Biology subjects

Le Maho, Y.

Publications and source records attributed to Le Maho, Y..

4 recordsLinked to original sources

bioRxiv2025

Multiannual environmental forcing shapes breeding phenology and success in a subantarctic seabird

Climate-driven phenological mismatches threaten avian reproduction by disrupting food availability during critical breeding stages. In marine ecosystems, time lags between environmental changes and their effects on food webs are challenging to model, yet they can have a profound impact on top-predator reproduction. We disentangle how oceanic and climatic variability influence the breeding phenology and success of a keystone seabird of the Southern Ocean drawing on 24 years of data from 17,000 marked king penguins. We document an exceptional 19-day advancement in breeding phenology, alongside increased breeding success (44% in 2000, 62% in 2023). A sliding-window analysis reveals that sea temperature and primary production in key foraging zones predict both phenology and breeding success, with lags ranging from several weeks to two years. While king penguins appear to be keeping pace with current changes, their dependence on multi-year environmental conditions underscores the vulnerability of top predators to unpredictable, fast-changing, and more frequent extreme conditions.

ecology↗

bioRxiv2025

Deep learning-based photo-identification for non-invasive monitoring of animal populations: Application to penguins and tortoises

We describe DL-ID, a deep learning-based framework for the individual identification of animals from images with higher accuracy and characteristics that make it more robust in challenging conditions, such as field studies, than widely used algorithms. This is demonstrated through testing with small datasets involving two species that exhibit distinctive morphological features: Humboldt penguins (Spheniscus humboldti Meyen, 1834) and Hermanns tortoises (Testudo hermanni Gmelin, 1789). We define a confidence index based on entropy within the model that significantly improves handling of the open set recognition problem, offering a new way to discriminate unknown individuals. DL-IDs accuracy of 87%, even with as few as four images per class, contrasts with the usual practice in deep learning of building large datasets to assess performance. The model outperforms traditional photo-identification methods like Wild-ID and I3S Pattern, offering a significant advancement for research and conservation efforts. Its efficiency and adaptability indicate its potential in real-time monitoring, opening new possibilities for wildlife conservation. Instead of designing a complex new deep learning model, we focused on adapting existing methods to address a relevant ecological problem. Our approach effectively tackles issues like limited training data and recognizing new individuals in field studies. Notably, it performs well even with small datasets, making it particularly useful for data-limited ecological research. This makes our approach a valuable step forward in applying deep learning to ecological studies.

ecology↗

bioRxiv2024

Sedentary life accelerates epigenetic ageing in King penguins

Introductory paragraphAdvances in medicine and food security have contributed to an increase in human lifespan1. Yet, the associated rise in sedentary behaviour and in obesity2,3 already threatens these gains4. Indeed, a growing body of evidence supports the central role of nutrient sensing and energy management pathways in regulating ageing rate and healthspan5,6, but the diversity of human lifestyles challenges our ability to identify the genetic and epigenetic drivers of this age acceleration. Here, we examine how the transition of wild King penguins to zoo husbandry can closely mimic the shift to a Western lifestyle in humans, and shed light on evolutionarily conserved epigenetic changes in responses to sedentary conditions. We show that, just like modern humans, zoo-housed King penguins experience an extended lifespan, but this comes at the cost of accelerated epigenetic ageing throughout life. This accelerated ageing is associated with differential methylation in key growth and maintenance pathways including the mTOR and PI3K/Akt networks, as well as in specific pathways of lipid-rich diet adaptation and heart-function. Our results demonstrate the deeply conserved link between sedentary behaviour and food availability on the one hand, and age acceleration on the other. Such evolutionary evidence may in turn help us to improve risk detection and, ultimately, therapeutics for lifestyle-induced age acceleration in humans7.

genomics↗

bioRxiv2016

Climate-driven range shifts in fragmented ecosystems

Range shift is the primary short-term response of species to rapid climate change but it is hampered by natural or anthropogenic habitat fragmentation. Fragmented habitats expose different critical areas of a species niche to heterogeneous environmental changes resulting in uncoupled effects. Modelling species distribution under complex real-life scenarios and incorporating such uncoupled effects has not been achieved yet. Here we identify the most vulnerable areas and the potential cold refugia of a top-predator with fragmented niche range in the Southern ocean by integrating genomic, ecological and behavioural data with atmospheric and oceanographic models. Our integrative approach constitutes an indispensable example for predicting the effect of global warming on species relying on spatially and ecologically distinct areas to complete their life-cycle (e.g., migratory animals, marine pelagic organisms, central-place foragers) and, in general, on species constrained in fragmented landscapes due to continuously-growing anthropogenic pressure.

evolutionary biology↗