Palm plantations should therefore only be established on ready-converted landscapes, they said.

The study​​ is one of the first definitive pieces of research into the impact of palm oil cultivation – replacing large areas of lowland tropical forest with plantations.

It brings together around 1,000 scientific studies and reports to assess the damage to 14 ecosystem functions including gas and climate change, water supply and regulation, moderation of extreme events and soil fertility.

The only function with a positive effect was the provision of food and raw materials, while effects on pollination were unclear (because the data available was too incomplete). Effects on biological control were also inconclusive and needed more data because the function is highly dependent on spread of pest species.

eplacing tropical lowland forests with oil palm plantations damages 11 out of 14 functions of a healthy ecosystem. ©iStock

Every other function was found to be impacted negatively by palm oil plantations moving in on forested areas.

“The most serious impacts occur when forest is cleared to establish new plantations, and immediately afterwards, especially on peat soils,” ​the team – led by Claudia Dislich, University of Göttingen, Germany – said.

“The only ecosystem function which increases in oil palm plantations is, unsurprisingly, the production of marketable goods.”​

The study – a joint effort between the University of Göttingen, the Helmholtz Centre for Environmental Research (UFZ) in Leipzig and Bogor Agricultural University in Indonesia – follows the disbanding​​ of the Indonesian Palm Oil Pledge. The organisation was reportedly under pressure​​ to back down on its anti-deforestation pledge.

Palm oil remains a controversial subject among governments and industry alike. A recent European push towards 100% sustainable palm oil​​ in Europe is backed by Norway, Germany, Denmark, France, Holland and the UK.

14 Ecosystem functions​ Gas and climate regulation Water regulation and supply Moderation of extreme events Erosion prevention Soil fertility Waste treatment Pollination Biological control Refugium & nursery functions Provision of food and raw materials Genetic resources Medicinal resources Ornamental resources Information functions.

Mitigation​

eplacing tropical lowland forests with oil palm plantations damages 11 out of 14 functions of a healthy ecosystem. ©iStock

The damage can to some extent, however, be cushioned, the team say.

The best way to stop greenhouse gas (GHG) emissions from palm oil cultivation is limiting cultivation to areas with low or moderate carbon stocks, the team said.

“Specifically, this would require stopping the development of new plantations on peat land as peat oxidation and peat fires are the largest oil palm-related GHG sources, and extending and enforcing the current moratorium on new concessions in primary forests,” ​the researchers said.

Rehabilitating already converted peatlands is another option.

“To variable degrees, specific plantation management measures can prevent or reduce losses of some ecosystem functions (for example avoid illegal land clearing via fire, avoid draining of peat, use of integrated pest management, use of cover crops, mulch, and compost).”​

“By knowing how oil palm affects the degree and the direction of changes in ecosystem functions for each category, strategies can be developed to reduce the degradation of ecosystem functions while maintaining or even increasing socio-economic functioning,”​ Dislich and co added.

Source: Biological Reviews​

First published online, doi: 10.1111/brv.12295​​

“A review of the ecosystem functions in oil palm plantations, using forests as a reference system”​

Authors: Claudia Dislich et al.