New research by the world’s leading researchers in orang-utans just published in Plus One, have shown that Borneo’s current orang-utan population size is affected by events that occurred thousands of years ago. The research “suggests that in some sites at least, orang-utan populations were affected by demographic events that started before the recent anthropogenic effects that
Environmental activists have attacked the palm oil industry, claiming that orang-utan populations have decreased as a result of the industry’s alleged environmental impact. However the emerging science indicates that the viability of today’s orang-utan populations has much to do with events that predated palm oil cultivation in Malaysia, perhaps by thousands of years.
The study found that orang-utan populations throughout Borneo probably declined several thousands of years ago. This population decline likely lead to a ‘population bottleneck’ which may have resulted in long-term constraints on the populations’ genetic viability. The findings point to a complex narrative, where today’s orang-utan populations are effected by both ancient and modern events.
The study sampled 126 individuals from a range of populations in order to test four potential hypotheses:
1) Orang-utan decline is recent and attributable to the commercial forest exploitation occurring in the last 200 years
2) Orang-utan decline started after the arrival of the first farmers but before the very recent forest exploitation (between 5000 and 200 years ago)
3) Orang-utan decline began following the arrival of hunter gatherers but before the arrival of the first farmers (around 40 000 and 5000 years ago), and
4) Orang-utan decline commenced following major climatic changes but before the arrival of hunter gatherers (between 100 000 and 40 000 years ago)
The results “provide strong support for orang-utan population decline following the arrival of the first farmers”. Under this scenario, it is most likely that the bottleneck occurred sometime between 5000 and 200 years ago. However, there is also evidence in some sites that the bottleneck significantly predated this period.
The first palm oil plantation was established in Malaysia only in 1917, but cultivation of the commodity did not become a major industrial activity until the 1970s.
Despite this fact, campaigners continue to claim that the Malaysian palm oil industry is driving orang-utan population decline. Their primary contention is that palm oil is the main driver of forest clearance, and by denying natural habitat, the industry is reducing the wild orang-utan populations.
This is unfounded. There are two species of orang-utans – Sumatran (Pongo abelii) and Borneo (Pongo pygmaeus). It is estimated that between 45 000 and 69 000 Borneo orang-utans live in the wild throughout the Malaysian States of Sarawak and Sabah, and Indonesian Province of Kalimantan. Sumatran orang-utans are estimated to be considerably rarer and are found only in Indonesia.
Accurate and precise data regarding historical orang-utan population sizes is not available, but there is little reason to believe that orang-utan populations in Malaysia are rapidly declining. Instead there have been several instances where significant orang-utan populations have been recently ‘discovered’. The estimate for Borneo orang-utan population sizes has been revised up from earlier estimates.
In Malaysia, orang-utan populations are protected through national legislation. The country’s strong record in forest management and falling rates of deforestation, state sponsored conservation initiatives, and a robust regime for agricultural land zoning have been attributed with conserving a relatively stable wild orang-utan population. Most new palm oil plantations in Malaysia have been developed on degraded land, or land converted from other crop plantations.
Understanding the real root causes of potential population decline is imperative to developing effective conservation strategies. The Malaysian palm oil industry is working to improve strategies for managing biodiversity and species habitat. For example, in one study site sampled in the research – the lower Kinabatangan in Northern Borneo – the palm oil industry is leading efforts to manage plantations that co-exist with a range of species and high levels of biodiversity, including orang-utan populations. A recent case study and plantation manual published by Wild Asia and supported by the Malaysian Palm Oil Council shows that well-managed palm oil plantations can maintain significant biodiversity.