Half-Earth in the Forest Canopy

Conservation innovation can help save endangered orangutans

Tepanuli orangutans build their nests in the forest canopy of Sumatra. These great apes swing far more often than they walk, and their airborne habitat offers a prime view of predators stalking below. The nests are growing scarce, however. At last count, scientists recorded less than 800 wild Tepanuli orangutans.
They are critically endangered, along with the world’s other two orangutan species, which inhabit the islands of Sumatra and Borneo, respectively. Fifty years ago, Bornean orangutans numbered near 300,000. Data project that less than 50,000 will be left in 2025. Conservation strategies must not only maintain the species, says Dr. Eric Meijaard, “but recover as many as possible.”
Dr. Meijaard and leading experts compared various conservation approaches, including Half-Earth principles, to determine the optimal strategy for Bornean orangutans. They found the Half-Earth approach would be impactful and comparatively easy to achieve, reducing decline to maintain populations at 87% by 2032. After a century, Bornean orangutans could bounce back to 148%.
Indonesia and Borneo have made progress in reducing deforestation, but investments must increase alongside the growing urgency. “At some stage, people are going to realize it’s more useful to have forest than not to have it,” Meijaard said. “When is that moment, and how much [will] we have left?”

“Half Earth provides guidance as to what we can do better.”

Restoring Orangutans in Borneo

Dr. Erik Miejaard, Director of Borneo Futures, spoke with Dennis Liu, VP of Education at the E.O. Wilson Biodiversity Foundation, about protecting orangutans in Borneo and the positive theorized outcomes for the great ape when applying the principle of “Half-Earth.”



Conserving orangutan habitat protects many other species. Borneo is home to over 16,000 plant species, 1/3rd of which are found nowhere else.

According to the Half-Earth Project Map, 11% of Indonesia’s land is protected, but in Indonesian Borneo, over half of its land is already protected – 67% of land is already designated as state forest. Indonesia needs a further 33% of its land protected in order for the country to meet the Half-Earth goal.

What's Next

What's Next

Indonesia is a signatory to the Kunming-Montreal Global Biodiversity Framework, which set a 30×30 target: protect 30% of land and sea by 2030. Decision-makers now must consider additional land protection in Indonesia that will impact orangutan populations.
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