Dynamics of Social–Ecological Systems: The Case of Farmers’ Food Security in the Semi-arid Tropics

Abstract

Since the dramatic transition in the 1990s from central planning to a market-based economy in Mongolia, modern pastoralism has transformed into a more sedentary system with increasing livestock densities. Following this shift, herders were able to live in the place of their choosing; many migrated to peri-urban areas in the central part of the country, where they increased their livestock numbers to maximize profits, resulting in overgrazing and land degradation. To minimize degradation associated with such shifts in Mongolian pastoralism, an understanding of how economic and social factors can affect human activities and environmental changes via pastoralism is critical. Herein, the author developed a spatially explicit simulation model that combined the behaviors of local people with vegetation pro- cesses according to precipitation patterns inMongolian grasslands to predict grassland degradation after 30 years.Thismodel was parameterized withempirical data relating to Mongolian pastoralism, including rainfall patterns, changes in grassland biomass, and spatiotemporalmovement patterns of nomadic peoples. Themodel was simulated using four scenarios that combined a mobility mode (nomadic or sedentary mode) with a specified degree of grazing pressure (high ormoderate). The results suggest that mobility is a key factor for environmental and economic sustainability in Mongolian pastoral systems because, in an unpredictable environment, nomadic pastoralismwas more sustainable and profitable compared to sedentary pastoralism.However, pastoral systems with excess grazing pressure were unsustainable, regardless of mobility mode. These predictions have important implications for the development of effective management strategies in the sustainability of pastoral systems.