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1. The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life-history stages even though they can represent a substantial proportion of the total population. 2. Here we develop a methodological framework for estimating populationlevel density distributions of seabirds, integrating tracking data across the main life-history stages (adult breeders and non-breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life-history stage. 3. We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non-breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population-level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all lifehistory stages. 4. Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data-poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at-sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations. Fundação para a Ciência e a Tecnologia - FCT; French Polar Institute IPEV; Falkland Islands Government info:eu-repo/semantics/publishedVersion

Identifying associations between phenotypes and environmental parameters is crucial for understanding how natural selection acts at the individual level. In this context, genetically isolated populations can be useful models for identifying the forces selecting fitness-related traits. Here, we use a comprehensive dataset on a genetically and ecologically isolated population of the strictly marine bird, the brown booby Sula leucogaster, at the tropical and remote Saint Peter and Saint Paul Archipelago, mid-Atlantic Ocean, in order to detect phenotypic adjustments from interindividual differences in diet, foraging behaviour, and nest quality. For this, we took biometrics of all individuals of the colony breeding in 2014 and 2015 and tested their associations with nest quality, diet parameters, and foraging behaviour. While body size was not related to the foraging parameters, the body size of the females (responsible for nest acquisition and defence) was significantly associated with the nest quality, as larger females occupied high-quality nests. Our findings suggest that the small breeding area, rather than prey availability, is a limiting factor, emphasizing the role of on-land features in shaping phenotypic characteristics and fitness in land-dependent marine vertebrates.

Understanding extinction events requires an unbiased record of the chronology and ecology of victims and survivors. The rhinoceros Elasmotherium sibiricum, known as the ‘Siberian unicorn’, was believed to have gone extinct around 200,000 years ago—well before the late Quaternary megafaunal extinction event. However, no absolute dating, genetic analysis or quantitative ecological assessment of this species has been undertaken. Here, we show, by accelerator mass spectrometry radiocarbon dating of 23 individuals, including cross-validation by compound-specific analysis, that E. sibiricum survived in Eastern Europe and Central Asia until at least 39,000 years ago, corroborating a wave of megafaunal turnover before the Last Glacial Maximum in Eurasia, in addition to the better-known late-glacial event. Stable isotope data indicate a dry steppe niche for E. sibiricum and, together with morphology, a highly specialized diet that probably contributed to its extinction. We further demonstrate, with DNA sequencing data, a very deep phylogenetic split between the subfamilies Elasmotheriinae and Rhinocerotinae that includes all the living rhinoceroses, settling a debate based on fossil evidence and confirming that the two lineages had diverged by the Eocene. As the last surviving member of the Elasmotheriinae, the demise of the ‘Siberian unicorn’ marked the extinction of this subfamily.

International audience; Understanding how complexity persists in nature is a long-standing goal of ecologists. In theoretical ecology, local stability is a widely used measure of ecosystem persistence and has made a major contribution to the ecosystem stability-complexity debate over the last few decades. However, permanence is coming to be regarded as a more satisfactory definition of ecosystem persistence and has relatively recently become available as a tool for assessing the global stability of Lotka - Volterra communities. Here we document positive relationships between permanence and Lotka - Volterra food web complexity and report a positive correlation between the probability of local stability and permanence. We investigate further the frequency of discrepancy (attributed to fragile systems that are locally stable but not permanent or locally unstable systems that are permanent and have cyclic or chaotic dynamics), associate non-permanence with the local stability or instability of equilibria on the boundary of the state-space, and investigate how these vary with aspects of ecosystem complexity. We find that locally stable interior equilibria tend to have all locally unstable boundary equilibria. Since a locally stable boundary is inconsistent with permanent dynamics, this can explain the observed positive correlation between local interior stability and permanence. Our key finding is that, at least in Lotka - Volterra model ecosystems, local stability may be a better measure of persistence than previously thought.

International audience; Skewed adult sex ratio (ASR) has been proposed as a common pattern in birds, frequently biased towards males and with larger biases in globally threatened species. In albatrosses and petrels, it has been suggested that differential mortality of one gender in fisheries is caused either by sexual size dimorphism giving males a competitive advantage, which allows more access of the larger sex (i.e. males) to discards and/or baits, or to at sea segregation of sexes. Here, we tested these hypotheses by determining ASRs in albatrosses and petrels trapped at sea when attending longline fishing vessels for discards in the southwestern Atlantic Ocean, and searched in the literature for patterns in ASR in albatrosses and petrels killed by fisheries in this area and elsewhere. We show that skewed ASR is common in albatrosses and petrels in the community attending vessels for discards, confirming results found for birds in general. There was no correlation between skewed ASR and conservation status, or between ASR and sexual size dimorphism. Our review of the sex of birds incidentally killed in fisheries found skewed ASR toward males, females or parity to be equally reported. Thus, sexual dimorphism in size does not explain skewed ASR in the community we sampled or in incidental captures in fisheries in the review. Differential at-sea distribution of sexes appears to be a better explanation of the patterns found in the community sampled at sea as well as skewed ASR in seabird fatalities, particularly distant from breeding areas.

International audience; Although oriented migrations have been identified in many terrestrial bird species, the post-breeding-season movements of seabirds are generally regarded as dispersive. We used geolocator tags to reveal post-breeding movements and winter distribution of northern gannets (Morus bassanus) at a meta-population scale. By focusing on five breeding colonies of European gannets, we show that their breeding and wintering grounds areconnected by a major flyway running along the coasts of Western Europe and Africa. Moreover, maximum winter distance to colony was similar across colonies despite their wide latitudinal range. In contrast with the general opinion that large pelagic birds such as gannets have unlimited ranges beyond the breeding season, our findings strongly suggest oriented chain migration in northern gannets (a pattern in which populations move uniformly southward) and highlight the benefit of meta-population approaches for studying seabird movements. We argue that the inclusion of such processes in ocean management plans is essential to improve efforts in marine biodiversity conservation.

The European starling (Sturnus vulgaris) has recently been found to eat eggs of the endangered roseate tern (Sterna dougallii) in the Azores. Azorean starlings are considered an endemic subspecies (S. vulgaris granti), so we investigated how much genetic divergence has accumulated between the Azores and other European populations in order to assess whether lethal control measures might be possible, as previous experiments have found that taste aversion is not likely to be successful. For this purpose, we sequenced a region of the protein-coding mitochondrial gene ND2 for samples from six different populations. Of the 1,026 base pairs sequenced, 19 (1.7%) were variable and formed 15 different haplotypes. The Azores had high and significant genetic differentiation from all the other populations studied. Haplotype diversity was high in the mainland populations studied, ranging from 0.767 to 0.900, but there was no variation among the Azores samples, which were collected from a geographically broad region. Given the lack of genetic variability in the Azores birds and their abundance throughout the archipelago, lethal control on a local basis and as part of an integrated control plan can be seen as a reasonable measure to protect tern colonies.