Riparian reserves in oil palm plantations: biodiversity, ecological processes and ecosystem services

Thesis

• As the human population expands, agricultural expansion and intensification will exert an increasing pressure on remaining habitats, especially in the tropics. Oil palm is one of the most rapidly expanding crops in these regions, and identifying management strategies that conserve biodiversity and ecosystem services in these landscapes is therefore a priority.
• I assess whether riparian forest fragments (riparian reserves) conserve species and the functions they support within oil palm landscapes. Riparian forests are legally required for their beneficial impact on hydrological dynamics and their potential to contribute to the conservation of terrestrial species is poorly documented.
• I focussed on two ecologically important indicator groups (ants and dung beetles) and the ecosystem processes that they support.
• Whilst protecting primary forest will remain the most important strategy for biodiversity conservation, I found that riparian reserves do support species of ants and dung beetles that would not otherwise persist in oil palm landscapes. However, the extent to which riparian reserves maintained key ecological functions differed between these two taxa. The amount of nutrient distribution carried out by ants in riparian reserves was similar to logged forest areas, and higher than in oil palm. In contrast, dung removal functions did not vary between these land uses.
• I also investigated how the vegetation structure and landscape context of riparian reserves affects the dung beetle communities they support. Increasing reserve width and proximity to other forest fragments had a positive impact on the species richness and diversity of dung beetles in riparian reserves.
• There was little evidence that riparian reserves enhance the provision of dung removal or pest control services in adjacent areas of oil palm.
• The results provide evidence to support the introduction and/or enforcement of legislation to protect riparian forest reserves in order to conserve biodiversity and ecological processes in oil palm landscapes.

Authors: Gray, C

• Publication date: 2014
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: ants; conservation; Palm oil; dung beetles; riparian zones
• Subjects: Environmental change; Biodiversity; Environment; Biology