BEIJING (AFP) – Authorities in northwestern China have resorted to using a contraception-abortion pill to rein in a plague of gerbils which is threatening the local desert ecosystem, state media said Wednesday.
Forestry officials in the city of Changji in the vast Xinjiang region began distributing the pellets last May to curb the exploding gerbil population, Xinhua news agency said.
The gerbils' large burrow systems in the Gurbantunggut Desert had begun to damage the root systems of the few plants that can survive in the area, while also damaging local agriculture, it said.The pellets contain a specially developed contraceptive and an abortion drug, the report quoted Du Yuefei, head of the epidemic prevention section of the city's forestry bureau, as saying.
"Besides pregnancy prevention, the drug can induce abortions and thus largely reduce their breeding rate," Du said.
"It's a good way to tackle the desert rodent plague."
The drug has "little effect" on other animals, the report said.
Previously, local authorities had set up perches for birds of prey, natural predators of the gerbils.
Du said the project could be extended to deal with rodent problems elsewhere in northwestern China.
About 200 kilograms (440 pounds) of pellets have been scattered near burrows across 49,000 hectares (121,000 acres) last year, causing a noticeable drop in gerbil population density, Du said.
However, the report gave no hard figures showing the population reduction.
It said a female can give birth to a new litter every three months.
Chinese try to curb 'plague of desert rats' in Tibet with contraceptives
Pika, relation of the rabbit, blamed for increasing desertification. But experts claim rodents help sustain biodiversity
Jonathan Watts, guardian.co.uk 25 Mar 09;
China's authorities have scattered 200kg of rodent contraceptive pellets across the Tibetan plateau to control what they describe as a "plague of desert rats".
The growing number of rodents have been blamed for destroying fragile high-altitude grasslands and accelerating the spread of deserts.
Biodiversity experts warn, however, that the extermination campaign could worsen the problem of soil degradation and the poisons could damage other parts of the plateau ecosystem.
China's chemists custom-designed the drugs to induce abortions and prevent pregnancy in "gerbils", according to the state-run Xinhua news agency. It is possible they are referring to pika, a small cousin of the rabbit with rounded ears and long whiskers that has long been the target of government eradication campaigns.
Government workers began spreading the contraceptive in the Gurbantunggut desert last May, leaving it in pellet form near the entrance of burrows. Since then they have reportedly distributed 200kg of the drug over 49,000 hectares in China's western region of Xinjiang. They say the drug will have a minimal impact on other animals.
"It's a good way to tackle the desert rat plague," local forestry official Du Yuefei was quoted as saying. He claimed populations of the pest have declined almost 10% as a result of the eradication campaign.
Pika and other rodents are accused of contributing to China's alarming desertification problem by over-eating grass and digging into the soil.
But foreign zoologists say the epidemic of the small mammals is a symptom rather than the cause of grassland degradation, which is mainly the result of human behaviour such as the exploitation of water resources and over-grazing.
"That the pellets have 'little effect' is highly debatable," said a conservationist who asked for anonymity. "All drugs have an effect when put into a system, on other rodents, on birds of prey that eat the rodents and so forth … It's business as usual — attack nature and hope for the best."
Conservationists say the small animals are an important source of food for bigger species such as bears, eagles and leopards, while their burrowing adds to the moisture of the soil.
Previous attempts to cull pika numbers, including mass poisoning campaigns and the construction of hundreds of perches for owls and eagles, have failed or had limited success.
Mass poisonings and the deliberate introduction of disease can hurt other wildlife and spread across borders, as was the case when Australia introduced myxomatosis to reduce the rabbit population in the 1950s.