Abstract
Indonesian Borneo (Kalimantan) sustains ~37 million hectares of native tropical forest. Numerous large-scale infrastructure projects aimed at promoting land-development activities are planned or ongoing in the region. However, little is known of the potential impacts of this new infrastructure on Bornean forests or biodiversity. We found that planned and ongoing road and rail-line developments will have many detrimental ecological impacts, including fragmenting large expanses of intact forest. Assuming conservatively that new road and rail projects will influence only a 1 km buffer on either side, landscape connectivity across the region will decline sharply (from 89% to 55%) if all imminently planned projects proceed. This will have particularly large impacts on wide-ranging, rare species such as rhinoceros, orangutans, and elephants. Planned developments will impact 42 protected areas, undermining Indonesian efforts to achieve key targets under the Convention on Biological Diversity. New infrastructure will accelerate expansion in intact or frontier regions of legal and illegal logging and land colonization as well as illicit mining and wildlife poaching. The net environmental, social, financial, and economic risks of several imminent projects—such as parallel border roads in West, East, and North Kalimantan, new Trans-Kalimantan road developments in Central Kalimantan and North Kalimantan, and freeways and rail lines in East Kalimantan—could markedly outstrip their overall benefits. Such projects should be reconsidered in light of rigorous cost-benefit frameworks.
Highlights
Infrastructure expansion is occurring at a dramatic rate across the globe
~90,000 ha of existing ‘loop’ forests — those that connect different sections of a core-forest patch (Fig. 2) — will be created because of increased fragmentation. All these findings clearly indicate that planned and ongoing road development in Indonesian Borneo will substantially alter the current spatial pattern of forests, leading to large-scale degradation and fragmentation of currently intact forest and a marked decline of forest connectivity (Fig. 2)
Our analysis shows that the Equivalent Connected Area (ECA) — a measure of the percentage of habitat accessible by wildlife based on the degree of network connectivity43— is currently 89% for forested areas of Indonesian Borneo
Summary
Infrastructure expansion is occurring at a dramatic rate across the globe. Paved roads have increased by ~12 million km worldwide since 2000, with an additional ~25 million km projected by mid-century[1,2]. Borneo (Fig. 1) sustains the largest intact forest area in Southeast Asia These forests harbour a global biodiversity hotspot, exceptionally high species endemism, and large carbon stocks. The ~37 million hectares of tropical forest in Indonesian Borneo (Kalimantan)[13] comprises diverse ecosystems including montane forests, lowland mixed-dipterocarp forests, and peat-swamp forests[14,15,16,17,18]. These forests have been undergoing clearance and degradation at varying but generally high rates[19,20,21] since the onset of industrial-scale extractive industries half a century ago[22]. The major impacts of this spate of new infrastructure and extractive industries on native forest, biodiversity and relevant attributes—forest fragmentation, landscape connectivity and current forests pattern— in Kalimantan have not been quantified
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