Vincent de Leijster

15 General introduction 1 non-linear pathways, in other words, there are variations in the order of magnitude of the change in supply over time (Bullock et al., 2011; Locatelli et al., 2017). Examples include a sigmoid trajectory (S-shape) when the change in supply is slow, then fast and then slow, a hump-shaped trajectory (increase then decrease), and an asymptotic trajectory (fast then slow). In a Canadian recovering forest, the development of carbon stock and wood volume followed a sigmoid trajectory, whereas the provision service, berry production, followed a U-shaped trajectory (Sutherland et al., 2016). These trajectories are increasingly being studied, but the development of ecosystem service trajectories on a small scale and in agricultural contexts is yet unknown; nor do we know much about the ecosystem services development in response to restoration activities. Since there are differences in ecosystem service provisioning between agroecosystems and conventional agricultural systems, I hypothesize that an agroecological intervention will trigger an ecosystem services response and will thus enable us to study ecosystem service trajectories and interactions. 1.3 Economic interventions In the context of an agroecological transition, I described earlier that it has been suggested that the intensification of ecological processes will contribute to higher crop productivity, as each agroecosystem relies on these ecological processes (Kleijn et al., 2019b). However, there are also studies that suggest that agroecological management reduces productivity due to competition processes for example (Rosa-Schleich et al., 2019), as well as studies that propose that there is a transitioning phase in which the productivity is first lower and then recovers (Giller et al., 2009). If the yield of the main crop were reduced by agroecological practices, then it could be compensated by the other farm economic performance components. These other economic performance components not only include the quantity of the products produced, but also their quality and diversity, and they include management costs and delivery of marketable services. The economic components are influenced by farmers’ decisions; for example, changes in input management may increase crop yield, improvement of soil fertility may improve crop quality, intercropping or polyculture may lead to diversification of the produce, attracting birds and insects may lead to savings on the costs of pesticides, and planting trees may facilitate the marketing of carbon credits. Some studies have shown that crop diversification (intercropping, polyculture, or agroforestry) improves the total land productivity compared to monoculture, despite a lower production of the main crop (Letourneau et al., 2009; Letourneau, 1973; Souza et al., 2011). Furthermore, it has been proposed that agroecological management provides better biological pest control, resulting in savings on pesticide costs (Rosa-Schleich et al., 2019). By producing a product of