Restoring tropical peatlands supports bird diversity and does not affect livelihoods of oil palm farmers, study suggests

A new study has found that oil palm can be grown more sustainable on peatlands by re-wetting the land.

The research looked at whether managing water levels on drained peatlands affects the viability of oil palm grown by farmers, as well as bird species diversity.

Large below-ground carbon stocks are found in tropical peatlands in Southeast Asia. Carbon emissions, biodiversity losses, and land subsidence are caused by the clearing and draining of peatlands. Toxic haze, deaths, and health and economic damage have been caused by fire in drained peatlands.

The islands of Borneo and Sumatra have the most tropical peatlands in the world. In 1990, forests covered most of Sumatra's peatland, but by 2015, they were mostly covered by oil palm plantations.

Flooding reduces fruit production and is considered necessary to maintain oil palm yields. Peat fires are a problem in Sumatra.

The study found that re-wetting should have a net positive effect on the lives of small business owners by reducing the risk of fires that can damage property, plantations, and human health.

Mr Udin said that even if the farm flooded for a few days, the yield wouldn't be affected.

The study was led by the University of York and ZSL, as well as colleagues from the Indonesian Center for Agricultural Land Resources Research and Development.

The study studied the water table depths on oil palm farms in Sumatra, Indonesia, to assess impacts on oil palm yields and bird species.

Peat is a carbon-rich soil formed from partly decomposing vegetation. Tropical peatlands are important for storing carbon in the ground, and also provide habitats for tropical wildlife, including tigers, gibbons, birds, and specially adapted plants, fish, and microbes.

Small-scale farmers growing oil palm are supported by cultivating peatlands.

Peatland needs to be drained to make the land suitable for farming, which can impact habitats and cause the land to emit carbon. Increased carbon emissions, toxic haze, and a threat to the lives of both people and wildlife can be caused by the dry land becoming prone to fire.

Restoring drained peatland involves a process of rewetting where canals are blocked or filled in, which makes it less likely that the peatlands will catch fire.

There were ninety bird species recorded in the area of a swamp forest next to the farms, but only 48 of them were found in oil palm. The species living in the forest were different, including 35 priority species, and tended to be larger-bodied species that play different roles in the forest.

The risk of forest burning and habitat loss for wildlife should be reduced by re-wetting the oil palm farms.

Eleanor Warren-Thomas, who led the study while a researcher at York, said that Indonesia has been very successful in reducing the amount of land that is destroyed.

One of the biggest challenges is the trade-off between livelihoods of owners of small farms.

The good news for farmers is that retaining more water in oil palm farms seems to have no effect on yields. Retaining water levels close to the surface still allows oil palm cultivation, in contrast to the concerns of some plantations.

Eleanor said that by 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 preservation.

If forest restoration becomes an option, these unique birds can act as seed dispersalrs.

One of the conclusions of the study is that larger-scale industrial farming 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.

More information: Eleanor Warren‐Thomas et al, No evidence for trade‐offs between bird diversity, yield and water table depth on oil palm smallholdings: Implications for tropical peatland landscape restoration, Journal of Applied Ecology (2022). DOI: 10.1111/1365-2664.14135 Journal information: Journal of Applied Ecology Citation: Restoring tropical peatlands supports bird diversity and does not affect livelihoods of oil palm farmers, study suggests (2022, March 15) retrieved 15 March 2022 from https://phys.org/news/2022-03-tropical-peatlands-bird-diversity-affect.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.