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Seeing the ocean through the eyes of seabirds: A new path for marine conservation?

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... Du fait de leur forte exposition aux menaces anthropiques marines et terrestres, les stratégies de conservation basées sur les besoins écologiques des oiseaux marins sont bénéfiques à l'échelle de tout l'écosystème, comme cela fut démontré pour d'autres prédateurs supérieurs (Sergio et al. 2008;Cury et al. 2011). Comme ils utilisent de larges aires pour leur alimentation et qu'ils développent de nombreuses interactions fonctionnelles avec l'écosystème dans lequel ils évoluent, les oiseaux marins sont également considérés comme des espèces parapluie et bio-indicatrices (Lescroel et al. 2016). Plusieurs études ont en effet démontré que les zones utilisées par les prédateurs supérieurs pour l'alimentation ou la reproduction se superposent largement avec des points chauds de biodiversité dans les océans (Worm et al. , 2005. ...
... De plus, leur étude permet de fournir des informations sur l'état de santé des écosystèmes, ainsi que sur la distribution d'autres prédateurs marins en milieu hauturier sur une large échelle spatiale (e.g. Hindell et al., 2020;Lescroel et al., 2016) Puffin fouquet Le puffin fouquet, Ardenna pacifica (Gmelin, 1789), est le plus grand puffin tropical avec un poids moyen de 390 g et une longueur totale d'environ 43 cm (Whittow 1997). Il possède un corps élancé, un bec crochu et une longue queue en pointe. ...
... Les prédateurs supérieurs jouent un rôle clé dans le fonctionnement des écosystèmes et fournissent de nombreuses informations sur leur état de santé (Heithaus et al. 2008;Lescroel et al. 2016). Ils subissent actuellement un très fort déclin, impactant de nombreuses autres espèces ainsi que leur habitat . ...
Thesis
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Les stratégies de recherche alimentaire chez les Procellariidés (puffins et pétrels) dépendent de nombreux facteurs environnementaux et intrinsèques et leur connaissance est souvent à la base des mesures de conservation de ces espèces en mer. Leur étude permet également d’apporter des informations sur la présence et l’abondance d’espèces associées à leurs zones d’alimentation. Cette thèse vise à apporter des éléments de connaissance sur les déplacements et l’utilisation de l’espace océanique et des ressources trophiques par deux espèces de Procellariidés se reproduisant en Nouvelle-Calédonie : le puffin fouquet (Ardenna pacifica) et le pétrel de Tahiti (Pseudobulweria rostrata). Pour cela, nous avons combiné l’étude de leurs déplacements en mer par suivi GPS avec l’étude de leur régime alimentaire par l’analyse d’isotopes stables et le barcoding ADN.Les principales zones d’alimentation et le type de proies consommées ont été identifiés pour chaque espèce et chaque population pendant leur période de reproduction. Les mécanismes de ségrégation intra-spécifique entre les différentes populations et de ségrégation interspécifique permettant la cohabitation des deux espèces ont été mis en évidence. Différents facteurs environnementaux déterminant les stratégies d’alimentation des espèces ont également été mis en évidence. Enfin, tenant compte de ces différents paramètres et interactions au sein et entre espèces, cette thèse a visé à déterminer des zones océaniques hauturières à fort enjeux de conservation, afin notamment de fournir des éléments d’aide à la décision aux gestionnaires du Parc Naturel de la Mer de Corail, la 4ème plus grande aire marine protégée de la Planète.
... Top predators are key species of marine ecosystems which integrate the state of underlying trophic chains . Among North Atlantic Ocean predators, seabirds are highly mobile, conspicuous and well-studied, making them ideal organisms to study the impacts of climate change on marine migratory species (Lescroël et al., 2016). Figure 9. Schematic summing the main impacts of climate change on the marine food web. ...
... indirect (through trophic mechanisms or modifications of their critical habitats) climate change impacts (Sydeman, Poloczanska, Reed, & Thompson, 2015). Seabirds are also ecological sentinels of marine ecosystems across their life cycles Lescroël et al., 2016), and the subject of long-term monitoring studies throughout the world (Paleczny, Hammill, Karpouzi, & Pauly, 2015). ...
... It is therefore essential to study polar ecosystem functioning and structure to determine and protect irreplaceable habitats. Seabirds, as highly-mobile boundary objects (Lescroël et al., 2016) sentinels and indicators of marine ecosystems, will certainly be privileged studies' models and we believe that the methodological approaches developed in this thesis will be highly relevant. ...
Thesis
Seabirds are particularly vulnerable to the direct and indirect effects of climate change, however little is known about those impacts outside of the breeding season. This lack of knowledge is problematic because the conditions encountered during migration and wintering strongly shape seabird population dynamics. It is therefore essential to understand the effects of climate on their winter distribution and migration routes. Linking the distribution of organisms to environmental factors is therefore a primary task benefiting from the concept of energyscapes (defined as the variation of an organism's energy requirements across space according to environmental conditions) which has recently provided a mechanistic explanation for the distribution of many animals. In this context, we have predicted the current and future winter habitats of five species representing 75% of the seabird community in the North Atlantic (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla). To this aim, we monitored the movements of more than 1500 individuals to identify the birds' preferred habitats through resource selection functions based on the modeling of their energy expenditure and prey availability. Electronic tracking data were also overlaid with cyclone locations to map areas of high exposure for the seabird community across the North Atlantic. In addition, we explored the energetic consequences of seabird exposure to storms using a mechanistic bioenergetic model (Niche MapperTM). Finally, we examined the impact of total summer sea ice melt from 2050 on Arctic bird migration. Our analyses predict a northward shift in the preferred wintering areas of the North Atlantic seabird community, especially if global warming exceeds 2°C. Our results suggest that cyclonic conditions do not increase the energy requirements of seabirds, implying that they die from the unavailability of prey and/or inability to feed during cyclones. Finally, the melting sea ice at the North Pole may soon allow 29 species of Arctic birds to make new trans-Arctic migrations between the Atlantic and the Pacific. We also estimate that an additional 26 currently migratory species could remain in the Arctic year-round. This work illustrates how climate change could radically alter the biogeography of migratory species and we provide a methodological toolbox to assess and predict these changes by combining movement ecology and energetic physiology.
... On the basis of these characteristics, Lescroël et al. (2016) recently proposed 'seeing the ocean through the eye of seabirds' as a new avenue to tackle pressing environmental issues. Indeed, marine ecosystems are in crisis, with past and present conservation measures seemly incapable of halting ecological degradation and the downfall of the world seabird community (Grémillet et al. 2018). ...
... Marine conservation debates are highly polarized, but there is hope that seabirds, because of their charisma, can act as boundary objects allowing better stakeholder dialogue. They could also help understanding ecological solidarities and vulnerability transfers (see Lescroël et al. 2016). To achieve this goal, it is critically important that marine stakeholders 'see the oceans through the eyes of seabirds', and this is where new electronic technologies can help. ...
... Miniature cameras can also be fitted to seabirds, providing their view on the marine environment and ecological processes Votier et al. 2013). This attractive communication material helps fostering a sense of common destiny between artisanal fishermen and coastal seabirds, especially in the context of vanishing food supplies (Lescroël et al. 2016). ...
Article
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To use seabirds as ecological sentinels of marine ecosystems under the incidence of global changes, it is essential to understand linkages between their spatial ecology and environmental conditions. Such information is still lacking for some key areas, including in Europe. We studied the spatial ecology of European shags (Phalacrocorax aristotelis) in Normandy, France, where > 1% of the species’ world population, and ca. 20% of its French population breeds. Working on 29 breeding individuals at two colonies (Chausey and Saint-Marcouf), we performed the first GPS-tracking study for the species in this region. On the basis of GPS positions and dive information across 244 foraging trips, we present a general methodological framework to map existing, and model potential seabird habitats. Shags performed dives between 9 and 17 h, and fed at average distances of 5.3 km (Chausey) and 3.3 km (Saint-Marcouf) from their nests. They used 186 km2 (Chausey) and 143 km2 (Saint-Marcouf) areas with a depth < 15 m over rocky and sandy habitats. Shags selected areas with an SST around 18 °C (Chausey) and 12–13 °C (Saint-Marcouf). There is strong evidence that they are year-round residents in these coastal areas and we identified four major environmental changes to which they may react as spatial ecological indicators: climate change, which may impact them directly, or indirectly via shifting prey distributions; fisheries, which may target small pelagic fish such as sandeels, upon which they depend; sediment extraction which may remove benthic habitats critically important to sandeels; and marine windfarms which may result in feeding habitat loss.
