Search results for "diversity"
showing 10 items of 3950 documents
Herons of French Polynesia. Threats, status and conservation.
2018
8 pages; International audience; In French Polynesia, only three Ardeidae are present: Cattle Egret (Bubulcus ibis), Tahiti Striated Heron (Butorides striata patruelis) and Eastern Reef-Heron (Egretta sacra), and the last two breed there. The Eastern Reef-Heron is widespread in the Pacific range and its conservation status is least concern. However, the status of the Tahiti Striated Heron is critically endangered on the International Union for the Conservation of Nature Red List. In 2009, only 70 birds were estimated living in Tahiti and thus the entire French Polynesia. Threats are mainly due to the restricted distribution of breeding habitat and habitat destruction. The Tahiti Striated He…
Distribution models and environmental changes : Application to echinoid faunas in the Southern Ocean and ecoregionalization
2018
Current environmental changes, which impact marine environments, cover major scientific and societal issues, especially as these environmental changes are expected to accelerate along the 21st century. Understanding and forecasting the response of marine biodiversity to these changes is a pregnant scientific issue. Biogeographic and macroecological approaches provide a scientific framework for that purpose. They allow describing and understanding species distribution patterns at large spatial scale as well as estimating their potential shift with regards to environmental change. This is particularly true in the Southern Ocean, where the effects of climate change are already occurring and wh…
Structuration spatiale des principaux poissons démersaux autour de l’île de la Réunion à partir de la formeexterne de leurs otolithes
2022
L’identification et la connaissance de la structuration spatiale de stocks sont essentielles pour étudier la dynamique des populations de poissons et ainsi gérer les pêcheries. Dans cette étude, la forme des otolithes a été employée pour comprendre la structuration des stocks des populations des principales espèces commerciales capturées à l’île de La Réunion. Un total de 1091 individus, appartenant à 9 espèces de poissons osseux bentho-pélagiques de différents compartiments d’habitats coralliens et profonds (Aphareus rutilans, Cephalopholis aurantia, Epinephelus fasciatus, Etelis carbunculus, Lutjanus kasmira, Lutjanus notatus, Pristipomoides argyrogrammicus, Pristipomoides filamentosus, V…
Développement postnatal et évolution du complexe craniofacial chezles rongeurs
2022
Understanding developmental mechanisms in evolution is crucial to apprehend the diversification of organismal forms. In mammals, changes occur during all development phases (prenatal and postnatal). Postnatal growth plays an essential role in the acquisition of the adult shape. During this period, the craniofacial complex undergoes many changes in functional constraint forcing the different tissue to accommodate while adjusting, along the growth and at the adult stage, to a certain level of functional performance. These different developmental interactions respond to several influencing factors such as molecular, genetic and cellular processes but also the environment. The latter will play …
Expanding genetic graphs' potential to analyse ecological connectivity: assessment of graphs construction methods
2019
International audience; Dispersal movements are often constrained in human-shaped landscapes, thereby threatening species survival. Landscape genetics approaches are commonly used to analyse ecological connectivity because genetic data well reflect dispersal capacities. When species occupy discrete habitat patches, graph-theoretic methods are a particularly relevant approach to study dispersal-driven gene flow. The links of a genetic graph can be weighted using different genetic distances between populations (nodes). Similarly, graph pruning (link set selection) can rely on different criteria. However, despite growing interest in genetic graphs, the influence of these parameters remains mos…
Gammarids and acanthocephalans, a multi-(cryptic) hosts and multi-parasites system?
2022
Multi-host parasites can exploit various host species that differ in abundance and susceptibility to infection, which will contribute unequally to their transmission and fitness. "Key hosts" are those contributing significantly more to the completion of the life cycle of such parasites. Three non-exclusive criteria may be used to identify a key host: its high abundance, its high exposure/susceptibility to infection, and the large number of infectious stages produced per infected individual. Many parasites with complex life cycles have evolved the ability to manipulate several traits of their intermediate hosts' phenotype, including behavior, thereby increasing the likelihood of transmission…
A single key-odorant accounts for the pheromonal effect of rabbit milk : further test of the mammary pheromone's activity againt a wide sample of vol…
2003
International audience
Validation des modèles de connectivité issus de la théorie des graphes en utilisant des données génétiques
2021
National audience; Modéliser la connectivité fonctionnelle des habitats est déterminant pour la conservation de la biodiversité. Les graphes paysagers, en modélisant des taches d’habitat reliées par des chemins de dispersion potentiels, permettent de quantifier la connectivité du paysage. Si cette approche semble prometteuse, sa validité écologique reste à démontrer. Tester sa validité implique de confronter des données de connectivité issues d’un graphe à des données reflétant la dispersion des individus, telles que des données génétiques. Dans cet objectif, nous avons modélisé la connectivité de l’habitat d’une espèce d’oiseau forestière, la Paruline caféiette (Setophaga plumbea), en Guad…
Evolutionary histories of symbioses between microsporidia and their amphipod hosts : contribution of studying two hosts over their geographic ranges.
2019
Title: Evolutionary histories of symbioses between microsporidia and their amphipod hosts : contribution of studying two hosts over their geographic ranges.Keywords: Symbioses, Phylogeny, Phylogeography, Amphipods, Host-Parasite, MicrosporidiaAbstract: Microsporidia are obligate endoparasites, exploiting their hosts with either vertical or horizontal transmission. While the former may promote co-speciation and host-specificity, the latter may promote shifts between host species. Freshwater amphipods are hosts for many microsporidian species, but no general pattern of host specificity and co-diversification is known.In my PhD work microsporidian infections, identified with SSU rDNA, were ass…
La conservation de la biodiversité et de la naturalité sont-ils des objectifs conciliables au sein du réseau des réserves naturelles
2008
Dans une définition étroite, la biodiversité ne transcrit qu’une des notions liées au fonctionnement de la Nature (organisation, complexité, spontanéité, continuités et diversité). Aujourd’hui, nombreux sont ceux qui expriment le besoin de gérer les forêts (ou les composantes forestières d'espaces naturels) suivant un principe impératif de naturalité et recherchent une vision intégrative et partagée sur tout ce que cela sous-entend. Les idées reçues sont nombreuses sur ce concept scientifique novateur et ses applications. Le colloque Biodiversité, Naturalité, Humanité - Pour inspirer la gestion des forêts a été organisé par le WWF France, Réserves Naturelles de France (RNF), le Réseau Ecolo…