Thursday, 19 January 2023

GEDA at the VIII Jornades de Medi Ambients 2023

Dr. A. Sanz-Aguilar joined the VII Jornades de Medi Ambients de les Illes Balears (Ibiza). She presented the results of the study of the Yellow legged gull population in Ibiza conducted in 2020-2022. 

Tuesday, 3 January 2023

New publication on Lilford's lizard microbiota!

Baldo L, Tavecchia G, Rotger A, Igual JM, Riera JL. 2023. Insular holobionts: persistence and seasonal plasticity of the Balearic wall lizard (Podarcis lilfordi) gut microbiota. PeerJ 11:e14511

Summary:Background: Integrative studies of animals and associated microbial assemblages (i.e., the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Insular vertebrates provide ideal natural systems to understand patterns of host-gut microbiota coevolution, the resilience and plasticity these microbial communities over temporal and spatial scales, and ultimately their role in the host ecological adaptation.  
Methods:Here we used the endemic Balearic wall lizard Podarcis lilfordi to dissect the drivers of the microbial diversity within and across host allopatric populations/islets. By focusing on three extensively studied populations/islets of Mallorca (Spain) and fecal sampling from individually identified lizards along two years (both in spring and autumn), we sorted out the effect of islet, sex, life stage, year and season on the microbiota composition. We further related microbiota diversity to host genetics, trophic ecology and expected annual metabolic changes. 
Photo: G. Tavecchia

Results:All the three populations showed a remarkable conservation of the major microbial taxonomic profile, while carrying their unique microbial signature at finer level of taxonomic resolution (Amplicon Sequence Variants (ASVs)). Microbiota distances across populations were compatible with both host genetics (based on microsatellites) and trophic niche distances (based on stable isotopes and fecal content). Within populations, a large proportion of ASVs (30–50%) were recurrently found along the four sampling dates. The microbial diversity was strongly marked by seasonality, with no sex effect and a marginal life stage and annual effect. The microbiota showed seasonal fluctuations along the two sampled years, primarily due to changes in the relative abundances of fermentative bacteria (mostly families Lachnospiraceae and Ruminococcaceae), without any major compositional turnover. 
Conclusions:These results support a large resilience of the major compositional aspects of the P. lilfordi gut microbiota over the short-term evolutionary divergence of their host allopatric populations (<10,000 years), but also indicate an undergoing process of parallel diversification of the both host and associated gut microbes. Predictable seasonal dynamics in microbiota diversity suggests a role of microbiota plasticity in the lizards’ metabolic adaptation to their resource-constrained insular environments. Overall, our study supports the need for longitudinal and integrative studies of host and associated microbes in natural systems

Wednesday, 21 December 2022

New publication on climate and sex-ratio!

Santidrián Tomillo, P. 2022 When population-advantageous primary sex ratios are female-biased: changing concepts to facilitate climate change management in sea turtles. Climatic Change 175, 15, doi:

Abstract: Sea turtles have temperature-dependent sex determination. Because females are produced at high temperatures, increasing global temperature may lead to population feminization. Primary sex ratios (PSR) of sea turtle hatchlings are naturally female-biased, but this translates into a more balanced operational sex ratio because male turtles reproduce more often than females. As a consequence, a balanced PSR and the temperature that produces it (pivotal temperature) are of limited use to guide climate mitigation management because an equal PSR may be demographically suboptimal. 

Photo from

Here, I define population-advantageous primary sex ratios (PA-PSR) as the PSR that will tend to be in equilibrium in a population and that will result in balanced operational sex ratios; I then estimate PA-PSR for different reproductive frequencies (years elapsed between reproductive seasons) of adult female and male turtles. I also define population equilibrium temperature (PET) as the temperature that would result in the equilibrium PSR of hatchlings (i.e., PA-PSR). These concepts may help assess the influence of rising temperatures on populations, as they can better indicate if PSRs depart from those at equilibrium. I compared PA-PSR and beach PSR for two populations of sea turtles for which male and female remigration intervals were known and found that a mild or no feminization over the PA-PSR may be occurring. Because PSR varies inter-annually, and hatchlings coming from beaches of different thermal conditions could recruit to the same population, it is critical to estimate beach PSR at the right temporal and spatial scales. Climate mitigation strategies based on these concepts could provide better management guidance for conservation practitioners. Similar approaches could be considered for other female-biased species with temperature-dependent sex determination.

