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National audience; The early successional vegetation stage is crucial for ecosystem development. A good understanding of this stage is especially important in restoration projects. Fluvial systems, heavily human-modified are now subject to increasing restoration efforts such as dam removal, are notably concerned. This study aims to describe the fine-scale spatial and temporal patterns of the initial phase of colonization in a dam removal context using a functional approach. The study was conducted on the Sélune River (Normandy, France), where two dams, 32 and 16 m high, respectively, are in the process of being removed. We recorded vegetation cover and composition changes during the 2015 growing season on dewatered alluvial deposits at two scales and three dates (March, May and July at site scale, March, June and September at impoundment scale). Grime Strategies and functional traits related to sediment stabilization and colonization capacity were recorded for each species according to databases. Physical drivers were estimated using spatial proxies: the distance to and the relative elevation from the channel, the longitudinal distance of the sampling station to upstream. Results showed at the two scales a rapid terrestrialization of the formerly submerged area. The colonization patterns of plant communities during the growing season exhibit an increase in species richness, a shift from ruderal to competitor species and a sediment stabilization potential notably by herbaceous species. Interestingly, we observed meaningful cover of species with hemirosettes all over the vegetation season. Moreover, pollination was mostly operated by abiotic factors in early season, and by biotic factors in late season. Woody species (Salix atrocinerea Brot and Alnus glutinosa (L.) Gaertn) regeneration was registered in the late growing season. Vegetation patterns were more influenced by abiotic factors in the early growing season than in the late growing season. These results highlight the passive restoration potential of vegetation colonization.

International audience; The removal of the two hydroelectric Sélune River dams (Normandy, West of France) –36m and 16m high, is expected by 2019 and 2021 respectively. It is a unique European renaturation project freeing an entire coastal river. This study, part of a global scientific program, focuses on 19kms of river stretch (the first disappearing lake’s length). Since 2015, the usual 1m summer tidal range of the Vezins impoundment is not established anymore in order to make sediment management easier during the emptying. Between early 2017 and late summer 2018, the water table has been slowly reduced to conduct these 700 000 m3 sediment flow prevention engineering works. The floodplain progressively goes back to its normal course. Hectares of dewatered muds were rapidly colonized by spontaneous vegetation over the following months. The former lake is slowly being replaced by a river meandering through resurgent fields and wetlands. The 4-year emptying has made a close vegetation change monitoring possible, highlighting how to ecologically restore the valley. This 2015 to 2018 survey is based on spatial (lateral and longitudinal variations) and temporal (intra- and inter-annual shifts) observations of riparian vegetation communities. The aim is to predict the vegetation’s ability to passively and ecologically restore the riparian area of the new Sélune River. It focuses on three axis: i) the temporal dynamics of the colonizing species, ii) the influence of environmental variables in spatially structuring communities, and iii) the functional successional patterns of the process. Species traits related to colonization and sediment stabilization potentials within the habitat mosaic are treated. We discuss how management decisions related to the ecological restoration of the valley could be supported by the community ecology and trait data obtained. Finally, we suggest prioritizing passive restoration issues according to the functions assigned in this new valley.

From 1985 to 2014, we monitored numbers of Red Knots Calidris canutus of the subspecies rufa occurring at Punta Rasa, Samborombón Bay, Buenos Aires province, Argentina during northward migration (March to April), and in the austral winter (mid-May to mid-August), when some knots, mainly immatures, remain in South America during the breeding season. Numbers occurring during northward migration declined over the monitoring period from a peak of 3,640 in 1987 to 168 in 2014. This is consistent with the concurrent decline of the main Tierra del Fuego wintering population (though the percentage of the Tierra del Fuego population stopping at Punta Rasa also declined from 5.4% to 1.3%). Numbers occurring at Punta Rasa during the austral winter have also declined, but not to the same extent and for the past decade more have been counted during the austral winter than during northward migration. Among those seen at Punta Rasa during the Arctic breeding season have been some with large amounts of rufous breeding plumage. The percentage of such birds has increased from 10–15% in 1987 to 19–54% during 2011–2014. Moreover, observations of individually marked birds show that some of those showing breeding plumage are mature adults, at least 3–7 years old. Conservation actions are required to manage Punta Rasa for the small but important numbers of Red Knots that occur there. Further research is needed to determine why some mature adults do not go to their Arctic breeding grounds and thereby fail to contribute to reproduction. Fil: Martínez Curci, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Bremer, Esteban. Fundación Vida Silvestre Argentina; Argentina Fil: Azpiroz, Adrián B.. Instituto de Investigaciones Biológicas "Clemente Estable"; Uruguay Fil: Battaglia, Gabriel E.. Municipalidad del partido de La Costa; Argentina Fil: Salerno, Javier C.. Municipalidad del partido de La Costa; Argentina Fil: Isacch, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: González, Patricia M.. Fundación Inalafquen; Argentina Fil: Castresana, Gabriel J.. Reserva Natural Bahía Samborombón; Argentina Fil: Rojas, Pablo. Reserva Natural Bahía Samborombón; Argentina

