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- Multispecies tracking reveals a major seabird hotspot in the North AtlanticPublication . Davies, Tammy E.; Carneiro, Ana P.B.; Tarzia, Marguerite; Wakefield, Ewan; Hennicke, Janos C.; Frederiksen, Morten; Hansen, Erpur Snær; Campos, Bruna; Hazin, Carolina; Lascelles, Ben; Anker‐Nilssen, Tycho; Arnardóttir, Hólmfríður; Barrett, Robert T.; Biscoito, Manuel; Bollache, Loïc; Boulinier, Thierry; Catry, Paulo; Ceia, Filipe R.; Chastel, Olivier; Christensen‐Dalsgaard, Signe; Cruz‐Flores, Marta; Danielsen, Jóhannis; Daunt, Francis; Dunn, Euan; Egevang, Carsten; Fagundes, Ana Isabel; Fayet, Annette L.; Fort, Jérôme; Furness, Robert W.; Gilg, Olivier; González‐Solís, Jacob; Granadeiro, J. P.; Grémillet, David; Guilford, Tim; Hanssen, Sveinn Are; Harris, Michael P.; Hedd, April; Huffeldt, Nicholas Per; Jessopp, Mark; Kolbeinsson, Yann; Krietsch, Johannes; Lang, Johannes; Linnebjerg, Jannie Fries; Lorentsen, Svein‐Håkon; Madeiros, Jeremy; Magnusdottir, Ellen; Mallory, Mark L.; McFarlane Tranquilla, Laura; Merkel, Flemming R.; Militão, Teresa; Moe, Børge; Montevecchi, William A.; Morera‐Pujol, Virginia; Mosbech, Anders; Neves, Verónica; Newell, Mark A.; Olsen, Bergur; Paiva, Vitor H.; Peter, Hans‐Ulrich; Petersen, Aevar; Phillips, Richard A.; Ramírez, Iván; Ramos, Jaime A.; Ramos, Raül; Ronconi, Robert A.; Ryan, Peter G.; Schmidt, Niels Martin; Sigurðsson, Ingvar A.; Sittler, Benoît; Steen, Harald; Stenhouse, Iain J.; Strøm, Hallvard; Systad, Geir H. R.; Thompson, Paul; Thórarinsson, Thorkell L.; Bemmelen, Rob S.A.; Wanless, Sarah; Zino, Francis; Dias, Maria P.The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population data, we mapped the abundance and diversity of 21 seabird species. This revealed a major hotspot associated with a discrete area of the subpolar frontal zone, used annually by 2.9–5 million seabirds from ≥56 colonies in the Atlantic: the first time this magnitude of seabird concentrations has been documented in the high seas. The hotspot is temporally stable and amenable to site-based conservation and is under consideration as a marine protected area by the OSPAR Commission. Protection could help mitigate current and future threats facing species in the area. Overall, our approach provides an exemplar data-driven pathway for future conservation efforts on the high seas.
- Oceanic seabirds chase tropical cyclonesPublication . Ventura, Francesco; Sander, Neele; Catry, Paulo; Wakefield, Ewan; De Pascalis, Federico; Richardson, Philip L; Granadeiro, José P.; Silva, Monica C.; Ummenhofer, Caroline C.In late summer and autumn, the passage of intense tropical cyclones can profoundly perturb oceanic and coastal ecosystems. Direct negative effects on individuals and marine communities can be dramatic, especially in the coastal zone,1–4 but cyclones can also enhance pelagic primary and secondary production.5–9 However, cyclone impacts on open ocean marine life remain poorly understood. Here, we investigate their effects on the foraging movements of a wide-ranging higher predator, the Desertas petrel (Pterodroma deserta), in the mid-latitude North Atlantic during hurricane season. Contrary to previously studied pelagic seabirds in tropical and mid-latitude regions,10,11 Desertas petrels did not avoid cyclones by altering course, nor did they seek calmer conditions within the cyclone eye. Approximately one-third of petrels tracked from their breeding colony interacted with approaching cyclones. Upon encountering strong winds, the birds reduced ground speed, likely by spending less time in flight. A quarter of birds followed cyclone wakes for days and over thousands of kilometers, a behavior documented here for the first time. Within these wakes, tailwind support was higher than along alternative routes. Furthermore, at the mesoscale (hours–weeks and hundreds of kilometers), sea surface temperature dropped and surface chlorophyll sharply increased, suggesting direct effects on ocean stratification, primary production, and therefore presumably prey abundance and accessibility for surface-feeding petrels. We therefore hypothesize that cyclone wakes provide both predictably favorable wind conditions and foraging opportunities. As such, cyclones may have positive net effects on the demography of many mid-latitude pelagic seabirds and, likely, other marine top-predators.
