A new study has found that oil palm can be farmed more sustainably on peatlands by re-wetting the land conserving both biodiversity and livelihoods.
The study investigated whether regulating water levels on drained peatlands affects the viability of oil palm farmed by farmers, as well as the diversity of bird species. In Southeast Asia, tropical peatlands have substantial below-ground carbon reservoirs, whereas peat swamp forests have unique and endangered biodiversity.
When peat forests are removed and peatlands are drained for farming, carbon emissions, biodiversity losses, and land subsidence ensue. Drained peatlands are also prone to fire, which has resulted in poisonous smog, deaths, and other health and economic consequences in the past.
Indonesia, primarily on the islands of Borneo and Sumatra, is believed to possess 47 percent of the world’s tropical peatlands. In 1990, forests covered 76 percent of Sumatra’s peatland, but by 2015, smallholder agriculture or industrial plantations, largely of oil palm, had taken over 66 percent.
Because prolonged flooding affects fruit output, drainage is deemed vital to preserve oil palm crops. Peatland drainage, on the other hand, has made Sumatra a hotspot for peat fires.
Re-wetting, according to the study, should have net positive impacts for smallholders by lowering the risk of fires, which can harm property, plantations, and human health, while having no discernible effect on oil palm yields.
A farmer collaborating on the project, Mr. Udin, said: “Even if the farm flooded for a few days, the yield is not decreased.”
By also surveying bird species in one of the remaining peat swamp forest areas nearby, we also showed the huge importance of protecting the remaining forest for bird conservation avoiding fires in the landscape is key to doing this. These unique birds can also act as seed dispersers crucial if in the longer-term forest restoration becomes an option.
Dr. Eleanor Warren-Thomas
The University of York and the Zoological Society of London, as well as colleagues from the Indonesian Center for Agricultural Land Resources Research and Development and Jambi University in Indonesia, led the study, which was published in the Journal of Applied Ecology.
The study focused on water table depths on oil palm farms maintained by smallholder farmers in Jambi province, Sumatra, Indonesia, to examine implications on oil palm yields and bird species living on the fields.
Peat is a carbon-rich soil that forms when partially digested plants is exposed to constant moisture. Tropical peatlands are vital for carbon storage in the ground, as well as providing habitat for tropical species such as tigers, gibbons, birds, and highly suited flora, fish, and bacteria.
People’s livelihoods are also supported by peatland cultivation, such as small-scale farmers planting oil palm.
To make the area fit for cultivation, peatland must be drained using canals, which has the potential to harm habitats and cause the peat to emit carbon. Dry ground can also be prone to fire, resulting in increased carbon emissions, poisonous smoke, and a hazard to human and wildlife lives.
The method of “rewetting” drained peatland involves blocking or filling in canals that drain water away, making it less likely that the peatlands will catch fire. In a peat swamp forest near the farms, ninety bird species were detected, but only 48 species were found in the oil palm.
Forest species were also diverse, with 35 conservation-priority species, and tended to be larger-bodied species with varied ecological roles, implying that forest protection is crucial for biodiversity conservation.
Re-wetting nearby oil palm farms to lessen fire danger should reduce the probability of forest fires and subsequent wildlife habitat loss while still sustaining farmer production.
Dr. Eleanor Warren-Thomas, now at Bangor University and IIASA, and who led the study while a researcher at York, said:
“Indonesia has been very successful in reducing deforestation and considerable effort has gone into peat restoration to avoid fires. But one of the big challenges is the trade-off between livelihoods of owners of small farms and ensuring biodiversity in these areas.”
“What this new study shows is that retaining more water in oil palm farms to reduce fire risk seems to have no effect on yields, which is good news for farmers. In contrast to the concerns of some plantations, retaining water levels close to the surface (40cm or less) still enables oil palm cultivation.”
Eleanor said: “By also surveying bird species in one of the remaining peat swamp forest areas nearby, we also showed the huge importance of protecting the remaining forest for bird conservation avoiding fires in the landscape is key to doing this. These unique birds can also act as seed dispersers crucial if in the longer-term forest restoration becomes an option.”
“One of the conclusions of the study is that larger-scale industrial farming organisations would be able to help further studies in this area, if they are able to publish their data and share their knowledge to inform sustainable oil palm production strategies.”
