Deforestation for oil palm: impact on microbially mediated methane and nitrous oxide emissions, and soil bacterial communities

Oil palm plantations, irreversibly claimed primarily from tropical forest, carpet the landscape in Malaysia and Indonesia, the largest global producers of palm oil. The impact of forest conversion to oil palm agriculture on the plant and animal diversity has gained worldwide attention, but knowledge on the effects on microbially mediated belowground soil processes which drive ecosystem-level responses such as greenhouse gas (GHG) fluxes, particularly methane and nitrous oxide, remain scarce and fragmented. Focusing on the soil microbiome, as well as environmental drivers of soil biogeochemical processes, we synthesize previous research works to provide an overview of the current state of scientific understanding on the effects of deforestation for oil palm agriculture. Forest conversion to oil palm plantations is associated with increased pH, and lowered C and N contents, as typically observed in agricultural soils. Interestingly, in contrast to plant and animal diversity, soil bacterial and functional diversity, as well as fungal abundance, were unaffected or increased. Furthermore, community composition was altered by the land transformation. This indicates the resilience of the microbial diversity to deforestation for oil palm agriculture. However, it remains to be determined whether and how such community resilience would translate to the resilience of soil microbial groups mediating methane- and N-cycling processes central to greenhouse gas turnover.