Pandas and horses eat about the same amount of bamboo, but herds of more than 20 horses made for a feeding frenzy, decimating areas the reserve was established to protect.
Giant pandas, it turns out, probably aren’t celebrating the Year of the Horse. Livestock, particularly horses, have been identified as a significant threat to panda survival. The reason? They’re beating the pandas to the bamboo buffet, a team of Michigan State University (MSU) researchers say.
“Across the world, people are struggling to survive in the same areas as endangered animals, and often trouble surfaces in areas we aren’t anticipating,” said Jianguo “Jack” Liu, MS, PhD, Rachel Carson Chair in Sustainability at MSU. “Creating and maintaining successful conservation policy means constantly looking for breakdowns in the system. In this case, something as innocuous as a horse can be a big problem.”
China invests billions to protect giant panda habitat and preserve the 1,600 remaining endangered wildlife icons living there. For years, timber harvesting has been the panda’s biggest threat. Pandas have specific habitat needs: they eat only bamboo and stay in areas with gentle slopes that are far from humans. Conservation programs that limit timber harvesting have chalked up wins in preserving such habitat.
However, Vanessa Hull, MS, PhD, a doctoral student in MSU’s Center for Systems Integration and Sustainability, started noticing it wasn’t just pandas chowing on bamboo.
She learned that some farmers in the Wolong Nature Reserve (which is home to more than 150 giant pandas) who traditionally hadn’t kept horses had started raising them. A horse, Hull said, is kind of a bank account: When funds were needed, owners would track the animals down and sell them.
Horses were barred from designated grazing areas because they competed with cattle, so farmers would let them graze unattended in the forests. In 1998, only 25 horses lived in Wolong. By 2008, 350 horses lived there in 20 to 30 herds.
To understand the scope of the problem, Hull and colleagues put the same type of GPS collars they were using to track pandas on one horse in each of the four herds they studied. Then over a year they compared their activity with that of three collared adult pandas in some of the same areas and combined it with habitat data.
They discovered that horses are indeed big on bamboo, and also are drawn to the same sunny, gently sloped spots as pandas. Pandas and horses eat about the same amount of bamboo, but a herd of more than 20 horses made for a feeding frenzy, decimating areas the reserve was established to protect.
The researchers presented their findings to Wolong’s managers, who have since banned horses from the reserve. But Hull and Liu note that this work has shed light on how competitive livestock can be in sensitive habitat, an issue that is repeated across the globe.
“Livestock affect most of the world's biodiversity hotspots,” Liu said. “They make up 20% of all of the earth's land mammals and therefore monopolize key resources needed to maintain the earth's fragile ecosystems.”
The study, "Impact of Livestock on Giant Pandas and their Habitat," has been accepted for publication in an upcoming issue of the Journal for Nature Conservation.