- Combining survey and remotely sensed environmental data to estimate the habitat associations, abundance and distribution of breeding thin-billed prions Pachyptila belcheri and Wilson’s storm-petrels Oceanites oceanicus on a South Atlantic tussac islandPublication . Stokes, Allan W.; Catry, Paulo; Matthiopoulos, Jason; Boldenow, Megan; Clark, T. J.; Guest, Amy; Marengo, Ilaria; Wakefield, EwanSmall petrels are the most abundant seabirds in the Southern Ocean. However, because they breed in burrows on remote and often densely vegetated islands, their colony sizes and conservation status remain poorly known. To estimate the abundance of these species on Bird Island in the Falkland archipelago, we systematically surveyed their breeding burrow density and occupancy across this near-pristine tussac (Poa flabellata)-covered island. By modelling burrow density as functions of topography and Sentinel 2 satellite-derived Normalised Difference Vegetation Index data, we inferred habitat associations and predicted burrow abundance of the commonest species—Thin-billed Prions (Pachyptila belcheri) and Wilson’s Storm-petrels (Oceanites oceanicus). We estimate that there are 631,000 Thin-billed Prion burrows on the island (95% CI 496,000–904,000 burrows). Assuming that burrow occupancy lies between 12 and 97%, this equates to around 76,000–612,000 breeding pairs, making Bird Island the second or third largest P. belcheri colony in the world, holding approximately 3–27% of the species’ breeding population. We estimate that 8200–9800 (95% CI 5,200–18,300 pairs) pairs of Wilson’s Storm-petrels also breed on the island. Notably, the latter burrowed predominantly under and within tussac pedestals, whereas they are usually assumed to breed in rock cavities. Thin-billed Prions are declining in the Kerguelen archipelago, but their population trends in the Falklands are unknown. Given the wide confidence intervals around our own and other population estimates for these cryptic species, we recommend that their populations should be monitored regularly, at multiple sites.
- Important At-Sea areas of colonial breeding marine predators on the Southern Patagonian ShelfPublication . Baylis, Matthew; Tierney, Megan; Orben, Rachael; Evans, Victoria Warwick; Wakefield, Ewan; Grecian, William James; Trathan, Phil; Reisinger, Ryan R.; Ratcliffe, Norman Arthur; Croxall, John; Campioni, Letizia; Catry, Paulo; Crofts, Sarah; Boersma, P. Dee; Galimberti, Filippo; Granadeiro, José Pédro; Handley, Jonathan; Hayes, Sean; Hedd, April; Masello, Juan; Montevecchi, William A.; Pütz, Klemens; Quillfeldt, Petra; Rebstock, Ginger A.; Sanvito, Simona; Staniland, Iain; Brickle, PaulThe Patagonian Shelf Large Marine Ecosystem supports high levels of biodiversity and endemism and is one of the most productive marine ecosystems in the world. Despite the important role marine predators play in structuring the ecosystems, areas of high diversity where multiple predators congregate remains poorly known on the Patagonian Shelf. Here, we used biotelemetry and biologging tags to track the movements of six seabird species and three pinniped species breeding at the Falkland Islands. Using Generalized Additive Models, we then modelled these animals' use of space as functions of dynamic and static environmental indices that described their habitat. Based on these models, we mapped the predicted distribution of animals from both sampled and unsampled colonies and thereby identified areas where multiple species were likely to overlap at sea. Maximum foraging trip distance ranged from 79 to 1,325 km. However, most of the 1,891 foraging trips by 686 animals were restricted to the Patagonian Shelf and shelf slope, which highlighted a preference for these habitats. Of the seven candidate explanatory covariates used to predict distribution, distance from the colony was retained in models for all species and negatively affected the probability of occurrence. Predicted overlap among species was highest on the Patagonian Shelf around the Falkland Islands and the Burdwood Bank. The predicted area of overlap is consistent with areas that are also important habitat for marine predators migrating from distant breeding locations. Our findings provide comprehensive multi-species predictions for some of the largest marine predator populations on the Patagonian Shelf, which will contribute to future marine spatial planning initiatives. Crucially, our findings highlight that spatially explicit conservation measures are likely to benefit multiple species, while threats are likely to impact multiple species.
