High-quality panda habitats in China's Wolong Nature Reserve have been disappearing faster than or at rates similar to unprotected areas outside the park since the reserve's creation, according to a new study in the 6 April issue of the international journal, Science.
This increased ecological degradation in a protected area may raise questions worldwide about the use and management of reserves as conservation tools. Established in 1975, the Wolong reserve is considered a "flagship" nature park, receiving exceptional support from the Chinese government and international organizations like the World Wildlife Fund.
Population pressure from the reserve's human residents are "the direct driving force behind the destruction of the forest and panda habitat," according to a team of Chinese and U.S. researchers led by Jianguo Liu of Michigan State University. Wolong's local population grew from 2560 people and 421 households in 1975, the year the reserve was created, to 4260 people and 904 households in 1995.
"To a large extent, Wolong's ecological fate represents the success or failure of tremendous conservation efforts" made by the government and other organizations, write the study's authors.
"The effectiveness of protected areas needs to be thoroughly examined and monitored, and new approaches that integrate ecology, demography, and socioeconomics are needed to truly protect protected areas," says Liu.
The Science researchers used remote sensing data, including Corona satellite photographs and Landsat satellite images, to compare forest cover in the reserve and surrounding area before and after Wolong was established as a nature reserve.
The team combined these data with information on elevation, slope of the land, and forest cover preferred by the pandas to rank regions within the reserve according to their suitability as panda habitat.
Liu and his colleagues found that the total amount of high-quality panda habitat, the number of individual habitat patches, and the average patch size within Wolong all decreased at a faster rate after the reserve was established, compared to degradation rates before the reserve's creation. The total amount and average patch size of high quality panda habitat also declined at a faster rate inside the reserve compared to surrounding areas after the reserve's establishment.
In most cases, habitats of average and marginal quality suffered a similar fate of shrinking area and fragmentation. The loss of high-quality habitats is a particular worry because these patches are usually "source areas," where pandas reproduce in higher numbers, says Liu.
Habitat loss is at least partially responsible for the dramatic decrease in wild pandas in the reserve, according to the research team. The wild panda population plummeted from 145 individuals in 1974 to 72 in 1986, and the current number of pandas "is likely to be even smaller," write the Science authors.
Human activities that pose a potential threat to the panda reserves include fuelwood harvesting, farming, house construction, and tourism. With farming and home construction limited to specific areas within the reserve, Liu says that fuelwood collection is "the most destructive force" within Wolong.
"Because forests at lower elevation were largely cut before the reserve was established, forests in areas of higher elevation--usually higher quality habitats for pandas--naturally became new targets of destruction for fuelwood," says Liu.
Tourism also has an indirect effect on the degradation of the Wolong panda habitat, stimulating the local economy in a way that increases the extraction of local resources.
"One of the local products purchased by some tourists is smoked pork. Because food for pigs needs to be cooked using fuelwood, higher demands for smoked pork by tourists leads to more consumption of fuelwood," says Liu.
Although the research team believes that immediate efforts to conserve high-quality panda habitat in the reserve are important, they feel that quality education for the reserve's children may be "the most socially acceptable and ecologically sound way" to limit ecological threats to Wolong. Better educational opportunities could allow residents to attend technical schools and colleges and obtain jobs outside the reserve, according to Liu.
"Our computer simulations suggest that even if only 22 percent of the reserve's young people relocate as a result of attending college, getting married, or taking outside jobs, the human population in the reserve would be reduced to about 700 people by the year 2047, and the giant panda habitat would recover and then increase by seven percent," said Liu.
The Wolong reserve contains about 10 percent of the world's remaining wild giant panda population, and is the birthplace of Mei Xiang and Tian Tian, the much-celebrated pandas on loan from the Chinese government to the Smithsonian National Zoo in Washington, D.C.