Riparian buffers act as microclimatic refugia in oil palm landscapes

1. There is growing interest in the ecological value of set-aside habitats around rivers in tropical agriculture. These riparian buffers typically comprise forest or other non production habitat, and are established to maintain water quality and hydrological processes, whilst also supporting biodiversity, ecosystem function and landscape connectivity. 2. We investigated the capacity for riparian buffers to act as microclimatic refugia by combining field-based measurements of temperature, humidity, and dung beetle communities with remotely-sensed data from LiDAR across an oil palm dominated landscape in Borneo. 3. Riparian buffers offer a cool and humid habitat relative to surrounding oil palm plantations, with wider buffers characterised by conditions comparable to riparian sites in continuous logged forest. 4. High vegetation quality and topographic sheltering were strongly associated with cooler and more humid microclimates in riparian habitats across the landscape. Variance in beetle diversity was also predicted by both proximity-to-edge and microclimatic conditions within the buffer, suggesting that narrow buffers amplify the negative impacts that high temperatures have on biodiversity. 5. Synthesis and applications. Widely-legislated riparian buffer widths of 20-30 m each side of a river may provide drier and less humid microclimatic conditions than continuous forest. Adopting wider buffers and maintaining high vegetation quality will ensure set-asides established for hydrological reasons bring co-benefits for terrestrial biodiversity, both now, and in the face of anthropogenic climate change.This work was funded by the Natural Environmental Research Council (NERC) through the Human Modified Tropical Forests programme (NE/K016261/1; NE/K016377/1), as well as the Newton--Ungku Omar Fund via the British Council and Malaysian Industry -Government Group for High Technology (216433953). NERC also funded the PhD studentship for JW (NE/L002485/1) and research fellowship of TJ (NE/S01537X/1)

Riparian buffers act as microclimatic refugia in oil palm landscapes

1. There is growing interest in the ecological value of set-aside habitats around rivers in tropical agriculture. These riparian buffers typically comprise forest or other non production habitat, and are established to maintain water quality and hydrological processes, whilst also supporting biodiversity, ecosystem function and landscape connectivity. 2. We investigated the capacity for riparian buffers to act as microclimatic refugia by combining field-based measurements of temperature, humidity, and dung beetle communities with remotely-sensed data from LiDAR across an oil palm dominated landscape in Borneo. 3. Riparian buffers offer a cool and humid habitat relative to surrounding oil palm plantations, with wider buffers characterised by conditions comparable to riparian sites in continuous logged forest. 4. High vegetation quality and topographic sheltering were strongly associated with cooler and more humid microclimates in riparian habitats across the landscape. Variance in beetle diversity was also predicted by both proximity-to-edge and microclimatic conditions within the buffer, suggesting that narrow buffers amplify the negative impacts that high temperatures have on biodiversity. 5. Synthesis and applications. Widely-legislated riparian buffer widths of 20-30 m each side of a river may provide drier and less humid microclimatic conditions than continuous forest. Adopting wider buffers and maintaining high vegetation quality will ensure set-asides established for hydrological reasons bring co-benefits for terrestrial biodiversity, both now, and in the face of anthropogenic climate change.This work was funded by the Natural Environmental Research Council (NERC) through the Human Modified Tropical Forests programme (NE/K016261/1; NE/K016377/1), as well as the Newton--Ungku Omar Fund via the British Council and Malaysian Industry -Government Group for High Technology (216433953). NERC also funded the PhD studentship for JW (NE/L002485/1) and research fellowship of TJ (NE/S01537X/1)

Riparian buffers can help mitigate biodiversity declines in oil palm agriculture

Agricultural expansion drives biodiversity decline in forested tropical regions. Consequently, it is important to understand the conservation value of remnant forest in production landscapes. In a tropical landscape dominated by oil palm we characterized faunal communities across eight taxa occurring within riparian forest buffers, which are legally protected alongside rivers, and compared them to nearby recovering logged forest. Buffer width was the main predictor of species richness and abundance, with widths of 40-100 m on each side of the river supporting broadly equivalent levels of biodiversity to logged forest. However, width responses varied markedly among taxa, and buffers often lacked forest-dependent species. Much wider buffers than are currently mandated are needed to safeguard most species. The largest biodiversity gains are achieved by increasing relatively narrow buffers. To provide optimal conservation outcomes in tropical production landscapes we encourage policymakers to prescribe width requirements for key taxa and different landscape contexts.Newton-Ungku Omar Fund (grants 216433953, 537134717) – delivered by the British Council and funded by the UK Department for Business, Energy and Industrial Strategy and the Malaysian Industry-Government Group for High Technology – as well as the UK Natural Environment Research Council (NE/K016407/1, NE/K016261/1; https://lombok.nerc-hmtf.info/). MJS was supported by a Research Leadership Award from the Leverhulme Trust