By Alister Doyle, Environment Correspondent
OSLO, March 4 (Reuters) - A quarter of the world's antelope species is under threat of extinction due to hunting and human damage to their habitats from the Sahara to Tibet, a study showed on Wednesday.
The South African springbok was the only antelope whose numbers were rising, bucking a dwindling or at best stable trend for all the 91 types of gazelles and other antelopes worldwide.
Twenty-five of 91 antelope species, or about a quarter, were rated "endangered" in a review by experts for the "Red List" of threatened species run by the International Union for Conservation of Nature (IUCN).
"The status of several species has become worse since the last complete assessment of all antelopes in 1996," it said in a statement. The IUCN groups governments, scientists and conservation organisations.
"Unsustainable harvesting, whether for food or traditional medicine, and human encroachment on their habitat are the main threats," said Philippe Chardonnet, co-chair of the antelope specialist group of the IUCN.
"Most antelopes are in developing countries which is why it's critically important that we collaborate with local communities there since it is in their own interest to help preserve these animals," he said in a statement.
In the worst case, the scimitar-horned oryx was rated extinct in the wild despite some unconfirmed reports of wild animals in Niger and Chad. Several thousand oryx are in captivity, with plans to reintroduce them the wild.
Populations of antelopes -- ranging from the Tibetan gazelle to the silver dik dik in east Africa -- were falling for 62 percent of species, stable for 31 percent and rising only for one -- the springbok.
The status of the other six percent was uncertain. The springbok has been helped by good management of the species, it said. The antelope is prized for its meat and many are raised in ranches.
The study adds to an IUCN study last year that estimated a quarter of all mammals, from elephants to shrews, were under threat.
A rising human population is putting strains on nature. In many countries, farmers are converting spare land to crops while cities and roads are encroaching more on grasslands. Climate change is adding to problems.
The report said the addax, a large Saharan antelope, was among those most at risk with an 80 percent plunge in numbers over the past two decades.
"The total population is estimated at less than 300 individuals," with most in Niger, the report said.
The saiga antelope in Kazakhstan, Russia and Mongolia was most threatened in Asia. Its numbers have crashed to about 50,000 from 1.2 million three decades ago.
-- For Reuters latest environment blogs click on: blogs.reuters.com/environment/ (Editing by Michael Roddy)