... However, despite these new insights, marine conservation is now facing the same research-implementation gap as its terrestrial counterpart (Knight et al., 2006(Knight et al., , 2008Ban and Klein, 2009;Biggs et al., 2011), partly stemming from the difficulty to develop true cooperation among typically diverse stakeholder groups, whose interests, norms, values, powers or communication skills may diverge. To overcome this hurdle, Lescroël et al. (2016) proposed to use charismatic marine predators, such as seabirds, as ambassadors of global ocean conservation to "see the oceans through the eyes of seabirds" and foster stakeholder cooperation. Part of this approach requires improved knowledge of seabird-fisheries interactions. ...
... This approach still requires research and development (e.g. observation event detection algorithms for automatic analysis of video sequences) and enhanced co-construction of video monitoring programmes with fishery stakeholders (Lescroël et al., 2016). ...
... The most obvious ones are birdborne cameras, which can directly record the visual landscape of the bird. It is then possible to detect when fishing vessels are present in the vicinity of the birds and whether there are direct interactions with them (Grémillet et al., 2010;Votier et al., 2013;Lescroël et al., 2016). However, in the case of video recordings, the battery size of such portable devices is still limiting the duration of image acquisition to a few hours. ...
Article
Full-text available
Seabirds and fisheries have been interacting from ancient times, sometimes with mutual benefits: Seabirds provided fishermen with visual cues of fish aggregations, and also fed upon food subsids generated by fishing activities. Yet fisheries and seabirds may also compete for the same resources, and their interactions can lead to additional seabird mortality through accidental bycatch and diminishing fishing efficiency, threatening vulnerable seabird populations. Understanding these complex relationships is essential for conservation strategies, also because it could enhance and ease discussion between stakeholders, towards a common vision for marine ecosystem management. As an aid in this process, we reviewed 510 scientific publications dedicated to seabirds–fisheries interactions, and compiled a methodological toolkit. Methods employed therein serve four main purposes: (i) Implementing distribution overlap analyses, to highlight areas of encounter between seabirds and fisheries (ii) Analysing movement and behavioural patterns using finer-scale information, to characterize interaction types (iii) Investigating individual-scale feeding ecology, to assess fisheries impacts at the scale of bird populations, and (iv) Quantifying the impacts of seabird–fishery interactions on seabird demography and population trends. This latter step allows determining thresholds and tipping points with respect to ecological sustainability. Overall, we stress that forthcoming studies should integrate those multiple approaches, in order to identify and promote best practices towards ecosystem-based fisheries management and ecologically sound marine spatial planning.
... Por este motivo, resulta clave conocer la distribución de las aves marinas, su ecología, los factores que determinan su supervivencia, y su resiliencia a los cambios ambientales. Plantear estrategias de conservación basadas en sus requerimientos ecológicos puede suponer amplios beneficios al ecosistema marino (Lescroël et al., 2016). Esto, sumado a que en muchos casos se trata de especies carismáticas, hace que las aves marinas actúen de especies "paraguas" de la biodiversidad marina. ...
... Además, las aves marinas sobrepasan los límites ecológicos y políticos, se mueven entre zonas protegidas y sin proteger, y revelan puntos calientes de biodiversidad (o "hotspots"; Lescroël et al., 2016). Por ello, resulta esencial conocer sus movimientos y distribución a lo largo del año, así como sus áreas de alimentación principales. ...
Book
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In the present publication we analyzed the migration and foraging ecology of Bulwer’s petrel (Bulweria bulwerii) in one locality at Canary Islands, based in the results obtained by the University of Barcelona in the framework of different research and conservation seabird projects. This monograph describes the foraging ecology and the year-round behaviour and movements of Bulwer’s petrels. More specifically, it includes the identification of their foraging areas used during the breeding season; the characteristics of the foraging trips carried out during the incubation and chick rearing periods; and the study of activity patterns at sea and along the day, the year and dependent on the location. The high number of foraging and migratory trips obtained during a long period of study makes it the most comprehensive study to date on the movement ecology of the Bulwer’s petrel. This work constitutes the fourth Migra Program monograph (www.migraciondeaves.org/en/), developed by SEO/BirdLife from 2011, which objective is to know the movements and migration of bird species in Spain.
... Increasingly, the relationship between seabird demography, foraging ecology, and oceanography is being explored to inves- tigate the utility of seabirds as sentinels in a range of questions from shifts in ocean productivity from climate change (Grémillet and Boulinier 2009), to fisheries management ( Bunce et al. 2002;Einoder 2009;Votier et al. 2010), and planning of marine protected areas ( Lescroël et al. 2016;Maxwell et al. 2016;Soanes et al. 2016). Central-place foragers may be particularly useful in this context as they are spatially constrained during their annual breeding cycle ( Wakefield et al. 2011), at different stages within the breeding period ( Angel et al. 2015), and by the distribution and availability of prey (Wormworth and S -ekerciog ˘lu 2011), increasing their potential as bioindicators of regional variation within the food landscape. ...
... Contrary to other studies which suggest that increased provisioning demands reduces foraging distance (Cairns 1988;Wakefield et al. 2011;Angel et al. 2015) our results showed longer trip distances (Fig. 4). This may have reflect reduced prey availability due to environmental effects such as sea surface temperature shifts (Cairns 1988;Lescroël et al. 2016). Some species circumvent this by prey-switching ( Leal et al. 2017;Miller et al. 2017), increasing their provisioning rate ( Wakefield et al. 2011), or amount of time spent foraging without increasing distance from the colony ( Angel et al. 2015). ...
Article
Increasingly, space use by foraging seabirds is being used as an indicator of ocean condition to inform projected planning for climate change, fisheries management and marine protected areas. We tracked foraging common noddies (Anous stolidus) from a colony in the East Indian Ocean using back-mounted solar GPS trackers during incubation and chick rearing to evaluate their suitability as biomonitors of ocean condition, and the overlap of flight tracks with marine protected area boundaries. This is the first study to track this species in its eastern distribution and across different stages of the breeding cycle. Six birds were tracked for 89 days in total, describing 10 089 km of flight. Birds made significantly longer trips during chick rearing, which may reflect reduced availability of prey. The tracking period coincided with a particularly strong ENSO event, which may have impacted foraging behaviour, but the foraging area was found to be at least 10 000 km². Foraging was associated with the end points of outward trips that were generally at the edge of the continental shelf, or within proximity of canyon-like bathymetric features or current structures on the shelf. Birds foraged over the shelf during incubation, suggesting a greater reliance on food web structures associated with Leeuwin Current structures. Home ranges and movement tracks showed limited overlap with proposed marine park boundaries, but are promising as indicators of ocean productivity, suggesting that their role in the design of marine reserve networks in the future should be maximised.
... Por este motivo, resulta clave conocer la distribución de las aves marinas, su ecología, los factores que determinan su supervivencia, y su resiliencia a los cambios ambientales. Plantear estrategias de conservación basadas en sus requerimientos ecológicos puede suponer amplios beneficios al ecosistema marino (Lescroël et al., 2016). Esto, sumado a que en muchos casos se trata de especies carismáticas, hace que las aves marinas actúen de especies "paraguas" de la biodiversidad marina. ...
... Además, las aves marinas sobrepasan los límites ecológicos y políticos, se mueven entre zonas protegidas y sin proteger, y revelan puntos calientes de biodiversidad (o "hotspots"; Lescroël et al., 2016). Por ello, resulta esencial conocer sus movimientos y distribución a lo largo del año, así como sus áreas de alimentación principales. ...
Conference Paper
La dieta y las áreas de alimentación son aspectos básicos de la ecología de cualquier especie, y conocerlos es imprescindible para su adecuado manejo y conservación. Sin embargo, sólo con los avances tecnológicos recientes, es posible abordarlos en aves marinas de pequeño porte como el petrel de Bulwer (Bulweria bulwerii). De 2015 a 2017 en Montaña Clara (archipiélago Chinijo, Lanzarote), instrumentamos petreles con diminutos dispositivos GPS y GLS (n=20), recogimos regurgitados espontáneos para la identificación directa de sus presas (n=26), y muestreamos sangre y plumas de adultos (n=62) y pollos (n=30) para el análisis de isótopos estables (δ13C y δ15N). Algunos animales realizaron largos viajes de alimentación de hasta 15 días, alcanzando incluso las Azores, aunque la mayoría se dirigieron hacia el sur, alcanzando las aguas oceánicas frente al Sahara Occidental. Los peces fueron las presas más frecuentes en los regurgitados (64%) frente a los cefalópodos (36%), tratándose de especies que realizan migraciones diarias verticales, la mayoría mictófidos y estomiiformes. Los pollos presentaron valores de δ13C en sangre más bajos que los adultos, lo que podría deberse a una selección diferencial de presas para cebar a los pollos o que éstas fuesen capturadas en áreas más cercanas a la colonia. Esta selección diferencial de presas para los pollos también explicaría los valores más bajos de δ15N en sangre de adultos reproductores al compararlos con los no reproductores. Los valores de δ13C en plumas de pollos muestreados a lo largo de su crecimiento mostraron un cambio de dieta o de las áreas de alimentación de los progenitores durante el período de cría. La miniaturización de GPS y GLS, en combinación con el análisis de isótopos estables, nos ha revelado por primera vez los hábitos oceánicos y las asombrosas estrategias de alimentación de estas pequeñas aves marinas, hasta ahora poco conocidos.
