Research Group and project information 

The use of gulls as sentinels to monitor environmental and public health: In the current context of global and human-induced changes, it is essential to efficiently track and anticipate the dynamics of infectious agents and pollutants in the environment to potentially be able to limit their impact on biodiversity and public health. To properly decipher the processes underlying the complex dynamics and spread of these detrimental agents, we often require long-time series of sampling and assessments at multiple sites. Abundant free-living top predators in close contact with human activities are often suggested as ideal biomonitoring candidates (i.e., sentinels) as they integrate, predictably, infectious agents and pollutant levels along the food chains they rely on. Given the global distribution of large gulls that currently links natural and urban settings, we will evaluate their long-term potential as sentinel species in the Mediterranean region, and will determine the processes involved in the exposure to infectious agents and pollutants in this system. Specifically, we aim: (1) to assess the spatial and trophic ecology of several gulls throughout their annual cycle, and, (2) to relate such ecologies to specific pathogen prevalences (eco-epidemiology) and pollutant burdens (eco-toxicology) of these gulls.

Gulls are well-known opportunistic species that feed abundantly on refuses from landfills and discards from fishery activities. Currently, both resources are targeted by: the EU Landfill Directive promoting the closure of open-air landfills and implemented since 2000, and the EU Common Fisheries Policy banning fishery discard from vessels and to be fully implemented in 2019. These Plans aim to reduce the availability of human food subsidies to scavenger species, such as the Yellow-legged gull (YLG). Thus, assessing past and current spatial and trophic ecology of YLGthroughout the annual cycle and at a metapopulation scale represents a key knowledge to foresee potential changes in its population dynamics derived from the inaccessibility to anthropogenic resources. Additionally, by assessing this knowledge not only on breeding adults of YLG sampled along the western Mediterranean and North Atlantic basins, but also on chicks and fledglings of the same species as well as on other sympatric gulls, we aim to gain robust evidences of the trophic ecology of most gull species year round. 

This project proposes combining field sampling (in up to 25 breeding sites of the western Mediterranean and North Atlantic basins), detection methods (GPS-tracking, stable isotope analysis in diverse avian tissues, bacterial identification, quantification of specific antibody and pollutant levels), analytical and modelling approaches relying on previous (from long-term monitoring programs and museum specimens) and current surveys based on different samples and individuals (eggs, chicks, fledglings, and adult breeders) of two species of gulls. First, we expect to report (i) temporal and spatial gradients in the use of dietary resources of gulls along the sampled area. Second, we expect to (ii) map exposure of gulls to several infectious agents and pollutants at broad and regional spatial scales, and (iii) test whether gull habitat use and diets are associated with their level of exposure to these detrimental agents. Finally, our sampling strategy, i.e., long-term, metapopulation, and multispecies, as well as our multidisciplinary analytical and modelling protocols will provide valuable information to explore eco-epidemiological and eco-toxicological patterns and to infer robustly their underlying processes.