When things go wrong : intra-season dynamics of breeding failure in a seabird

We thank all fieldworkers who helped monitor nests and deploy/retrieve GPS loggers, notably Muriel Dietrich, Elisa Lobato, Julien Gasparini, Vincent Staszewski and Thierry Chambert. We are grateful to Victor Garcia‐Mattarranz from the Ministerio de Medio Ambiente y Medio Rural y Marino (MARM, Spain) and Jacob Gonzalès‐Solís from University of Barcelona for their help on PTTs functioning and deployment. We thank Nina Dehnhard and two anonymous referees who provided useful comments and suggestions to improve this manuscript and Matthieu Authier for statistical advice. This study was funded by the French Polar Institute (IPEV, programme n°333 PARASITO‐ARCTIQUE), CNRS, ANR, OSU OREME, NINA, University of Tromsø, SEAPOP (www.seapop.no) and CEDREN. All work was carried out in accordance with standard animal care protocols and approved by the Ethical Committee of the French Polar Institute and the Norwegian Animal Research Authority. The PhD thesis of A. P. is partly funded via a Région Languedoc‐Roussillon program ‘Chercheur d'Avenir' support to T. B. and University of Montpellier 2.Peer reviewedPublisher PD

Contacts and foot and mouth disease transmission from wild to domestic bovines in Africa

Wildlife is a maintenance host for several significant livestock diseases. Interspecific pathogen transmission may occur in complex socio-ecological systems at wild-domestic interfaces that have so far been seldom studied. We investigated the relationship between the dynamics of foot and mouth disease (FMD) in vaccinated and unvaccinated cattle populations with respect to frequency of contacts with African buffalo at different buffalo-cattle interfaces. A total of 36 GPS collars were deployed on African buffalo (Syncerus caffer) and cattle (Bos taurus, Bos indicus) to assess contact patterns at the periphery of 3 protected areas in Zimbabwe. Simultaneously, a longitudinal survey of 300 cattle with five repeated sampling sessions on known individuals during 16 months was undertaken. Immunological assays (ELISAs), that allowed tracking the production of antibodies following infection or vaccination, were used to assess serological transitions (i.e., incidence and reversion) in the surveyed cattle. Variation in rates of serological transitions across seasons, sites and as a function of the frequency of contact with buffalo was analyzed using generalized linear mixed models. The incidence in the cattle populations of FMD antibodies produced following infection varied among sites and as a function of contact rates with African buffalo. The incidence was higher for sites with higher contact rates between the two species. The serological incidence was also related to seasons, being higher during the dry or rainy seasons depending on sites. The reversion rate pattern was the opposite of this incidence rate pattern. Vaccination seemed partly efficient at the individual level, but it did not prevent the diffusion of FMD viruses from the wild reservoir host to the domestic cattle population. Furthermore, antibodies were detected in areas where cattle had not been vaccinated, suggesting that the virus may have spread without being detected in domestic populations. Access to resources shared by buffalo and livestock, particularly water and grazing areas during the dry season, could partly explain the observed patterns of FMD transmission. We discuss how insights on ecological processes leading to wildlife-livestock contacts may provide some innovative solutions to improve FMD management, including surveillance, prevention or control of buffalo-borne outbreaks, by adopting strategies targeting risky areas and periods. (Résumé d'auteur

Self-Stabilizing Byzantine Asynchronous Unison

We explore asynchronous unison in the presence of systemic transient and permanent Byzantine faults in shared memory. We observe that the problem is not solvable under less than strongly fair scheduler or for system topologies with maximum node degree greater than two. We present a self-stabilizing Byzantine-tolerant solution to asynchronous unison for chain and ring topologies. Our algorithm has minimum possible containment radius and optimal stabilization time

Collective Animal Behavior from Bayesian Estimation and Probability Matching

Animals living in groups make movement decisions that depend, among other factors, on social interactions with other group members. Our present understanding of social rules in animal collectives is based on empirical fits to observations and we lack first-principles approaches that allow their derivation. Here we show that patterns of collective decisions can be derived from the basic ability of animals to make probabilistic estimations in the presence of uncertainty. We build a decision-making model with two stages: Bayesian estimation and probabilistic matching.
In the first stage, each animal makes a Bayesian estimation of which behavior is best to perform taking into account personal information about the environment and social information collected by observing the behaviors of other animals. In the probability matching stage, each animal chooses a behavior with a probability given by the Bayesian estimation that this behavior is the most appropriate one. This model derives very simple rules of interaction in animal collectives that depend only on two types of reliability parameters, one that each animal assigns to the other animals and another given by the quality of the non-social information. We test our model by obtaining theoretically a rich set of observed collective patterns of decisions in three-spined sticklebacks, Gasterosteus aculeatus, a shoaling fish species. The quantitative link shown between probabilistic estimation and collective rules of behavior allows a better contact with other fields such as foraging, mate selection, neurobiology and psychology, and gives predictions for experiments directly testing the relationship between estimation and collective behavior

