Changes in Pastoral Land Use and Their Effects on Rangeland Vegetation Indices
Drastic changes have occurred in Mongolia’s grazing land management over the last two decades, but their effects on rangelands are ambiguous. After the democratic changes in 1992, formerly state-owned livestock collectives were disbanded and Mongolia’s livestock population was privatized. There was no longer a state institution to formally regulate pasture use and herders became responsible for pasture use management. Temporal trends in Mongolia’s rangeland condition have not been well documented relative to the effects of long-term management changes. We studied the changes in pastoral land use management in Tsahiriin tal of northwestern Mongolia and their effects on rangeland vegetation productivity using a remote sensing satellite-based approach. Grazing lands in Tsahiriin tal that were formerly managed by the socialist collective are now used by numerous nomadic households with their privately-owned herds, although the lands remain publicly owned. Grazing pressure has more than tripled and herd distribution has changed from a few, spatially-clustered large herds of sheep to numerous smaller herds of multiple species including sheep, goats, horses, and cattle. Our satellite image analyses indicate that rangeland vegetation significantly decreased (p-value <0.001) from the collective to the post-collective period. The observed decrease was significantly correlated with changes in the grazing management system and increased herd size. The decrease in rangeland vegetation might be further accelerated, if current grazing land use continues with no formal rangeland management institution or organized, well-structured efforts by the local herding households.