flickr hivemindWhat is the best form of management to protect tropical rainforests? CEED researchers recently set out to answer this question for Kalimantan. In the process they discovered that the manner in which the Indonesian government defines 'degraded land' is critical to conservation outcomes in the region.

Kalimantan, the Indonesian part of Borneo, is one of the most biodiverse places on Earth, but the Indonesian conservation authorities are struggling to effectively maintain the island's rich natural values. Over half of the land mass comprises infertile acidic soil. Such soils are commonly associated with peat swamp, coastal swamp and acidic dryland areas. These areas are typically labelled 'unproductive' or 'marginal'.

In the 1980s and 1990s, extensive tracts of this 'marginal' land were cleared of forest to make way for agriculture (and associated transmigration programs). Unfortunately, due to poor land management, most of these converted lands were abandoned causing considerable damage to the terrestrial and aquatic ecosystems found on and around these areas. The massive smog-generating fires of 2015 indicate that these poor land management practices continue today. They are also the result of the growing pressure to clear lands to make way for oil-palm plantations.

Oil-palm plantations were introduced to Kalimantan in the 1970s. In recent years they have spread rapidly. Over the last decade the area assigned to oil-palm concessions has doubled from about 8% to 16% of the Kalimantan landmass. The oil-palm estate now roughly matches that of the protected-area estate. Oil-palm concessions have often been assigned to 'degraded land', as areas so classified (by the Indonesian government) are comparatively cheap.

"Our analysis of land use in Kalimantan has revealed that while about two thirds of the concessions have been assigned to degraded areas without forest, the remaining third has been assigned to degraded areas that are still forested," says Truly Santika, a postdoctoral researcher based at the University of Queensland who led this study. "And this forested portion has high biodiversity value."

The problem is that the term 'degraded land' is used by the government to represent a wide variety of land conditions. This includes land covered by degraded forest (areas that have been severely logged), critical lands (non-forested areas that have been subject to intensive agricultural practices) and marginal lands (areas considered to be unproductive with high soil acidity) that can either be forested or are already cleared. The broad definition of the term 'degraded land' has led to the legal deforestation of land to make way for oil-palm concessions.

"The definition of 'degraded land' has far-reaching consequences for deforestation in a wide range of land uses," says Assoc Professor Kerrie Wilson, a co-author on the study. "Our analysis shows that inside protected areas, the deforestation rate on fertile soils has been minimal, but on marginal lands it has been three times higher. Inside logging concessions, the deforestation rate on fertile soil is slightly higher than inside protected areas, but the rate on marginal lands is six times higher.

"Over the last decade, there is an increasing pressure to clear forest in Kalimantan but the drivers of deforestation has shifted from logging to oil palm. In 2000 the deforestation rate was highest inside logging or oil palm concessions averaging 4 ha/km2. We have determined that the deforestation rate inside oil palm concessions is now a staggering 20 ha/km2 on average."

The good news, according to the research, is that protected areas have been relatively successful in mitigating most, but not all, of the increase in deforestation pressure with an average deforestation rate inside protected areas of 1-2 ha/km2. In logging concessions the deforestation rate has also remained fairly constant averaging 2-3 ha/km2. The key is that this rate is lower than concession-free areas.

"Our findings have important consequences for environmental management and conservation policy in Indonesia," says Santika. "First, government-identified land type ('degraded' or not) may be more important in driving deforestation that legal protective status (eg, land classed as protected). This suggests strongly that the definition of 'degraded land' needs to be rectified to only include non-forested areas, and this new definition should be adopted across different government levels and sectors. As marginal lands are also found in about two thirds of the island of Sulawesi and half of Papua, the current definition could lead to further forest loss in these two islands as well.

"Second, illegal logging in concession-free areas remains common in Kalimantan. Effective conservation requires that existing controls are enhanced and enforced.

"And finally, logging concessions reduce the rate of deforestation compared to both plantation concessions and concession-free areas. Our findings support recommendations for the reclassification of logging concessions to become protected areas under the IUCN Protected Area Category VI."

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Reference: Santika T, E Meijaard & KA Wilson (2015). Designing multifunctional landscapes for forest conservation. Environmental Research Letters 10, 114012.

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