Forage Distributions, Range Condition, and the Importance of Pastoral Movement in Central Asia - A Remote Sensing Study

Abstract

Pastoral ecosystems in Central Asia have been undergoing many changes, with important implications for their sustainability. Pastoralists traditionally moved over large distances, either following regular migrations between seasonal pastures or opportunistically following forage; however, the ranges of pastoral movements have been reduced. Remote sensing methods were used to assess 1) whether these changes in pastoral land use have promoted or reversed affected rangeland degradation, and 2) how spatial and temporal variations in forage biomass might affect livestock movements and productivity. The remote sensing approach involved measurements of an index of plant productivity, the NDVI, over broad geographic areas. The relationships of plant production to precipitation over time and space were examined in order to differentiate the potential effects of precipitation from the potential effects of livestock grazing on rangeland condition. This was accomplished by assessing “rain use efficiency” or “RUE”, which is an index of the amount of plant production per unit of precipitation. Four study sites or regions were assessed; two in Turkmenistan and two in Kazakstan. Each of the four case studies revealed a different situation with respect to the distribution of resources, the importance of movement, the degree to which movements have been altered, and the consequences for rangeland condition. The analyses revealed spatio-temporal patterns of precipitation, forage, water, and topography which necessitate movement and adaptability. Although traditional regional scale migrations have been lost, the analyses suggested that smaller scale movements, coupled with appropriate stocking rates, can partially avert the negative consequences of complete sedentarization for pastoral production and rangeland condition. To maintain or improve pastoral productivity and sustainability in Central Asia, it will be essential to integrate the spatial distributions of forage, water, climate, and the effects of alternative livestock movements on the condition of the livestock as well as the condition of the rangelands.