Maternal Antibody Transmission in Relation to Mother Fluctuating Asymmetry in a Long-Lived Colonial Seabird: The Yellow-Legged Gull Larus michahellis

Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer of maternal antibodies against type A influenza viruses (anti-AIV antibodies) by a long-lived colonial seabird, the yellow-legged gull (Larus michahellis), in relation to fluctuating asymmetry in females, i.e. the random deviation from perfect symmetry in bilaterally symmetric morphological and anatomical traits. In particular, we tested whether females with greater asymmetry transmitted fewer antibodies to their eggs, and whether within-clutch variation in yolk antibodies varied according to the maternal level of fluctuating asymmetry. We found that asymmetric females were in worse physical condition, produced fewer antibodies, and transmitted lower amounts of antibodies to their eggs. We also found that, within a given clutch, yolk antibody level decreased with egg laying order, but this laying order effect was more pronounced in clutches laid by the more asymmetric females. Overall, our results support the hypothesis that maternal quality interacts with egg laying order in determining the amount of maternal antibodies transmitted to the yolks. They also highlight the usefulness of fluctuating asymmetry as a sensitive indicator of female quality and immunocompetence in birds

Conservation of Forest Birds: Evidence of a Shifting Baseline in Community Structure

Quantifying changes in forest bird diversity is an essential task for developing effective conservation actions. When subtle changes in diversity accumulate over time, annual comparisons may offer an incomplete perspective of changes in diversity. In this case, progressive change, the comparison of changes in diversity from a baseline condition, may offer greater insight because changes in diversity are assessed over longer periods of times. Our objectives were to determine how forest bird diversity has changed over time and whether those changes were associated with forest disturbance.We used North American Breeding Bird Survey data, a time series of Landsat images classified with respect to land cover change, and mixed-effects models to associate changes in forest bird community structure with forest disturbance, latitude, and longitude in the conterminous United States for the years 1985 to 2006. We document a significant divergence from the baseline structure for all birds of similar migratory habit and nest location, and all forest birds as a group from 1985 to 2006. Unexpectedly, decreases in progressive similarity resulted from small changes in richness (<1 species per route for the 22-year study period) and modest losses in abundance (-28.7 - -10.2 individuals per route) that varied by migratory habit and nest location. Forest disturbance increased progressive similarity for Neotropical migrants, permanent residents, ground nesting, and cavity nesting species. We also documented highest progressive similarity in the eastern United States.Contemporary forest bird community structure is changing rapidly over a relatively short period of time (e.g., approximately 22 years). Forest disturbance and forest regeneration are primary factors associated with contemporary forest bird community structure, longitude and latitude are secondary factors, and forest loss is a tertiary factor. Importantly, these findings suggest some regions of the United States may already fall below the habitat amount threshold where fragmentation effects become important predictors of forest bird community structure

A Holistic Landscape Description Reveals That Landscape Configuration Changes More over Time than Composition: Implications for Landscape Ecology Studies

International audienceBackground: Space-for-time substitution—that is, the assumption that spatial variations of a system can explain and predict the effect of temporal variations—is widely used in ecology. However, it is questionable whether it can validly be used to explain changes in biodiversity over time in response to land-cover changes.Hypothesis: ere, we hypothesize that different temporal vs spatial trajectories of landscape composition and configuration may limit space-for-time substitution in landscape ecology. Land-cover conversion changes not just the surface areas given over to particular types of land cover, but also affects isolation, patch size and heterogeneity. This means that a small change in land cover over time may have only minor repercussions on landscape composition but potentially major consequences for landscape configuration.Methods: sing land-cover maps of the Paris region for 1982 and 2003, we made a holistic description of the landscape disentangling landscape composition from configuration. After controlling for spatial variations, we analyzed and compared the amplitudes of changes in landscape composition and configuration over time.Results: For comparable spatial variations, landscape configuration varied more than twice as much as composition over time. Temporal changes in composition and configuration were not always spatially matched.Significance: The fact that landscape composition and configuration do not vary equally in space and time calls into question the use of space-for-time substitution in landscape ecology studies. The instability of landscapes over time appears to be attributable to configurational changes in the main. This may go some way to explaining why the landscape variables that account for changes over time in biodiversity are not the same ones that account for the spatial distribution of biodiversity

Win-stay, lose-switch and public information strategies for patch fidelity of songbirds with rare extra-pair paternity

Determining where organisms breed and understanding why they breed in particular locations are fundamental biological questions with conservation implications. Breeding-site fidelity is common in migratory, territorial songbirds and is typically thought to occur following reproductive success with a social mate and success of nearby conspecifics. It is currently unknown if frequency of extra-pair paternity in a population influences use of information about reproductive success of nearby conspecifics for site fidelity decisions. We investigated patch fidelity of white-eyed vireos (Vireo griseus) based on reproductive success and quantified frequency of extra-pair paternity. We found support only for females making patch fidelity decisions following reproductive success with a social mate. Patch fidelity of males was not associated with reproductive success of nearby conspecifics, suggesting males may not use this information when extra-pair paternity is infrequent or the association is non-existent in this species