May 12, 2009

Largest Gazelle Herd Of 250,000 Sighted In Mongolia

A gigantic herd of a quarter of a million Mongolian gazelles has been sighted off the country's steppes, in one of the world's last enormous wildernesses.

The gathering is the largest in history.

The biologists who witnessed it approximate that it contained a quarter of all Mongolian gazelles on Earth.

"It was stunning," said Kirk Olson of the University of Massachusetts to BBC News. "I don't know if I was surprised or simply blown away by what we came across."

Olson and his colleagues have written details of the impressive herd in the journal Oryx.

In September 2007, Olson and his team were driving through eastern Mongolian steppes looking at the environment of the Mongolian gazelle, one of the last nomadic ungulates that live in large groups.

As they moved eastward they saw herds of a thousand gazelles.

"Groups of this size are impressive and beautiful to see," wrote Olson. Then the next day, they went to a hillside to have a better view of what they thought was a herd of 1,000 or so.

"But it was really one edge of a group that ended up being over 250,000 by one estimate. We were simply amazed at the sight. The image I have in my mind of seeing this massive aggregation of gazelles will always be etched into my memory," Olson said.

While Mongolian gazelles usually form large groups, the largest herd up to that time known was only 80,000.

"I expected that we would come across gazelles at times in large and impressive numbers," says Olson. "But not a couple hundred thousand in one sweep across the horizon. I had never seen that many before and that many had never been documented."

Olson thinks the herd formation was a natural happening caused by exceptional circumstances. The summer of 2007 was extremely dry and prone to severe drought. The gazelles were losing areas to graze, and moved, forming in the few residual green areas of the steppe.

The area where they gathered experienced a huge rainfall two weeks prior, making it a perfect sanctuary for the nomadic animals.

"The fact that bit of suitable habitat exists and the gazelles were able to access this during an extremely dry summer is at present good news," says Olson. "It means the steppe is still intact."

The gazelles used to form in large numbers, but the grassland steppes are being blocked by fences, roads, agriculture, and people, and with oil fields and pipelines being set up in the region.

"The 250,000 sq km in Eastern Mongolia is simply the remaining natural example of a much larger ecosystem that spanned over Inner Mongolia and Manchuria totaling about 1.5 million sq km," Olson said.

If a similar set of circumstances were to happen again, but the only suitable grazing areas were just 30 km south, then a border fence would have prevented the animals reaching food.

"We would have been reporting a massive die-off of gazelles."

Hunting has already decimated populations of the saiga antelope and the kulan, also known as the Mongolian wild ass.

Olson wished that conservationists would intensify their attempts to help and protect the gazelles, before their numbers reduce.

"Grasslands and long distance migrants throughout the world are facing intense pressure and numerous threats," he says. "Eastern Mongolia is arguably one of the best remaining examples of ecologically complete grassland in the world. The Mongolian gazelles are the largest remaining population of wild ungulate remaining in Central Asia," he says.
"What will seal the fate for the gazelles is if their habitat is degraded and fragmented to a point where the large herds that exist today no longer have a place to go, and then they will be lost."


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