Empleo de análisis de datos a gran escala para evaluar rasgos de historia vital y de comportamiento: el caso de la población de cigüeñas blancas Ciconia ciconia reintroducidas en los Países Bajos

The White stork Ciconia ciconia has been the object of several successful reintroduction programmes in the last decades. As a consequence, populations have been monitored over large spatial scales. Despite these intense efforts, very few reliable estimates of life history traits are available for this species. Such general knowledge however constitutes a prerequisite for investigating the consequences of conservation measures. Using the large–scale and long–term ringing and resighting data set of White storks in the Netherlands, we investigated the variation of survival and resighting rates with age, time and previous individual resighting history, and in a second step supplementary feeding, using capture–recapture models. Providing food did not seem to affect survival directly, but may have an indirect effect via the alteration of migratory behaviour. Large–scale population monitoring is important in obtaining precise and reliable estimates of life history traits and assessing the consequences of conservation measures on these traits, which will prove useful for managers to take adequate measures in future conservation strategies.Durante las últimas décadas, la cigüeña blanca Ciconia ciconia ha sido objeto de diversos y satisfactorios programas de reintroducción, lo que ha permitido controlar poblaciones a grandes escalas espaciales. Pese a la intensidad de tales esfuerzos, se dispone de muy pocas estimaciones fiables acerca de los rasgos de la historia vital de esta especie. No obstante, estos conocimientos generales constituyen un requisito previo para investigar las consecuencias de las medidas de conservación. El empleo de datos de reavistaje y de anillamiento a largo plazo y a gran escala de las cigüeñas blancas de los Países Bajos nos ha permitido investigar la variación en las tasas de supervivencia y de reavistaje según la edad, el tiempo y la historia previa de reavistajes individuales. Asimismo, en una segunda fase, hemos analizado los efectos de la alimentación suplementaria a partir de modelos de captura–recaptura. Parece que la provisión de alimentos no incidió directamente en la supervivencia, pero es posible que tuviera un efecto indirecto como consecuencia de la alteración del comportamiento migratorio. El control de la población a gran escala es fundamental para obtener estimaciones precisas y fiables de rasgos de historia vital, así como para evaluar las consecuencias de las medidas de conservación de dichos rasgos, que resultarán de especial utilidad para los gestores a la hora de emprender iniciativas apropiadas con respecto a las estrategias de conservación futuras

Differences in the oxidative balance of dispersing and non-dispersing individuals: an experimental approach in a passerine bird.

Dispersal is often associated with a suite of phenotypic traits that might reduce dispersal costs, but can be energetically costly themselves outside dispersal. Hence, dispersing and philopatric individuals might differ throughout their life cycle in their management of energy production. Because higher energy expenditure can lead to the production of highly reactive oxidative molecules that are deleterious to the organism if left uncontrolled, dispersing and philopatric individuals might differ in their management of oxidative balance. Here, we experimentally increased flight costs during reproduction via a wing load manipulation in female collared flycatchers (Ficedula albicollis) breeding in a patchy population. We measured the effects of the manipulation on plasmatic markers of oxidative balance and reproductive success in dispersing and philopatric females. The impact of the wing load manipulation on the oxidative balance differed according to dispersal status. The concentration of reactive oxygen metabolites (ROMs), a marker of pro-oxidant status, was higher in philopatric than dispersing females in the manipulated group only. Differences between dispersing and philopatric individuals also depended on habitat quality, as measured by local breeding density. In low quality habitats, ROMs as well as nestling body mass were higher in philopatric females compared to dispersing ones. Independently of the manipulation or of habitat quality, plasma antioxidant capacity differed according to dispersal status: philopatric females showed higher antioxidant capacity than dispersing ones. Nestlings raised by philopatric females also had a higher fledging success. Our results suggest that dispersing individuals maintain a stable oxidative balance when facing challenging environmental conditions, at the cost of lower reproductive success. Conversely, philopatric individuals increase their effort, and thus oxidative costs, in challenging conditions thereby maintaining their reproductive success. Our study sheds light on energetics and oxidative balance as possible processes underlying phenotypic differences between dispersing and philopatric individuals

Transient growth-enhancing effects of elevated maternal thyroid hormones at no apparent oxidative cost during early postnatal period

