Wild birds from the forest apparently play a crucial, but often underappreciated, role in plantation ecosystems, including oil palm plantations. In his doctoral dissertation, Dimas Haryo Pradana revealed that understorey birds from surrounding forests have the potential to reduce insect pest infestations, particularly by controlling herbivory on oil palm leaves in smallholder oil palm plantations.

Research was conducted in smallholder plantations on Rupat Island, Riau and Central Kalimantan, and showed that this potential has not been optimally utilized, due to the low abundance of predatory birds in the plantation landscape, which is largely caused by habitat degradation and fragmentation of the surrounding forest.

This study found that birds like Centropus sinensis, which is known to prey on fire caterpillars – one of the main pests of oil palms – is difficult to find in landscapes with little and scattered forest cover.

“These findings send a strong message that conservation isn’t enough by simply leaving small forest fragments around plantations. It requires a sufficiently extensive source habitat to support the existence of natural predatory birds,” Dimas explained to the examining panel during his doctoral defense.

He also highlighted that the presence of undergrowth in plantations has the potential to become a microhabitat that supports the presence of birds, as long as it is managed selectively and not completely cleared.

This doctoral promotion took place on Thursday, June 26, 2025, at the Faculty of Mathematics and Natural Sciences, University of Indonesia (FMIPA UI). The defense was led by the Dean of FMIPA UI, Prof. Dede Djuhana, Ph.D., and accompanied by a promoter team consisting of Prof. Dr. rer. nat. Mufti Petala Patria, M.Sc. as Promoter, and Nurul Laksmi Winarni, M.Sc., Ph.D. and Dr. rer. nat. Yasman, M.Sc. as Co-Promoters. Dimas was declared to have graduated with honors. cumlaude.

According to Prof. Mufti, this research shows the importance of a landscape approach in biodiversity conservation, especially in areas that have been dominated by land use for agriculture and plantations.

“Dimas’s study is a concrete example of how an ecological approach can be used to support sustainable agriculture. It’s not just about preserving species, but also about how we can utilize the ecosystem services they provide, such as natural pest control,” he said.

This research, Prof. Mufti continued, provides an important contribution to efforts to increase the productivity and sustainability of smallholder oil palm, while also supporting the implementation of sustainable certification principles such as RSPO and ISPO.

With a science-based approach and field data, this research is expected to form the basis for plantation landscape management policies that are more integrated between production and conservation.