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Apetahia and Sclerotheca are two small genera of Campanulaceae (subfam. Lobelioideae) endemic to South East Polynesia (French Polynesia and the Cook Islands).These groups comprise from small shrubs to small trees (up to 3 m tall) that are restricted to upland tropical rainforests and montane cloud forests, where they are generally found between 400 and 2000 m above sea level. We investigated their molecular phylogenetics by sequencing four plastid loci. We found that the two genera together form a well-supported Glade but did not find support for their reciprocal monophyly. The genus Sclerotheca is supported as monophyletic Glade that may be nested within a paraphyletic Apetahia. Because of their morphological similarities, we opted to treat them as a single genus, Sclerotheca s.l., comprising ten species, and here provide the necessary new combinations, Sclerotheca raiateensis comb. nov. and Sclerotheca seigelii comb. nov. The expanded genus Sclerotheca has a patchy geographical distribution with remarkable disjunctions and may be undergoing a long-term decline. Conservation efforts to protect these highly threatened endemic species (all classified CR or EN according to the IUCN red List) are urgently needed, as they may be also considered as indicators of long-term ecological changes.

International audience; Compared to traditionally used plastid or ribosomal markers, nuclear gene markers provide many advantages for molecular systematics of plants, and high-throughput sequencing technologies are making large nuclear datasets available at an unprecedented rate. We used targeted amplicon sequencing of 44 nuclear genes to construct a time-calibrated phylogeny of genus Metrosideros (Myrtaceae), evaluate recent systematic revisions, and assess whether phylogenetic signal within the Hawaiian Archipelago is correlated with island biogeography or morphological diversification. We generated a final dataset of 40 nuclear genes for 187 specimens, used multiple search heuristics and species-tree analysis to estimate a phylogeny, and incorporated new fossils for the genus to estimate divergence times across the dataset. All analyses supported the monophyly of Metrosideros, including Carpolepis and Tepualia. Hawaiian Metrosideros were monophyletic and dated to 3.1 MYA using new fossils for the genus, which is intermediate to previous estimates based on nuclear ribosomal/chloroplast loci and calibrated with island ages. Within the Hawaiian Metrosideros clade, we observed short branch lengths and unresolved relationships, and phylogenetic patterns were not concordant with biogeographic hypotheses of island progression, or the delineation of taxa or morphotypes. Average nucleotide diversity was relatively consistent across the Hawaiian Islands with the exception of slightly lower diversity on Kaua'i. These results provide a data-rich estimate of the timing of a single introduction of Metrosideros to Hawai'i and highlight the need for molecular markers with higher evolutionary rates for resolution of relationships within this recent radiation.

International audience; Since Linnaeus popularized the system of binomial nomenclature to describe living organisms, it has been common practice to name species after people (eponyms). Trends in species naming were analyzed in the endemic flora of New Caledonia, a biodiversity hotspot in the South-West Pacific. It was found that eponyms were predominantly from France and other European countries, and to a lesser extent from neighboring countries in Oceania or North America. Today, just 7% of these eponyms were born in New Caledonia, and 6% were women. Most of the corresponding species were described in the past five decades. Although the evidence is still preliminary, the name of a species appears to have a significant impact on how people relate to it, and this may be especially important for threatened endemic species and the willingness of local populations to preserve them. Because newly described species are often rare and endangered, adopting a more balanced approach to species naming may help to secure their future, particularly given the current extinction crisis.