... Migratory seabirds are ideal organisms for monitoring the impact of climate change in the marine ecosystem. They are at or near the top of marine food webs and the variation in their demographic parameters and/or their diet may reflect changes occurring at lower levels (Lescroël et al., 2016); many are relatively easy to monitor (Hazen et al., 2019); and their wide-ranging distributions and the differences and distance between their breeding and non-breeding areas allow comparisons between dissimilar biogeographic areas and regions (Ramos and González-Solís, 2012). ...
Article
Climate change has repeatedly been shown to impact the demography and survival of marine top predators. However, most evidence comes from single populations of widely distributed species, limited mainly to polar and subpolar environments. Here, we aimed to evaluate the influence of environmental conditions on the survival of a tropical and migratory seabird over the course of its annual cycle. We used capture-mark-recapture data from three populations of Bulwer's petrel (Bulweria bulwerii) spread across the NE Atlantic Ocean, from the Azores, Canary, and Cabo Verde Islands (including temperate to tropical zones). We also inferred how the survival of this seabird might be affected under different climatic scenarios, defined by the Intergovernmental Panel on Climate Change. Among the environmental variables whose effect we evaluated (North Atlantic Oscillation index, Southern Oscillation Index, Sea Surface Temperature [SST] and wind speed), SST estimated for the breeding area and season was the variable with the greatest influence on adult survival. Negative effects of SST increase emerged across the three populations, most likely through indirect trophic web interactions. Interestingly, our study also shows that the survival of Bulwer's petrel will be profoundly affected by the different scenarios of climate change, even with the most optimistic trajectory involving the lowest greenhouse gas emission. Furthermore, for the first time, our study predicts stronger impacts of climate change on tropical populations than on subtropical and temperate ones. This result highlights the devastating effect that climate change may also have on tropical areas, and the importance of considering multi-population approaches when evaluating its impacts which may differ across species distributions.
... It follows that by exposing offspring to different weather conditions within the same reproductive season, for example, experiencing low temperatures during the incubation stage followed by more benign conditions during the brood care stage, weather variability can alter a population's demography. Therefore, there is an urgent need to understand how organisms respond to intra-annual climate variability, particularly in declining populations with long rearing periods, such as those of seabirds (Lescroël et al. 2016). ...
Article
Full-text available
Weather conditions can profoundly affect avian reproduction. It is known that weather conditions prior to and after the onset of reproduction can affect the breeding success of birds. However, little is known about how seasonal weather variability can affect birds' breeding performance, particularly for species with a slow pace of life. Long-term studies are key to understanding how weather variability can affect a population's dynamics, especially when extreme weather events are expected to increase with climate change. Using a 32-year population study of the Blue-footed booby (Sula nebouxii) in Mexico, we show that seasonal variation in weather conditions, predominantly during the incubation stage, affects offspring survival and body condition at independence. During most of the incubation period, warm sea surface temperatures were correlated with low hatching success, while rainfall in the middle of the incubation stage was correlated with high fledging success. In addition, chicks from nests that experienced warm sea surface temperatures from the pre-laying stage to near-fledging had lower body condition at 70 days of age. Finally, we show that variable annual SST conditions before and during the incubation stage can impair breeding performance. Our results provide insight into how seasonal and interannual weather variation during key reproductive stages can affect hatching success, fledging success, and fledgling body condition in a long-lived neotropical seabird.
... There is a particular lack of information about at-sea distributions for many South Pacific seabird taxa, despite this region representing the largest expanse of ocean on Earth (Croxall et al., 2012;Rodrıǵuez et al., 2019). Such fundamental ecological knowledge is key to achieving effective conservation and enables researchers and policy makers to more accurately identify current and future threats (Burger and Shaffer, 2008;Lescroël et al., 2016;Bernard et al., 2021). ...
Article
Full-text available
Gadfly petrels (genus Pterodroma) are one of the most threatened groups of birds. They are exceptionally well adapted to forage over enormous areas to maximize chances of encountering prey. Their wide-ranging travel, extensive use of oceanic habitats beyond national jurisdictions (the high seas), and limited information on their at-sea distributions and foraging ecology pose several management challenges. Here, we examined the foraging distributions and habitat preferences of three gadfly petrels that breed on Phillip Island (Norfolk Island Group), in the southwest Pacific Ocean, and tested the ability of species distribution models (SDMs) to predict important marine habitats. GPS loggers were deployed in 2018 and 2019 on chick-provisioning black-winged petrels (P. nigripennis) and white-necked petrels (P. cervicalis) and in 2020 on Kermadec petrels (P. neglecta), and hidden Markov models (HMMs) were used to estimate behavioral states across 387 foraging trips. SDMs were built using six algorithms and the predictive performance of models constructed using conventional random cross-validation (CV) was compared to those constructed with spatially independent CV. All three species demonstrated dual-foraging strategies with short trips closer to the colony and longer, presumably self-provisioning, trips with maximum distances from the colony of several thousand kilometers for black-winged and white-necked petrels. Foraging areas of each species were distinctly partitioned across the Tasman Sea during long trips, but there was high overlap during short trips. Black-winged and white-necked petrels exhibited area-restricted search foraging behavior throughout their foraging ranges which spanned almost the entire Tasman Sea and into the western Pacific, whereas the foraging range of Kermadec petrels was restricted closer to the colony. Approximately half of each species’ foraging range extended into the high seas. Response curves and variable importance between the two SDM CV approaches were similar, suggesting that model fitting was robust to the CV approach. However, evaluation using spatially independent CV indicated that generalizability of ensemble SDMs to new data ranged from poor to fair for all three species. This suggests that the maximal-area foraging strategy of gadfly petrels (whereby they search opportunistically for resources across expansive oceanic habitats) results in weak or wide associations with environmental features making predicting important habitats extremely challenging.
... For instance, diet and demographic monitoring have been used as indicators of ecosystem health and to prioritise conservation goals (Furness 1997, Piatt andSydeman 2007). Moreover, they may act as important umbrella species facilitating protection of habitats and less charismatic taxa (Lescroël et al. 2016). In this way, seabird tracking has emerged as a powerful complement with the ability to monitor biodiversity and reveal key information about the potential winners and losers of global change (BrissonCuradeau et al. 2017, Hays et al. 2019. ...
Chapter
In the past three decades scientists have been equipping free-living seabirds with biologging devices to provide information about their behaviour in unprecedented detail. However, more recently the miniaturisation of tracking devices, have enabled scientists to understand the precise distribution patterns of seabirds across a variety of scales and species. As tags have become smaller and cheaper, seabird tracking studies and number of individuals have increased exponentially. This has allowed scientists to identify the major sources of anthropogenic stressors affecting seabirds in the marine environment and for resolving marine conservation issues. The increasing volume and complexity of tracking data has lead scientists to develop effective tools for data mining and spatial analysis with further benefits for seabird conservation. However, they often require high levels of expertise and considerable computation capacities which turn their use by policy makers and managers challenging. In this book chapter we overview the recent advances in tracking devices currently used to study seabird distribution and discuss the challenges and how they can be important for resolving marine conservation issues.
... This is currently the key issue, which expands to the entire biosphere, and will not be solved through the production and use of big data alone. As the general public is generally fascinated both by charismatic megafauna and by electronic technologies, animal bio-logging has a strong potential for winning people's attention (Lescroël et al., 2016). Nevertheless, publishing in scientific journals, on websites, or in conventional media is not sufficient any more. ...
Article
Satellite remote-sensing and wildlife tracking allow researchers to record rapidly increasing volumes of information on the spatial ecology of marine megafauna in the context of global change. This field of investigation is thereby entering the realm of big data science: Information technology allows the design of completely new frameworks for acquiring, storing, sharing, analysing, visualizing, and publicizing data. This review aims at framing the importance of big data for the conservation of marine megafauna, through intimate knowledge of the spatial ecology of these threatened, charismatic animals. We first define marine megafauna and big data science, before detailing the technological breakthroughs leading to pioneering “big data” studies. We then describe the workflow from acquiring megafauna tracking data to the identification and the prediction of their critical habitats under global changes, leading to marine spatial planning and political negotiations. Finally, we outline future objectives for big data studies, which should not take the form of a blind technological race forward, but of a coordinated, worldwide approach to megafauna spatial ecology, based on regular gap analyses, with care for ethical and environmental implications. Employing big data science for the efficient conservation of marine megafauna will also require inventing new pathways from research to action.
