Oil palm plantations support fewer ant species than rainforest

Oil palm plantations support substantially less biodiversity than natural forests when it comes to ant species, reports new research published in Basic and Applied Ecology

Rhett A. Butler | mongabay.com | March 02, 2010

Tom Fayle, a Cambridge University biologist, and colleagues sampled ant populations in a rainforest in Danum Valley Conservation Area and nearby oil palm plantations in Sabah, a state in Malaysian Borneo. The researchers counted 16,000 worker ants from 309 species in the natural forest but only in 110 species at the oil palm plantation.

The results are similar findings for other groups of animals, including birds and butterflies. Overall oil palm plantations are biologically impoverished relative to even selectively logged forests. The single-species monoculture offers fewer ecological niches than natural forests, providing fewer opportunities for plants and animals.

"Although oil palm plantations a higher diversity of ants than previously reported, we found that expansion of oil palm into rain forest still causes the loss of 81% of forest ant species," Fayle told mongabay.com.

Oil palm plantation and logged natural forest, Sabah, Malaysia. Photo: R. Butler/mongabay.com

The researchers also noted that invasive species are more common in oil palm plantations.

Fayle, T.M., et al (2010). Oil palm expansion into rain forest greatly reduces ant biodiversity in canopy, epiphytes and leaf-litter. Basic and Applied Ecology, doi:10.1016/j.baae.2009.12.009

Abstract:  Oil palm cultivation is expanding rapidly into many of the world's most biodiverse tropical regions. One of the most functionally important and ecologically dominant animal groups in these environments is the ants. Here, we quantify the overall impacts of clear-felling lowland dipterocarp rainforest and conversion into oil palm plantation on ant diversity. At study sites in Sabah, Malaysia we collected ants from three microhabitats: 1 – the canopy, 2 – bird's nest ferns ( Asplenium nidus complex, a common epiphyte in forest and oil palm), and 3 – leaf litter. We also measured temperature, humidity and light at collection sites to assess their impacts on ant community composition. Total ant species richness decreased from 309 to 110 (−64%) between forest and oil palm plantation. However, this impact was not the same across all microhabitats, with bird's nest ferns maintaining almost the same number of ant species in oil palm compared to forest (forest-oil palm, ferns: 36–35 (3% loss), canopy: 120–58 (52% loss), leaf litter: 216–56 (74% loss)). Relative abundance distributions remained the same for fern-dwelling ants, but became less even for oil palm ants in both the canopy and the leaf litter. These differences may be due in part to the ability of bird's nest ferns to provide a stable microclimate in hot, dry plantations. We also found that non-native ant species were more abundant in oil palm than in forest, and few forest ant species survived in plantations in any of the microhabitats. Only 59 of the 309 forest species persisted in oil palm plantations, corresponding to an 81% loss of forest species resulting from habitat conversion. Although oil palm supports many more ant species than has been previously reported, converting forest into plantation still leads to a dramatic reduction in species richness. The maintenance of forested areas is therefore vital for the conservation of ant biodiversity.

Copyright mongabay 2010

Read more... Sphere: Related Content