Does logging and forest conversion to oil palm agriculture alter functional diversity in a biodiversity hotspot?
© The Ecological Society of America www.frontiersinecology.org A greenhouse-gas emissions by reducing the rate of conversion of forests across the globe is widely considered to be a cost-effective means of climatechange mitigation (Stern 2007; Nepstad et al. 2009). Whether through a global mechanism – such as “REDD+” (Reducing Emissions from Deforestation and Forest Degradation or enhancement of carbon stocks) – or voluntary offset markets, several studies have suggested that offsetting the opportunity costs of forest conservation will be economical in developing countries, where most of the conversion threat and much of global biodiversity resides (Stern 2007; Kindermann et al. 2008). For example, the Stern Review estimated that up to 50% of the world’s deforestation can be stopped for as little as US$5 per metric ton of carbon dioxide (tCO2; Stern 2007). Others have estimated that a 50% cut in global deforestation could be achieved at a price of US$10–$21 per tCO2 (Kindermann et al. 2008). This latter range could also end deforestation in Brazil within 10 years, according to Nepstad et al. (2007). These seemingly inexpensive mitigation costs have given hope to conservationists that carbon payments in the speciesdiverse tropics can be an effective tool for preventing species extinction (Venter et al. 2009). At the same time, researchers have noted that the costs of conservation are spatially heterogeneous (Balmford et al. 2003; Naidoo and Iwamura 2007). In some parts of the world, the foregone profits that conservation would entail might be too great to be offset by carbon payments. For example, several studies have shown that the expansion of oil-palm plantations into forests in Southeast Asia is a case where carbon payments fail to meet the opportunity costs of conservation, given the lucrative and expanding palm-oil market (Butler et al. 2009; Venter et al. 2009; Persson and Azar 2010). These studies suggest that higher carbon prices (Butler et al. 2009; Venter et al. 2009) or other payments for ecosystem services (Persson and Azar 2010) might help to make the conservation of forests in Southeast Asia more economically competitive with conversion. Understanding the magnitude of the difference between the costs of conservation and the benefits of conversion in this region is critical for several reasons: