Sustainability: Setting aside land boosts biodiversity on oil palm plantations

Setting aside patches of original forest on oil palm plantations could boost biodiversity and may reduce some of the negative environmental impacts associated with this land use, according to a modelling study in Nature Sustainability. The findings, based on oil palm plantations in Borneo, suggest that these areas are most effective at boosting ecological benefits when approximately 15% of the original land is conserved and around 85% is cultivated.

Oil palm is one of the world’s fastest expanding crops, mostly grown in Southeast Asia where it often replaces tropical forests. Its cultivation is expected to double by 2050 along with associated deforestation, which is predicted to impact 54% and 64% of globally threatened mammals and birds, respectively. Palm oil can be produced much more efficiently than other oil crops using only a fraction of the land surface, so finding sustainable solutions for conserving biodiversity and ecosystem functions on oil palm plantations is important.

Jake Bicknell and colleagues modelled approaches to optimize set-asides (land left uncultivated) on Borneo’s oil palm plantations, to maximize both crop production and ecological benefits including biodiversity, nutrient cycling and above-ground carbon storage. They compared uniform configurations, where all plantations adopt set-asides of the same size and steepness, and variable configurations, where the size and steepness of configurations differ among plantations. While all set-aside configurations supported ecological improvements, the authors found that the most benefit to local biodiversity and ecosystems comes from set-asides with variable configurations across plantations, focused along rivers and streams: the most efficient of these would have 85% of the land cultivated and 15% of the land made up of variable set-asides. This variable configuration approach could offer up to double the positive ecological outcomes compared with the uniform configuration approach, without limiting cultivation area.

The authors conclude that their analysis could guide the planning and management of current and future plantations, and suggest that incorporating targeted strategies to conserve land could help to reduce some of the negative ecological impacts.