Movement of forest‐dependent dung beetles through riparian buffers in Bornean oil palm plantations

Ross E J Gray,Arthur Y C Chung,Otso Ovaskainen,Luisa F Rodriguez,Owen T Lewis,Eleanor M Slade

doi:10.1111/1365-2664.14049

Abstract

AbstractFragmentation of tropical forests is increasing globally, with negative impacts for biodiversity. In Southeast Asia, expansion of oil palm agriculture has caused widespread deforestation, forest degradation and fragmentation.Persistence of forest‐dependent species within these fragmented landscapes is likely to depend on the capacity of individuals to move between forest patches. In oil palm landscapes, riparian buffers along streams and rivers are potential movement corridors, but their use by moving animals is poorly studied.We examined how six dung beetle species traversed riparian buffers connected to a continuous forest reserve area within an oil palm plantation in Sabah, Malaysian Borneo. We used a mark–release–recapture study and a new Bayesian Joint Species Movement Modelling (JSMM) approach, extended to a continuous capture process model.Dung beetle species were fairly generalist in their habitat use, but two species showed a statistically supported preference for riparian buffer forest over oil palm, and one species showed a strong preference for forest reserve over riparian buffer, indicating the importance of forested areas within oil palm landscapes for some species.A land‐use change simulation indicated that the loss of riparian buffers in oil palm will result in reduced movement by forest‐dependent species.Synthesis and applications. Our results provide evidence for the use of riparian buffers in oil palm plantations for forest‐dependent dung beetle species, strengthening the case for their retention, restoration and re‐establishment. Furthermore, our study demonstrates the wider applicability of the Joint Species Movement Modelling (JSMM) framework to assess movement behaviour of species in fragmented landscapes, a vital tool for future forest and landscape management and conservation prioritisation exercises.

Highlights

Threats to tropical forest biodiversity are unprecedented due to the unparalleled rates of forest degradation, fragmentation and conversion to agriculture (Barlow et al, 2016; Hansen et al, 2013; Newbold et al, 2014; Phalan et al, 2013)
We examined how six dung beetle species traversed riparian buffers connected to a continuous forest reserve area within an oil palm plantation in Sabah, Malaysian Borneo
Dung beetle species were fairly generalist in their habitat use, but two species showed a statistically supported preference for riparian buffer forest over oil palm, and one species showed a strong preference for forest reserve over riparian buffer, indicating the importance of forested areas within oil palm landscapes for some species

Summary

| INTRODUCTION

Threats to tropical forest biodiversity are unprecedented due to the unparalleled rates of forest degradation, fragmentation and conversion to agriculture (Barlow et al, 2016; Hansen et al, 2013; Newbold et al, 2014; Phalan et al, 2013). Remaining forest patches within mosaic oil palm landscapes are often found in the form of strips of natural or restored vegetation by the side of waterways known as riparian buffers ( called riparian reserves or riparian strips; Luke et al, 2019). Despite the importance of connectivity of fragments for conservation planning, relatively few studies have investigated the movement behaviour of tropical forest-associated taxa (Bouchard & Brooks, 2004; Brouwers & Newton, 2009; Gray et al, 2019b; Khazan, 2014; Lucey & Hill, 2012; Scriven et al, 2017). We extend the framework to account for a continuous capture process and to model different land-use change scenarios We used these methods to ask how riparian buffers influence the movement of dung beetles within oil palm landscapes. We test the following hypotheses: (a) Dung beetles are more likely to prefer moving in riparian buffers than in oil palm plantations, and to prefer moving in continuous forest reserve to riparian forest buffers. (b) Movement ability and the rates at which dung beetles cross habitat boundaries will differ among species. (c) Conversion of forest to oil palm will limit the ability of dung beetles to move within fragmented landscapes, reducing the number of individuals captured in oil palm

| MATERIALS AND METHODS

Findings

| DISCUSSION