Wei Zhang

Impact of farm size on the function of landscape-level payments for ecosystem services: An agent-based model study

Reducing pesticide use and restoring biodiversity are among the most pressing environmental challenges. Enhancing natural pest control ecosystem services through the integration of non-crop habitats (NCH) offers promising potential, creating a positive feedback loop by harnessing insect biodiversity to reduce pesticide reliance. Policy support is needed at the landscape level to encourage adoption of this currently underutilized approach, which depends on spatial coordination and collective behavioral change. Farm size, which critically influences farmers’ agrochemical inputs, agroecological practices, and interactions with neighboring farms, varies across agricultural landscapes. It is unclear what role farm size plays in landscape-scale agri-environmental incentive programs, which have recently seen growing attention in scientific research and policy implementation. We employ framed field games and agent-based modeling as complementary research tools, exploring how farm size impacts the function of landscape-scale NCH subsidies aimed at encouraging coordinated provision and sharing of natural pest control services to reduce pesticide use. Our model simulation shows that, in landscapes of larger average farm size or lower farm size heterogeneity, NCH subsidies are significantly more effective at reducing pesticide use and increasing NCH efficiency in providing joint production benefits. Our results imply that landscape-scale payments for natural pest control ecosystem services face fewer obstacles as incentive-based mechanisms in landscapes of larger, more homogeneous farms, supporting the implementation of landscape-scale initiatives in such areas to effectively enhance ecosystem services. Our findings contribute to the growing discussion around landscape-level financial incentive programs that depend on spatial coordination, highlighting the importance of farmers’ land holding size.

Understanding pastoralist adaptations to drought via games and choice experiments: Field testing among Borana communities

Transhumant and nomadic pastoralism in arid and semi-arid spaces from West through Central, East, and Southern Africa is regarded as critical to regional system resilience and food security. Although pastoral systems are highly adapted and adaptive to uncertainty and change, recent decades of severe climatic events and increasing resource pressure are pushing pastoral systems to adopt novel norms and practices. Importantly, forage residue conservation and private forage enclosures are becoming important practices among herders and non-herders alike. As one part of considering the relevance of these responses in shaping the future trajectory of transhumant pastoralism, we developed a multi-part intervention for measuring and observing preferences in pastoral systems, including a novel experimental game called GreenReserve, and tested it in Borana communities in northern Kenya. We found that GreenReserve captured dimensions of human-environment dilemmas faced by pastoralists, and shifted preferences around herd size, losses, and the use of time, as measured through a repeated discrete choice experiment. We found game groups with younger players and with more female players to include more exploration of pastoral adaptations such as the use of grass reserves and the harvesting of grass, as well as to have less conflict within the game. We also observed both preferences as well as game strategy to shift along the length of the study: as the region moved further into a drought and failed short rainy season, players were more conscious of large herds, bad rainfall-year losses, and made better use of reserves in game play, though it was beyond the scope of the current study to determine causality. Future research is needed to unpack the mechanisms underlying the variations and possible shift in preferences and subsequently help identify entry points for targeted interventions (including agricultural extension services) to support pastoral communities in climate change adaptation. Further, these first fieldwork findings suggest two key dimensions for expanded work beyond this study to identify whether mixed methods approaches such as this aid experiential learning in agriculture contexts.

Experiential learning tools for sustainable water management [India]