New publication on gulls and landfills!

Delgado, S., Tavecchia, G., Herrero, A. et al. Model projections reveal a recent decrease in a yellow-legged gull population after landfill closure. Eur J Wildl Res 69, 99 (2023). https://doi.org/10.1007/s10344-023-01723-w

 In a shell: The study reveals that the closure of local landfills leads to a decline in survival rates, especially in younger birds, ultimately causing a population decrease with continuing consequences.

Abstract: The food available in open-air landfills, one of the most common predictable anthropogenic food subsidies (PAFS), can have a profound impact on animal biodiversity. Understanding how and to what extent PAFS affect wildlife is crucial for a sustainable management of resources. Most large gulls behave as opportunistic foragers and constitute a good avian model to analyze the effect of PAFS reduction on animal populations. 

Using individual data from a yellow-legged gull population of the Basque coast (northern Iberia) collected over a 15-year period, we estimated survival and reproductive parameters and used them to parameterize an age-structured population model to explore the effects of the local landfill closure. Local survival probability declined with time as a consequence of the progressive closure of the local landfill sites. The top-ranked models included a quadratic function of time, suggesting an acceleration of mortality during the later years, especially in juveniles, while survival in adults was linear. An effect more pronounced in first year birds than in older birds. Population models predict a decrease of the population and confirmed a greater sensitivity of the population growth rate to adult survival probability. Overall, our results suggest that the reduced carrying capacity of the system resulted after landfill closures have caused a population decline which is expected to continue in the near future.

New publication on plastic and Storm Petrels!

Clark, B.L., Carneiro, A.P.B., [...] Sanz-Aguilar, A.,[...] Rotger, A., et al. Global assessment of marine plastic exposure risk for oceanic birds. Nat Commun 14, 3665 (2023). https://doi.org/10.1038/s41467-023-38900-z

 In a shell: Unevenly distributed plastic pollution in the ocean can impact on vulnerable marine organisms, particularly petrel seabirds. High exposed zones were found in the Mediterranean, Black Seas, Pacific oceans, South Atlantic, and Indian Ocean. We emphasize the need for international collaboration to mitigate these risks.

Photo: Y.Muzika - eBird

Abstract: Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species.  Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

 

 

 

New Publications on prospection!

Kralj, J., Ponchon, A., [...], Igual, J.-M.,[...], Tavecchia, G. [...] 2023.Active breeding seabirds prospect alternative breeding colonies. Oecologia .h ttps://doi.org/10.1007/s00442-023-05331-y

 Abstract:Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Prospecting in active breeders occurred in 85.7% of studied species, across 61.3% of sampled populations. 

Prospecting was more common in populations with frequent inter-annual changes of breeding sites and among females. These results contradict theoretical models which predict that prospecting is expected to evolve in relatively predictable and stable environments. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and understand the consequences of prospecting on fitness at the individual and population level.

"La Caixa" Foundation Fellowships. Apply and join the GEDA!

Incoming call for  INPhINIT Doctoral Fellowship ("LA CAIXA" Foundation) !! 

 

Are you interested in obtaining a Ph.D. on seabirds ecology ? The La Caixa Foundation grants 65 fellowships for talented early-stage researchers of any nationality to pursue their PhD studies in Spain or Portugal.  Apply at   https://fundacionlacaixa.org/en/inphinit-doctoral-fellowships-call and select our project. Find our project on seabirds (here) and join the GEDAi

Research Project / Research Group Description

Seabirds are in rapid decline worldwide, but the relative importance of the multiple threats to their populations is not always clear, nor the birds’ response to current global changes.  As top-predators their behavior, dynamics and life-history strategy reflect ocean state and condition and their decline is showing that the marine ecosystems is changing. 

Photo: Victor Paris

The research project aims to investigate the life-history strategy of seabirds under the current chemo-physical changes of the ocean. The project will take advantage of the long term monitoring databases collected by the team and the data collected by GPS and GLS devices to follow birds during their foraging movements and migratory routes. It will focus on two species of conservation interest, belonging to the order of Procellariformes, the European storm petrel Hydrobates pelagicus and the Scopoli’s shearwater Calonectris diomedea. Birds will be studied in the Balearic archipelago and Alicante region (Eastern Spain). The deployment of tracking devices will allow to investigate the individual and the species-specific movements in order to detect the important foraging and overwinter areas to help policy makers to reduce the threats to their populations.

 If you need more information on the project: g.tavecchia-at-uib.es

Apply here!!

New Publication on seabird egg volume !

