Restoring tropical peatlands supports bird diversity and does not affect the livelihoods of oil palm growers, study finds

A new study has found that oil palm can be grown more sustainably on peatlands by re-wetting the land, helping to conserve both biodiversity and livelihoods.

The research focused on tropical peatland restoration efforts in Indonesia and investigated whether managing water levels on drained peatlands affects the viability of oil palm grown by farmers, as well as the diversity of tree species. ‘birds.

Southeast Asia’s tropical peatlands contain large underground carbon stocks, while peat swamp forests contain unique and threatened biodiversity. However, when peat forests are cleared and peatlands are drained for cultivation, it leads to carbon emissions, biodiversity loss and land subsidence. Drained peatlands are also prone to fires, which in the past have resulted in toxic haze, deaths, and health and economic damage.

Indonesia is estimated to contain 47% of the world’s tropical peatlands, mostly on the islands of Borneo and Sumatra. Forests covered 76% of Sumatra’s peatlands in 1990, but in 2015, 66% was covered by small farms or industrial plantations, mainly oil palms.

Drainage is considered necessary to maintain oil palm yields because prolonged flooding reduces fruit production. However, draining peatlands mean that Sumatra is now a hotspot for peat fires.

The study found that rewetting is expected to have net positive effects for smallholders by reducing the risk of fires that can damage property, plantations and human health, without having a detectable effect on palm tree yields. oil.

A farmer collaborating in the project, Mr. Udin, said: “Even if the farm is flooded for a few days, the yield is not diminished.”

The study, published in Journal of Applied Ecologywas led by the University of York and ZSL (Zoological Society of London), together with colleagues from the Indonesian Center for Agricultural Land Resources Research and Development and the University of Jambi in Indonesia.

The study – which focused on Jambi Province in Sumatra, Indonesia – investigated the depths to the water table in oil palm farms managed by smallholder farmers, to assess the impacts on yields of oil palms and on the species of birds living on the farms.

Peat is carbon-rich soil formed from partially decomposed vegetation under permanently moist conditions. Tropical peatlands are critically important for storing carbon in the soil and also provide habitats for tropical wildlife, including tigers, gibbons, birds and specially adapted plants, fish and microbes.

Cultivation of peatlands also supports the livelihoods of people, such as small farmers who cultivate oil palm.

The bog must be drained using canals to make the land suitable for agriculture, which can impact habitats and cause peat to release carbon. Dry land can also become prone to fires, leading to increased carbon emissions, toxic haze and a threat to the lives of people and wildlife.

Restoration of drained peatlands involves a process of “re-wetting” where channels that drain water are blocked or filled, reducing the risk of the peatlands igniting.

Ninety species of birds were recorded in an area of ​​peat swamp forest adjacent to the farms, but only 48 species were found in the oil palm. The species living in the forest were also different, including 35 priority species for conservation, and tended to be larger species that play different ecological roles, meaning forest protection is essential for the conservation of the biodiversity.

Reducing fire risk in nearby oil palm farms through rewetting should reduce the risk of forest burning and further loss of wildlife habitat, while supporting farmers’ 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 the deforestation and considerable effort has gone into restoring the peat to prevent fires.

“But one of the big challenges is the trade-off between the livelihoods of smallholders and the preservation of biodiversity in these areas.

“What this new study shows is that retaining more water in oil palm plantations to reduce fire risk does not appear to have an effect on yields, which is good news for farmers. Contrary to the concerns of some plantations, maintaining water levels near the surface (40 cm or less) still allows the cultivation of oil palm.”

Eleanor said: “By also studying bird species in one of the nearby remaining peat swamp forest areas, we have also shown the huge importance of protecting the remaining forest for bird conservation – preventing fires in the landscape is essential to achieve this.

“These unique birds can also act as seed dispersers – which is crucial if, in the longer term, forest restoration becomes an option.

“One of the conclusions of the study is that larger-scale industrial agriculture organizations 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.”

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