Eco-evolutionary dynamics in plant-soil interactions during land use transition: consequences for soil functioning and resilience to drought

European grasslands have been shaped by millennia of low-intensity management and are unique cultural and biodiversity hotspots providing critical ecosystem services. However, the area of traditionally-managed grassland has declined dramatically during the last century, with land-use intensification on productive soil and abandonment of unfertile land both causing species loss and deterioration of ecosystem services. Recent evidence suggests that land-use change also leads to genetic and phenotypic changes in plant populations. How population-level processes mediate the impact of land use on ecosystem functions and affect adaptive potential to future perturbations is entirely unknown. Filling this knowledge gap is urgent as grasslands face additional pressure from climate change, particularly an increasing frequency of droughts. I hypothesise that land use intensification and abandonment lead to evolutionary shifts in plant function away from resource conservation towards fast resource acquisition and low stress tolerance. Combined with the disruption of co-evolved mutualistic plant-microbial interactions, this has cascading effects on essential ecosystem services provided by soils and their resilience to drought-induced perturbation. The hypothesis will be tested using laboratory tests of the mechanisms underlying eco-evolutionary dynamics in plant-soil interactions during land-use change and community-level experiments to uncover the consequences of adaptation for soil functioning and resilience to drought. I will use the world's longest-running fertilization experiment and grassland networks in three European regions, representing different histories and contrasting management regimes. The project will provide a step-change in our understanding of the selective pressures imposed on plant-soil systems by human land use and will inform future policies for sustainable land management and maintenance of adaptive potential in the face of climate change.