Biodiversity restoration in grasslands; understanding the role of plant traits and their plasticity in N:P-stoichiometry and competition

Biodiversity decline in European grasslands is assumed to be driven primarily by nitrogen (N) enrichment. However, recent findings challenge the validity of this prevailing paradigm. Large-scale field surveys as well as studies on plant nutrient uptake and use at the individual plant level suggest that both N and phosphorus (P) availability have to be taken into account. This requires a stoichiometric approach. We suggest that plant species with a large phenotypic plasticity for acquiring and using nutrients are better able to cope with changes in nutrient availabilities (both N and P) than less plastic species. This could explain why opportunistic plastic species are competitive winners along N:P stoichiometric gradients in a eutrophying world. This study aims to (1) identify key traits for nutrient acquisition and use along N:P stoichiometric gradients in grasslands; (2) assess the phenotypic plasticity of these traits for species of Dutch grasslands and (3) understand how plasticity affects species competition and plant community dynamics along N:P gradients. The proposed research will generate new knowledge about the mechanisms of species loss from a highly-valued and potentially species-rich ecosystem. The project is carried out in a transdisciplinary approach with active participation of nature managers. The knowledge generated is vital for effective grassland conservation and management since it enables nature managers to identify measures that can prevent species extinction or restore species diversity in grasslands. This allows for optimization of management and spatial planning of different types of grasslands in rural areas where space and low fertility soils are scarce.