News and Notes

Recovering Orangutans in Borneo with Half-Earth Principles

NEW: Study Shows “Half-Earth” Doubles Gains for Orangutans

A new orangutan study recently published in the conservation journal Oryx,  found by applying Half-Earth principles, concluded that it would reduce population decline of orangutans by at least half compared to current management.

“The good news is that this analysis predicts that, if orangutan killing and habitat loss were stopped, orangutan populations could rebound and reach 148 per cent of their current size by 2122,” offered Hutan-Kinabatangan Orangutan Conservation Programme Scientific director Dr. Marc Ancrenaz in Borneo Echo.

Dr. Erik Meiijaard, co-author of the study, explored which parts of the orangutan range are protected currently or could be protected under “Half-Earth” and “Whole-Earth” scenarios, focusing analysis on orangutan range in Sabah (Malaysia) and Kalimantan (Indonesia), based on up-to-date forest cover and species presence data. “Bornean orangutans are listed as “critically endangered” as its habitat is being destroyed and many are killed for food, for profit or simply because people fear them (direct killing remains a major problem on a par with deforestation),” says Dr. Erik Meijaard.

In a two-part interview, Dr. Dennis Liu, VP of Education at the E.O. Wilson Biodiversity Foundation sat down with Dr. Meijaard to learn about orangutan biodiversity in Borneo.

Watch Part 1: Restoring Orangutans in Borneo

In his 2016 book, Half-Earth, Our Planet’s Fight for Life, E.O. Wilson calls Borneo, one of the “best places in the biosphere.” The 18,307 islands of Indonesia contain a staggering amount of biodiversity. Borneo has lost a substantial fraction of its rain forest due to settlement and conversion to oil palm plantations.  Yet the interior of the great island, the “heart of Borneo, “ remains the leading single harbor of Asia’s tropical biodiversity.

An Indonesian government orangutan assessment established that an estimated 14,290 Sumatran orangutans (Pongo abelii) and 57,350 Bornean orangutans (Pongo pygmaeus) remain in the wild, reports Mongabay. Recently, the government of Indonesia announced its orangutan population was resurgent, but this has been debated and rejected by independent scientists. As a result, Indonesia banned several scientists including Dr. Meijaard for publicly disputing official findings.

A female of the orangutan with a cub in a native habitat. Rainforest of Borneo.


Dr. Meijard, who has a PhD in biological anthropology, has been working in South-East Asia since the early 1990s, focused on the island of Borneo, with orangutans and pigs as primary research objects. Meijaard founded the Borneo Futures – Science for Change programme that implements research with a specific goal of changing public perceptions and policies on land and natural resource-use and wildlife conservation in Borneo. In 2017, Meijaard set up the IUCN Oil Palm Task Force, which he chairs.

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 (sufficient land and sea protection to preserve global biodiversity).

In a part 2 of his interview with the E.O. Wilson Biodiversity Foundation, Meijaard discusses how Half-Earth is applied to protecting orangutans in Borneo.

Watch Part 2: Applying Half-Earth Principles to Orangutan Conservation

Indonesia has over 4800 species. Over 30% are endemic (they are only found in Indonesia). Indonesia has a higher than average Species Protection Index score (an SPI of 44) where stewardship is gaining ground on human modifications like logging and deforestation. However, the island is divided among three countries: Malaysia and Brunei in the north, and Indonesia to the south, meaning orangutans in Borneo require joint stewardship. The Malaysian portion of Orangutan habitat protects about 65% of its state forests.

“We have lost a lot of orangutan habitat (on Borneo) but there’s a lot left we can work with. That’s where concepts like Half-Earth are exciting. We could really lock-in these remaining forests and keep them connected, restore some of the land, and get people engaged in it,” shared Meijaard in his interview with Liu.

Conserving orangutan habitat in Borneo protects many other species, key to preserving biodiversity. Borneo is home to over 16,000 plant species, 1/3rd of which are found nowhere else. E.O. Wilson once remarked that a quarter acre of rainforest in Borneo had over 700 species, “more than all the species of trees found in the US.”

“Ed (E.O. Wilson) would be so pleased that the idea (Half-Earth) is a source of motivation here for what kinds of actions people can take in Borneo,” remarked Liu.

Meijaard agrees, “There’s actually a hopeful message in this paper – that we’re heading in the right direction.”

Learn more about Eik Meijaard’s ground-breaking orangutan study using Half-Earth principles.

Explore Indonesia, its species and National SPI on the Half-Earth Project Map.

Read more on the growing trend of Indonesia government opposition to conservation science.

Read the study.

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