Biology subjects

Slade, E. M.

Publications and source records attributed to Slade, E. M..

4 recordsLinked to original sources

bioRxiv2026

Riparian buffer management, rather than surrounding forest cover and buffer width, drives pest attacks in oil palm plantations

The rapid expansion of oil palm plantations in Southeast Asia has caused extensive deforestation and landscape fragmentation. Riparian buffers (vegetated strips along the edges of rivers) have been shown to enhance biodiversity, water quality, and erosion control. However, plantation managers have raised concerns that these buffers may harbour pests such as nettle caterpillars, bagworms, and rhinoceros beetles (Oryctes rhinoceros). These pests damage the palms and facilitate the spread Ganoderma boninense (a fungal pathogen). Using causal inference modelling we examined how riparian buffer characteristics (width and habitat quality), oil palm age, and surrounding landscape features influence pest and disease incidence in oil palms adjacent to riparian areas in Sabah, Malaysian Borneo. We surveyed 47,500 palms for pest and disease damage and used mark-release-recapture techniques to track O. rhinoceros movements in oil palms adjacent to riparian buffers. Most O. rhinoceros activity (66.30%) occurred within the plantations, and only 6.10% occurred within riparian buffers, with limited movement between habitats. Oil palm age was a dominant driver of pest attacks: young palms were more susceptible to lepidopteran caterpillars and O. rhinoceros, whereas G. boninense was more prevalent in mature palms. Neither the surrounding forest cover nor the quality of the riparian buffer affected the incidence of pest attacks. Riparian buffer width increased O. rhinoceros attacks, reduced G. boninense infection, and had no effect on lepidopteran caterpillars, highlighting that surrounding forest cover and riparian buffers do not drive pest attacks in oil palm plantations. Instead, management of oil palms within the buffers s is likely to be more important in managing pests; increases in invasive oil palms within the buffers increased the incidence of caterpillar damage, and higher numbers of remnant old oil palms increased O. rhinoceros attacks in adjacent oil palms. Overall, riparian buffers were found to contribute little to pest spillover, suggesting that their biodiversity and connectivity benefits outweigh minor pest risks, especially if invasive young and remnant old oil palms within the buffers are effectively managed and native vegetation restored.

ecology↗

bioRxiv2022

Logging alters tropical forest structure, while conversion reduces biodiversity and functioning

The impacts of degradation and deforestation on tropical forests are poorly understood, particularly at landscape scales. We present an extensive ecosystem analysis of the impacts of logging and conversion of tropical forest to oil palm from a large-scale study in Borneo, synthesizing responses from 82 variables categorized into four ecological levels spanning a broad suite of ecosystem properties: 1) structure and environment, 2) species traits, 3) biodiversity, and 4) ecosystem functions. Responses were highly heterogeneous and often complex and non-linear. Variables that were directly impacted by the physical process of timber extraction, such as soil structure, were sensitive to even moderate amounts of logging, whereas measures of biodiversity and ecosystem functioning were generally resilient to logging but more affected by conversion to oil palm plantation. One-Sentence SummaryLogging tropical forest mostly impacts structure while biodiversity and functions are more vulnerable to habitat conversion.

ecology↗

bioRxiv2021

Morph-specific investment in testes mass in a trimorphic beetle, Proagoderus watanabei

When competition between males for mates is intense it is common to find that some males will adopt alternative tactics for acquiring fertilisations, often involving the use of sneak tactics whereby males avoid contests. These alternative tactics are sometimes associated with discrete differences in male morphology, with sneak males investing less in weaponry but more in traits such as testes which will give an advantage in sperm competition. In some cases it appears that males develop into more than two morphs, with a number of examples of tri- and even tetramorphic arthropod species being described. Here we analyse the scaling relations of the dung beetle species Proagoderus watanabei, which expresses two distinct weapon traits: paired head horns and a pronotal horn. We find that males of this species are trimorphic, with alpha males expressing long head horns and a pronotal horn, beta males with long head horns but no pronotal horn, and gamma males with short head horns only. We also find that alpha males invest less in testes than do beta or gamma males, indicating that beta and gamma males in this species probably experience higher risks of sperm competition than do alphas.

evolutionary biology↗

bioRxiv2021

Dung beetles as vertebrate samplers: a test of high throughput analysis of dung beetle iDNA

The application of environmental DNA (eDNA) sampling in biodiversity surveys has gained widespread acceptance, especially in aquatic systems where free eDNA can be readily collected by filtering water. In terrestrial systems, eDNA-based approaches for assaying vertebrate biodiversity have tended to rely on blood-feeding invertebrates, including leeches and mosquitoes (termed invertebrate-derived DNA or iDNA). However, a key limitation of using blood-feeding taxa as samplers is that they are difficult to trap, and, in the case of leeches, are highly restricted to humid forest ecosystems. Dung beetles (superfamily Scarabaeoidea) feed on the faecal matter of terrestrial vertebrates and offer several potential benefits over blood-feeding invertebrates as samplers of vertebrate DNA. Importantly, these beetles can be easily captured in large numbers using simple, inexpensive baited traps; are globally distributed; and also occur in a wide range of biomes, allowing mammal diversity to be compared across habitats. In this exploratory study, we test the potential utility of dung beetles as vertebrate samplers by sequencing the mammal DNA contained within their guts. First, using a controlled feeding experiment, we show that mammalian DNA can be retrieved from the guts of large dung beetles (Catharsius renaudpauliani) for up to 10 hours after feeding. Second, by combining high-throughput sequencing of a multi-species assemblage of dung beetles with PCR replicates, we show that multiple mammal taxa can be identified with high confidence. By providing preliminary evidence that dung beetles can be used as a source of mammal DNA, our study highlights the potential for this widespread group to be used in future biodiversity monitoring surveys.

ecology↗