Maternal thyroid hormones (THs) have been proven crucial for embryonic development in humans, but their influence within the natural variation on wild animals remains unknown. So far the only two studies that experimentally investigated the potential fitness consequences of maternal THs in birds found inconsistent results. More studies are thus required to assess the general effects of maternal THs and their influences on more behavioral and physiological parameters. In this study, we experimentally elevated yolk TH content in a wild migratory passerine species, the collared flycatcher Ficedula albicollis, to investigate the effects on hatching success, nestling growth and oxidative stress. We found that TH-injected eggs had a higher hatching success, and the nestlings hatched from TH-injected eggs were heavier and larger than control nestlings, but only during the early postnatal period. These differences vanished by fledging. Nestlings from TH-injected eggs exhibited lower activity of the glutathione-s-transferase, a major antioxidant enzyme, than control nestlings at day 12, a few days before fledging, but they did not differ in oxidative damage and overall intracellular oxidative state. These results suggest that the early growth-enhancing effects incurred no observable oxidative stress. We hypothesize that such a transient growth-enhancing effect might be adaptive in advancing the development and maturation of the offspring so they are well-prepared in time for the upcoming migration. Further studies investigating whether such advancing effects can influence long-term fitness, will be more than valuable

A multidisciplinary modeling approach to assess facies-dolomitization-porosity interdependence in a lower cretaceous platform (Northern spain)

An innovative methodology for diagenesis characterization and quantification is presented. It includes different geostatistical modeling workflows applied to a partially dolomitized carbonate platform. The case study consists of a Lower Cretaceous (upper Aptian) shallow-water carbonate platform from the Basque\u2013Cantabrian basin (northern Spain), in which a widespread burial dolomitization occurs. Previous studies at basin scale suggested that the flow of dolomitizing fluids through the carbonate succession was channeled by regional faults and that subsequently the dolomite distribution was partially controlled by depositional facies and their modifications after early meteoric diagenesis. Here, at reservoir scale, several carbonate facies were differentiated and grouped in five depositional environments. Two depositional sequences corresponding to transgressive\u2013regressive cycles and three stages of the platform evolution were distinguished. The statistical data treatment indicated that the dolomitization is mainly concentrated in the regressive part of the first sequence, corresponding to the second stage of the platform evolution. The most dolomitized environments are the inner platforms and the shoal. Facies from these shallower/proximal depositional environments were more exposed to early meteoric diagenesis, possibly controlling later dolomitization. The total macroscopic porosity is directly proportional to the degree of dolomitization: pores are most abundant in fully dolomitized portions of the succession, particularly in the rudist-bearing and grain-dominated facies. Abundant aragonitic shells (rudists, corals), easily leached or recrystallized during early meteoric diagenesis, could justify the higher moldic porosity in these facies. For geostatistical modeling purposes, several statistical rules were elaborated in order to associate to each depositional environment, in each of the three platform stages, different proportions of dolomitization and related pore abundance. A direct simulation of the distribution of depositional environments, degree of dolomitization, and pore abundance was achieved using a bi-plurigaussian simulation (PGS) algorithm. A nested-PGS algorithm was used to simulate the same parameters independently: dolomite and pore abundance were distributed within each depositional environment, based on the statistical rules previously defined. These simulations allowed three-dimensional (3D) visualization of the original depositional facies and textures affecting the distribution of dolomitization and pore abundance. Modeling using both bi-PGS and nested simulations accounted for the 3D dolomite body extension: the dolomitized succession is thicker in the north and thins toward the south, in agreement with evidence from mapping of the dolomite geobodies

Geostatistical modeling and spatial distribution analysis of porosity and permeability in the Shurijeh-B reservoir of Khangiran gas field in Iran

The main objectives of this study are analysis of spatial behavior of the porosity and permeability, presenting direction of anisotropy for each variable and describing variation of these parameters in Shurijeh B gas reservoir in Khangiran gas field. Porosity well log data of 32 wells are available for performing this geostatistical analysis. A univariate statistical analysis is done on both porosity and permeability to provide a framework for geostatistical analysis and modeling. For spatial analysis of these parameters, the experimental semivariogram of each variable in different direction as well as their variogram map plotted to find out the direction of anisotropy and their geostatistical parameters such as range, sill, and nugget effect for later geostatistical work and finally for geostatistical modeling, two approaches kriging and Sequential Gaussian Simulation are used to get porosity and permeability maps through the entire reservoir. All of statistical and geostatistical analysis has been done using GSLIB and PETREL software. Maximum and minimum direction of continuity are found to be N75W and N15E, respectively. Geostatistical parameters of calculated semivariogram in this direction like range of 7000 m and nugget of 0.2 are used for modeling. Both kriging and SGS method used for modeling but kriging tends to smooth out estimates but on the other hand SGS method tends to show up details. Cross-validation also used to validate the generated modeling

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

Scale-free memory model for multiagent reinforcement learning. Mean field approximation and rock-paper-scissors dynamics

