Biology subjects

Delorme-Hinoux, V.

Publications and source records attributed to Delorme-Hinoux, V..

3 recordsLinked to original sources

bioRxiv2026

Life-history traits may buffer genetic erosion under isolation in mountain sky-island systems

Sky-island systems provide natural case studies for understanding how geography and Quaternary history shape genomes, phenotypes and life-history traits in mountain endemics. We investigated Xatartia scabra (Apiaceae), a monotypic scree specialist plant species restricted to sky-island summits in the eastern Pyrenees, by integrating population genomics with abiotic condition-informed distribution modeling. Using a ddRAD-seq-like protocol (nGBS), we genotyped 125 individuals (21,970 SNPs), and applied species distribution modeling to identify suitable environmental conditions from the Last Glacial Maximum to 2100. Genetic analyses revealed unexpected genetic "resilience", with moderate genome-wide diversity (HE = 0.17, Ho = 0.15) and low inbreeding (FIS = 0.07), despite small census sizes and strong isolation. Significant overall genetic differentiation (FST = 0.16), with pronounced summit-level structure and strong isolation-by-distance, supports deep valleys as barriers to gene flow. Abiotic niche reconstructions recovered extensive Heinrich Stadial 1 connectivity (+ 58,4% relative to present), followed by postglacial loss of suitable habitats at lower elevations and increasing fragmentation; projections under climate change forecast contraction (-61,2%, relative to present) of climatic suitability, expected to intensify drift in small, isolated populations. Demographic inferences align with this narrative, indicating postglacial decline in effective population sizes. Taken together, genetic, climatic, and demographic evidence supports a transition from historically connected lowland corridors to modern sky islands where distance-limited drift dominates. The maintenance of moderate genetic diversity and low inbreeding under strong isolation suggests that X. scabra may have evolved life-history strategies including outcrossing and monocarpy that allow limiting genetic erosion in such extreme and fragmented environments.

genomics↗

bioRxiv2025

Predicting spatiotemporal bioclimatic niche dynamics of endemic Pyrenean plant species under climate change: how much will we lose?

Species distributions are shifting under global change, with mountain ecosystems among the most vulnerable. In such landscapes, ability to track changing conditions is limited, threatening narrowly distributed species. As a mountain biodiversity hotspot in southwestern Europe, the Pyrenees harbors many such species, making it a key case study for climate vulnerability assessments. This study implements a bioclimatic niche modeling pipeline to evaluate climate change impact on endemic Pyrenean plant species by 2100. Objectives are to (i) map current bioclimatic niche suitability, (ii) forecast its future spatial dynamics, and (iii) identify potential climate refugia for conservation. Species occurrences were combined with 19 bioclimatic variables (1x1 km resolution) to characterize bioclimatic niche suitability, using an ensemble modeling approach integrating five algorithms (MaxEnt, Generalized Linear Model, Generalized Additive Model, Gradient Boosting Machine, and Random Forest). Their future spatiotemporal dynamics were projected under four climate scenarios (Shared Socioeconomic pathways 126, 245, 370, 585) for four successive periods spanning 2021 to 2100. By 2100, 69% of endemic species are projected to lose over 75% of their bioclimatic niche, and half to face complete losses under high-emission scenarios. Only two species may gain suitable areas, highlighting the need for species-specific conservation strategies. Bioclimatic niches are projected to shift by [~]180 m upslope and [~]3 km in latitude on average, with areas of highest multi-species suitability, referred to as bioclimatic hotspots, becoming restricted to elevation above 2000 m. These trends intensify after 2041-2060 period, reflecting escalating climate pressures as the century progresses. Our findings highlight the profound threat climate change may pose to endemic Pyrenean flora, with widespread bioclimatic niche losses projected by the centurys end and high elevation refugia emerging as key conservation priorities. Anticipating these shifts and integrating them into conservation planning will be crucial to mitigating high-elevation biodiversity loss in a rapidly changing world.

ecology↗

bioRxiv2025

Non-invasive eDNA reveals the ecological and genetic status of the Western Capercaillie (Tetrao urogallus aquitanicus) in the Eastern Pyrenees

The Anthropocene era is expected to bring about significant biodiversity and habitat loss for many species. These geographical changes, whether driven by climatic or anthropogenic factors, are likely to lead to considerable alterations in population size, structure, and genetic diversity. Monitoring natural populations is therefore essential to assess these impacts and enable informed conservation strategies for threatened species. The Western Capercaillie (Tetrao urogallus, L. 1758) has a widespread distribution in Boreal forests but fragmented in mountainous regions of the Palearctic, and is locally threatened by climate change, habitat destruction, and human disturbance. Our study focused on the eastern population of the subspecies T. u. aquitanicus, which is endemic to the Pyrenees mountains. The monitoring of this population has relied on direct methods and no genetic information had been generated so far. Here, we conducted a molecular study based on 229 non-invasive samples (faeces) to assess the ecological and genetic status of local population in the Catalan Nature Reserves of the Pyrenees-Orientales (Occitanie region, France). At the individual level, we assessed multi-locus genotypes, sexing, levels of inbreeding, stress level (Fecal Corticosterone Metabolites; FCMs) and diet. At the population level, we assessed sex ratio, genetic diversity and structure. We identified 62 individuals with a balanced sex ratio and estimated a census size of 79 individuals [95%CI = 68-92] in the study area. Genetic diversity was low and suggested significant inbreeding levels. FCM levels were lower in birds of areas considered as disturbed by humans and metabarcoding approach indicated a geographical structuring of diet composition at the reserve scale, with individuals exhibiting feeding behavior upon only one or few plant species. Our estimate of population census size was higher with figures assessed from lek counts, and the genetic approach provided additional insights on this population, establishing a baseline that will support conservation management plans.

ecology↗