... Migratory seabirds are the ideal organisms to monitor the impact of climate change in the marine ecosystem: they are at or near the top of the marine food chains and the variation in their demographic parameters and/or their diet reflect the changes produced at lower levels (Lescroël et al., 2016); they are easy to monitor (Hazen et al., 2019); and their vast distributions and the differences and distance between their breeding and non-breeding areas allow comparisons among unalike biogeographic areas and regions (Ramos & González-Solís, 2012). ...
... Observations of foraging behaviours can give information about preferred prey type (Elliott et al. 2008) and accessibility limitations such as depth (Burger 2001) and are relevant for evaluating the costs and benefits of foraging because behavioural factors like flapping, landing, and take-off can influence foraging effort (Shaffer et al. 2001). Furthermore, it is crucial to comprehend the natural foraging ecology of seabirds to describe the impact of human activities such as exploitation by fisheries on marine ecosystems (Furness et al. 2007;Lescroël et al. 2016;Le Bot et al. 2018). ...
Article
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Conventional bio-logging techniques used for ethological studies of seabirds have their limitations when studying detailed behaviours at sea. This study uses animal-borne video cameras to reveal fne-scale behaviours, associations with conspecifcs and other species and interactions with fshery vessels during foraging of a Mediterranean seabird. The study was conducted on Scopoli's shearwaters (Calonectris diomedea) breeding in Linosa island (35°51′33″ N; 12°51′34″ E) during summer 2020. Foraging events were video recorded from a seabirds' view with lightweight cameras attached to the birds' back. Foraging always occurred in association with other shearwaters. Competitive events between shearwaters were observed, and their frequency was positively correlated to the number of birds in the foraging aggregation. Associations with tunas and sea turtles have been frequent observations at natural foraging sites. During foraging events, video recordings allowed observations of fne-scale behaviours, which would have remained unnoticed with conventional tracking devices. Foraging events could be categorised by prey type into “natural prey” and “fshery discards”. Analysis of the video footage suggests behavioural diferences between the two prey type categories. Those diferences suggest that the foraging efort between natural prey and fshery discards consumption can vary, which adds new arguments to the discussion about energy trade-ofs and choice of foraging strategy. These observations highlight the importance of combining tracking technologies to obtain a complete picture of the at-sea behaviours of seabirds, which is essential for understanding the impact of foraging strategies and seabird-fshery interactions.
... highly dependent on understanding basic predator ecology (Game et al., 2009;Marshall et al., 2016;Guerra, 2019) and the processes driving their distribution (Afán et al., 2015;Gladics et al., 2015;García-Barón et al., 2019). The importance of this not only lies in the fact that top predators are key ecological indicators in marine ecosystems (Maxwell et al., 2013;Hazen et al., 2019), but also because many of them are facing severe conservation problems and are subject to protection measures regulated by law, the application of which is not always completely effective (Soulé et al., 2005;Lescroël et al., 2016). ...
Article
1. Spatial modelling is an important research tool to improve our knowledge about the distribution of wildlife in the ocean. Using different modelling techniques (MaxEnt and a generalized linear mixed model), a predictive habitat suitability model was developed for one of the most threatened seabirds in the world: the Balearic shearwater, Puffinus mauretanicus. 2. Models were developed using a 10-year dataset from the Gulf of Cádiz (on the southwestern Iberian Peninsula), a key foraging area for Balearic shearwaters during migration and the non-breeding season. 3. Predictive habitat maps strongly matched the observed distribution patterns, pointing to bathymetric features as the main modelling drivers. The species was concentrated on shallow areas (up to approximately 100 m in depth) of the continental shelf, very close to the mouth of the Guadalquivir River. In contrast with previous studies, Balearic shearwater distribution in the highly dynamic Gulf of Cádiz was not correlated with areas of high chlorophyll a concentration. 4. This lack of spatial correlation probably arises from the delay between the phytoplankton bloom and the response of the zooplankton and small fish that are preyed upon by Balearic shearwaters, which may result in important displacements of this trophic chain across the Gulf of Cádiz. 5. The analysis presented contributes to a better understanding of the spatial distribution and ecology of the critically endangered top predator in the Gulf of Cádiz and offers important information to improve management plans.
... As top-order predators, seabirds are frequently used as sentinel organisms for monitoring marine ecosystems (Lescroël et al. 2016). However, over a third of all seabird species are currently globally threatened, raising concern for the health of the oceans and associated ecosystem functions (Dias et al. 2019). ...
Article
Extreme weather events are increasing in frequency, causing disruption to global ecosystems. Large-scale events, such as marine heatwaves, can impact the abundance of prey species, which consequently influences the behaviour of top-level predators such as seabirds. The short-tailed shearwater Ardenna tenuirostris is a trans-hemispheric migrant with typically a highly synchronous breeding phenology. Here, we document short-tailed shearwater colony occupancy for the period 2011-2020, with a focused assessment of their breeding success in the 2019/20 season, which followed a marine heatwave that occurred predominantly the non-breeding areas in the North Pacific Ocean. The birds’ return to their breeding colonies in southeast Australia was delayed by approximately two weeks in October 2019, and the subsequent breeding season ended in only 34% breeding success, with nest abandonment beginning in the incubation phase. A North Pacific marine heatwave in 2019, associated with a mass mortality event of over 9000 birds (‘wreck’ of beach-washed birds), led to reduced adult body condition and carry-over effects causing egg and chick failures during the subsequent breeding season. Localised weather events (i.e., flooding of burrows due to heavy rainfall) also influenced breeding outcomes of the 2019/20 season. The relationship between wreck events and seabird breeding ecology is an understudied area, partly due to the difficulties around quantifying the scale of wrecks. Our study is one of few that documents poor seabird breeding success following the extreme marine conditions which have persisted in the North Pacific Ocean since 2013.
... Indeed, detailed information on their movements at sea is shedding light on the structure and dynamics of marine systems in time and space (Grémillet et al., 2008;Péron et al., 2012). Finally, conveying maps and animations of seabirds movements to decision-makers and the public is key to winning their commitment for marine conservation (Burger & Shaffer, 2008;Lescroël et al., 2016). ...
Article
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Electronic tracking technologies revolutionized wildlife ecology, notably for studying the movements of elusive species such as seabirds. Those advances are key to seabird conservation, for example in guiding the design of marine protected areas for this highly threatened group. Tracking data are also boosting scientific understanding of marine ecosystem dynamics in the context of global change. To optimize future tracking efforts, we performed a global assessment of seabird tracking data. We identified and mined 689 seabird tracking studies , reporting on > 28,000 individuals of 216 species from 17 families over the last four decades. We found substantial knowledge gaps, reflecting a historical neglect of tropical seabird ecology, with biases toward species that are heavier, oceanic, and from high-latitude regions. Conservation status had little influence on seabird tracking propensity. We identified 54 threatened species for which we did not find published tracking records, and 19 with very little data. Additionally, much of the existing tracking data are not yet available to other researchers and decision-makers in online databases. We highlight priority species and regions for future tracking efforts. More broadly, we provide guidance toward an ethical, rational, and efficient global tracking program for seabirds, as a contribution to their conservation.
... Effective management and conservation in the open ocean is highly dependent on understanding basic predator ecology (Game et al., 2009;Marshall et al., 2016;Guerra, 2019) and the processes driving their distribution (Afán et al., 2015;Gladics et al., 2015;García-Barón et al., 2019). The importance of this fact not only lies in the fact that top predators are key ecological indicators in marine ecosystems (Maxwell et al., 2013;Hazen et al., 2019), but also because many of them are facing severe conservation problems and are subject to protection measures regulated by law whose application is not always completely effective (Soulé et al., 2005;Lescroël et al., 2016). ...
... Seabirds are among the most threatened of all bird groups (Dias et al., 2019), with demonstrated sensitivity to direct (through physiological modifications or change in extreme events exposure) and indirect (through trophic mechanisms or modifications of their critical habitats) climate change impacts (Sydeman, Poloczanska, Reed, & Thompson, 2015). Seabirds are also ecological sentinels of marine ecosystems across their life cycles (Durant et al., 2009;Lescroël et al., 2016), and the subject of long-term monitoring studies throughout the world (Paleczny, Hammill, Karpouzi, & Pauly, 2015). Yet, because of technological limitations and practical difficulties, most of these studies dealing with climate change impacts on seabirds focus on population processes (Descamps et al., 2017) or on their responses during the breeding season (Frederiksen, Anker-Nilssen, Beaugrand, & Wanless, 2013), rather than climate change impacts on their at-sea distributions during the non-breeding period. ...
