Rowcliffe, J. M. | bioRxiv Science

bioRxiv2025

Stand age drives changes in the biodiversity and microclimate of oil palm plantations

Tree plantation age strongly dictates its environment. As they mature, the canopy closes and habitat complexity tends to increase, which in turn affects biodiversity. However, for oil palm, one of the most important and widespread tree plantations, we lack a detailed understanding of how this process affects microclimate and biodiversity. We therefore compiled environmental and biodiversity data of oil palm plantations that were repeatedly sampled over a 6 year period in Malaysian Borneo. Using these data, we made a chronosequence of the microclimate and biodiversity of oil palm plantations between the ages 5 and 18. We found that oil palm plantations increasingly buffer temperature and humidity over time, becoming cooler and less dry. Animal responses differed between taxa: spider and beetle abundance increased, ant abundance decreased, and mammal and dung-beetle abundances stayed constant. The diversity of beetles in general increased and family-level community composition changed, while dung-beetle and mammal diversity stayed constant. Some taxa are therefore likely limited by the harsh microclimate of young plantations, while increased habitat complexity and fruit and leaf production in older plantations could also drive increased abundances of other taxa. Our results reveal that oil palm plantations undergo considerable changes, even over a decade after establishment. Correspondingly, plantation age should be considered in studies into oil palm plantations impact on climate and biodiversity, and landscape level diversity could be increased by allowing multiple oil palm stand-ages to co-exist.

ecology↗

bioRxiv2020

Density responses of lesser-studied carnivores to habitat and management strategies in southern Tanzanias Ruaha-Rungwa landscape

Compared to emblematic large carnivores, less charismatic or smaller carnivore species often receive little conservation attention, despite facing increasing anthropogenic pressure, and their status being poorly understood across much of their range. We employed systematic camera trapping and spatially explicit capture-recapture modelling to estimate variation in population density of serval, striped hyaena and aardwolf across the mixed-use Ruaha-Rungwa landscape in southern Tanzania. Three sites were selected as representative of different habitat types, management strategies, and levels of anthropogenic pressure: Ruaha National Parks core tourist area, dominated by Acacia-Commiphora bushlands and thickets; the Parks miombo woodland; and the neighbouring community-run MBOMIPA Wildlife Management Area, also covered in Acacia-Commiphora. Our results show that the Parks miombo woodlands supported a higher serval density than the core tourist area and Wildlife Management Area, with 5.56 [Standard Error = {+/-}2.45], 3.45 [{+/-}1.04] and 2.08 [{+/-}0.74] individuals per 100 km2, respectively. This variation is likely driven by precipitation, the abundance of apex predators, and the level of anthropogenic pressure. Striped hyaena were detected only in the Wildlife Management Area and at low density (1.36 [{+/-}0.5] individuals per 100 km2), potentially due to the location of the surveyed sites at the edge of the species global range, high densities of sympatric competitors and anthropogenic edge effects. Finally, aardwolf were captured in both the Parks core tourist area and the Wildlife Management Area, with a higher density in the Wildlife Management Area (13.25 [{+/-}2.48] versus 9.19 [{+/-}1.66] individuals per 100 km2), possibly as a result of lower intraguild predation and late fire outbreaks in the area surveyed. By shedding light on three understudied African carnivore species, this study highlights the importance of miombo woodland conservation and community-managed conservation, as well as the value of camera trap data to improve ecological knowledge of lesser-studied carnivores.

zoology↗