By Sarah Luke
Lead author Dedi Purnomo conducting plant surveys in ground and oil palm trunk quadrats. Photo credit: Jaka Irawan.
A recent study conducted by members of the Insect Ecology Group and collaborators from Sinar Mas Agro Resources and Technology Institute (SMARTRI), Indonesia, is one of just a handful to consider the diversity of plant communities within oil palm plantations, and has found that a wide range of species can be supported.
The team surveyed mature oil palm plantations near the SMARTRI office site in Riau, Sumatra, Indonesia. A total of 120 different plant species were recorded, which comprised a mixture of native and non-native species, some that were considered ‘beneficial’ for the plantation – because they are hosts for helpful parasitoids, they’re nitrogen fixers, or they help to maintain soil moisture – and others that were considered to be ‘problem species’ – because they inhibit the growth of the oil palms or other beneficial plants.
Different areas of the plantation were found to support different species, with the plant community found growing on the ground at the edge of planting blocks being different from that found growing within the core areas of the oil palm plantation blocks. Both of these ground areas had different plant communities from those growing on the trunks of oil palms. It was found that both ground and trunk communities were affected by drought, with changes in either biomass, percentage cover, or species richness seen in all habitats during low-rainfall periods.
There were also significant impacts on plant communities as a result of the management strategies that are chosen within the plantation. As part of the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Understory Vegetation Project experiment (www.oilpalmbiodiversity.com), herbicide-use and levels of manual cutting were adjusted to replicate different types of management commonly used within the oil palm industry. These treatments had substantial impacts on ground plant communities, but there were no spillover effects of herbicide-use and cutting on plant communities growing on oil palm trunks.
Together, this shows that despite being a single-age, monoculture crop, the oil palm plantation surveyed was able to support a mixed plant community, made up of a range of different microhabitats and species. Plant communities within the landscape vary as a result of microhabitat, drought, and because of plantation management decisions. This variation in plant communities is likely to have important influences on the overall complexity of the landscape and therefore other species – including insects, and other animals – that can be supported within the plantation. To view the full paper, please visit: https://www.frontiersin.org/articles/10.3389/ffgc.2019.00033/full