Systematic mapping shows the need for increased socio-ecological research on oil palm

In the past century, oil palm has developed from a sustenance crop in West Africa to a major global agricultural commodity, with substantial impacts on biodiversity, the environment, society, and livelihoods. Although the oil palm industry contributes to local and national economies across the tropics, there are significant concerns about the negative effects of oil palm cultivation on biodiversity and ecosystem functioning, as well on local communities and farmers. There is a growing awareness of the need for managing agricultural landscapes more sustainably, and the importance of ecological, social, and also interdisciplinary research to inform this. To understand the current status of research across these areas for oil palm, we carried out a systematic mapping exercise to quantify social, ecological, and interdisciplinary socio-ecological research on oil palm cultivation, assess trends in the research, and to identify priority knowledge gaps in the literature. Literature was searched using adapted preferred reporting items for systematic reviews and meta-analyses and Collaboration for Environmental Evidence protocols. We reviewed 4959 publications on the ecological, social, and socioecological effects of oil palm cultivation. Each publication was classified according to study context (the study site location and type), comparators (the type of comparison the study makes), intervention (the potential action or decision being studied), and outcome (the effects of the intervention on the population). This resulted in 443 classified papers, which we then analyzed in more detail, to identify co-occurrence of different research foci between the disciplines and in socio-ecological research. We found a global increase in oil palm research over the past three decades, with a clear bias to Malaysia and Indonesia, mirroring global production trends. Over 70% of the research was focused on ecological outcomes, 19% on social, and less than 10% interdisciplinary. The majority of studies were conducted within industrial plantations, with comparisons to non-modified habitats, such as forests. Research has focused most on the effects of cultivation on yield, invertebrate biodiversity, and livelihood. To place our findings in context of production of palm oil and sustainability priorities, we used information on regional oil palm production in Tonnes, priorities of sustainable certification bodies, and recognized causes of yield gaps. The most pressing knowledge gaps included a lack of studies on the effects of plantation inputs on pollination and herbivory, the relationship between ecological factors and human health and wellbeing, and comparisons of different management practices within oil palm plantations. We advocate that these gaps become the focus of future research attention, as they lie in identified priority research areas and outcomes are likely to be critical to informing the development of more sustainable palm oil production.