Ecological management to benefit ecosystem services and sustainable production in smallholder oil palm systems in Malaysia and Indonesia This project will build on a large-scale experimental project, based within large industrial oil palm plantations in Riau, Indonesia, that investigated the impact of varying herbicide use and manual cutting of understory vegetation on biodiversity, ecosystem functioning, greenhouse gas (GHG) emissions, resilience to drought, and palm oil yield. Key findings from the work included a positive effect of reducing herbicide use and allowing more understory vegetation to grow on predator numbers, plant diversity, soil biodiversity, rate of decomposition and below ground processes, but with only limited impacts on GHG emissions and yield. In addition to benefitting biodiversity and ecosystem processes in oil palm, reducing levels of herbicide spraying can also potentially save money and pollution risk through runoff of herbicides into waterways . Although these findings have been well-publicised for large-scale industrial plantations, they have not yet been disseminated to small-scale farmers ("smallholders"), although they produce roughly 40% of palm oil production in Indonesia and Malaysia.  This project brings together a strong team of researchers and practitioners from the UK (University of Cambridge and NERC Centre for Ecology and Hydrology (CEH)), Indonesia (IPB University (Bogor Agricultural University) and Sinar Mas Agro Research and Technology Research Institute (SMARTRI)) and Malaysia (Universiti Putra Malaysia (UPM) and Wild Asia), who have expertise in oil palm management, experience of working with smallholders, and a diverse range of viewpoints (researcher, industry and NGO). Using existing strong connections between project team members and the smallholder community, this project will run workshops with networks of smallholders in both Indonesia and Malaysia, to promote uptake of management recommendations from the previous project and solicit feedback from smallholders on the feasibility of using different understory management options within their farms. To assess whether findings from the original project also hold true in a smallholder context, we will measure biodiversity, ecosystem functioning (including GHG emissions) and yield across a range of smallholder plantations that currently use different understory management practices. We will then experimentally trial three different understory management options within smallholder farms that currently have low levels of understory vegetation. We will collect data on biodiversity, ecosystem functioning and yield within these areas as before and use results to identify  management options that benefit both biodiversity, ecosystem processes and food production.  We will ensure outcomes from the project are disseminated clearly with opportunities for feedback, by running workshops and field visits with participating smallholders in both Indonesia and Malaysia. We will also work with sustainability schemes, such as the Roundtable on Sustainable Palm Oil (RSPO) to make sure that results feed into sustainability guidelines, promoting the uptake of successful management options on a wider scale and over a longer timeframe than this project alone can achieve. By identifying management options that promote more environmentally friendly palm oil production, greater diversity of crops, as well as reduced herbicide applications, the results of this work have the potential to benefit the environment, as well as smallholder productivity, health, income and food security. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.