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- Corrigendum to “Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identification” [Biol. Conserv. 281 (2023) 109994]Publication . Beal, Martin; Catry, Paulo; Phillips, Richard A.; Oppel, Steffen; Arnould, John P.Y.; Bogdanova, Maria; Bolton, Mark; Carneiro, Ana P.B.; Clatterbuck, Corey; Conners, Melinda; Daunt, Francis; Delord, Karine; Elliott, Kyle; Fromant, Aymeric; Granadeiro, José P.; Green, Jonathan A.; Halsey, Lewis; Hamer, Keith C.; Ito, Motohiro; Jeavons, Ruth; Kim, Jeong-Hoon; Kokubun, Nobuo; Koyama, Shiho; Lane, Jude V; Lee, Won Young; Matsumoto, Sakiko; Orben, Rachael; Owen, Ellie; Paiva, Vitor H.; Patterson, Allison; Pollock, Christopher J.; Ramos, Jaime A.; Sagar, Paul; Sato, Katsufumi; Shaffer, Scott; Soanes, Louise; Takahashi, Akinori; Thompson, David; Thorne, Lesley; Torres, Leigh; Watanuki, Yutaka; Waugh, Susan M.; Weimerskirch, Henri; Whelan, Shannon; Yoda, Ken; Xavier, J. C.; Dias, Maria P.Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed areabased conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: − 0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds.
- Monitoring of mercury in the mesopelagic domain of the Pacific and Atlantic oceans using body feathers of Bulwer's petrel as a bioindicatorPublication . Furtado, Ricardo; Granadeiro, José Pedro; Gatt, Marie C.; Rounds, Rachel; Horikoshi, Kazuo; Paiva, Vitor H.; Menezes, Dilia; Pereira, Eduarda; Catry, PauloGlobal mercury pollution has markedly and consistently grown over the past 70 years (although with regional variations in trends) and is a source of major concern. Mercury contamination is particularly prevalent in biota of the mesopelagic layers of the open ocean, but these realms are little studied, and we lack a large scale picture of contamination in living organisms of this region. The Bulwer's petrel Bulweria bulwerii, a species of migratory seabird, is a highly specialised predator of mesopelagic fish and squid, and therefore can be used as a bioindicator for the mesopelagic domain. Mercury accumulated by the birds through diet is excreted into feathers during the moulting process in adults and feather growth in chicks, reflecting contamination in the non-breeding and breeding periods, respectively, and hence the influence of different, largely non-overlapping breeding and non-breeding ranges. We studied mercury in feathers and the trophic position in two colonies from the Atlantic Ocean (Portugal and Cape Verde) and two colonies from the Pacific Ocean (Japan and Hawaii). We found significantly lower levels of mercury in adult and chick samples from the Pacific Ocean compared with samples from the Atlantic Ocean. However, we did not detect differences in trophic position of chicks among colonies and oceans, suggesting that differences in mercury measured in feathers reflect levels of environmental contamination, rather than differences in the structure of the trophic chain in different oceans. We conclude that despite a reduction in mercury levels in the Atlantic in recent decades, mesopelagic organisms in this ocean remain more heavily contaminated than in the Pacific at tropical and subtropical latitudes. We suggest that Bulwer's petrel is a highly suitable species to monitor the global contamination of mercury in the mesopelagic domain.
- Methods to detect spatial biases in tracking studies caused by differential representativeness of individuals, populations and timePublication . Pujol, Virginia Morera; Catry, Paulo; Magalhães, Maria; Peron, Clara; Reyes‐González, José Manuel; Granadeiro, José P.; Militão, Teresa; Dias, Maria P.; Oro, Daniel; Dell'Omo, Giacomo; Müller, Martina; Paiva, Vitor H.; Metzger, Benjamin; Neves, V C; Navarro, Joan; Karris, Georgios; Xirouchakis, Stavros; Cecere, Jacopo G.; Zamora‐López, Antonio; Forero, Manuel G.; Ouni, Ridha; Romdhane, Mohamed Salah; De Felipe, Fernanda; Zajková, Zuzana; Cruz‐Flores, Marta; Grémillet, David; González‐Solís, Jacob; Ramos, RaülAim Over the last decades, the study of movement through tracking data has grown exceeding the expectations of movement ecologists. This has posed new challenges, specifically when using individual tracking data to infer higher-level distributions (e.g. population and species). Sources of variability such as individual site fidelity (ISF), environmental stochasticity over time, and space-use variability across species ranges must be considered, and their effects identified and corrected, to produce accurate estimates of spatial distribution using tracking data. Innovation We developed R functions to detect the effect of these sources of variability in the distribution of animal groups when inferred from individual tracking data. These procedures can be adapted for their use in most tracking datasets and tracking techniques. We demonstrated our procedures with simulated datasets and showed their applicability on a real-world dataset containing 1346 year-round migratory trips from 805 individuals of three closely related seabird species breeding in 34 colonies in the Mediterranean Sea and the Atlantic Ocean, spanning 10 years. We detected an effect of ISF in one of the colonies, but no effect of the environmental stochasticity on the distribution of birds for any of the species. We also identified among-colony variability in nonbreeding space use for one species, with significant effects of population size and longitude. Main conclusions This work provides a useful, much-needed tool for researchers using animal tracking data to model species distributions or establish conservation measures. This methodology may be applied in studies using individual tracking data to accurately infer the distribution of a population or species and support the delineation of important areas for conservation based on tracking data. This step, designed to precede any analysis, has become increasingly relevant with the proliferation of studies using large tracking datasets that has accompanied the globalization process in science driving collaborations and tracking data sharing initiatives.
- Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identificationPublication . Beal, Martin; Catry, Paulo; Phillips, Richard A.; Oppel, Steffen; Arnould, John P.Y.; Bogdanova, Maria I.; Bolton, Mark; Carneiro, Ana P.B.; Clatterbuck, Corey; Conners, Melinda; Daunt, Francis; Delord, Karine; Elliott, Kyle; Fromant, Aymeric; Granadeiro, José P.; Green, Jonathan A.; Halsey, Lewis; Hamer, Keith C.; Ito, Motohiro; Jeavons, Ruth; Kim, Jeong-Hoon; Kokubun, Nobuo; Koyama, Shiho; Lane, Jude V.; Lee, Won Young; Matsumoto, Sakiko; Orben, Rachael A.; Owen, Ellie; Paiva, Vitor H.; Patterson, Allison; Pollock, Christopher J.; Ramos, Jaime A.; Sagar, Paul; Sato, Katsufumi; Shaffer, Scott; Soanes, Louise; Takahashi, Akinori; Thompson, David R.; Thorne, Lesley; Torres, Leigh; Watanuki, Yutaka; Waugh, Susan M.; Weimerskirch, Henri; Whelan, Shannon; Yoda, Ken; Xavier, José C.; Dias, Maria P.Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed areabased conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: − 0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds.