Horses are pigging out on pandas’ bamboo supply

Giant pandas are under assault from logging, farming, and new roads that slash through their habitat. Now this endangered species faces a new threat: bamboo-hogging horses.

There are only about 1,600 giant pandas left in the wild, and they depend on nature reserves in China’s southwestern forests. But pandas don’t have these forest patches all to themselves. In a recent survey, researchers found that 11 percent of plots in giant panda habitat had been grazed by livestock.

To find out how farm animals were affecting the pandas’ food supply, the authors of a new study in the Journal for Nature Conservation collected data in China’s Wolong Nature Reserve, where about 10 percent of remaining wild giant pandas live. Thousands of farmers also live in the reserve and raise livestock such as cows and yaks. Over the last two decades, horse rearing has become more popular, and herds often graze on bamboo patches frequented by pandas.

The researchers followed four horse herds for a year using a combination of GPS collars and field surveys. They also attached GPS collars to three pandas. Finally, the team searched for signs of horse grazing on bamboo and panda visits before and after horses arrived.

For three herds, about half of the area roamed by the horses overlapped with giant panda habitat, the team reports. In 37 and 49 percent of plots in the reserve’s Fangzipeng and Yusidong regions, respectively, horses had chowed down on more than one-fifth of the bamboo. After horses arrived in Fangzipeng, the number of plots with panda feces or signs of panda grazing dropped by 5 to 10 times. And mother pandas appeared to have abandoned two den trees in Fangzipeng where they used to raise their cubs.

The results suggest that “bamboo foraging by horses could potentially threaten the availability of food for the giant pandas, if horse populations are unchecked,” the authors warn. Fortunately, this story has a happy ending: After hearing about the team’s findings, managers decided that horses were no longer welcome in the reserve. Roberta Kwok | 6 March 2014

Source: Hull, V. et al. 2014. Impact of livestock on giant pandas and their habitat. Journal for Nature Conservation doi: 10.1016/j.jnc.2014.02.003.

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