A continuous time model for multiagent systems governed by reinforcement learning with scale-free memory is developed. The agents are assumed to act independently of one another in optimizing their choice of possible actions via trial-and-error search. To gain awareness about the action value the agents accumulate in their memory the rewards obtained from taking a specific action at each moment of time. The contribution of the rewards in the past to the agent current perception of action value is described by an integral operator with a power-law kernel. Finally a fractional differential equation governing the system dynamics is obtained. The agents are considered to interact with one another implicitly via the reward of one agent depending on the choice of the other agents. The pairwise interaction model is adopted to describe this effect. As a specific example of systems with non-transitive interactions, a two agent and three agent systems of the rock-paper-scissors type are analyzed in detail, including the stability analysis and numerical simulation. Scale-free memory is demonstrated to cause complex dynamics of the systems at hand. In particular, it is shown that there can be simultaneously two modes of the system instability undergoing subcritical and supercritical bifurcation, with the latter one exhibiting anomalous oscillations with the amplitude and period growing with time. Besides, the instability onset via this supercritical mode may be regarded as "altruism self-organization". For the three agent system the instability dynamics is found to be rather irregular and can be composed of alternate fragments of oscillations different in their properties.Comment: 17 pages, 7 figur

Translocation as a Novel Approach to Study Effects of a New Breeding Habitat on Reproductive Output in Wild Birds

Environmental conditions under which species reproduce have major consequences on breeding success and subsequent fitness. Therefore breeding habitat choice is ultimately important. Studies rarely address the potential fitness pay-offs of alternative natural breeding habitats by experimental translocation. Here we present a new tool to study fitness consequences of free living birds in different habitats. We translocated a migratory passerine, the pied flycatcher (Ficedula hypoleuca), to a novel site, where pairs were subjected to a short stay (2–4 days) in a nest box-equipped aviary before being released. We show that it is technically possible to retain birds in the new area for breeding, allowing the study of reproductive consequences of dispersal under natural conditions. The translocation resulted in an extension of the interval between arrival and egg laying of four days, highlighting the importance of having an adequate control group. Clutch size and nestling parameters did not differ significantly between translocated and unmanipulated females, which suggests that the procedure did not affect birds in their reproductive performance later on. This method could be applied broadly in evolutionary and ecological research, e.g., to study the potential fitness benefits and costs for dispersing to more northern latitudes as a way of adapting to climate change

Neighbours' Breeding Success and the Sex Ratio of Their Offspring Affect the Mate Preferences of Female Zebra Finches

Several hypotheses on divorce predict that monogamous pairs should split up more frequently after a breeding failure. Yet, deviations from the expected pattern “success-stay, failure-leave” have been reported in several species. One possible explanation for these deviations would be that individuals do not use only their own breeding performance (i.e., private information) but also that of others (i.e., public information) to decide whether or not to divorce. To test this hypothesis, we investigated the relative importance of private and public information for mate choice decisions in female zebra finches (Taeniopygia guttata).We manipulated the reproductive performance of breeding pairs and measured females' preferences for their mate and the neighbouring male first following pair formation and then seven weeks later when all females had laid eggs and the young were independent. Although all females reduced their preference for their mate after a breeding failure, the decrease was significant only when the neighbouring pair had reproduced successfully. Furthermore, there was no evidence that females biased the sex ratio of their offspring according to their mate's attractiveness. On the other hand, after reproduction, both successful and unsuccessful females increased their preferences for males who had produced a larger proportion of sons. Despite the fact that other mechanisms may have also contributed to our findings, we suggest that females changed their mate preferences based on the proportion of sons produced by successful males, because offspring sex ratio reflects the male's testosterone level at the moment of fertilization and hence is an indicator of his immune condition

Wild zebra finches choose neighbours for synchronized breeding

Organisms should aim to time their reproduction to match the optimal ecological conditions and thus maximize their fitness. However, social cues have been identified as determinants of reproductive decisions and might also be involved in coordinating the timing of reproduction. Breeding synchronously with other individuals can bring several advantages, including a reduced individual predation risk and an increased opportunity for social foraging. The behavioural mechanisms underlying reproductive synchrony are versatile and not well understood, particularly in species inhabiting unpredictable environments. In contrast to highly seasonal environments, more variable and unpredictable environments can support periods of extended breeding with lower levels of synchronous breeding overall, but opportunities for individuals to breed synchronously at a finer temporal and spatial scale. Zebra finches, Taeniopygia guttata, are a highly social species, naturally inhabiting the ecologically unpredictable arid zone of Australia. In the wild, reproduction at a broad population level is not highly synchronized and, at any time during a period of breeding activity, reproductive attempts can be found at different stages. However, previous work has suggested that at a finer spatial scale neighbours tend to breed at approximately the same time. Using nestboxes, we tested whether wild zebra finches preferentially seek to settle and initiate a breeding attempt adjacent to conspecifics at an early stage of breeding (nest building), as opposed to others at later stages of breeding and with which the opportunity to breed synchronously was reduced or absent. Pairs were more likely to initiate egg laying in nestboxes close to conspecifics at an early stage of breeding, suggesting that they do try to maximize the level of synchronicity with neighbours. Our results indicate the importance of social effects on both the phenology and spatial distribution of breeding