive to climate warming. The results also highlight the fact that overlooking local abiotic variation can significantly bias bioclimatic modelling results.