28 dec. 2008

Double Trouble

Research Highlights

Nature Reports Climate Change

Olive Heffernan

Conservation Biol. doi:10.1111/j.1523–1739.2008.01096.x (2008)

Replacing tropical rainforests with oil palm plantations threatens biodiversity and efforts to reduce greenhouse gas emissions, report scientists. One of a number of biofuel crops touted as a sustainable, environmentally friendly energy source, palm oil now covers some 13 million hectares of land surface worldwide, mostly in Southeast Asia.

An international team of researchers, led by Finn Danielsen of Denmark's Nordic Agency for Development and Ecology, has carried out the most comprehensive analysis yet of the impact of oil palm plantations on tropical forests. They estimate it would take 75 to 93 years for the carbon saved through the use of biofuels to compensate for the carbon lost through clearing tropical rainforest. This payback time would increase to more than 600 years if the original habitat was peatland, and would decrease to just 10 years on degraded grassland, they say. Based on a meta-analysis of faunal data and a comparative field study of flora on forested and converted land in Indonesia, they also show that plantations support species-poor communities compared to forests, and that the most abundant species in converted lands are generalists of low conservation value.

The authors call for global standards to assess the sustainability of biofuel crops.

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