Ecohydrology of Agroecosystems: Interactions Between Local and Global Processes

Abstract

As a source of food, feed, biomass, and income, agriculture is central for human welfare, locally and globally. At the same time, agriculture exerts often unsustainable demand on natural resources, with potential negative cascading environmental effects. Population growth, richer diets, rising international trade, and climate change are expected to increase and redistribute resource demand in unprecedented ways. The inherent coupling of local and global aspects of agricultural production is particularly strong in drylands, as the result of multiple and often competing demands on water resources. In this chapter, we explore these interactions and how global influences may be manifested in local cropping decisions and how local conditions can influence large-scale food supply and food security. Global drivers of food demand and international food trade act as telecoupling mechanisms, linking individual consumer choices with (sometimes geographically distant) environmental impacts of food production within dryland regions. Local production decisions can lead to consumptive water use exceeding renewable water availability: these human-made “anthropogenic drylands” occur disproportionately in dryland regions. As farmers must contend with local conditions, strategies to ensure high and stable yields under highly variable precipitation typical of drylands often come at the cost of further pressure on local water resources. In light of the particularly strong coupling between agriculture and water resources in dryland regions, and the bidirectional local–global influences, policies aimed at food system sustainability in these regions should thus consider both local and global processes, while also aiming at enhancing resilience and redundancy within agroecosystems.