Biology subjects

Slade, E.

Publications and source records attributed to Slade, E..

5 recordsLinked to original sources

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↗

bioRxiv2019

Rapid acquisition of near optimal stopping using Bayesian by-products

Prior to any decision, animals (including humans) must stop deliberating. Both accumulating evidence for too little or too long can be costly. In contrast to accounts of decision making, accounts of stopping do not typically claim that animals use Bayesian posteriors. Considering a generic perceptual decision making task we show that, under approximation, only two variables are relevant to the question of when to stop evidence accumulation; time and the maximum posterior probability. We explored the rate at which stopping rules are learned using deep neural networks as model learners. A network which only used time and the maximum posterior probability learned faster than any other network considered. Therefore, such an approach may be highly adaptive, and animals may be able to reuse the same neural machinery they use for decisions for stopping. These results suggest that Bayesian inference may be even more important for animals than previously thought.

neuroscience↗

bioRxiv2017

Designing oil palm landscapes to retain biodiversity using insights from a key ecological indicator group

Oil palm expansion threatens biodiverse ecosystems across the tropics. However, palm oil is a widely used and profitable crop, so identifying strategies that mitigate the impact of oil palm expansion on biodiversity is important. Riparian reserves (strips of forest along rivers) are protected in many countries for hydrological reasons and also support species that would not otherwise persist in oil palm. However, management guidelines for riparian zones have been informed by relatively few ecological studies. We assessed how the structural features and landscape context of riparian reserves in Sabah, Malaysia affected dung beetle communities. We also tested the use of flight intercept traps to study movement of dung beetles along linear forest corridors. Overall, dung beetle abundance in riparian reserves was 54% lower than in logged forest areas, but all species observed in the logged forest were found in at least one riparian reserve site and both species richness and diversity increased with reserve width. Distance from a large block of continuous forest affected dung beetle community composition but not species richness, abundance, or functional diversity. The amount of forest cover in the surrounding landscape improved the retention of species within riparian reserves, and increases in vegetation complexity corresponded with higher functional richness and functional dispersion. The flight intercept traps did not indicate that there is net movement of individuals out of logged forest areas into the riparian reserves. The species richness of 30 m reserves (the suggested requirement of reserves in Sabah) was only 10% lower than in logged forest, but our data indicate that riparian reserves of at least 50 - 80 m are needed for species richness and diversity to equal that in nearby logged forest. These findings, particularly if they apply more widely to forest-dependent taxa, should be taken into account when setting policy and sustainability guidelines for oil palm plantations, both in areas undergoing conversion from forest and in existing oil palm plantations where forest restoration is required.

ecology↗

bioRxiv2017

Riparian reserves in oil palm plantations may provide movement corridors for invertebrates

Tropical forests are becoming increasingly fragmented through conversion to agriculture, with negative consequences for biodiversity. Movement of individuals among the remaining fragments is critical to allow populations of forest-dependent taxa to persist. In SE Asia, conversion of forests to oil palm plantations is a particular threat. Many oil palm dominated landscapes retain forested riparian reserves along streams and rivers, but the extent to which these riparian reserves are used for movement, relative to the oil palm matrix, is poorly understood. We used mark-release-recapture methods to investigate the movement of five moth taxa in riparian reserves connected to a continuous forest area within oil palm matrix in Sabah, Malaysian Borneo. Moths were recaptured on average 68m from the release point, and the mean time to recapture was between 2 and 3 days. Moths showed a significant tendency to move within forested riparian reserves than into adjacent oil palm. When moving within riparian reserves moths also showed a tendency to orient their movement away from the continuous forest into the riparian reserve rather than towards continuous forest or into oil palm. Overall, our results show a role for riparian reserves as movement corridors through oil palm plantations for some invertebrate species, strengthening the case for their retention and re-establishment.

ecology↗

bioRxiv2017

Diagnostic Yield And Treatment Impact Of Targeted Exome Sequencing In Early-Onset Epilepsy

BackgroundTo examine the impact on diagnosis, treatment and cost with early use of targeted whole-exome sequencing (WES) in early-onset epilepsy.\n\nMethodsWES was performed on 50 patients with early-onset epilepsy ([≤] 5 years) of unknown cause. Patients were classified as retrospective (epilepsy diagnosis > 6 months) or prospective (epilepsy diagnosis < 6 months). WES was performed on an Ion ProtonTM and variant reporting was restricted to the sequences of 565 known epilepsy genes. Diagnostic yield and time to diagnosis were calculated. An analysis of cost and impact on treatment was also performed.\n\nResultsA likely/definite diagnosis was made in 17/50 patients (34%) with immediate treatment implications in 8/17 (47%). A possible diagnosis was identified in 9 additional patients (18%) for whom supporting evidence is pending. Time from epilepsy onset to genetic diagnosis was faster when WES was performed early in the diagnostic process (mean: 143 days prospective versus 2,172 days retrospective). Costs of prior negative tests averaged $8,344 in the retrospective group, suggesting savings of up to $5,110 per patient.\n\nInterpretationThese results support the clinical utility and potential cost-effectiveness of using targeted WES early in the diagnostic workup of patients with unexplained early-onset epilepsy. The costs and clinical benefits are likely to continue to improve. Advances in precision medicine and further studies regarding impact on long-term clinical outcome will be important.

genetics↗