Real, E., Oro, D., Bertolero, A., Igual, J.M., Sanz-Aguilar, A., Genovart, M., Hidalgo, M., Tavecchia,G. 2022. It’s not all abundance: Detectability and accessibility of food also explain breeding investment in long-lived marine animals. PLoS One

 Summary: Large-scale climatic indices are extensively used as predictors of ecological processes, but the mechanisms and the spatio-temporal scales at which climatic indices influence these processes are often speculative. Here, we use long-term data to evaluate how a measure of individual breeding investment (the egg volume) of three long-lived and long-distance-migrating seabirds is influenced by i) a large-scale climatic index (the North Atlantic Oscillation) and ii) local-scale variables (food abundance, foraging conditions, and competition). Winter values of the North Atlantic Oscillation did not correlate with local-scale variables measured in spring, but surprisingly, both had a high predictive power of the temporal variability of the egg volume in the three study species, even though they have different life-history strategies. 

The importance of the winter North Atlantic Oscillation suggests carry-over effects of winter conditions on subsequent breeding investment. Interestingly, the most important local-scale variables measured in spring were associated with food detectability (foraging conditions) and the factors influencing its accessibility (foraging conditions and competition by density-dependence). Large-scale climatic indices may work better as predictors of foraging conditions when organisms perform long distance migrations, while local-scale variables are more appropriate when foraging areas are more restricted (e.g. during the breeding season). Contrary to what is commonly assumed, food abundance does not directly translate into food intake and its detectability and accessibility should be considered in the study of food-related ecological processes.

ERASMUS+ with the GEDA-i !

Sofia Bolumar Rosa, from the "Dipartimento di Scienze della Vita e Biologia dei Sistemi" of the University of Turin is joining out team within the frame of the ERASMUS+ program. She will be working on the ecology of seabirds and join our fieldwork activities in the Balearic Archipelago. Welcome Sofia!

Seabirds on the news!

Photo: Victor Paris

 J.-M. Igual wrote an overview of what we know about seabirds, what has been done and about the actions that should be undertaken for their conservation. He resumes in few lines his thirty-year experience working with these amazing birds. Read the full text (in spanish) here

 

 

Master Thesis with the GEDA

Simon Coroller, from the University of La Rochelle, arrived today to begin his Master Thesis within the GEDA during 2020. Simon will investigate the resilience of seabird populations to natural and human-caused perturbations. Welcome Simon!

Upcoming Conference at the University of Valencia

GEDA was invited to present a conference at the University of Valencia on seabird survival Thursday the 19th of September 2019.

New Publication on population dynamics of Audouin's Gull !

Genovart, M., Oro, D. and Tenan, S. 2018. Immature survival, fertility, and density dependence drive global population dynamics in a long‐lived species. Ecology, https://doi.org/10.1002/ecy.2515

Abstract: Disentangling the influence of demographic parameters and the role of density dependence on species’ population dynamics is a challenge, especially when fractions of the population are unobservable. Additionally, due to the difficulty of gathering data at large spatial scales, most studies ignore the global dynamic of a species, which would integrate local heterogeneity dynamics and remove the noise of dispersal. We developed an integrated population model (IPM) at a global scale to disentangle the main demographic drivers of population dynamics in a long‐lived species.

We used 28 yr of Audouin's Gull demographic data encompassing 69 local patches (comprising 90% of the world population). Importantly, we took into account the unobservable fraction of non‐breeders and also assessed the strength of density dependence for this fraction of the population. As predicted by life histories of long‐lived organisms, temporal random variation in survival was highest for immature individuals (1.326, 95% credible interval [CRI] 1.290–1.940) and lowest for adults (0.499, 95% CRI 0.487–0.720). Large temporal fluctuations in the probability of taking a reproductive sabbatical would partly explain the consistency in adult survival, with individuals most likely refraining from breeding when environmental conditions were harsh. Immature survival and fertility were the main drivers of population dynamics during the study period (r² = 0.83, 0.77–0.87 and 0.73, 0.63–0.79, respectively). We found strong evidence of density dependence, not only due to the number of breeders (r² = −0.34, −0.43 to −0.24) but also due to individuals on sabbatical (r² = −0.18, −0.33 to −0.01). From a conservation point of view, the species shows a 5% annual global decrease during the last 10 years, and we propose an update of its conservation status. Even though population dynamics of long‐lived organisms are very sensitive to changes in adult survival, we show here that, in the absence of strong environmental perturbations affecting this vital rate, fluctuations in population density are mainly driven by variations in survival of immature individuals and fertility. Integrated models based on long‐term monitoring at a global scale may enhance our ecological and evolutionary understanding of how demographic drivers influence population dynamics.

