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