- Changes and consistencies in marine and coastal bird numbers on Kidney Island (Falkland Islands) over half a centuryPublication . Catry, Paulo X; Clark, T. J.; Crofts, Sarah; Stanworth, Andrew J.; Wakefield, EwanDetecting change is necessary for effective ecosystem management, yet temporal data on key ecosystem components are lacking for many polar and subpolar regions. For example, although the Falkland Islands hosts internationally important marine and coastal bird populations, few of these were surveyed until the late twentieth century. The avifauna of one small island, Kidney Island, was surveyed between 1958 and 1963, however. This typical tussac-covered island has remained free of non-native predators, so changes in its avifauna may reflect variation in the wider marine environment. In order to obtain a rare snapshot of such changes, we re-surveyed Kidney Island’s avifauna between 2017 and 2019, counting either individuals, breeding pairs or nest sites of marine and coastal waterbirds. Waterfowl, waders and cormorant populations were broadly stable, but several populations showed profound differences over the six decades between surveys. In particular, Southern Rockhopper penguins Eudyptes chrysocome collapsed from > 3000 to 200 pairs, while Sooty Shearwaters Ardenna grisea expanded by two orders of magnitude. Due to its isolation and tight fisheries management, the Falklands marine environment is assumed to be relatively pristine. Our limited results suggest that sufficient changes may nevertheless have occurred in the region’s marine ecosystem to have detectable impacts on breeding seabirds.
- Overlap between marine predators and proposed Marine Managed Areas on the Patagonian ShelfPublication . Baylis, Alastair; Lecea, Ander M. De; Tierney, Megan; Orben, Rachael; Ratcliffe, Norman; Wakefield, Ewan; Catry, Paulo; Campioni, Letizia; Costa, Marina; Boersma, P. Dee; Galimberti, Filippo; Granadeiro, José P.; Masello, Juan; Puetz, Klemens; Quillfeldt, Petra; Rebstock, Ria; Sanvito, Simona; Staniland, Iain; Brickle, PaulAbstract. Static (fixed-boundary) protected areas are key ocean conservation strategies, and marine higher predator distribution data can play a leading role toward identifying areas for conservation action. The Falkland Islands are a globally significant site for colonial breeding marine higher predators (i.e., seabirds and pinnipeds). However, overlap between marine predators and Falkland Islands proposed Marine Managed Areas (MMAs) has not been quantified. Hence, to provide information required to make informed decisions regarding the implementation of proposed MMAs, our aims were to objectively assess how the proposed MMA network overlaps with contemporary estimates of marine predator distribution. We collated tracking data (1999–2019) and used a combination of kernel density estimation and model-based predictions of spatial usage to quantify overlap between colonial breeding marine predators and proposed Falkland Islands MMAs. We also identified potential IUCN Key Biodiversity Areas (pKBAs) using (1) kernel density based methods originally designed to identify Important Bird and Biodiversity Areas (IBAs) and (2) habitat preference models. The proposed inshore MMA, which extends three nautical miles from the Falkland Islands, overlapped extensively with areas used by colonial breeding marine predators. This reflects breeding colonies being distributed throughout the Falklands archipelago, and use being high adjacent to colonies due to central-place foraging constraints. Up to 45% of pKBAs identified via kernel density estimation were located within the proposed MMAs. In particular, the proposed Jason Islands Group MMA overlapped with pKBAs for three marine predator species, suggesting it is a KBA hot spot. However, tracking data coverage was incomplete, which biased pKBAs identified using kernel density methods, to colonies tracked. Moreover, delineation of pKBA boundaries were sensitive to the choice of smoothing parameter used in kernel density estimation. Delineation based on habitat model predictions for both sampled and unsampled colonies provided less biased estimates, and revealed 72% of the Falkland Islands Conservation Zone was likely a KBA. However, it may not be practical to consider such a large area for fixed-boundary management. In the context of wide-ranging marine predators, emerging approaches such as dynamic ocean management could complement static management frameworks such as MMAs, and provide protection at relevant spatiotemporal scales.