International audience; Aim The diversity and composition of species pools within oceanic archipelagos is determined by a combination of colonization, abiotic tolerance, in situ diversification, biotic interactions and extinction. The signature of biogeographic events and evolutionary processes, however, may be masked by recent coalescence and hybridization between closely related species. We used the species-rich plant genus Cyrtandra (Gesneriaceae) to investigate the roles of colonization and hybridization in shaping community assemblages on the geologically young Hawai'i Island. Location Hawaiian Islands. Taxon Cyrtandra (Gesneriaceae). Methods We sampled 29 Cyrtandra taxa and putative hybrids across the main Hawaiian Islands and generated single nucleotide polymorphisms (SNPs) from nine single-copy nuclear genes. Maximum likelihood and Bayesian inference were used to reconstruct phylogenetic relationships, divergence times were estimated using secondary calibrations and island ages, and ancestral area estimation was done using likelihood models. Lastly, we used a Bayesian population assignment test and principal components analysis to infer population genetic structure. Results Cyrtandra colonization of the main Hawaiian Islands appears to have followed the progression rule, whereby the oldest high Hawaiian Islands (Kaua'i and O'ahu) were colonized first, followed by colonization of the younger islands as habitat became available. Hawai'i Island was colonized four times, with two dispersal events from O'ahu and two from Maui Nui. The different colonization events gave rise to significantly uneven numbers of species, and hybridization among the incipient lineages was detected in the form of intermediate genotypes. Main conclusions Our investigation into community assembly in a species-rich plant genus on a geologically young oceanic island revealed a history of multiple colonizations and hybridization among colonizing lineages. The rapid diversification (3.5 species/My) of one of four Cyrtandra lineages on Hawai'i Island may be the result of hybridization between genetically diverse lineages that stem from independent colonization events. Multiple colonization events followed by a merging of lineages may be particularly common during early-stage community assembly on islands and, through the generation of genetic variation, may be especially important for species diversification.

International audience; Background and aims: The co-existence of large number of competing plant species with the same basic needs is a major question in ecology, particularly when this involves closely related species. Methods: We investigated the ecology of six heather species (Calluna vulgaris & Erica spp., Ericaceae) able to cohabit in the same heathlands. We characterised the ionome, i.e. the mineral composition of the plants using a sampling strategy specifically designed to control for soil effects. Nine plant communities in Limousin, France, were investigated, representing eight combinations of different species, on serpentine and non-serpentine substrates. Results: Ionome was influenced by both taxonomic and environmental factors with significant interactions between them. We found that species growing in sympatry had distinct ionomic profiles, i.e. they differ in their leaf mineral content, suggesting different nutritional strategies. Different mycorrhizal associations may be hypothesised to explain these different chemical signatures. Conclusions: Differential use of the soil nutrients could explain the co-existence of closely related species. It may also explain the diversity of certain shrubby ecosystems or large shrubby genera such as Erica. Ionomics is therefore a promising tool for ecological studies in non-model organisms.

International audience

International audience

International audience; L'huile d'argan du Maroc, produite à partir d'un arbre géré séculairement par les populations locales au sein d'un écosystème forestier très domestiqué, a fait l'objet de nombreuses opérations de valorisation et de patrimonialisation. Partant de l'analyse des mobilisations par plusieurs catégories d'acteurs, des savoirs locaux relatifs à la gestion de l'arganier et de ses produits, nous discutons de la façon dont la confrontation des imaginaires, des cadres normatifs et des modèles de développement des uns et des autres ont conduit à se focaliser sur les savoirs liés à la production de l'huile en effaçant ceux de l'amont, moins visibles. Cela nous conduit à analyser comment des formes de reconnaissance des savoirs locaux peuvent conduire à séparer des connaissances interdépendantes, et induire des dynamiques sociocognitives et socioenvironnementales elles aussi dissociatives. Il importe alors d'évaluer l'impact que peuvent avoir ces mobilisations sélectives des savoirs sur les dynamiques et les résiliences des systèmes socioécologiques en présence.

International audience; The Mvae and the Ntumu, two African rainforest ethnic groups belonging to same Fang linguistic sub-group, live together as good neighbors in the Ntem watershed of southern Cameroon. Like most forest dwellers in the Congo Basin, these two societies have implemented a multi-active type of subsistence economy: hunting, trapping, gathering and fishing are practiced in addition to a predominant slash-and-burn agriculture. The aim of this paper is to emphasize that these ethnic groups, which do not have fishery as their most salient production domain, have nevertheless acquired a remarkable expertise in wild fishery, notably through a diversity of techniques and socio-ecological conditions of practice. The sizable variety of fishing methods takes advantage of the great vascularity of the hydrographic network and involves in a complementary way all the members of the community - young and old, of both genders, in solo, in pairs or in larger groups of participants. This large range of possibilities ensures a continuous provision of fish over the year and establishes inland capture fishery as a real safety net that can provide - in all circumstances and in sufficient quantities - resources that are culturally valued, that are an appreciable extra-source of income, and whose nutritional role is acknowledged. Despite of being the pervasive basis of the subsistence economy of forest peoples in Central Africa, the contribution of inland capture fishery to the livelihoods of Congo basin forest dwellers remains unobtrusive and is overlooked by development agencies.