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We explored the implications of reaching the Paris Agreement Objective of limiting global warming to <2°C for the future winter distribution of the North Atlantic seabird community. We predicted and quantified current and future winter habitats of five North Atlantic Ocean seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla) using tracking data for ~1500 individuals through resource selection functions based on mechanistic modeling of seabird energy requirements, and a dynamic bioclimate envelope model of seabird prey. Future winter distributions were predicted to shift with climate change, especially when global warming exceed 2°C under a “no mitigation” scenario, modifying seabird wintering hotspots in the North Atlantic Ocean. Our findings suggest that meeting Paris agreement objectives, will limit changes in seabird selected habitat location and size in the North Atlantic Ocean during the 21st century. We thereby provide key information for the design of adaptive marine protected areas in a changing ocean.
... The Rouzic gannet colony is a major emblem of French metropolitan biodiversity, with constant media attention. We, therefore, anticipate that our work will contribute to foster a sense of common destiny between seabirds and humans in coastal marine ecosystems severely affected by global change, leading to the urgently needed transformation of marine policies (Lescroël et al. 2016). Notably, we are currently using scientific evidence gathered through the long-term monitoring of the Rouzic colony to promote the establishment of a marine extension to the National Nature Reserve of the Sept-Iles archipelago, and to warn the European Union for the consequences of its fishing activities off West Africa (Ramos and Grémillet 2013). ...
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Seabirds are one of the most threatened of all bird groups, with a marked community-wide decline across the last decades. Yet, some seabird species are more resilient than others, and it is essential to study under which conditions even these highly resilient organisms are affected by global changes. Here, we report such a case in northern gannets (Morus bassanus). Using global location sensors (GLS), demographic and stable isotope analyses, we performed a long-term study of the migration biology and inter-annual survival of gannets breeding on Rouzic Island in Brittany, France. Across 2006–2015, our analyses showed that the birds spent the inter-breeding period off Western Europe, in the Mediterranean or off West Africa. There were no inter-annual trends in the use of these different areas, but isotopic analyses suggested food competition between gannets and industrial-scale fisheries. Crucially, we found a precipitous decline in the return rates of birds equipped with GLS, from 100% in 2006–2007 to less than 30% after 2015. This decline was consistent with a marked decrease in inter-annual survival probabilities for ringed adult gannets, from > 90% in 2014–2015 to < 60% in 2018–2019, and with a population decline of the Rouzic gannet breeding colony in recent years. Strong ecological signals provided by northern gannets point to critical marine ecosystem perturbation in the Eastern Atlantic, and the decline of this resilient and emblematic species should lead to the urgently needed transformation of marine policies.
... Increased knowledge sharing between stakeholders was proposed as a key prerequisite for success in changing perceptions (Bruckmeier & Larsen, 2008). This should be directed towards allowing fishers and managers to understand the ecology and the conservation concerns around species, but also the scientists and environmentalists to understand the socio-economic stakes around fishing (Lescroël et al., 2016;Redpath et al., 2013). ...
Article
The sustainable mitigation of human–wildlife conflicts has become a major societal and environmental challenge globally. Among these conflicts, large marine predators feeding on fisheries catches, a behaviour termed “depredation,” has emerged concomitantly with the expansion of the world’s fisheries. Depredation poses threats to both the socio‐economic viability of fisheries and species conservation, stressing the need for mitigation. This review synthesizes the extent and socio‐ecological impacts of depredation by sharks and marine mammals across the world, and the various approaches used to minimize it. Depredation was reported in 214 fisheries between 1979 and 2019 (70% post‐2000) and affected fleets from 44 countries, in all sectors (commercial, artisanal and recreational), and in all major fishing techniques (nets, traps and hook‐and‐lines). A total of 68 predator species were involved in depredation (20 odontocetes, 21 pinnipeds and 27 sharks), and most (73%) were subject to either by‐catch and/or retaliatory killing from fishers when interacting with gear. Impacts on fishers were primarily associated with catch losses and gear damage but often lacked assessments. Deterrence was a major mitigation approach but also the least effective. Gear modifications or behavioural adaptation by fishers were more promising. This review highlights the need for improved monitoring, and interdisciplinary and integrated research to quantify the determinants and impacts of depredation in the socio‐ecological dimension. More importantly, as the conflict is likely to escalate, efforts directed towards changing perceptions and integrating knowledge through adaptive co‐management are raised as key directions towards coexistence between fisheries and large marine predators.
... Our results reinforce earlier studies that have shown strong and sometimes unexpected effects of seabirds in local flora and fauna 10-13 . We believe that such seabird mediated cross-scale ecosystem interactions are often overlooked, and should be considered more generally, e.g., in constructing management plans of protected areas [33][34][35] . ...
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Seabirds redistribute nutrients between different ecosystem compartments and over vast geographical areas. This nutrient transfer may impact both local ecosystems on seabird breeding islands and regional biogeochemical cycling, but these processes are seldom considered in local conservation plans or biogeochemical models. The island of Stora Karlsö in the Baltic Sea hosts the largest concentration of piscivorous seabirds in the region, and also hosts a large colony of insectivorous House martins Delichon urbicum adjacent to the breeding seabirds. We show that a previously reported unusually high insectivore abundance was explained by large amounts of chironomids-highly enriched in δ 15 N-that feed on seabird residues as larvae along rocky shores to eventually emerge as flying adults. Benthic ammonium and phosphate fluxes were up to 163% and 153% higher close to the colony (1,300 m distance) than further away (2,700 m) and the estimated nutrient release from the seabirds at were in the same order of magnitude as the loads from the largest waste-water treatment plants in the region. The trophic cascade impacting insectivorous passerines and the substantial redistribution of nutrients suggest that seabird nutrient transfer should be increasingly considered in local conservation plans and regional nutrient cycling models.
... Comparisons of mercury concentrations over time and space using generalist predators are likely to remain a challenge despite methodological improvements. Nevertheless, seabirds represent an important sentinel group of flagship species that can be used in the communication of data to policy makers and the public (Lescroël et al., 2016). The utility of feathers as discrete sampling units of large temporal and spatial scales is possibly unparalleled. ...
Article
Monitoring mercury concentration in the marine environment is pivotal due to the risks that mercury intake poses to the ecosystem and human health. It is therefore of interest to make reliable, comparative measurements over large geographic areas. Here, the utility of wide-ranging generalist seabirds as mercury biomonitors at an ocean basin scale was assessed, using the Cory's Shearwater as a model species. The mercury concentration in flight feathers moulted at distant non-breeding areas of geolocator-tracked birds was quantified, reflecting contamination in various geographic areas. Compound-specific isotope analysis of amino acids was used to obtain comparable trophic positionestimates controlled for baseline isoscape. Birds that remained resident in the Canary Current integrated less mercury into their feathers than those that migrated to either the Benguela or Agulhas currents. Residents also occupied a significantly lower trophic position during the non-breeding season than migrants, largely explaining the difference in mercury exposure. Both mercury concentration and trophic position were similar in individuals spending the non-breeding period in the Benguela and Agulhas currents. This paper highlights the importance of accurate trophic position calculation in order to understand mercury exposure in wide-ranging predators and for meaningful spatial comparisons.
... Wilson et al. 2002, Wakefield et al. 2009). By combining knowledge of ocean conditions, breeding biology, and foraging behavior, we can discern overall ecosystem health (Lescroël et al. 2016, Brisson-Curadeau et al. 2017, monitor the human ecological footprint (Bodey et al. 2014), and make management decisions (Gaston et al. 2013). ...
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Biologging has revealed many of the mysteries surrounding seabird behavior far from land. However, tagging seabirds with biologgers may influence the very traits they are designed to observe. Such ‘tag effects’ are often argued to be minimal below a threshold of 3% of body mass. Nonetheless, few studies carefully separate handling from tagging effects, so the effect of tag size is often confounded with the effect of handling. Puffins, including rhinoceros auklets Cerorhinca monocerata, are notoriously difficult to work with due to high nest abandonment rates. To examine tagging and handling effects in rhinoceros auklets, we compared abandonment rates of individuals equipped with a GPS weighing~ 2.3% of body mass with abandonment rates of birds handled but not equipped, and of birds not handled at all (controls). We used the egg flotation technique to estimate egg development and predict hatching date, thus allowing treatments to be applied at the appropriate time. Handling more than doubled abandonment rates compared to control birds, and tagging more than doubled abandonment rates compared to birds that were handled but not tagged. Abandonment rates decreased as incubation progressed and were lowest during chick-rearing. We conclude that both handling and tagging of auklets increase abandonment, and that effects are lowest during chick-rearing.
