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Summary Seabirds are declining globally and are one of the most threatened groups of birds. To halt or reverse this decline they need protection both on land and at sea, requiring site-based conservation initiatives based on seabird abundance and diversity. The Important Bird and Biodiversity Area (IBA) programme is a method of identifying the most important places for birds based on globally agreed standardised criteria and thresholds. However, while great strides have been made identifying terrestrial sites, at-sea identification is lacking. The Chagos Archipelago, central Indian Ocean, supports four terrestrial IBAs (tIBAs) and two proposed marine IBAs (mIBAs). The mIBAs are seaward extensions to breeding colonies based on outdated information and, other types of mIBA have not been explored. Here, we review the proposed seaward extension mIBAs using up-to-date seabird status and distribution information and, use global positioning system (GPS) tracking from Red-footed Booby Sula sula – one of the most widely distributed breeding seabirds on the archipelago – to identify any pelagic mIBAs. We demonstrate that due to overlapping boundaries of seaward extension to breeding colony and pelagic areas of importance there is a single mIBA in the central Indian Ocean that lays entirely within the Chagos Archipelago Marine Protected Area (MPA). Covering 62,379 km2 it constitutes ~10% of the MPA and if designated, would become the 11th largest mIBA in the world and 4th largest in the Indian Ocean. Our research strengthens the evidence of the benefits of large-scale MPAs for the protection of marine predators and provides a scientific foundation stone for marine biodiversity hotspot research in the central Indian Ocean.

Studying the effects of prey distribution on predator behavior is complex in systems where there are multiple prey species. The role of prey density in predator behavior is rarely studied in closed ecosystems of one predator species and one prey species, despite these being an ideal opportunity to test these hypotheses. In this study, we investigate the effect of prey density on the foraging behavior of a predatory species in an isolated Antarctic ecosystem of effectively a single predatory species and a single prey species. We use resource selection models to compare prey density in areas utilized by predators (obtained from fine‐scale GPS telemetry data) to prey density at randomly generated points (pseudoabsences) throughout the available area. We demonstrate that prey density of breeding Antarctic petrels (Thalassoica antarctica) is negatively associated with the probability of habitat use in its only predator, the south polar skua (Catharacta maccormicki). Skuas are less likely to utilize habitats with higher petrel densities, reducing predation in these areas, but these effects are present during chick rearing only and not during incubation. We suggest that this might be caused by successful group defense strategies employed by petrel chicks, primarily spitting oil at predators., We used habitat selection models to analyse the effect of prey density on predator behavior in a uniquely straightforward system of one predator species and one prey species. We found that probability of habitat use by south polar skuas is negatively associated with antarctic petrel density and that this effect varies depending on whether predator or prey is incubating eggs or brooding chicks. We suggest that this effect is a result of successful group defense strategies employed by petrels.

1. Individual specialisations in behaviour are predicted to arise where divergence benefits fitness. Such specialisations are more likely in heterogeneous environments where there is both greater ecological opportunity and competition-driven frequency dependent selection. 2. Such an effect could explain observed differences in rates of individual specialisation in habitat selection, as it offers individuals an opportunity to select for habitat types that maximise resource gain while minimising competition; however, this mechanism has not been tested before. 3. Here, we use habitat selection functions to quantify individual specialisations while foraging by black-legged kittiwakes Rissa tridactyla, a marine top predator, at 15 colonies around the United Kingdom and Ireland, along a gradient of environmental heterogeneity. 4. We find support for the hypothesis that individual specialisations in habitat selection while foraging are more prevalent in heterogeneous environments. This trend was significant across multiple dynamic habitat variables that change over short time-scales and did not arise through site fidelity, which highlights the importance of environmental processes in facilitating behavioural adaptation by predators. 5. Individual differences may drive evolutionary processes, and therefore these results suggest that there is broad scope for the degree of environmental heterogeneity to determine current and future population, species and community dynamics.

Given the recent trend towards establishing very large marine protected areas (MPAs) and the high potential of these to contribute to global conservation targets, we review outcomes of the last decade of marine conservation research in the British Indian Ocean Territory (BIOT), one of the largest MPAs in the world. The BIOT MPA consists of the atolls of the Chagos Archipelago, interspersed with and surrounded by deep oceanic waters. Islands around the atoll rims serve as nesting grounds for sea birds. Extensive and diverse shallow and mesophotic reef habitats provide essential habitat and feeding grounds for all marine life, and the absence of local human impacts may improve recovery after coral bleaching events. Census data have shown recent increases in the abundance of sea turtles, high numbers of nesting seabirds and high fish abundance, at least some of which is linked to the lack of recent harvesting. For example, across the archipelago the annual number of green turtle clutches (Chelonia mydas) is ~ 20,500 and increasing and the number of seabirds is ~ 1 million. Animal tracking studies have shown that some taxa breed and/or forage consistently within the MPA (e.g. some reef fishes, elasmobranchs and seabirds), suggesting the MPA has the potential to provide long-term protection. In contrast, post-nesting green turtles travel up to 4000 km to distant foraging sites, so the protected beaches in the Chagos Archipelago provide a nesting sanctuary for individuals that forage across an ocean basin and several geopolitical borders. Surveys using divers and underwater video systems show high habitat diversity and abundant marine life on all trophic levels. For example, coral cover can be as high as 40–50%. Ecological studies are shedding light on how remote ecosystems function, connect to each other and respond to climate-driven stressors compared to other locations that are more locally impacted. However, important threats to this MPA have been identified, particularly global heating events, and Illegal, Unreported and Unregulated (IUU) fishing activity, which considerably impact both reef and pelagic fishes.