International audience

International audience

Anthropic and climate changes reduced the vegetation cover and induced dunes movement in South-east of Niger. This work aimed to characterize wind erosion on moving dunes of the Manga in Niger. Specially, it aimed to measure wind erosion flux and to determine the velocity of the dunes fronts dynamics and the optimal period of their movement. Thus, an automatic meteorological station is installed in the village of Kilakina to direction and velocity of wind and rainfall. Metallic pickets have been installed in front of 22 dunes to measure theirs dynamics. And 3 masts of BSNE sand catcher have been installed to characterize wind erosion horizontal flux. The results show that wind erosion flux is maximal at the beginning of the rainy season while wind speeds are high. Dunes front without fixation device are more mobile. On their surfaces wind erosion happened all the year because of wind speed is regularly superior to the threshold velocity. Indeed, wind erosion flux present spatial and temporal variability which make complex thee comprehension of their dynamics., Dans le Manga (Sud-est du Niger), l'un des effets de la pression anthropique et de la variation climatique se traduit la disparition de la végétation qui a pour principale conséquence la mobilisation du sable dunaire. L'objectif de ce travail est de caractériser l'érosion éolienne au niveau des dunes vives. Spécifiquement, il s'agit de i) mesurer le flux d'érosion éolienne sur les dunes vives et ii) déterminer les vitesses et les périodes optimales de déplacement de ces dunes. La méthodologie utilisée a consisté baliser dans le sens de l'avancée des fronts dunaires avec les piquets en fer 22 dunes répartie au sud du 14e parallèle, à installer une station météorologique automatique et des capteurs de sédiments de type BNSE sur le flanc et au sommet de la dune vive. Les résultats obtenus montrent que l'érosion éolienne est fonction de la vitesse du vent dont les phases de vents extrêmes s'observent avec le passage des tempêtes convectives des débuts de la saison des pluies. Le reste du temps, les vents restent inférieurs à 10 m / s mais régulier. Les fronts dunaires dépourvus de système de fixation sont les plus mobiles. La vitesse moyenne de l'avancée de leurs fronts a été de 5,60 ± 2,02 m / an. La mesure des flux éoliens montre que l'érosion se produit sur les dunes vives toute l'année du fait de l'existence des vents très souvent largement au-dessus de la vitesse seuil d'érosion. Elle connait, cependant, une baisse d'intensité entre août et octobre. Le flux d'érosion mesuré au sommet de la dune vive a atteint en moyenne 1,61 fois (± 0,6) celui mesuré sur le flanc durant la saison des pluies. Cependant, au cours de la saison sèche, le flux mesuré au sommet des dunes a été inférieur à celui mesuré sur le flanc d'en moyenne 3,7 (± 4,8) fois. La variabilité spatiale et temporelle montre ainsi la complexité de l'appréhension de la dynamique des dunes vives dans le Manga.

International audience

International audience

International audience; The island of Moorea in French Polynesia is representative of a relatively well preserved small tropical oceanic island but both its terrestrial and marine ecosystems arc currently under strong anthropogcnic pressures. The terrestrial ecosystems are facing an increasing urbanization, and the destruction and modification of their natural habitats by cultivation and forestry plantations, accidental or intentional fires, and particularly by the invasion of alien plant and animal species. Coastal areas and reef ecosystems are threatened by shoreline artificialization, sedimentation due to soil erosion, increasing uses of marine and lagoon resources and frequency of coral bleaching events. A significant erosion of terrestrial and marine biodivcrsity is observed on the island since the last decades. In the context of the Land Management Plan (PGA) and Marine Area Management Plan (PGEM) recently set up in the island by local authorities, scientific surveys and inventories were made in 2006 in order to assess the status of terrestrial biodivcrsity (vascular plants) and marine biodiversity (reef fishes) and compare areas with different anthropogcnic pressures. Studies conducted on the flora and the vegetation at low and middle elevation along attitudinal transects show that the plant invasion process is related to climatic and topographic factors, and species autoecology. The marine study aims to compare the protected areas with control areas in order to test the effectiveness of protection measures and to propose a streamlined monitoring protocol. A methodological study in both terrestrial and marine ecosystems was conducted in order to propose biodivcrsity indicators which are crucial for decision making in conservation and sustainable development of island biodiversity. We used Geographic Information System (GIS) as a fast and intuitive tool for mapping indicators and their variability. This methodological approach developed on the island of Moorca could be used as a model for other tropical islands.