... Similarly, polar bears (Ursus maritimus) have become the "public face" of climate change, as declines in their health and increased instances of bear-human conflict have been linked to declines in the solid pack ice on which their seal prey are found (Regehr et al. 2016). Polar bears are highly sensitive sentinels that have captured public attention and provide a tangible impetus for changes in governance to address the global impacts of climate change (Friedrich et al. 2014;Lescroël et al. 2016). ...
Article
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The rapid pace of environmental change in the Anthropocene necessitates the development of a new suite of tools for measuring ecosystem dynamics. Sentinel species can provide insight into ecosystem function, identify hidden risks to human health, and predict future change. As sentinels, marine apex (top) predators offer a unique perspective into ocean processes, given that they can move across ocean basins and amplify trophic information across multiple spatiotemporal scales. Because use of the terms “ecosystem sentinel” and “climate sentinel” has proliferated in the scientific literature, there is a need to identify the properties that make marine predators effective sentinels. We provide a clear definition of the term “sentinel”, review the attributes of species identified as sentinels, and describe how a suite of such sentinels could strengthen our understanding and management of marine ecosystems. We contend that the use of marine predators as ecosystem sentinels will enable rapid response and adaptation to ecosystem variability and change.
... The fate of the Rouzic breeding colony is emblematic because of the highly charismatic status of Northern gannets, and because of the message they convey about the state of the marine environment (Lescroël et al., 2016). Our findings therefore go far beyond a case study of Northern gannet foraging ecology. ...
Article
Fisheries modify ecosystem balance by harvesting through marine food webs and producing large amounts of discards subsidizing scavengers. Among them, seabirds are the most conspicuous and have been benefiting from anthropogenic food sources generated by fisheries. However, this modified feeding behaviour also exposes them to threats, such as accidental bycatch on fishing gear and ecological traps set by discards of lower nutritional value compared to seabird natural prey. Seabird-fishery interactions have been the focus of numerous studies, but very few integrative investigations tested multi-annual dynamics. To explore this temporal dimension, we performed stable isotopic and body condition analyses, as well as GPS-tracking in Northern gannets (Morus bassanus) over a 12-year period (2005-2017), during which they coexisted with fisheries in the English Channel. We demonstrate that gannets fed either on natural prey, or fishery wastes, but that discard consumption induced increased seabird foraging effort and reduced adult body condition. These changes are concomitant with reduced gannet reproductive success, and reduced growth rate of their breeding population. Our work provides essential, novel understanding of scavengers-fisheries interactions, by showing that fishery discards do not compensate natural prey shortage in the longer term. Altered gannet foraging and fitness strongly suggest pelagic fish depletion threatening Northern gannets in the English Channel. To improve gannet conservation in this ecoregion, fishery discards may be banned, but, efforts should in priority go towards rebuilding Northern gannet pelagic prey populations, particularly by strongly reducing fishing effort on North Atlantic mackerel.
... Seabirds are top predators and a significant component of marine ecosystems, making them key indicators of marine ecosystem functioning (including climate change). Changes and fluctuations in seabird population sizes, ranges, foraging ecology and breeding success have been used to detect environmental changes, document direct threats (e.g., poaching) and monitor success or failure of conservation management policies in protected areas and beyond (Lescroël et al., 2016;Dunlop, 2017). ...
Article
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Shearwaters and petrels (hereafter petrels) are highly adapted seabirds that occur across all the world’s oceans. Petrels are a threatened seabird group comprising 124 species. They have bet-hedging life histories typified by extended chick rearing periods, low fecundity, high adult survival, strong philopatry, monogamy and long-term mate fidelity and are thus vulnerable to change. Anthropogenic alterations on land and at sea have led to a poor conservation status of many petrels with 52 (42%) threatened species based on IUCN criteria and 65 (52%) suffering population declines. Some species are well-studied, even being used as bioindicators of ocean health, yet for others there are major knowledge gaps regarding their breeding grounds, migratory areas or other key aspects of their biology and ecology. We assembled 38 petrel conservation researchers to summarize information regarding the most important threats according to the IUCN Red List of threatened species to identify knowledge gaps that must be filled to improve conservation and management of petrels. We highlight research advances on the main threats for petrels (invasive species at breeding grounds, bycatch, overfishing, light pollution, climate change, and pollution). We propose an ambitious goal to reverse at least some of these six main threats, through active efforts such as restoring island habitats (e.g., invasive species removal, control and prevention), improving policies and regulations at global and regional levels, and engaging local communities in conservation efforts.
... As our study indicates, this threat should not be neglected as it is substantial and global. Signals from seabirds strongly call for improved management of the world's fisheries [26], with the aim of restoring marine ecosystem function and resilience. ...
Article
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Fisheries transform marine ecosystems and compete with predators [1], but temporal trends in seabird-fishery competition had never been assessed on a worldwide scale. Using catch reconstructions [2] for all fisheries targeting taxa that are also seabird prey, we demonstrated that average annual fishery catch increased from 59 to 65 million metric tons between 1970-1989 and 1990-2010. For the same periods, we estimated that global annual seabird food consumption decreased from 70 to 57 million metric tons. Despite this decrease, we found sustained global seabird-fishery food competition between 1970-1989 and 1990-2010. Enhanced competition was identified in 48% of all areas, notably the Southern Ocean, Asian shelves, Mediterranean Sea, Norwegian Sea, and Californian coast. Fisheries generate severe constraints for seabird populations on a worldwide scale, and those need to be addressed urgently. Indeed, seabirds are the most threatened bird group, with a 70% community-level population decline across 1950-2010 [3].
... Seabird populations have declined worldwide during the last decades, increasing the conservation concern for this species group (Croxall et al. 2012, Lewison et al. 2012, Lescroël et al. 2016. There is thus an urgent need to identify and understand the ecological mechanisms leading to reduced performance of seabirds. ...
Article
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To identify priorities for management of seabirds during the breeding season, it is important to understand the ecological mechanisms driving chick growth and survival. In this study, we examined the effects of diet and prevailing weather on the growth and survival of chicks of black-legged kittiwakes Rissa tridactyla over a 10 yr period at Anda, a seabird colony in northern Norway. We show that across all years, there was a significant effect of diet composition delivered to chicks on their growth and survival. A higher proportion of sandeel Ammodytes spp. in the chick diet was associated with an increase in daily growth rates, a pattern that was especially pronounced for the youngest chick in 2-chick broods. A high proportion of mesopelagic fish in the chick diet was associated with a decrease in survival, again, especially for the youngest chick in 2-chick broods. Periods of strong southerly winds also led to reduced survival, probably linked to nests being washed down from the colony. Growth rates of kittiwake chicks were negatively affected by wind speed, likely due to adults having to work more in the exposed habitats in strong winds, causing a reduction in the amount of food supplied to the chicks. Our results emphasise the importance of conservation of specific marine habitats shown to be important foraging areas in ensuring the reproductive success of seabirds. This might prove increasingly important if future climate regimes make ecological conditions more challenging for seabirds.
... Interactions between marine top predators (e.g., seabirds) and fisheries involve a trade-off between conservation and resource harvesting in marine systems (Lescroël et al. 2016). Seabirdfish-fisheries interactions include direct mortality due to bycatch (Lewison et al. 2014), seabirds foraging on fishing discards (Bartumeus et al. 2010, Votier et al. 2004, and resource competition (Cury et al. 2011, Furness & Camphuysen 1997. ...
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We studied the at-sea distribution of two auks (Common Murre Uria aalge, Razorbill Alca torda), two gulls (Lesser Black-backed Gull Larus fuscus, Herring Gull Larus argentatus), and Great Cormorant Phalacrocorax carbo during the peak breeding season of 2014 around Stora Karlsö, the main Baltic Sea seabird colony. Simultaneously, we quantified forage fish abundance and distribution using hydro-acoustics and pelagic trawling. The auks and gulls had a roughly similar distribution, foraging mainly about 40 km west-northwest from the colony. Great Cormorants were found only in inshore areas, close to the colony. Sprat Sprattus sprattus and herring Clupea harengus biomass was, respectively, 1.38 and 2.68 mt/km² averaged over the whole study area. These estimates represent a total biomass for small pelagic fish of 17 900 t in the 4 408 km² study area. The estimated prey consumption over the breeding season was 2 310 t for Common Murre and Razorbill combined. Thus, auks may have a non-negligible impact on their prey sources in the region. Common Murres foraged closer to the colony (median 36.3 km) than Razorbills (median 41.1 km), but we found no significant correlation between auk at-sea numbers and fish densities. We discuss how new technology can contribute to detailed monitoring of the interactions between seabirds and fish at different spatial and temporal scales, with the ultimate aim of providing a scientific basis for ecosystem-based management.
