Fleiss, SusannahParr, Catherine LucyPlatts, Philip J.McClean, Colin J.Beyer, Robert M.King, HenryLucey, Jennifer M.Hill, Jane K.2024-05-302024-05-302023-02Fleiss, S., Parr, C.L., Platts, P.J. et al. Implications of zero-deforestation palm oil for tropical grassy and dry forest biodiversity. Nature Ecology and Evolution 7, 250–263 (2023). https://doi.org/10.1038/s41559-022-01941-6.2397-334X (online)10.1038/s41559-022-01941-6http://hdl.handle.net/2263/96279DATA AVAILABILITY : Existing datasets analysed in the article are available at references given within the manuscript. The final models of climatic suitability for rainfed and irrigated oil palm cultivation, and summary data of suitability per ecoregion, are available at https://doi.org/10.17605/OSF.IO/2RH6N. Source data are provided with this paper.CODE AVAILABILITY : The code used to generate oil palm suitability models and conduct analyses is available at https://doi.org/10.17605/OSF.IO/2RH6N.Many companies have made zero-deforestation commitments (ZDCs) to reduce carbon emissions and biodiversity losses linked to tropical commodities. However, ZDCs conserve areas primarily based on tree cover and aboveground carbon, potentially leading to the unintended consequence that agricultural expansion could be encouraged in biomes outside tropical rainforest, which also support important biodiversity. We examine locations suitable for zero-deforestation expansion of commercial oil palm, which is increasingly expanding outside the tropical rainforest biome, by generating empirical models of global suitability for rainfed and irrigated oil palm. We find that tropical grassy and dry forest biomes contain >50% of the total area of land climatically suitable for rainfed oil palm expansion in compliance with ZDCs (following the High Carbon Stock Approach; in locations outside urban areas and cropland), and that irrigation could double the area suitable for expansion in these biomes. Within these biomes, ZDCs fail to protect areas of high vertebrate richness from oil palm expansion. To prevent unintended consequences of ZDCs and minimize the environmental impacts of oil palm expansion, policies and governance for sustainable development and conservation must expand focus from rainforests to all tropical biomes.en© The Author(s), under exclusive licence to Springer Nature Limited 2023.Zero-deforestation commitment (ZDC)BiodiversityConservation biologyEcological modellingGrassland ecologyTropical ecologySDG-15: Life on landPostprint Article