Now Palm Oil Is Killing the Frogs

Researchers find that half of Borneo’s forest amphibian species are disappearing near plantations that produce an ingredient widely used in consumer products.
Green tree frog in Borneo, Malaysia. (Photo: Robbie Shone/Barcroft Media/Getty Images)
Sep 23, 2015· 2 MIN READ
John R. Platt covers the environment, wildlife, and technology and for TakePart, Scientific American, Audubon, and other publications.

You’ve probably heard that palm oil plantations in Indonesia and Malaysia are destroying the habitats of orangutans, tigers, and birds. Well, now we know that these destructive agricultural activities are taking a toll on another group: frogs.

New research published in the journal Biotropica reveals that palm oil plantations are pretty awful for Malaysia’s frogs and other amphibians. Palm oil plantations on Borneo are “a forest frog’s worst nightmare,” lead researcher Oliver Konopik of the University of Würzburg in Germany said in a statement.

To complete their study, Konopik and his fellow researchers examined the frogs and toads living in streams on seven plantations, eight streams in natural rainforests, and seven streams in forests that had been logged for the lumber industry.

They found that plantations contained an average of 11 frog species and as few as nine. By comparison, untouched forests contained as many as 21 species.

Of the 43 total species observed throughout the study, only 19 were on plantations. In addition to species loss, the overall number of individual frogs on the plantations was also much lower.

The decline was similar to what has been observed in birds and mammals that lived in the habitats taken over by plantations, according to the researchers. That’s bad news not just for frogs but for the many species that eat them as major components of their diet.

The news did not come as too big of a surprise to conservationists. “This study confirms that amphibian biodiversity at streams in palm plantations is significantly lower than it would be if rainforests still survived at those streams,” said Kerry Kriger, founder of Save the Frogs, who was not involved in the research.

He said people could help these Asian species no matter where they live by avoiding products that contain palm oil. “Palm oil has quickly become the world’s most commonly used vegetable oil, appearing in all types of food we eat, as well as soaps and other household products,” Kriger said. “Consumers should seek products that don’t use palm oil, and food producers should use alternative oils.”

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The study did find a silver lining: The streams near logged forests contained a relatively high level of frogs, an average of 15 species at healthy population levels. That’s because loggers targeted trees selectively instead of clear-cutting the habitat, although the landscape was still “heavily degraded.”

The major reason the frogs did better in these logged habitats is that the industry left a fair number of trees and other vegetation along the banks of the streams and rivers. This riparian habitat, the researchers wrote, is essential to healthy amphibian populations, as it provides cover from predators and shade from the sun.

The technique could be applied to palm oil plantations as well. Konopik said the damaging effects to amphibians “could be mitigated in part by rigorously enforcing the creation of riparian buffer zones within plantations.” In practice, that could mean protecting those zones before they’re cut down or replanting them on active plantations.

The researchers pointed out that local legislation often already mandates that riparian zones be protected, something that most palm oil plantations ignore. They also wrote that protecting stream habitats is “not an adequate substitute for the large-scale preservation of native habitat”—something that both frogs and orangutans would probably agree with.