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Seminari "From satellites to seabirds"

Personal acadèmic
From satellites to seabirds: using oceanographic remote-sensing to investigate seabird responses to climate-driven environmental variability

The structure and functioning of natural communities have evolved in response to predictable patterns of food availability. However, current fast environmental changes are disrupting otherwise tight trophic interactions among species within food webs, with important fitness consequences. These changes are felt stronger in marine systems, which are largely affected by climate driven environmental perturbations. Despite the scale of these perturbations, our understanding of how environmental variability is affecting trophic interaction within marine communities has lagged far behind our knowledge of their impacts on their terrestrial counterparts. In part, this is because changes in key environmental conditions within marine systems are notoriously difficult to trace, thus resulting in considerable uncertainty regarding the spatial and temporal details of such environmental stressors.

Within this scenario, satellite remote-sensing records have emerged as important tools for studying the most recent and striking trends and patterns in both environmental (e.g. sea surface temperature -SST- or ocean currents) and biological (chlorophyll-a concentrations -CHL-; a proxy to phytoplankton biomass) features in the world's oceans. Remarkably, these environmental products are now provided at a high enough spatio-temporal resolution for capturing the large degree of spatial heterogeneity inherent to the marine systems and the short-term variability typical of seasonal environments. The latter, temporal dimension is particularly important when investigating the impacts of environmentally driven trophic disruptions, as climate fluctuations are known to result in phenological shifts, sometimes differently across species and trophic levels.

Little penguins (Eudyptula minor) from the temperate region of Australia have provided one of the first documented examples of a phenological adaption for a marine vertebrate to climate driven changes on seasonal patterns of key environmental conditions at the Southern Hemisphere. By combining long-term (1981-2015) data on the diet, phenology and reproductive performance of little penguins with high-temporal resolution remote-sensing records on SST and CHL, we showed that penguins' phenology has moved forward over the last decades following changes in seasonal patterns of SST (the environmental feature triggering penguin reproduction). In turn, reproductive timing was revealed as an important driver of penguin reproductive performance, as occurs also for the accessibility of penguins to certain prey types whose availability was likely coupled to seasonal patterns in CHL. Finally, changes in local SST stands as the single most essential driver for the contrasting population trends observed for ca. 600 colonies distributed throughout the little penguin entire distribution range (including Australia and New Zealand).

A càrrec de Dr. Francisco Ramírez (investigador del CSIC, EBD)

El dia 9 de gener del 2017 de 15-17h a l'Aula 33. Facultat de Biologia