Smithsonian National Zoological Park l Friends of the National Zoo



Spatial Patterns in Relative Primary Productivity and Gazelle (Procapra gutturosa) Migration in the Eastern Steppes of Mongolia

The Eastern Steppes of Mongolia are some of the largest and last remaining temperate grasslands in the world. They are also home to the Mongolian gazelle (Procapra gutturosa), or zeer, which migrate annually in herds ranging from 35,000 to 80,000 between winter and calving grounds spread throughout the steppes. Although the Eastern Steppes are still relatively undisturbed, the overall geographic range of zeer has declined dramatically from 1.2 million km2 in 1950 to less than 400,000 km2 in the late 1990s. Gazelles have experienced a corresponding decline in population.

Historic and present distribution of Mongolan gazelles

Peter Leimgruber and other researchers at the Conservation and Research Center used a normalized difference vegetation index (NDVI), derived from coarse-resolution satellite imagery to map relative primary productivity of steppes between April 1992 and December 1995. Although productivity varied during these years, winter and calving grounds had the highest NDVI scores during periods of use by the gazelles. In fact, gazelle movements to these areas followed shifts in primary productivity across the steppe. By mapping productivity "hotspots" used by gazelles during critical periods in their life cycle, researchers hope to identify which areas should be priorities for conservation.

Seasonal patterns in aboveground net primary productivity (ANPP).

Relative differences in aboveground net primary productivity (ANPP) between calving, summer and winter grounds.