New Publication on Shearwaters!

Genovart, M., Ramos, R., Igual, J.M., Sanz-Aguilar, A., Tavecchia, G., Rotger, A., Militão, T., Vicente-Sastre, D., Garcia-Urdangarin, B., Pradel, R., González-Solís, J. and Oro, D. (2024), Individual Choices of Wintering Areas Drive Adult Survival Heterogeneity in a Long-Lived Seabird. Ecol Evol, 14: e70675. https://doi.org/10.1002/ece3.70675

In a shell:Wintering area preferences and environmental variability drive survival heterogeneity in long-distance migratory seabirds.

 Abstract:Seasonal migration has evolved as an adaptation for exploiting peaks of resource abundance and avoiding unfavourable climatic conditions. Differential migratory strategies and choices of wintering areas by long-distance migratory species may impose varying selective pressures and mortality risks with fitness consequences. Recently developed tracking technologies allow wintering movements of migratory species to be studied. However, these technologies typically involve a limited number of tracked individuals, which gives low statistical power for any robust estimate of survival probabilities. Additionally, when utilising geolocators, data become accessible only upon individual recapture, presenting a potential source of bias. We used multievent modelling to include information of 147 identified wintering tracks in the analysis of 1104 long-term individual capture histories (2000–2022) of migratory seabird Calonectris diomedea and then test if individual preferences for wintering areas may drive heterogeneity in adult survival. 

Photo: P. Arcos

We also examined individual fidelity to wintering areas and tested if climatic and oceanographic conditions, as represented by the wNAO and SOI climatic indices, influenced survival and fidelity. The probability of fidelity to a wintering area was ca. 0.79. Annual changes between areas were influenced by environmental variability driven by the wNAO. Survival probability was influenced by the SOI and differed between wintering areas; these differences coupled with high wintering site fidelity, generated individual heterogeneity in adult survival. Our study reveals that, over the last two decades, some individuals wintered in less suitable areas, with nonnegligible consequences on adult survival, the parameter to which the population growth rate is most sensitive in long-lived species. Winter oceanographic conditions such as stormy weather or the proximity to upwellings probably play a relevant role in driving survival heterogeneity. Further research is needed to enhance our understanding of how the interlinked effects of climate, local selective pressures and individual condition shape population dynamics in migratory species.

 

New publication on European Storm Petrel foraging areas!

 Bolumar Roda, S., Rotger, A., santangeli A., Tavecchia, G., Sola, A., [...] and Sanz-Aguilar, A., 2024. Coping with ocean dynamics: Foraging strategy and implications for conservation of a small petrel. Biological Conservation, 302: 110913 https://doi.org/10.1016/j.biocon.2024.110913  

 In a shell: The study used GPS tracking and oceanographic data to model foraging habitats of European Storm-petrels in the Western Mediterranean, identifying key regions influenced by dynamic oceanographic features that largely fall outside Marine Protected Areas, highlighting the need for conservation measures.

Abstract: Seabirds' distribution is generally influenced by the ecological dynamics of marine environments. Understanding how oceanographic features shape seabird foraging behaviour remains a challenge. We combined GPS tracking locations (n = 2883) of 39 European Storm-petrels (Hydrobates pelagicus) breeding in four West Mediterranean colonies during incubation over multiple years (2019–2021) with near-real-time remotely sensed oceanographic drivers. We model habitat selection using GPS tracking data from one colony, Benidorm Island, and use data from other three colonies for validation.

Photo: V. Paris

We show that suitable foraging areas are strongly characterized by low sea surface temperature, high chlorophyll concentration and eddy kinetic energy. Based on this model, we predict habitat suitability maps for 2018–2022. Cross-validation using data from the other three colonies highlights that the identified suitable areas are universally applicable across other Storm-petrel colonies in the Western Mediterranean. We identified the Alboran Sea, the North African coast, the Gulf of Lion and the Ebro River Delta as the most suitable regions. These areas are characterized by high mesoscale variability, suggesting the importance of dynamic oceanographic features in determining foraging habitat. Identified main foraging areas are largely outside of Marine Protected Areas (MPAs), thus vulnerable to anthropogenic threats such as overfishing and energy infrastructure development. The critical foraging areas identified for this species underscore the need to expand the MPA network and/or adopt sustainable resource extraction in unprotected marine areas.