Drought stress inducing intraspecific variability in Potentilla tabernaemontani (Rosaceae), a calcareous grassland species

Background and aims - Calcareous grasslands are among the most species-rich habitats in Western Europe. Populations of plant species characterizing these ecosystems are naturally submitted to high variability in environmental conditions at the very local scale, resulting in pronounced variation in functional traits. Individuals located on xeric parts of calcareous grasslands are characterized by plant traits that potentially ensure more successful performance under stressful conditions. In the context of increased frequency of summer heat waves based on climate change, our aim was to determine a possible intraspecific variability in drought response among individuals of one calcareous grassland plant species. Methods - A greenhouse experiment was set up to follow survival of Potentilla tabernaemontani Asch. individuals according to their habitat of origin (xeric or mesic parts of Belgian calcareous grasslands) and the treatment applied (low or high drought stress). Key results - The results demonstrated that individuals originating from xeric parts survived drought stress better than individuals from mesic parts of calcareous grasslands. Specific leaf area (SLA) of all individuals was very low in the experiment, allowing them to decrease water loss during drought stress. Leaf production was lower for individuals exposed to high drought stress while flower production was higher. That potentially expressed a trade-off between tolerance to water stress, individual growth and reproduction. Conclusions - Local scale environmental heterogeneity deserves to be considered in conservation and restoration plans as it induces intraspecific functional variability between individuals and impacts individuals' ability to survive drought stress.