Vincent de Leijster

210 Summary The resources of our planet are the supporting system of human livelihoods and their well- being. Nevertheless, human-induced pressures have strongly affected the Earth, reducing its biocapacity at unprecedented speed, leading to massive losses of species, ecosystem functions and the loss of ecosystems’ capacity to provide vital services. Agriculture has been identified as the most dominant driver of land degradation. Agricultural intensification and crop specialization have increased yield of single crops, but with strong trade-offs, resulting in environmental degradation. The damage to the environment, as for example through the loss of regulating and supporting ecosystem services, in turn is expected to make agricultural systems more vulnerable to external stressors and threatens their sustainability. Agricultural production strongly relies on ecosystem services, for example, soil fertility maintenance, pollination, natural pest control and erosion control are of vital importance for the performance of an agricultural system. Securing livelihoods and biodiversity therefore requires an alternative land management approach that promotes both crop production and a balanced set of ecosystem services. Agroecology has been proposed as such an alternative as it is not based on a fixed set of land management practices, but rather promotes several concepts around the functioning of biophysical processes, such as minimizing soil disturbance, securing favorable soil conditions, diversifying species (including crops), recycling biomass, and minimizing the loss and leaching of soil, water, nutrients and biomass. In this thesis I investigate how agroecological interventions in woody crop systems affect the supply of ecosystem services and farm economic performance, and which incentives influence them. Therefore, I defined the following four research questions: 1. How does ecological performance differ between agroecological and conventional systems? 2. How do ecosystem service trajectories develop following agroecological interventions? 3. How do agroecological interventions influence the economic performance of a farm, and what is the role of farming strategies and incentives? 4. Which trade-offs or synergies emerge in agroecological transitions? After the general introduction (Chapter 1), I introduce the two case studies of this thesis (Chapter 2). These are almond orchards in Andalusia (Spain) and coffee plantations in Risaralda (Colombia). In both areas I analyzed the ecological and economic performance