From challenges to opportunities in abandoned farmlands: Assessing benefits and trade-offs of alternative farmland abandonment trajectories.

With urbanisation, agricultural intensification, land degradation and climate change, Europe faces increasing pressures on land use. To address these challenges, the European Union (EU) defined new targets in the Green Deal and related policies for more sustainable land management and to restore natural ecosystems. However, it is challenging to find sufficient space that is not in conflict with current land uses to implement these new management practices. Contrary to land use intensification, farmland abandonment is an ongoing process in many European regions. It is characterised by the withdrawal of farming activities on land that was initially under agricultural use. Following the cessation of management, semi-natural vegetation generally re-grows on the land, leading to positive or negative outcomes depending on the local conditions. To assess opportunities and constraints for the development of alternative management responses to farmland abandonment in Europe, with considerations for environmental benefits and trade-offs, as well as the barriers and constraints for implementation, the following research questions are examined: (1) What are the different farmland abandonment trajectories and their potential consequences (benefits and trade-offs) in different contexts? (2) What are the barriers faced by decision-makers (including landowners and policy-makers) for the implementation of these different trajectories, and what scientific knowledge is important to support decisions on the responses to farmland abandonment? This first research question is mostly addressed in Chapters 2 and 4, while the second research question is examined in Chapters 3 and 5. The introduction (Chapter 1) presents the general context for the thesis. Overall, this thesis demonstrates that there is variety of farmland abandonment trajectories, with the potential to bring a wide range of benefits, risks, and trade-offs. The various possible outcomes from abandonment as well as diverse management strategies that exist show opportunities for flexible and adaptive uses of these areas. Abandonment can be positive on its own (i.e., spontaneous land restoration), however, when favourable outcomes are unlikely, or to reach specific targets, active support for management is often needed. Therefore, guiding abandonment trajectories towards such favourable directions, and responding effectively to future abandonment, will require contributions from science, policy, and local knowledge. Overall, a takeaway from this thesis is that although abandoned farmlands have lost their productive function, they remain key in landscape planning as they hold a great potential for alternative functions. It is therefore essential to integrate them into the global societal, rural, natural, and environmental perspectives.