Geographic variation in the response to drought in nine grassland species

Summer precipitation is expected to decrease in Europe due to climate change, which in turn will increase the risk for plants to suffer from drought. To maintain ecosystem functions in grasslands under the conditions of climate change, drought adapted varieties of plant species may be needed. With our experiment, we bridge the gap between single species experiments and field experiments with whole plant communities under proposed scenarios of climate change. In a greenhouse experiment, we investigated the drought response of nine common grassland species which are normally utilized for restoration of mesic grasslands. We chose five European provenances of each species to test for a consistent, provenance-specific drought response. Plants of all nine species were negatively affected by drought with respect to their biomass production, and consistently allocated less resources to roots than control plants. On the other hand, reproductive allocation increased under drought conditions in some species whereas no response to drought could be detected in specific leaf area. In contrast to our expectation, we found little evidence for intraspecific variation in response to simulated drought. However, we found a clear correlation between responsiveness in root allocation, and climatic conditions at the provenance's origin. This pattern became evident only when all species were analysed together, highlighting the advantage of multi-species experiments.