New Publication on seabirds and fishery discards!

Real, E., Tavecchia, G., Genovart, M., Sanz-Aguilar, A., Payo-Payo, A. and Oro, D. 2018 Discard-ban policies can help improve our understanding of the ecological role of food availability to seabirds Scientia Marina. Special Issue. Discards regulation vs Mediterranean fisheries sustainability. M. Demestre and F. Maynou (eds.) doi: 10.3989/scimar.04746.10A

Abstract: Discards from fisheries are the most important predictable anthropogenic food subsidies (PAFS) that are being incorporated into marine ecosystems. Changes on their availability and predictability can help us to understand the role that food availability (i.e. an important indicator of the carrying capacity) plays at different ecological levels, from individual fitness to community dynamic and ecosystem functioning. For several reasons, seabirds are an excellent model for

Photo: J. Bos

evaluating the ecological effects arising from a lack of discards: 1) they are one of the most important discard scavengers, 2) they are easy to monitor and 3) they are apical predators are globally distributed, which makes them suitable health indicators of ecosystems. Here we review the existing information on seabird-discard interactions to identify the main knowledge gaps and propose new challenges for improving our understanding of the general role of food availability. We conclude that the new policies on the ban of fishery discards that are being progressively implemented in the European Union, Norway, Chile and New Zealand offer a suitable experimental scenario for improving our understanding of how a large decrease in the carrying capacity may alter demographic parameters such as survival, dispersal and reproduction, the resilience of populations against perturbations and the role of individual specialization in the foraging process.

GEDA at "Meteo y Natura"

Ana Sanz-Aguilar explains the results from a meta-analysis investigating whether seabirds adapt their breeding phenology to the recent warming of the sea temperature. The study used the long-term data of nearly 200 seabird populations. Among them those studied by the GEDA. The full interview can be viewed here (at min 4:30)

New publication on seabird phenology and climate change !

Keogan, K., Daunt, F. [...], Igual, J.M. [...], Sanz-Aguilar, A. [...], Lewis, S. 2018. Global phenological insensitivity to shifting ocean temperatures among seabirds. Nature Climatre Change 8,313–318 doi:10.1038/s41558-018-0115-z

Photo: from CEHseabirds

Abstract: Reproductive timing in many taxa plays a key role in determining breeding productivity, and is often sensitive to climatic conditions. Current climate change may alter the timing of breeding at different rates across trophic levels, potentially resulting in temporal mismatch between the resource requirements of predators and their prey. This is of particular concern for higher-trophic-level organisms, whose longer generation times confer a lower rate of evolutionary rescue than primary producers or consumers. However, the disconnection between studies of ecological change in marine systems makes it difficult to detect general changes in the timing of reproduction. Here, we use a comprehensive meta-analysis of 209 phenological time series from 145 breeding populations to show that, on average, seabird populations worldwide have not adjusted their breeding seasons over time (−0.020 days yr⁻¹) or in response to sea surface temperature (SST) (−0.272 days °C⁻¹) between 1952 and 2015. However, marked between-year variation in timing observed in resident species and some Pelecaniformes and Suliformes (cormorants, gannets and boobies) may imply that timing, in some cases, is affected by unmeasured environmental conditions. This limited temperature-mediated plasticity of reproductive timing in seabirds potentially makes these top predators highly vulnerable to future mismatch with lower-trophic-level resources.

GEDA at the Seabird Group Conference!

The next Seabird Group Conference at the University of  Liverpool the 3-6^th September 2018 will have A. Sanz-Aguilar among the keynotes speakers. We will keep you posted. 
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New publications on seabirds and terrestrial predators !

Payo-Payo, A., Sanz-Aguilar, A., Genovart, M., Bertolero, A., Piccardo, J., Camps, D., Ruiz-Olmo, J, and Oro, D. 2018  Predatorarrival elicits differential dispersal, change in age structure andreproductive performance in a prey population Sceintific Report doi:10.1038/s41598-018-20333-0

Abstract. Predators are an important ecological and evolutionary force shaping prey population dynamics. Ecologists have extensively assessed the lethal effects of invasive predators on prey populations.However, the role of non-lethal effects, such as physiological stress or behavioural responses like dispersal, has been comparatively overlooked and their potential population effects remain obscure. Over the last 23 years, we developed a mark-recapture program for the Audouin’s gull and an intensive carnivore monitoring program to assess how the appearance and invasion of the study site by carnivores affects population dynamics. We evaluate changes in turnover of discrete breeding patches within the colony, age structure and breeding performance.

