Climate gradients explain changes in plant community composition of the forest understorey: An extrapolation after climate warming

摘要

Over the past 100 years, the global average temperature has increased by approximately 0.6degreesC and is expected to increase by 1.4 to 5.8degreesC in the 21(st) century. This climate warming is expected to alter distribution ranges and boundaries of many plant and animal species, including forest plant species. We used 677 existing vegetation releves, recorded in Querco-Fagetea forests in France, Belgium and the Netherlands on the one hand, and temperature and precipitation data of 150 meteorological stations distributed throughout the study area on the other hand, for a correlational analysis. The current plant species distributions in relation to present-day climate are used to make predictions about possible climate-induced range-boundary changes in the future. Analysis of climatic gradients showed that the expected increase of 3degreesC in the northern part of the study area will result there in a climate very similar to the climate nowadays in the center of the study area. Several forest plant species can be expected to move several hundreds of kilometers northward and to thereby change present-day community structures. Based on the species attribute results, we can expect species with higher Ellenberg-T values, scleromorphic species, hemicryptophytes and stress-tolerant species to become relatively more abundant in the northern regions of the study area. Four phytoclimatic groups, i.e., groups of species with similar responses to climatic variables, were identified based on the species' climate optima within the study area. The results of this analysis suggest that more than 50 % of the total number of species occurring in the study area might have a chance to become vulnerable to extinction after climate warming.