Ecological conditions in breeding and non-breeding areas of migrant birds have been linked to their annual survival and production of young, but the role of stopover sites is under-appreciated. Through banding studies and censuses along the flyway from Tierra del Fuego to the Canadian Arctic, the drastic decline in 2000–2001 of Red Knots (Calidris canutus rufa) population summering in southern South America in the northern winter was shown to be related to the overharvesting of horseshoe crabs (Limulus polyphemus) in Delaware Bay, USA, their last stopover site before reaching their breeding grounds, and to the late arrival of the birds at this site. In San Antonio Oeste, Argentina, where 25–50% of the Tierra del Fuego Red Knots population congregates every northward migration season, annual survival of the cohort of experienced birds banded in March 1998 was impacted a year later than the general decline. Knots marked at San Antonio Oeste earlier in March arrived in Delaware Bay on average before those marked 15 days later. Additionally, early migrating knots with active body moult in San Antonio Oeste exhibited a higher return rate in the following years than late and non-moulting birds. Since the decline, birds arriving late in Delaware Bay have been at increased risk of not being able to refuel properly or on time because food is no longer superabundant at that stopover site. These domino effects indicate that there are fitness consequences to individual migration strategies adopted by birds at austral summering and stopover sites, which can be amplified by compressed timing in Delaware Bay when food is depleted at this final stopover site. Si bien se ha relacionado la condición de las áreas de estadía no reproductiva y reproductiva de las aves migratorias con su supervivencia y producción de crías, el papel de los sitios de escala como limitante del tamaño poblacional es escasamente conocido. Mediante estudios de anillado y censos a lo largo de la ruta de vuelo desde Tierra del Fuego hasta el Ártico de Canadá, hemos relacionado la drástica declinación de la población de Playero Rojizo (Calidris canutus rufa) ocurrida durante 2000–2001 con la sobrepesca del cangrejo herradura (Limulus polyphemus) en su última escala en la migración hacia el norte (Bahía Delaware, EEUU) y la llegada tardía de las aves. En San Antonio Oeste, Argentina, donde se congrega el 25–50% de la población de Tierra del Fuego durante la migración al norte, el seguimiento de aves experimentadas de la cohorte anillada en marzo de 1998 permitió estimar que su supervivencia fue afectada un año más tarde que la declinación general. Las aves marcadas más temprano en marzo llegaron antes a Bahía Delaware, en promedio, que las marcadas 15 días después. Además, las aves tempranas con presencia de muda activa de plumaje corporal mostraron una tasa de retorno significativamente mayor en años posteriores que las aves sin muda activa. Desde la declinación, las aves tardías incrementaron el riesgo de no acumular reservas apropiadamente o a tiempo, debido a que el recurso trófico dejó de ser superabundante en Bahía Delaware. Estos efectos dominó indican que las estrategias de migración individuales originadas en las áreas de estadía austral y en los sitios de escala migratoria tienen consecuencias sobre la adecuación biológica y que éstas pueden ser amplificadas por la reducción en el tiempo de estadía en Bahía Delaware cuando el recurso trófico es escaso en este sitio.

The main ecosystem in northern Patagonia, Argentina, is the Monte, a semi-desert scrubland home to a high biodiversity. Monte is the most endangered ecosystem of southern South America, with an annual rate of clearance of the native vegetation estimated at 3.7%. Here we report the results of bird surveys carried out in the province of Río Negro, northern Patagonia. We surveyed four localities mostly dominated by the Monte ecosystem, between 1986 and 2010. Three localities are Important Bird Areas (IBAs): El Cóndor, San Antonio Oeste and Meseta de Somuncurá. The fourth locality is the Paso Córdoba nature reserve. We recorded a total of 263 bird species. The highest species richness was observed at San Antonio Oeste, followed by El Cóndor. Information regarding the period of occurrence and habitats are provided for all species and localities. Additionally, we indicated the cases in which breeding behavior was observed. This information is urgently needed for the evaluation of the consequences of habitat destruction and deterioration as well as for the success of intended remediation measures.

To assess population size and the conservation status of the Red Knot Calidris canutus rufa population in Maranhão, N Brazil, an aerial census and field studies were conducted in February 2005. The aerial count showed a population of 7,575 Knots, which is down about 600 from a previous census in the 1980s. However, the count for all shorebird species combined was only 24,000 compared to 198,600 in the 1980s, paralleling a world-wide trend of population decline in shorebirds. Resightings of colour-banded knots confirmed that this is a separate population from the larger wintering population in Tierra del Fuego. All species of shorebirds captured in Maranhão were found to be infested with feather lice and mites. Body masses of knots in Maranhão were significantly lower than in Tierra del Fuego, and about half the birds were below the hypothesized fat-free mass of the species. Blood and feather samples were taken from 38 Knots for subsequent assessment of virus loads, and for detecting sites where primary feather moult had occurred. This will enable us to establish whether significant mortality is associated with pathogen loads and the energetic demands of delayed moulting. The small size of the Maranhão population and the loss of another 13,000 knots this winter from the Tierra del Fuego population means that both are now endangered. Brochures on the need for Red Knot conservation were designed and printed, and have been circulated among fishing communities and school classes in Maranhão. Fil: Baker,Allan J.. Royal Ontario Museum; Canadá Fil: González, Patricia M.. Fundación Inalafquen; Argentina Fil: Serrano, Ines L.. CEMAVE, Centro Nacional de Pesquisa para Conservação das Aves Silvestres; Brasil Fil: Júnior, Wallace R. T.. CEMAVE, Centro Nacional de Pesquisa para Conservação das Aves Silvestres; Brasil Fil: Efe, Marcio A.. Universidade Federal de Alagoas; Brasil Fil: Rice, Susan. Eastern Shore of Virginia National Wildlife Refuge; Estados Unidos Fil: D'amico, Veronica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Rocha, Marcia C.. Belém, Pará; Brasil Fil: Echave, María Eugenia. Fundación Inalafquen; Argentina