Increased demand for palm oil has caused widespread deforestation and biodiversity loss in Southeast Asia, and a new study by CNR researchers demonstrates that the impacts of expanding plantations of oil-producing palm trees are much worse than previously thought. Wildlife feeding on oil palm fruit can become overabundant and subsequently cause the chronic degradation of remaining nearby forests.
In a study lasting more than two decades, an international team of scientists observed immense shifts in tropical forests in Peninsular Malaysia. “We knew that forest understory was dying, but we didn’t understand why,” said Matthew Luskin, PhD ’16 Environmental Science, Policy, and Management (ESPM), lead author of the study. “Once we started looking outside the forest to the surrounding palm oil plantations, the story became clear.”
Oil palms produce fruit rich in an oil that can be found in a wide range of food and cosmetic products. Forest animals like monkeys and pigs also feed on the fruit, and with a proliferation of palm oil plantations their numbers can rapidly multiply.
In their study, published last December in the journal Nature Communications, the researchers found that the presence of oil palm fruit on such plantations led to a 100-fold increase in the number of wild boars living in the adjacent forests. In addition to eating tree fruits, wild boars have destructive behaviors such as rooting up soil for food and building nests, which can disrupt tree sapling density. By comparing such forests with forest areas that were fenced to exclude wild boars, the team found that wild boars reduced the number of small trees by over 50 percent, raising concerns about the future health of the forests.
“What’s most concerning about these findings is that the negative impacts of palm oil plantations are occurring deep within what otherwise looks like pristine forest—miles from the nearest plantation,” said ESPM professor Matthew D. Potts, a co-author of the study along with ESPM professor Justin Brashares.