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Mécanique statistique des systèmes désordonnés, en particulier inspirés par des systèmes à l'interface avec la biologie
(2) Production(s) de l'année 2025
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Island biogeography through the lens of multiscale metapopulation dynamics: insights into species-area relationships 
Auteur(s): Clenet Maxime, Munoz François, Picard Coline, Bernard Adam, Pitard E.
(Document sans référence bibliographique) 2025-03-21
Ref HAL: hal-05391292_v1
DOI: 10.1101/2025.03.21.644586
Exporter : BibTex | endNote
Résumé: While island biogeography focuses on species richness equilibrium driven by immigration and extinction, and metapopulation theory examines single-species dynamics across fragmented habitats, their interplay remains poorly understood. In particular, the species-area relationship remains a subject of ongoing debate, yet there are limited theoretical foundations to explain it. To address this, we developed a multiscale stochastic metapopulation model to investigate diversity patterns on islands, bridging the gap between island biogeography and metapopulation theory. Our model integrates regional colonization from a mainland with local colonization-extinction processes within islands at the single-species level, then extends this to multiple, independent species. By analyzing the stationary properties of this model, we generate novel predictions of Species Area Relationship (SAR) based on local extinction rates, within-island colonization rates, and mainland immigration rates. We demonstrate how the interplay of these parameters influences the relationship, predicting patterns that can resemble either the power-law of Arrhenius or the semi-logarithmic relationship of Gleason, depending on the relative importance of mainland immigration versus within-island dynamics, and on the nature of the species abundance distribution in the mainland. This unified framework offers new insights into the mechanisms driving species richness and distribution across spatial scales, providing a more holistic understanding of biodiversity patterns in fragmented landscapes.
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Environmental factors governing spatio-temporal series of aquatic vegetation in the Bagnas lagoon
Auteur(s): Bernard A., Alleaume Samuel, Fortuny X., Munoz F., Pitard E.
(Article) Publié:
Estuarine, Coastal And Shelf Science, vol. 319 p.109261 (2025)
Ref HAL: hal-05050636_v1
DOI: 10.1016/j.ecss.2025.109261
Exporter : BibTex | endNote
Résumé: Macrophytes are a key component of lagoon ecosystems, and the spatio-temporal variation of their biomass reflects the effect of environmental drivers. Understandingthese dynamics is essential for managing, preserving and anticipating the fate of such fragile ecosystems. First, using both satellite data and field observations,we showcase here a machine learning approach to accurately detect submerged vegetation in a preserved lagoon in South France, the Bagnas lagoon. Second,we investigate the statistical relationship between the surface area of Stuckenia pectinata and abiotic factors known to influence the life history of this aquatic plant.We thus identify and evaluate the factors that most impact Stuckenia pectinata population dynamics within the lagoon. We find that water temperature, salinity, anddepth are significantly related to submerged aquatic vegetation (SAV) coverage. We show that the SAV surface area reaches a peak during summer, which can varyacross years. Furthermore, we examine the lifetime distribution of SAV during each year cycle across the pond. We show that the average annual lifespan differssignificantly from one year to the next, which can be explained by annual differences in exposure time to sufficiently high water levels.
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