Drought Stress Distribution Responses of Continental Beech Forests at their Xeric Edge in Central Europe

In order to develop adequate adaptation measures for environmental vulnerability, we need detailed knowledge on the climatic performance of forest ecosystems. In this study, we aim to explore climate function variability of lowland beech forest distribution at a landscape scale. We also construct the response profiles of these forests near their xeric limit under wet continental climatic conditions. We studied distribution responses using presence-absence forest records and 18 bioclimatic variables. We performed exploratory factor analysis and frequency estimation to evaluate climate function distribution responses. We found that temperature adjusted precipitation measures during summer were the most important, followed by winter rainfall indices. The relative Drought Response Range (rDRR) in the response profile presented the climate limitation function of the distribution. According to our results, higher level of climate function variability is associated with lower level of rDRR, presenting an ecological trade-off. Our results suggest that distribution functions of the rDRR, especially the Ombrothermic index, can be used as landscape indicators of drought stress. Consequently, rDRR could be a useful measure to assess regional climatic vulnerability of forest occurrence and distribution patterns.