On the horizon: Deforestation expansion of plantations and infrastructure threaten Indo-Malay island species

The latest post in our ‘On the horizon’ series sees Nafeesa Esmail and Alice Hughes highlight the potential effects of a developing palm oil industry on Southeast Asisa’s forests. 

Southeast Asia’s forests are some of the most diverse on Earth, representing a number of global biodiversity hotspots. Yet this region is also undergoing an unparalleled rate of deforestation. Given the small ranges of many species (especially on Southeast Asian islands) this is potentially devastating to biodiversity. These islands have incredible species richness and endemism (meaning they are found nowhere else), yet less than 2% of the region is formally protected at present, and many islands lack an up-to-date inventory of locally found species.

Within insular Southeast Asia, one of the greatest drivers of deforestation is palm oil plantations and associated infrastructure development. Palm production has increased by over 430% since 1999 with Indonesia and Malaysia supplying 83% of all palm oil globally.

Borneo is well-known for its orangutans

Development of these new plantations is preceded by expanding logging roads across the region. Roads threaten species because they fragment forests, provide access to poaching, and increase roadkill and other forms of resource exploitation. However, these roads are often not included on maps used to indicate forest intactness and to inform conservation strategies. Up to 99% of roads in some of this region are missing from global roads map. This becomes even more significant when consequences of associated deforestation are considered; there can be as much as 90% of forest loss within 2.5km of a road. Accounting for these roads therefore decreases the average distance to a road 10-fold for 40% of the region, and thus increases associated deforestation following their construction. This, combined with other forms of exploitation could impact a significant proportion of the forests across the Indo-Malaysian region.

Yet these roads, and their associated deforestation footprint are spreading from the major areas such as Borneo (where the average oil palm plantation is currently around 10km) onto even smaller and less protected islands. Industrial oil palm production is just starting on smaller islands. For example, the island of Halmahera (Indonesia) experienced a 250% increase in deforestation following the completion of industrial housing the previous year, of course preceded by the construction of road networks to access the formally intact forest.

This IUCN Report on Palm Oil identifies huge projected increases in oil palm production across this region and similar small and unique islands (such as Nusa Tenggara and Maluku) that are vulnerable to cultivation. Areas like the Solomon Islands are already showing deforestation rates 10 times greater than a decade ago.

Consequences of habitat change (due to deforestation and forest fragmentation from impeding infrastructure development) and wildlife exploitation (i.e. illegal hunting) are cumulative in tropical ecosystems such as Sundaland, and their combined impacts are severely underestimated. This represents an even greater potential magnitude of impact if plantations and infrastructure continue to expand in the Indo-Malay Archipelago.

Nestled between a series of zoogeographic divides, and with high levels of site endemism, the expected development of the palm oil industry across Indo-Malay (and wider Southeast Asian) islands suggests an urgent need to protect the region’s remaining forest for any hope to retain its species. If efforts can be implemented now to mitigate threats in parts of the region that haven’t yet been transformed, we may be able to prevent the same fate, especially as these islands are small yet unique, meaning that the loss of species on a single island can have a profound effect more widely. The aim of horizon scanning is to raise awareness of what is to come so we can focus attention and resources on proactive actions before full potential negative impacts are realized (and it is too late).

A Horizon Scan of Emerging Issues for Global Conservation in 2019 is available to read in Trends in Ecology and Evolution.

Read more from our ‘On the horizon’ series here:

Introduction  by Bill Sutherland and Nancy Ockendon

Climate change and the capacity of Antarctic benthos to store carbon by Nathalie Pettorelli

Options for cultivating rice as climate changes and salinity increases by Erica Fleishman

Plastic alternatives – the ecological impact is not always clear by Becky LeAnstey

Mercury rising by Colleen Seymour



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