... Flexible foraging strategies are often the most effective short-term responses to climate change and may buffer predators against the uncertainty of locating food in a stochastic and exploited system such as the Benguela region [28]. In such areas, due to their restricted foraging range when breeding and the availability of a realtime monitoring method with limited sampling effort and disturbance [86], greater crested terns may be important ocean sentinels indicating localized human-induced alterations in common and non-commercialized species. The non-invasive method used in this study offers a fine-scale window into their diet and behaviour that can be implemented to undertake systematic and detailed monitoring of changes in the availability of prey in the vicinity of breeding colonies. ...
Article
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Marine predators, such as seabirds, are useful indicators of marine ecosystem functioning. In particular, seabird diet may reflect variability in food-web composition due to natural or human-induced environmental change. Diet monitoring programmes, which sample diet non-invasively, are valuable aids to conservation and management decision-making. We investigated the diet of an increasing population of greater crested terns Thalasseus bergii in the Western Cape, South Africa, during three successive breeding seasons (2013 to 2015), when populations of other seabirds feeding on small pelagic schooling fish in the region were decreasing. Breeding greater crested terns carry prey in their bills, so we used an intensive photo-sampling method to record their diet with little disturbance. We identified 24,607 prey items from at least 47 different families, with 34 new prey species recorded. Fish dominated the diet, constituting 94% of prey by number, followed by cephalopods (3%), crustaceans (2%) and insects (1%). The terns mainly targeted surface-schooling Clupeiformes, with anchovy Engraulis encrasicolus the most abundant prey in all three breeding seasons (65% overall). Prey composition differed significantly between breeding stages and years, with anchovy most abundant at the start of the breeding season, becoming less frequent as the season progressed. The proportion of anchovy in the diet also was influenced by environmental factors; anchovy occurred more frequently with increasing wind speeds and was scarce on foggy days, presumably because terns rely in part on social facilitation to locate anchovy schools. The application of this intensive and non-invasive photo-sampling method revealed an important degree of foraging plasticity for this seabird within a context of locally reduced food availability, suggesting that, unlike species that specialise on a few high-quality prey, opportunistic seabirds may be better able to cope with reductions in the abundance of their preferred prey.
... Flexibility in foraging behavior is pivotal to buffer spatial and temporal variations in food availability and abundance (Pettex et al., 2012). Hence, to implement proper long-term conservation measures intended to protect marine top predators, it is crucial to understand their foraging flexibility and how this is related to the oceanographic (e.g., Daunt et al., 2002;Pettex et al., 2012;Votier et al., 2010) and environmental conditions (Lescroël et al., 2016;Lewis, Phillips, Burthe, Wanless, & Daunt, 2015;Yamamoto et al., 2016) that surround them. ...
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For marine top predators like seabirds, the oceans represent a multitude of habitats regarding oceanographic conditions and food availability. Worldwide, these marine habitats are being altered by changes in climate and increased anthropogenic impact. This is causing a growing concern on how seabird populations might adapt to these changes. Understanding how seabird populations respond to fluctuating environmental conditions and to what extent behavioral flexibility can buffer variations in food availability can help predict how seabirds may cope with changes in the marine environment. Such knowledge is important to implement proper long-term conservation measures intended to protect marine predators. We explored behavioral flexibility in choice of foraging habitat of chick-rearing black-legged kittiwakes Rissa tridactyla during multiple years. By comparing foraging behavior of individuals from two colonies with large differences in oceanographic conditions and distances to predictable feeding areas at the Norwegian shelf break, we investigated how foraging decisions are related to intrinsic and extrinsic factors. We found that proximity to the shelf break determined which factors drove the decision to forage there. At the colony near the shelf break, time of departure from the colony and wind speed were most important in driving the choice of habitat. At the colony farther from the shelf break, the decision to forage there was driven by adult body condition. Birds furthermore adjusted foraging behavior metrics according to time of the day, weather conditions, body condition, and the age of the chicks. The study shows that kittiwakes have high degree of flexibility in their behavioral response to a variable marine environment, which might help them buffer changes in prey distribution around the colonies. The flexibility is, however, dependent on the availability of foraging habitats near the colony.
... Arctic breeding seabirds may be affected by climate change, habitat degradation, predation, changes in their marine food sources, and environmental contaminants [1]. Seabirds are ecologically relevant study organisms in ecotoxicological studies and monitoring because they are considered to be good indicators of environmental health and human-induced environmental changes [2]. Because of their trophic level in the marine food web, many seabird species accumulate high concentrations of persistent contaminants [3]. ...
Article
Environmental contaminants are found throughout Arctic marine ecosystems, and their presence in seabirds has been associated with toxicological responses. However, there are few studies of genotoxicity in Arctic avian wildlife. The purpose of the present study was to quantify DNA damage in lymphocytes of selected seabird species and to examine whether accumulation of organohalogen contaminants ( OHCs) affects DNA damage. Blood was sampled from common eider (Somateria mollissima), black guillemot (Cepphus grylle), black-legged kittiwake (Rissa tridactyla), glaucous gull (Larus hyperboreus), arctic skua (Stercorarius parasiticus), and great skua (Stercorarius skua) in Kongsfjorden, Svalbard. Contaminant concentrations found in the six species differed presumably due to foraging ecology and biomagnification. Despite large differences in contaminant concentrations, ranging from ΣOHCs 3.3 ng/g ww in the common eider to ΣOHCs 895 ng/g ww in the great skua, there was no strong difference among the species in baseline DNA damage or sensitivity to a genotoxic stressor (i.e. hydrogen peroxide). Baseline levels of DNA damage were low, with median values ranging from 1.7% in the common eider to 8.6% in the great skua. There were no associations between DNA damage and contaminants in the investigated species, suggesting that contaminant concentrations in Kongsfjorden are too low to evoke genotoxic effects, or possibly that lymphocytes are resistant to strand breakage. Clearly, genotoxicity is a topic for future studies of Arctic seabirds. This article is protected by copyright. All rights reserved.
... In conclusion, GPS-tracking of scavenging birds may be an additional, surprisingly efficient tool to fight illegal waste dumping which contains organic garbage. Animal-borne cameras, used in combination with GPS-trackers, will soon allow a better characterization of waste contents [21,22], similar to their utility to address conservation and management issues in oceanic environments [23]. Moreover, the widespread distributions during the breeding and wintering periods of different scavenger gull species across Europe (Fig 3B), which overlaps with some of the most important European cities, suggest a potential use of this methodology at a continental scale. ...
Article
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Urban waste impacts human and environmental health, and waste management has become one of the major challenges of humanity. Concurrently with new directives due to manage this human by-product, illegal dumping has become one of the most lucrative activities of organized crime. Beyond economic fraud, illegal waste disposal strongly enhances uncontrolled dissemination of human pathogens, pollutants and invasive species. Here, we demonstrate the potential of novel real-time GPS tracking of scavenging species to detect environmental crime. Specifically, we were able to detect illegal activities at an officially closed dump, which was visited recurrently by 5 of 19 GPS-tracked yellow-legged gulls (Larus michahellis). In comparison with conventional land-based surveys, GPS tracking allows a much wider and cost-efficient spatiotemporal coverage, even of the most hazardous sites, while GPS data accessibility through the internet enables rapid intervention. Our results suggest that multi-species guilds of feathered detectives equipped with GPS and cameras could help fight illegal dumping at continental scales. We encourage further experimental studies, to infer waste detection thresholds in gulls and other scavenging species exploiting human waste dumps.
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The concept of Ecological Solidarity (ES) is a major feature of the 2006 law reforming National Park policy in France. In the context of biodiversity conservation, the objectives of this paper are to outline the historical development of ES, provide a working definition, and present a method for its implementation that combines environmental pragmatism and adaptive management. First, we highlight how ES provides a focus on the interdependencies among humans and non-human components of the social-ecological system. In doing so we identify ES within a framework that distinguishes ecological, social-ecological and social-political interdependencies. In making such interdependencies apparent to humans who are not aware of their existence, the concept of ES promotes collective action as an alternative or complementary approach to state-based or market-based approaches. By focusing on the awareness, feelings and acknowledgement of interdependencies between actors and between humans and non-humans, we present and discuss a learning-based approach (participatory modeling) which allows stakeholders to work together to construct cultural landscapes for present and future generations. Using two case studies we show how an ES analysis goes beyond the ecosystem management approach to take into account how human interactions with the environment embody cultural, social and economic values and endorse an ethically integrated science of care and responsibility. ES recognizes the diversity of these values as a practical foundation for socially engaged and accountable actions. Finally, we discuss how ES enhances academic support for a social-ecological systems approach to biodiversity conservation and promotes collaboration with decision-makers and stakeholders involved in the adaptive management of protected areas and their surrounding landscapes.
