GRAssland Communities Experiment

Grasslands make up a third of European agricultural area, include some of the most diverse habitats on Earth, and have significant economic and cultural value. They are also uniquely human habitats, and without regular intervention, most would revert to forest within decades. However, ongoing changes in landscape management have dramatically altered the extent and spatial structure of these habitats and given the ever-mounting pressures of more intense management methods, increasing urbanisation, and climate change, Central European grasslands are facing an increasingly uncertain future. In the GRAssland Communities Experiment (GRACE), we draw on insights from three centuries of changes in management across the historical extent of the Austro-Hungarian empire to learn how landscape composition and structure impacted the region over this time period, and how these changes have influenced grassland plant community diversity and composition. To quantify changes in landscapes and grassland plant community structure, we use an unprecedented combination of historical data and novel methods, including: (i) >100.000 botanical plot records collected in grasslands across Central Europe over the past century; (ii) an intensive fieldwork campaign to resurvey ~1.200 of these plots; (iii) three centuries of surveys mapping landcover change across the historical extent of the Austro-Hungarian empire; and (iv) cutting-edge theoretical tools for interpolating, forecasting, and explaining complex dynamics with state space modelling and machine learning. Jointly, these tools allow us to quantify the impacts of large-scale landscape change via a natural experiment driven by differences in the timing and intensity of agricultural collectivisation across Central Europe in the 20th century. One of the most important anticipated outcomes of this project is that it will help quantify the extent to which large-scale historical landscape changes in Central Europe have had major impacts on grassland plant communities. Past analyses in other regions have yielded conflicting results, making it difficult to predict the impact of ongoing landscape changes on grassland communities. To overcome these challenges, GRACE leverages insights from a new group of large-scale datasets, and draws on novel information from a long-running natural experiment, to more effectively gain specific, causal understanding of the relationships between landscape and community structure. Our results have the potential to improve understanding of Central European grasslands, and to help resolve uncertainty surrounding the impacts of landscape change on grassland plant communities around the world. Primary researchers involved in the project include Adam T. Clark (Uni. Graz), Petr Keil (Charles Uni. Prague), Hana Skokanov (VUKOZ, Brno), and Franz Essl (Uni. Vienna)