Impacts of non-oil tree plantations on biodiversity in Southeast Asia

Tree plantations are rapidly expanding throughout Southeast Asia, and likely pose threats to the conservation of native biodiversity. While the impacts of oil palm expansion on tropical biodiversity has received increasing attention, and several recent reviews, the effects of other tree crops on native flora and fauna biodiversity remain understudied. Here we assess and compare the impact of rubber, acacia, eucalyptus, teak, and cacao plantations on biodiversity throughout the region, and discuss spatial and temporal factors that influence a production landscape’s ability to support native species. Using a meta-analysis, we show that rubber and cacao plantations support lower biodiversity than intact forests, and are approximately equivalent to oil palm in their impacts on native biota. In contrast, richness of native species in acacia plantations was not statistically different from that in intact or secondary forests, though species composition could still be radically altered. Furthermore, older plantations are more similar to primary forests regarding community composition than younger plantations, likely due to increased habitat complexity and heterogeneity with plantation age. Though non-oil palm tree plantations are not ecologically equivalent to primary forests with regards to maintaining native community composition, they can support greater biodiversity than other modified landscapes such as annual crops. Increasing habitat complexity and spatial heterogeneity within plantations can improve the quality of the habitat they provide to native species. With industrial plantations projected to continue to expand, identifying ways to mitigate their impacts on biodiversity are increasingly critical.