The environmental impacts of palm oil in context

Delivering the Sustainable Development Goals (SDGs) requires balancing demands on land between agriculture (SDG 2) and biodiversity (SDG 15). The production of vegetable oils, and in particular palm oil, illustrates these competing demands and trade-offs. Palm oil accounts for 40% of the current global annual demand for vegetable oil as food, animal feed, and fuel (210 million tons (Mt)), but planted oil palm covers less than 5-5.5% of total global oil crop area (ca. 425 Mha), due to oil palm’s relatively high yields5. Recent oil palm expansion in forested regions of Borneo, Sumatra, and the Malay Peninsula, where >90% of global palm oil is produced, has led to substantial concern around oil palm’s role in deforestation. Oil palm expansion’s direct contribution to regional tropical deforestation varies widely, ranging from 3% in West Africa to 47% in Malaysia. Oil palm is also implicated in peatland draining and burning in Southeast Asia. Documented negative environmental impacts from such expansion include biodiversity declines, greenhouse gas emissions, and air pollution. However, oil palm generally produces more oil per area than other oil crops, is often economically viable in sites unsuitable for most other crops, and generates considerable wealth for at least some actors. Global demand for vegetable oils is projected to increase by 46% by 20509. Meeting this demand through additional expansion of oil palm versus other vegetable oil crops will lead to substantial differential effects on biodiversity, food security, climate change, land degradation, and livelihoods. Our review highlights that, although substantial gaps remain in our understanding of the relationship between the environmental, socio-cultural and economic impacts of oil palm, and the scope, stringency and effectiveness of initiatives to address these, there has been little research into the impacts and trade-offs of other vegetable oil crops. 65 Greater research attention needs to be given to investigating the impacts of palm oil production 66 compared to alternatives for the trade-offs to be assessed at a global scale

Targeted cattle grazing as an alternative to herbicides for controlling weeds in bird-friendly oil palm plantations

The use of agrochemicals is expected to increase with the global expansion of oil palm plantations. In line with environmentally sustainable palm oil certification, targeted grazing can minimize the dependency on herbicides for controlling weeds in plantations. Here, we show for the first time that targeted grazing would control weeds and improve biodiversity of desired animal species. We sampled birds at 45 oil palm plantations in Peninsular Malaysia that were systematically grazed, non-systematically grazed, or herbicide controlled plantations without cattle grazing. We found that bird species richness increased with size of grazing area, but decreased with number of cattle. Bird abundance was higher in the systematic grazing system, but negatively related to number of cattle. These factors explained 18.41 and 25.34% of the observed variations in bird species richness and abundance, respectively. Our findings suggest that targeted cattle grazing can be instrumental for transforming conventional oil palm agriculture into more biodiversity-friendly agroecosystems. Targeted grazing is likely to be practical under field conditions in major palm oil producing countries. In addition, the use of targeted grazing as a biological control method for weeds would be welcomed by palm oil consumers and encouraged by sustainable palm oil certification bodies such as the Roundtable on Sustainable Palm Oil (RSPO)

Do silvopastoral management practices affect biological pest control in oil palm plantations?

The reliance of conventional oil palm production on agrochemicals to control understory vegetation has caused devastating impacts on the environment. Overuse of chemical herbicides leads to the decline of native biodiversity and production-related ecosystem services, including biological pest control. In contrast to herbicide applications, livestock integration is a chemical-free approach to eradicate weeds without negative consequences on the environment. In this sentinel prey experiment, we assessed the predation pressure (based upon the number of bite marks left by natural predators such as arthropods, birds, and mammals) in three oil palm plantations with different weeding practices (i.e., rotational grazing, free-range grazing, and conventional weeding) located on the south-west part of Peninsular Malaysia. We also investigated the effects of site level characteristics on the predation pressures of artificial caterpillars. Across all types of weeding systems, we found that the majority of the predation attempts on the deployed artificial caterpillars were made by arthropods (532 attempts), whereas mammals (66 attempts) and birds (60 attempts) played much smaller roles. Our results showed that predation pressures were consistent across sites indicating that oil palm-cattle integrated plantations (either free-range or rotational grazing systems) would experience similar level of pest control services as conventional herbicide-sprayed plantations. Our results also indicate the influence of site-level habitat variables (i.e., mean of palm heights, canopy cover, and elevation) on predation pressures. Our results suggest that livestock-oil palm integration may sustain natural predation with little or no herbicide input