The condition of pastoral resources of a land of reception and transit for transhumant herders : the Kotchari territory (Southeastern Burkina Faso). Kotchari pasturelands, which include a portion of the W National Park, were characterized by three complementary methods : an analysis of a colour composition of an Aster image, a floristical analysis and a pastoral survey. Nine pastoral landscape units with diverse tree cover were described, they include ten agrostological groups. The landscape units located outside the protected area, especially on thin to fairly deep soils, show the highest density in ligneous species and the highest herbaceous richness as well as the least dominance between species. Conversely, herbaceous phytomass and ligneous cover are higher in the protected area, particularly on the deep hydromorphic soils units. In addition, these units are more or less heterogeneous, some containing several agrostological groups. In general, the pasture lands located outside the protected area tend to be the most degraded : in some of them there is a regeneration of trees and a decrease of perennial herbaceous species. In all, although the phytomass is rather abundant and the pastoral values are acceptable in most units, those located outside the W park appear not very interesting in terms of pastoral use. Their ability to produce herbaceous regrowth after vegetation fires is low, the landscape is highly fragmented and the access to some units is not possible all year long. The pastoral status of the pastoral units inside the protected area, which have the highest phytomasses and the best pastoral values, is clearly much better. The strong interest of transhumant herders in this region seems guided on the one hand by the quality and availability of forage that is better at the end of the dry season than in their home grazing territory, and on the other hand by the opportunity of illegal use of pastoral resources in protected areas., Les pâturages du terroir de Kotchari, qui incluent une portion du Parc national du W, ont été caractérisés par trois méthodes complémentaires : une analyse en composition colorée d’une image satellitaire Aster, une analyse floristique et une enquête pastorale. Neuf unités paysagères pastorales plus ou moins densément boisées qui comprennent dix groupements agrostologiques ont été décrites. Celles situées à l’extérieur de l’aire protégée présentent la densité en ligneux la plus élevée et la strate herbacée la plus riche en espèces avec la dominance entre espèces la moins marquée, surtout sur les sols minces à moyennement profonds. La phytomasse herbacée sur pied et le recouvrement ligneux apparaissent en revanche plus élevés dans l’aire protégée, notamment dans les unités sur sols profonds hydromorphes. Par ailleurs, ces unités sont plus ou moins hétérogènes, certaines renfermant plusieurs groupements agrostologiques. De manière générale, il y a une tendance à la dégradation des pâturages dans les unités situées en dehors de l’aire protégée : certaines d’entre elles présentent un début d’embuissonnement et les herbacées pérennes y sont en diminution. Au total, malgré une phytomasse globalement satisfaisante et des valeurs pastorales acceptables, la plupart des unités situées hors du parc W apparaissent peu intéressantes au plan pastoral. Leur potentiel en repousses herbacées après les feux est faible, les milieux sont fortement fragmentés et il est impossible d’accéder à certaines d’entre elles toute l’année. Le statut pastoral des unités pastorales à l’intérieur de l’aire protégée, qui ont les plus fortes phytomasses et les meilleures valeurs pastorales, est clairement bien meilleur. Le fort attrait des transhumants pour ce terroir semble s’expliquer par une production fourragère meilleure et plus disponible en fin de saison sèche que dans les territoires d’attache d’une part, par l’usage possible des ressources interdites des aires protégées d’autre part., Sawadogo Issa,Devineau Jean-louis,Fournier Anne. État des ressources pastorales dans une terre d’accueil et de transit des pasteurs transhumants : le terroir de Kotchari (sud-est du Burkina Faso). In: Revue d'Écologie (La Terre et La Vie), tome 67, n°2, 2012. pp. 157-178.