Browsing by Author "Navarro, Joan"
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- Meta-population feeding grounds of Cory's shearwater in the subtropical Atlantic Ocean: implications for the definition of Marine Protected Areas based on tracking studiesPublication . Ramos, Raül; Granadeiro, José Pedro; Rodríguez, Beneharo; Navarro, Joan; Paiva, Vitor H.; Bécares, Juan; Reyes-González, José M.; Fagundes, Isabel; Ruiz, Asunción; Arcos, Pep; González-Solís, Jacob; Catry, PauloAim: Apical pelagic species forage in predictable habitats, and their movements should signal biologically and ecologically significant areas of the marine ecosystem. Several countries are now engaged in identifying these areas based on animal tracking, but this is often limited to a few individuals from one breeding population, which may result in biased portrayals of the key marine habitats. To help identify such foraging areas, we compiled tracking data of a marine top predator from the main breeding colonies in the Central Macaronesia. Location: North-east Atlantic Ocean. Methods: Over seven years, we tracked the foraging movements of Cory’s shearwaters (Calonectris borealis) from several populations during the chick-rearing period using global positioning system and platform terminal transmitter devices. Results: We obtained foraging trips from 174 shearwaters breeding on six important colonies representative of the range occupied in the Macaronesian Archipelagos of Madeira, Salvages and Canaries. Our results show that birds orient and move rapidly towards the closest neritic waters over the African continental shelf. Birds from different colonies show substantial spatial segregation in their foraging grounds but consistently overlap in some specific foraging areas along the Canary Current characterized by high productivity. By weighting the use of foraging grounds according to the size of each study population, we inferred the overall exploitation of such areas. Main: conclusions Our meta-population approach provides a more comprehensive picture of space use from both perspectives: the studied species and the Canary Current system. Foraging grounds consistently used by several populations may not be adequately identified by tracking a single population, and therefore, multiple population tracking studies are needed to properly delineate key conservation areas and inform conservation planning in the marine ecosystem. Finally, we highlight the long-term stability and sustainability of identified foraging areas and propose that countries with geographical jurisdictions over the Canary Current area should work towards multilateral agreements to set management plans for this key marine ecosystem.
- 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.