IBER research highlights: The march of alien invasive Acacias on Brunei

Acacia working in tandem with fire is severely degrading the Kerangas (heath) forests of Brunei reports James Margrove, a research intern from University of Aberdeen, UK working with the Institute for Biodiversity and Environmental Research (IBER) at UBD.

Kerangas forest occurs throughout Borneo on raised beaches and is known for its inability to support agriculture: the word Kerangas is an Iban word that roughly translates as ‘land which cannot grow rice’. These forests have not evolved to withstand burning and so recovery after fires takes decades. Acacias belong to a family of exotic trees native to Australia. Their adaptive ecology to fire allows Acacia to dominate these disturbed environments, and there is a fear that this will prevent native Kerangas’ subsequent recovery. 

After completing his Masters of Biological Sciences specialising in tropical forest ecology at the University of Aberdeen, James jumped at the opportunity to extend his studies into Kerangas forests, and embarked on a 6 month field based project to investigate how Brunei’s forests are being changed by Acacia and fire. He is collaborating with Dr Rahayu Sukri and Assoc Prof Dr Kushan Tennakoon of the Faculty of Science and IBER at UBD, and Prof David Burslem of the School of Biological Sciences, University of Aberdeen in the UK. Prof Burslem visited UBD for the second time on 8th January 2014 to continue work with the team. This particular project work is being supported by a research grant from UBD while James’ visit is funded by the British High Commission in Brunei.

Acacia is prized for its quick growth and production of useful timber for furniture, making it a great choice for forestry plantations and stabilising soil after anthropogenic or natural disturbances. As a result, Acacia has been planted in environments around the globe, from Mediterranean climates in South Africa to tropical Southeast Asia. However, due to its vigorous growth, Acacia can become an invasive pest, outcompeting native flora and putting pressure on native ecosystems. Here in Brunei, observations suggest that Acacia, assisted by fire, is spreading and will ultimately severely degrade the forest’s biodiversity, as well as preventing regeneration of native Kerangas plant species.

The current project investigates the impact of invasive Acacia in conjunction with fire on the Kerangas forest of Brunei. The research group is looking at changes in edaphic conditions, species compositions and light environments in localities that were formally pristine Kerangas forest. No studies as yet have investigated changes in these characteristics, and the team hope that the results will provide a solid foundation for a more comprehensive assessment of Acacia invasion in Brunei Darussalam, as well as the research and development of restorative measures.   

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