Spatial distribution in Norwegian lemming Lemmus lemmus in relation to the phase of the cycle

Competition between individuals of the same or different species affects spatial distribution of organisms at any given time. Consequently, a species geographical distribution is related to population dynamics through density-dependent processes. Small Arctic rodents are important prey species in many Arctic ecosystems. They commonly show large cyclic fluctuations in abundance offering a potential to investigate how landscape characteristics relates to density-dependent habitat selection. Based on long-term summer trapping data of the Norwegian lemming (Lemmus lemmus) in the Scandinavian Mountain tundra, we applied species distribution modeling to test if the effect of environmental variables on lemming distribution changed in relation to the lemming cycle. Lemmings were less habitat specific during the peak phase, as their distribution was only related to primary productivity. During the increase phase, however, lemming distribution was, in addition, associated with landscape characteristics such as hilly terrain and slopes that are less likely to get flooded. Lemming habitat use varied during the cycle, suggesting density-dependent changes in habitat selection that could be explained by intraspecific competition. We believe that the distribution patterns observed during the increase phase show a stronger ecological signal for habitat preference and that the less specific habitat use during the peak phase is a result of lemmings grazing themselves out of the best habitat as the population grows. Future research on lemming winter distribution would make it possible to investigate the year around strategies of habitat selection in lemmings and a better understanding of a fundamental actor in many Arctic ecosystems.publishedVersio

Diagnóstico situacional Hospital Gaspar García Laviana- Rivas y Ernesto Sequeira- Región Autónoma Atlántico Sur. Nicaragua. Año 2004.

Estudio de tipo descriptivo de corte transversal, en los Hospitales Ernesto Sequeira de la Región Autónoma del Atlántico Sur y Gaspar García Laviana de Rivas durante el año 2004. Se encontró que en ambos Hospitales brindan atención general, de prioridad Materno-Infantil, ubicados en las cabeceras de los departamentos; pertenecen al Segundo nivel de atención, con un nivel de complejidad básico, de referencias departamental para los centros de salud, cuyo propietario es el Ministerio de Salud. Con poblaciones objetivos mayores de 175,000 habitantes donde el 65% de las personas son niños o mujeres en edad de procrear. La cartera de servicios que ofertan ambos hospitales es acorde a su complejidad en las que se encuentran las cuatro especialidades básicas Medicina Interna, Cirugía General, Pediatría y Gineco obstetricia y los servicios de apoyo tales como: Farmacia, Radiología, Laboratorio así como en su estructura física cuenta con consultorios para consulta externa, emergencia, quirófanos, salas de parto y camas censables. El número de recursos humanos en cada hospital es mayor a 300 personas, donde el 55 al 60% es asistencial. En los recursos financieros el 80% del presupuesto proviene de fondo fiscal y el mayor gasto es en el pago de recursos humanos. El equipamiento asistencial de los hospitales se encuentra desfasado y obsoleto, entre el 20 al 40% en regular y muy mal estado y tienen más de un año de estar sin funcionamiento y no han sido reparados. El modelo de gestión de ambos hospitales es tradicional, sin implementación de herramientas gerenciales, ni toma de decisiones. La producción de servicios es baja en relación a su capacidad instalada

Effect of age and experience on foraging strategies in a long-lived seabird,King penguin

La théorie des traits d'histoire de vie est basée sur le principe d'allocation d'énergie optimale entre la maintenance et la reproduction. À un jeune âge, les espèces longévives favorisent leur maintenance, pour ensuite progressivement favoriser leur reprLife history theory predicts that long-lived species should firstly favour their survival at young ages since their chances to engage in future reproductive attempts is high, and then progressively favour their reproduction when growing old. This theory

Effect of age and experience on foraging strategies in a long-lived seabird,King penguin

La théorie des traits d'histoire de vie est basée sur le principe d'allocation d'énergie optimale entre la maintenance et la reproduction. À un jeune âge, les espèces longévives favorisent leur maintenance, pour ensuite progressivement favoriser leur reproduction lorsqu ils prennent de l'âge et acquièrent de l'expérience dans les tâches liées à la prospection alimentaire et la reproduction. Ils favorisent de nouveau leur maintenance lorsqu ils atteignent un stade correspondant à la sénescence. Etant donné que les stratégies de recherche alimentaire sont le point central des compromis d'allocation d'énergie, une des hypothèses de ce succès reproducteur âge-dépendant réside en la capacité des individus à améliorer leur efficacité de prospection alimentaire. Nous nous sommes donc demandé quels sont les effets de l'âge et de l'expérience sur les comportements de recherche alimentaire chez une espèce d'oiseau marin longévive, le manchot royal (Aptenodytes patagonicus). Nous avons étudié les stratégies de recherches alimentaires chez des reproducteurs d'âge et d'histoire reproductrice connus à différentes échelles. Nous avons mis en évidence qu avec l'âge et l'acquisition d'expérience, le manchot royal de Crozet adopte diverses stratégies leur permettant de réduire leur effort de recherche alimentaire : optimisation de l'effort fourni durant les phases de transit de la plongée ou dans le choix des proies. L'effort excédentaire dans la recherche alimentaire produit par les jeunes reproducteurs se répercute sur leur succès reproducteur. Néanmoins, nous n avons pas clairement mis en évidence d'effet de l'âge et/ou de l'expérience sur l'efficacité de pêche. Nos résultats suggèrent que l'efficacité de recherche alimentaire serait plus liée à des processus physiologiques une fois que les individus ont atteint le stade reproducteur, et notamment à certains processus de vieillissement cellulaire.Life history theory predicts that long-lived species should firstly favour their survival at young ages since their chances to engage in future reproductive attempts is high, and then progressively favour their reproduction when growing old. This theory has received much support from experimental and field data as reproductive success often increases with age until the individual reaches senescence. One explanation of age-dependent reproductive performance could be the improvement in foraging efficiency with age and acquisition of experience. We examined age and experience effects on foraging behaviour in a long-lived seabird, the king penguin (Aptenodytes patagonicus). We highlighted that, with increasing age and experience, king penguin in Crozet Archipelago conduct strategies that aim at reducing the foraging effort, such as diving optimization or age-specific choice of prey. The extra foraging effort of first breeders had an impact on their breeding success. Nevertheless, we found no differences in hunting efficiency according to age and/or experience. Our results suggest that foraging efficiency of breeders could be more linked to physiological processes, such as cellular ageing, than to age or experience

