Limiting factors for nomadic pastoralism in Mongolian steppe: A hydrologic perspective

- Shallow groundwater as drink is sufficient for continuing nomadic pastoralism.
- A temporal lack of feed (vegetation) to animals due to drought is a limiting factor.
- A deterioration of the traditional well network is another limiting factor.
- Groundwater recharge occurs only rarely during heavy rainfall in valley bottoms.
- Mean residence time of soil water is 102-103 days and that of groundwater 102 years.

SummaryIn this study, limiting factors for continuing nomadic pastoralism in steppe areas were studied based on a hydrologic perspective. Two small watersheds in central Mongolia were selected for an assessment of water balance and hydrologic processes. We determined that the majority of annual precipitation, ∼88-96 mm, was lost by evaporation (82%) while only a small proportion went to groundwater discharge, surface runoff, and groundwater consumption by nomadic activities. The soil column was found to absorb large fluctuations in precipitation although its connection to groundwater was very weak. Groundwater recharge was, therefore, very small and occurred only rarely during heavy rainfall events in valley bottoms. However, current water storage in shallow groundwater was determined to be quite sufficient for continuing nomadic pastoralism when compared to the drinking water requirements of livestock. The main limiting factors identified were a temporal lack of feed to animals due to a loss of aboveground biomass resulting from soil moisture shortages during drought conditions, and a decline in the number and maintenance level of the traditional well network that, due to access to shallow groundwater, has allowed herders to migrate to areas with better conditions in remote Mongolian steppe.