The paradigm-changing opportunities of biologging sensors for ecological research, especially movement ecology, are vast, but the crucial questions of how best to match the most appropriate sensors and sensor combinations to specific biological questions and how to analyse complex biologging data, are mostly ignored. Here, we fill this gap by reviewing how to optimize the use of biologging techniques to answer questions in movement ecology and synthesize this into an Integrated Biologging Framework (IBF). We highlight that multisensor approaches are a new frontier in biologging, while identifying current limitations and avenues for future development in sensor technology. We focus on the importance of efficient data exploration, and more advanced multidimensional visualization methods, combined with appropriate archiving and sharing approaches, to tackle the big data issues presented by biologging. We also discuss the challenges and opportunities in matching the peculiarities of specific sensor data to the statistical models used, highlighting at the same time the large advances which will be required in the latter to properly analyse biologging data. Taking advantage of the biologging revolution will require a large improvement in the theoretical and mathematical foundations of movement ecology, to include the rich set of high-frequency multivariate data, which greatly expand the fundamentally limited and coarse data that could be collected using location-only technology such as GPS. Equally important will be the establishment of multidisciplinary collaborations to catalyse the opportunities offered by current and future biologging technology. If this is achieved, clear potential exists for developing a vastly improved mechanistic understanding of animal movements and their roles in ecological processes and for building realistic predictive models. Fil: Williams, Hannah J.. Swansea University; Reino Unido Fil: Taylor, Lucy. University of Oxford; Reino Unido. Save The Elephants; Kenia Fil: Benhamou, Simon. Centre National de la Recherche Scientifique; Francia Fil: Bijleveld, Allert. Utrecht University; Países Bajos Fil: Clay, Thomas. University of Liverpool; Reino Unido Fil: de Grissac, Sophie. Swansea University; Reino Unido Fil: Demsar, Urska. University of St. Andrews; Reino Unido Fil: English, Holly M.. Swansea University; Reino Unido Fil: Franconi, Novella. Swansea University; Reino Unido Fil: Gómez Laich, Agustina Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Griffiths, Rachael. Swansea University; Reino Unido Fil: Kay, William P.. Swansea University; Reino Unido Fil: Morales, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Potts, Jonathan. University of Sheffield; Reino Unido Fil: Rogerson, Katharine F.. University of East Anglia; Reino Unido Fil: Rutz, Christian. University of St. Andrews; Reino Unido Fil: Spelt, Anouk. University of Bristol; Reino Unido Fil: Trevail, Alice. University of Liverpool; Reino Unido Fil: Wilson, Rory P.. Swansea University; Reino Unido Fil: Börger, Luca. Swansea University; Reino Unido

Environmental heterogeneity shapes the uneven distribution of resources available to foragers, and is ubiquitous in nature. Optimal foraging theory predicts that an animal's ability to exploit resource patches is key to foraging success. However, the potential fitness costs and benefits of foraging in a heterogeneous environment are difficult to measure empirically. Heterogeneity may provide higher-quality foraging opportunities, or alternatively could increase the cost of resource acquisition because of reduced patch density or increased competition. Here, we study the influence of physical environmental heterogeneity on behaviour and reproductive success of black-legged kittiwakes, Rissa tridactyla . From GPS tracking data at 15 colonies throughout their British and Irish range, we found that environments that were physically more heterogeneous were associated with longer trip duration, more time spent foraging while away from the colony, increased overlap of foraging areas between individuals and lower breeding success. These results suggest that there is greater competition between individuals for finite resources in more heterogeneous environments, which comes at a cost to reproduction. Resource hotspots are often considered beneficial, as individuals can learn to exploit them if sufficiently predictable. However, we demonstrate here that such fitness gains can be countered by greater competition in more heterogeneous environments.

Plastic pollution has become one of the largest environmental challenges we currently face. The United\ud Nations Environment Program (UNEP) has listed it as a critical problem, comparable to climate change,\ud demonstrating both the scale and degree of the environmental problem. Mortalities due to entanglement\ud in plastic fishing nets and bags have been reported for marine mammals, turtles and seabirds, and to date\ud over 690 marine species have been reported to ingest plastics. The body of literature documenting plastic\ud ingestion by marine megafauna (i.e. seabirds, turtles, fish and marine mammals) has grown rapidly over the\ud last decade, and it is expected to continue grow as researchers explore the ecological impacts of marine\ud pollution. Unfortunately, a cohesive approach by the scientific community to quantify plastic ingestion by\ud wildlife is lacking, which is now hindering spatial and temporal comparisons between and among species/\ud organisms. Here, we discuss and propose standardized techniques, approaches and metrics for reporting\ud debris ingestion that are applicable to most large marine vertebrates. As a case study, we examine how the\ud use of standardized methods to report ingested debris in Northern Fulmars (Fulmarus glacialis) has enabled\ud long term and spatial trends in plastic pollution to be studied. Lastly, we outline standardized metric\ud recommendations for reporting ingested plastics in marine megafauna, with the aim to harmonize the data\ud that are available to facilitate large-scale comparisons and meta-analyses of plastic accumulation in\ud a variety of taxa. If standardized methods are adopted, future plastic ingestion research will be better able\ud to inform questions related to the impacts of plastics across taxonomic, ecosystem and spatial scales.

Northern fulmars are seabirds which feed exclusively at sea, and as such, they are useful indicators of ocean health. Marine plastic pollution is an ever-increasing and global issue that affects the northern fulmar as they are frequently found to have ingested plastic. In this report we investigate whether the amount of ingested plastic affects the concentration of certain plastic-adsorbed toxicants in their tissues. Marine plastic pollution is a field of utmost importance. It is our hope that this continues to be an area which receives increased attention in order to elucidate the potential harmful effects plastics have on the northern fulmar and ocean health, in general.