Photo: en-wikipedia.org

Photo e.wikipedia.com

Once carnivores entered the colony, the number of occupied patches increased, indicating a higher patch turnover. Breeders responded by moving to areas less accessible to carnivores. More importantly, the presence of carnivores caused differential (and density-independent) breeding dispersal: experienced, better-performing breeders were more likely to leave the colony than younger breeders. This differential dispersal modified the age structure and reduced the reproductive performance of the population. Our results confirm the importance experience in the study of populations. The role of differential dispersal for animal population dynamics might be more important than previously thought, especially under scenarios of global change.

New Publication on seabird mortality and fishery !

Genovart M, Bécares J, Igual J-M, Martinez-Abrain, A., Escandell, R., Sánchez, A., Rodriguez, R., Arcos, J.-M., Oro, D. 2018 Differentialadult survival at close seabird colonies: The importance of spatial foragingsegregation and bycatch risk during the breeding season. Global Change Biology.00:1–13. https://doi.org/10.1111/gcb.13997

Abstract: Marine megafauna, including seabirds, are critically affected by fisheries bycatch. However, bycatch risk may differ on temporal and spatial scales due to the uneven distribution and effort of fleets operating different fishing gear, and to focal species distribution and foraging behavior. Scopoli's shearwater Calonectris diomedea is a long-lived seabird that experiences high bycatch rates in longline fisheries and strong population-level impacts due to this type of anthropogenic mortality. Analyzing a long-term dataset on individual monitoring, we compared adult survival (by means of multi-event capture–recapture models) among three close predator-free Mediterranean colonies of the species. Unexpectedly for a long-lived organism, adult survival varied among colonies. We explored potential causes of this differential survival by (1) measuring egg volume as a proxy of food availability and parental condition; (2) building a specific longline bycatch risk map for the species; and (3) assessing the distribution patterns of breeding birds from the three study colonies via GPS tracking. Egg volume was very similar between colonies over time, suggesting that environmental variability related to habitat foraging suitability was not the main cause of differential survival. On the other hand, differences in foraging movements among individuals from the three colonies expose them to differential mortality risk, which likely influenced the observed differences in adult survival. The overlap of information obtained by the generation of specific bycatch risk maps, the quantification of population demographic parameters, and the foraging spatial analysis should inform managers about differential sensitivity to the anthropogenic impact at mesoscale level and guide decisions depending on the spatial configuration of local populations. The approach would apply and should be considered in any species where foraging distribution is colony-specific and mortality risk varies spatially. 

You can see more information in the Press Note by IMEDEA here (in Spanish)

New Publication on immune response in seabirds

Garnier, R., Ramos, R. Sanz-Aguilar, A., Poisbleau, M., Weimerskirch, H., Burthe, A., Tornos, J. and Boulinier, T., 2017. Interpreting ELISA analyses from wild animal samples: Somerecurrent issues and solutions Funcitonal Ecology, 31, 2255–2262 .DOI: 10.1111/1365-2435.12942

Abstract
1.Many studies in disease and ecological immunology rely on the use of assays that quantify the amount of specific antibodies (immunoglobulin) in samples. Enzymelinked immunosorbent assays (ELISAs) are increasingly used in ecology due to their availability for a broad array of antigens and the limited amount of sampling material they require. Two recurrent methodological issues are nevertheless faced by researchers: (1) the limited availability of immunological assays and reagents developed for non-model species, and (2) the statistical determination of the cut-off threshold used to distinguish individual samples that are likely to have or not to have antibodies against a specific antigen.

Photo: Victor París

2. Here, we outline two solutions to deal with these issues. First, we show that implementing two assays with differing detection methods can help validate the use of reagents, such as antibodies, in species different from their intended target. We illustrate this by comparing the quantification of  specific vaccinal antibodies against Newcastle disease virus (NDV) using two ELISA approaches in four seabird species (Cory’s shearwater, European shag, European storm petrel and Southern rockhopper penguin).
3. Second, we provide a simple way to determine from the distribution of ELISA values whether the assayed samples are likely to be made of a single group of individuals (likely negative) or of two groups of individuals (negative and positive). We illustrate the use of this approach with two independent datasets: NDV antibody levels following vaccination and anti-Borrelia antibody levels following natural exposure.
4. The practical implementation of these methodological approaches could provide a way to efficiently apply ELISAs and other immune-based assays to address questions in the growing fields of ecological immunology and disease ecology.