- Diet of non-breeding leach’s storm-petrels (Hydrobates leucorhous) in the sub-polar frontal zone of the North AtlanticPublication . C. Silva, Monica; Catry, Paulo; Newton, Jason; Nunes, Vera L; Wakefield, EwanABSTRACT: In order to understand the drivers of the distribution and abundance of pelagic seabirds it is necessary to know what they eat, yet there remains little detailed, geo-referenced information on the diets of pelagic seabird. In particular, due to sampling difficulties, information is lacking for non-breeding stages, smaller species, such as storm-petrels, and r· Hydrobatesemote oceanic areas, which may include important diversity hotspots. In this study, we aimed to characterize the trophic ecology of Leach’s storm-petrels foraging in the vicinity of the North Atlantic Current and Evlanov Seamount Marine Protected Area using a combination of survey methods. On a cruise undertaken in June 2017 to characterize the distribution and ecology of seabirds in the region, nineteen Leach’s storm-petrels were caught, sampled and released unharmed. Regurgitations and faecal samples were collected, as well as blood and feather tissues for stable isotope analyses. Of the 12 males, 6 females and 1 unsexed bird, 84% were in active flight feather moult, suggesting they were non-breeders. Prey species, assayed via molecular metabarcoding, were dominated by mesopelagic fish, principally lanternfishes (Myctophidae) and hatchetfishes (Sternoptychidae), but also included cephalopods and crustaceans. Additionally, almost half of the birds had microplastics in their regurgitates. Stable isotopic ratios did not differ significantly between sexes. Our results, combined with those of previous studies, suggest that within the oceanic North Atlantic, Leach’s storm-petrels feed at a similar trophic level to much larger seabirds, targeting mesopelagic fishes that are a key component of the North Atlantic pelagic food web.
- The role of seabird guano in maintaining North Atlantic summertime productivityPublication . Browning, Thomas J.; Al-Hashem, Ali A.; Achterberg, Eric P.; Carvalho, Paloma C.; Catry, Paulo; Matthiopoulos, Jason; Miller, Julie A.O.; Wakefield, EwanNutrients supplied via seabird guano increase primary production in some coastal ecosystems. A similar process may occur in the open ocean. To investigate this directly, we first measured bulk and leachable nutrient concentrations in guano sampled in the North Atlantic. We found that guano was strongly enriched in phosphorus, which was released as phosphate in solution. Nitrogen release was dominated by reduced forms (ammonium and urea) whilst release of nitrate was relatively low. A range of trace elements, including the micronutrient iron, were released. Using in-situ bioassays, we then showed that supply of fresh guano to ambient seawater increases phytoplankton biomass and photochemical efficiencies. Based on these results, modelled seabird distributions, and known defecation rates, we estimate that on annual scales guano is a minor source of nutrients for the surface North Atlantic. However, on shorter timescales in late spring/summer it could be much more important: Estimates of upper-level depositions of phosphorus by seabirds were three orders of magnitude higher than modelled aerosol deposition and comparable to diffusion from deeper waters.