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We examine alternative hypotheses for the decline of 20 cod Gadus morhua stocks in the North Atlantic. The year of the lowest observed biomass of spawners did not correspond to low juvenile survival for the cohorts that should have contributed to the stock in that year. However, fishing mortality was very high for the years preceding the collapse. The collapse of the cod stocks was not caused by a lack of resilience at low population abundance because all spawners were able to produce many potential replacements at low population size. We show that as populations collapsed, fishing mortality increased until the populations were reduced to very low levels. We conclude that increased fishing mortality caused the population declines, and often the collapses, of the cod stocks.
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Peterson, M. J., Mueter, F., Hanselman, D., Lunsford, C., Matkin, C., and Fearnbach, H. 2013. Killer whale (Orcinus orca) depredation effects on catch rates of six groundfish species: implications for commercial longline fisheries in Alaska. – ICES Journal of Marine Science, 70: 1220–1232. Killer whale (Orcinus orca) depredation occurs when whales damage or remove fish caught on longline gear. This study uses National Marine Fisheries Service longline survey data from 1998–2011 to explore spatial and temporal trends in killer whale depredation and to quantify the effect of killer whale depredation on catches of six groundfish species within three management areas in Alaska: the Bering Sea, Aleutian Islands and Western Gulf of Alaska. When killer whales were present during survey gear retrieval, whales removed an estimated 54–72% of sablefish (Anoplopoma fimbria), 41–84% of arrowtooth flounder (Atheresthes stomias) and 73% (Bering Sea only) of Greenland turbot (Reinhardtius hippoglossoides). Effects on Pacific halibut (Hippoglossus stenolepis) and Pacific cod (Gadus macrocephalus) were significant in the Western Gulf only with 51% and 46% reductions, respectively. Overall catches (depredated and non-depredated sets) for all groundfish species significantly impacted by killer whale depredation were lower by 9–28% (p < 0.05). Effects on shortspine thornyhead (Sebastolobus alascanus) catches were not significant in any management area (p > 0.05). These results provide insight into the potential impacts of killer whale depredation on fish stock abundance indices and commercially important fisheries in Alaska and will inform future research on apex predator–fisheries interactions.
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Our paper analyses the conceptual basis of the concept of ecological solidarity, a core feature of the 2006 law reforming National Park policy in France. Based on lessons learnt from the original 1960 policy, we show the multidimensional nature of ecological solidarity and how it is based on the recognition of the natural spatial interdependence among natural organisms and their physical environment. This sets the scene for a new vision of nature conservation. Ecological solidarity offers a pragmatic compromise between ecocentric and anthropocentric ethics. We designed a typology of ecological solidarities that integrates the diverse functional aspects of the organization and dynamics of biodiversity at different spatial and temporal scales. This typology departs from the previous model of central and buffer zones and sets protected areas within their wider social and ecological contexts. We outline how this gives sense to the elaboration of ecological networks and to the integrated management of cultural landscapes. Its efficient integration into land planning and conservation management strategies will require, however, the collective exploration by local communities and stakeholders of the diverse facets of ecological solidarity.
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We explore the social dimension that enables adaptive ecosystem-based management. The review concentrates on experiences of adaptive governance of social-ecological systems during periods of abrupt change (crisis) and investigates social sources of renewal and reorganization. Such governance connects individuals, organi-zations, agencies, and institutions at multiple organizational levels. Key persons provide leadership, trust, vision, meaning, and they help transform management organizations toward a learning environment. Adaptive governance systems often self-organize as social networks with teams and actor groups that draw on various knowledge systems and experiences for the development of a common understanding and policies. The emergence of "bridging organizations" seem to lower the costs of collaboration and conflict resolution, and enabling legislation and governmental policies can support self-organization while framing creativity for adaptive comanagement efforts. A re-silient social-ecological system may make use of crisis as an opportunity to transform into a more desired state.
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We review the ecological rationale behind the potential compatibility be-tween top predators and biodiversity conservation, and examine their ef-fectiveness as surrogate species. Evidence suggests that top predators pro-mote species richness or are spatio-temporally associated with it for six causative or noncausative reasons: resource facilitation, trophic cascades, dependence on ecosystem productivity, sensitivity to dysfunctions, selection of heterogeneous sites and links to multiple ecosystem components. There-fore, predator-centered conservation may deliver certain biodiversity goals. To this aim, predators have been employed in conservation as keystone, um-brella, sentinel, flagship, and indicator species. However, quantitative tests of their surrogate-efficacy have been astonishingly few. Evidence suggests they may function as structuring agents and biodiversity indicators in some ecosystems but not others, and that they perform poorly as umbrella species; more consensus exists for their efficacy as sentinel and flagship species. Con-servation biologists need to use apex predators more cautiously, as part of wider, context-dependent mixed strategies.
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Summary • Because of their popular appeal, top vertebrate predators have frequently been used as flagship or umbrella species to acquire financial support, raise environmental awareness and plan systems of protected areas. However, some have claimed that the utilization of charismatic predators may divert a disproportionate amount of funding to a few glamorous species without delivering broader biodiversity benefits, an accusation aggravated by the fact that the conservation of top predators is often complex, difficult and expensive. Therefore, tests are needed of whether apex predators may be employed to achieve ecosystem-level targets. • To test such a hypothesis, we compared the biodiversity values recorded at the breeding sites of six raptor species, differing widely in diet and habitat associations, with those observed at three types of control locations, (i) sites randomly chosen in comparable habitat, (ii) breeding sites of a randomly selected bird species of lower trophic level and (iii) breeding sites of a lower trophic level species with specialized ecological requirements. Biodiversity was measured as the richness and evenness of bird, butterfly and tree species. • Biodiversity levels were consistently higher at sites occupied by top predators than at any of the three types of control sites. Furthermore, sites occupied by top predators also held greater densities of individual birds and butterflies (all species combined) than control sites. • In a reserve-selection simulation exercise, networks of protected sites constructed on the basis of top predators were more efficient than networks based on lower trophic level species, enabling higher biodiversity coverage to be achieved with a smaller number of reserves. • Synthesis and applications. Our results provide evidence of a link between the strategic utilization of top predatory species and ecosystem-level conservation. We suggest that, at least in some biological systems, conservation plans based on apex predators could be implemented to deliver broader biodiversity benefits. Journal of Applied Ecology (2006) 43, 1049–1055 doi: 10.1111/j.1365-2664.2006.01218.x
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Objets fronti_re = s'adaptent pour prendre en compte plusieurs points de vue et maintenir une identité entre eux Cet espace de travail se construit grâce à des objets-frontières tels que des systèmes de classification, qui relient entre eux les concepts communs et les rôles sociaux divergents de chaque groupe professionnel. Les objet-frontière contribuent à la stabilité du système de référence en offrant un contexte partagé pour la communication et la coopération. Les objets peuvent être considérés comme frontière (Star et Griesemer, 1989) en tant qu’ils contribuent à la stabilité du système de référence en offrant un contexte partagé pour la communication et la coopération.
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The concept of Ecological Solidarity (ES) is a major feature of the 2006 law reforming National Park policy in France. In the context of biodiversity conservation, the objectives of this paper are to outline the historical development of ES, provide a working definition, and present a method for its implementation that combines environmental pragmatism and adaptive management. First, we highlight how ES provides a focus on the interdependencies among humans and non-human components of the social-ecological system. In doing so we identify ES within a framework that distinguishes ecological, social-ecological and social-political interdependencies. In making such interdependencies apparent to humans who are not aware of their existence, the concept of ES promotes collective action as an alternative or complementary approach to state-based or market-based approaches. By focusing on the awareness, feelings and acknowledgement of interdependencies between actors and between humans and non-humans, we present and discuss a learning-based approach (participatory modeling) which allows stakeholders to work together to construct cultural landscapes for present and future generations. Using two case studies we show how an ES analysis goes beyond the ecosystem management approach to take into account how human interactions with the environment embody cultural, social and economic values and endorse an ethically integrated science of care and responsibility. ES recognizes the diversity of these values as a practical foundation for socially engaged and accountable actions. Finally, we discuss how ES enhances academic support for a social-ecological systems approach to biodiversity conservation and promotes collaboration with decision-makers and stakeholders involved in the adaptive management of protected areas and their surrounding landscapes.
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