A US-based research team focused on small streams flowing through oil palm plantations, smallholder agriculture and forests in and around Gunung Palung National Park in Indonesia. They found that streams draining recently cleared plantations were almost 4°C warmer than forest streams and that sediment concentrations were up to 550 times greater. Stream metabolism – a measure of the rate at which streams consume oxygen and an important measure of a stream’s health – was also observed to increase significantly during a drought. ‘Although we previously documented carbon emissions from land use conversion to oil palm, we were stunned by how these oil palm plantations profoundly alter freshwater ecosystems for decades,’ said author Lisa M Curran of Stanford University in California.
The authors warned of a ‘perfect storm’, in which the crop’s environmental effects combined with those of an El Niño-associated drought. ‘This could cause collapse of freshwater ecosystems and significant social and economic hardships in a region,’ Curran said.
This story was published in the August 2014 edition of Geographical Magazine