Search
We report findings from the first survey for Mongolian saiga to
utilize statistically rigorous methodology, using line transect
distance sampling in 2006 and 2007 to obtain population estimates
in and around the Sharga Nature Reserve, the southern part of the
species current range.
Saiga have faced the long term threat of climate change and now
the more immediate danger of human persecution and habitat
degradation. In less than two decades, numbers have dropped 95%
from 1,000,000 to 50,000.
The current but untested hypothesis is that a combination of
unusual weather, topography and pasture improvement resulted in
fast-growing, moist and atypically composed forage, which caused a
form of metabolite toxicosis.
An analysis of assumptions underlying this hypothesis using
meteorological data and satellite imagery revealed that neither
temporal variation in weather nor highly-productive, moist forage
are likely to have been factors in the die-offs; although
significantly lower vegetation or soil moisture in die-off zones
than in the surrounding landscape indicates events were
location-dependent, and therefore precipitated by changes in
calving site selection driven by human…
The die-offs were very location specific and individuals from
the same sub-population who grazed elsewhere suffered no mortality
event. Adult antelope died suddenly whilst grazing, and calves died
subsequently, apparently as a result of starvation.Acute pulmonary
oedema and emphysema (APE), or fog fever, results from sudden
expose to lush vegetation and is proposed as the cause of this die-
off due to the observed acute and pasture-related nature of the
mortality events.
One of the hypotheses is that an environmental factor triggered
the precipitation of a polymicrobial disease, primarily
haemorrhagic septicaemia caused by Pasteurella multocida serotype
B.
This study describes gross pathological findings obtained during
field investigations and tests if weather conditions preceding the
outbreaks acted as a common trigger. For this purpose, weather
conditions at different known die-off sites were compared with
those from unaffected sites, using meteorological data from
regional, ground-based weather stations.