Individual parameters shape foraging activity in breeding king penguins

International audienceThe variability in individual fitness within a population is likely to be mediated through individual foraging ability and tactics, themselves linked to age- or experience-related processes, but also to differences in individual quality. Not only age, experience, and quality but also sex-related foraging strategies should particularly play an important role in long-lived central-place foragers that have to cope with strong environmental constraints. We monitored the foraging effort (foraging trip durations and number of trips) of 262 known-age micro-tagged king penguins, Aptenodytes patagonicus, at different breeding stages during one of their breeding cycles. We investigated how their age (4–11 years old), sex, past breeding experience (the number of successful breeding attempts), and breeding quality (the expected breeding success, corresponding to the residual of the linear relationship between the age and on the number of past breeding success divided by the number of breeding attempts) affected foraging over a whole breeding season. During the incubation, younger birds (4 years old) undertook longer foraging trips compared with older ones. During the brooding phase and the second period of the crèching phase, more experienced birds performed shorter foraging trip than those with a low breeding experience, whereas, during the first period of the crèching phase, individuals with better breeding quality performed shorter foraging trips at sea than low breeding quality individuals. Sex-specific foraging patterns were also observed depending on the period of the breeding cycle. Our study shows, for the first time, how foraging effort can be driven by a complex interplay of several individual parameters according to breeding stage and resource availability and abundance

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Excel file describing body mass, oxidative stress and telomere dynamics of chicks after the winter tim

Catching-up but telomere loss: half-opening the black box of growth and ageing trade-off in wild king penguin chicks

One of the reasons for animals not to grow as fast as they potentially could is that fast growth has been shown to be associated with reduced lifespan. However, we are still lacking a clear description of the reality of growth-dependent modulation of ageing mechanisms in wild animals. Using the particular growth trajectory of small king penguin chicks naturally exhibiting higher-than-normal growth rate to compensate for the winter break, we tested whether oxidative stress and telomere shortening are related to growth trajectories. Plasma antioxidant defences, oxidative damage levels and telomere length were measured at the beginning and at the end of the post-winter growth period in three groups of chicks (small chicks, which either passed away or survived the growth period, and large chicks). Small chicks that died early during the growth period had the highest level of oxidative damage and the shortest telomere lengths prior to death. Here, we show that small chicks that grew faster did it at the detriment of body maintenance mechanisms as shown by (i) higher oxidative damage and (ii) accelerated telomere loss. Our study provides the first evidence for a mechanistic link between growth and ageing rates under natural conditions

Species range expansion constrains the ecological niches of resident butterflies

Aim: Changes in community composition resulting from environmental changes modify biotic interactions and affect the distribution and density of local populations. Such changes are currently occurring in nettle-feeding butterflies in Sweden where Araschnia levana has recently expanded its range northward and is now likely to interact with resident species (Aglais urticae and Aglais io). Butterfly occurrence data collected over years and across regions enabled us to investigate how a recent range expansion of A. levana may have affected the environmental niche of resident species. Location: We focused on two regions of Sweden (Skåne and Norrström) where A. levana has and has not established and two time periods (2001–2006 and 2009–2012) during its establishment in Skåne. Methods: We performed two distinct analyses in each region using the PCA-env and the framework described in Broennimann et al. (2012). First, we described the main sources of variation in the environment. Second, in each time period and region, we characterized the realized niches of our focal species across topographic and land use gradients. Third, we quantified overlaps and differences in realized niches between and within species over time. Results: In Skåne, A. levana has stabilized its distribution over time, while the distribution of the native species has shifted. These shifts depicted a consistent pattern of avoiding overlap between the native species and the environmental space occupied by A. levana, and it was stronger for A. urticae than for A. io. In both regions, we also found evidence of niche partitioning between native species. Main conclusions: Interspecific interactions are likely to affect local species distributions. It appears that the ongoing establishment of A. levana has modified local biotic interactions and induced shifts in resident species distributions. Among the mechanisms that can explain such patterns of niche partitioning, parasitoid-driven apparent competition may play an important role in this community

How age and sex drive the foraging behaviour in the king penguin

International audienceAs predicted by life history theory, once recruited into the breeding population and with increasing age, long-lived animals should be able to manage more efficiently the conflict between self-maintenance and reproduction. Consequently, breeding performances should improve with age before stabilizing at a certain level. Using temperature-depth recorders and isotopic analysis, we tested how age affects the foraging behaviour of king penguin Aptenodytes patagonicus during one trip in the chick-rearing phase. Depending on sex and age, king penguins expressed two different foraging strategies. Older birds gained more daily mass per unit body mass than younger ones. Older females conducted shorter trips, dived deeper and performed more prey pursuits. They also had higher blood levels of d15N than younger individuals and males indicating sex- and age-specific dietary regimes. However, we found no differences in carbon isotopic signature, suggesting that individuals exploited the same foraging areas independently of sex and age. Our results suggest that king penguins are able to increase the quantity of energy extracted with increasing age and that such a strategy is sex-related. Our study is the first to reveal of an interaction between age and sex in determining foraging efficiency in king penguins