An estimated 1,500 orangutans now live in rescue and rehabilitation centers located across Sumatra and Borneo. As habitat loss due to deforestation and forest fires continues, these institutions are struggling to keep up with demand.
Release into the wild is the ultimate, urgent, goal for most of these animals, but a new study warns that there could be serious genetic implications for the offspring of reintroduced animals — and orangutan populations in general — if those rescued from one region are released into a different region.
The study, led by primatologist Graham Banes, examined the genetic consequences when orangutans from different, divergent, subspecies interbreed. Borneo’s three recognized subspecies — from three distinct regions — are thought to have diverged from each other 176,000 years ago, meaning that hybridization between them may result in negative genetic effects. If hybrid offspring reproduce, combinations of genes that were beneficial for one lineage can be disrupted, resulting in poor health and reduced reproductive success, the researcher said. These effects, known as “outbreeding depression,” could threaten the survival of individuals and populations in the long-term.
Read the full article on Mongabay.
A Bornean orangutan in a rehabilitation center in Sabah. Photo by Rhett A. Butler
The long-limbed, canopy-swinging, duet-singing gibbons of Southeast Asia are under threat as industrial agriculture eats into their forest habitat. Palm oil plantation expansion is famously bad news for all sorts of wildlife, as are the new sugar and rubber plantations also driving deforestation across the region. But gibbon species are especially vulnerable: the cutting of trees makes their favored high-flying locomotion impossible — a potentially fatal plight for this overlooked great ape.
Finding the balance between economic development, industrial agricultural production, and great ape conservation is an urgent challenge facing governments and conservation organizations in many parts of Asia and Africa, as highlighted by the recent report, “State of the Apes: Industrial Agriculture and Ape Conservation”.
One such struggle is playing out in the Northern Plains of Cambodia, where the Pileated Gibbon (Hylobates pileatus) is the ape at risk. There, a mixture of evergreen and deciduous forest is home to not only H. pileatus, but a host of other species pressured by encroaching agribusiness. This besieged region includes one of the largest remnants of deciduous dipterocarp forest — dubbed the Central Indochina Dry Forest ecoregion — that once extended across much of Thailand, Vietnam, Laos and Cambodia.
WCS is working with local communities and government ministries to conserve the gibbons. You can read the full article to learn more about their gibbon project on Mongabay.
Photo courtesy of Julia Dolhem (WCS).