Monday, 12 December 2022

New Publication on Lizard lifspan!

Rotger, A., Tenan, S., Igual, J.-M, Bonner, S. and Tavecchia, G., 2022. Life span, growth, senescence and island syndrome: Accounting for imperfect detection and continuous growth Journal or Animal Ecology,


  1. Small vertebrates on islands are expected to attain a larger body size, and a greater survival than their mainland counterparts. Comparative studies have questioned whether lizards exhibit this set of adaptations, referred to as the ‘island syndrome’.
  2. We collected data on 730 individuals the endemic Lilford's lizard Podarcis lilfordi throughout a 10-year period on a small island of the Balearic archipelago (Spain). We coupled a growth function with a capture–mark–recapture model to simultaneously estimate size- and sex-dependent growth rate and survival. To put our results into a wider context, we conducted a systematic review of growth, life span and age at maturity in different Podarcis species comparing insular and mainland populations.

  3. We found a low average growth coefficient (0.56 and 0.41 year−1 for males and females to reach an asymptotic size of 72.3 and 65.6 mm respectively), a high annual survival probability of 0.81 and 0.79 in males and females, and a large variability between individuals in growth parameters.
  4. Survival probability decreased with body size in both sexes, indicating a senescence pattern typical of long-lived species or in populations with a low extrinsic mortality. Assuming a constant survival after sexual maturity, at about 2 years old, the average life span was 6.18 years in males and 8.99 in females. The oldest animal was a male last captured at an estimated age of ≥13 years and still alive at the end of the study.
  5. Our results agree with the predictions of the ‘island syndrome’ for survival, life span and growth parameters. A comparative analysis of these values across 29 populations of 16 different species of Podarcis indicated that insular lizards grow slower and live longer than their mainland counterparts. However, our data differed from other island populations of the same species, suggesting that island-specific characteristics play an additional role to isolation.
  6. Within this study we developed an analytical approach to study the body size-dependent survival of small reptiles. We discuss its applicability to contrast hypotheses on senescence in different sexes of this species, and provide the code used to integrate the growth and capture–mark–recapture models.

Thursday, 1 December 2022

GEDAi at the Spanish Ornithological Congress 9-13/11/2022 !

This fall the GEDAi joined the 25th Spanish Ornithological Congress.

A. Sanz-Aguilar was on the scientific committee. A. Santangeli and S. Bolumar made a poster presentation of their work and projects.

Monday, 28 November 2022

New Publication on early-life conditions !

Payo-Payo, A. Sanz-Aguuilar, A. and Oro, D. 2022. Long-lasting effects of harsh early-life conditions on adult survival of a long-lived vertebrate. Oikos e09371,

Summary: Early life conditions, especially in long-lived organisms, can have both immediate and long-lasting effects in vital traits generating demographic structure across cohorts. Multiple non-exclusive hypotheses have been proposed to explore this question. For instance, the silver spoon, the viability selection or the predictive adaptive response hypothesis, predict that long lasting effects resulting from harsh early conditions could be negative, positive or vary with current environmental conditions, respectively. We use an 18-year capture–mark–recapture dataset on adult Audouin's gulls Ichthyaetus audouinii to test for these different hypotheses while accounting for age, breeding experience and large-scale dispersal. Audouin's gull cohorts experiencing harsh conditions during early life (i.e. nestling period and first winter) are known to experience lower first year survival. Here, we show that early life conditions also explained a large proportion (54%) of adult survival variation among cohorts. However, adulthood cohorts experiencing poor early life conditions had higher adult survival, in accordance with the viability selection hypothesis. Our results also show that apparent inexperienced breeders showed lower survival than experienced ones. Moreover, adult survival decreased with age. These results could suggest an increased cost of reproduction for deferred breeders, individual quality differences or survival senescence in this population. Overall, our study highlights the importance of early development, age and breeding experience as potential factors generating heterogeneity of survival between cohorts. Understanding the mechanisms driving responses to early life conditions at different life stages is fundamental to understanding the long-term dynamics of wild populations.

Friday, 25 November 2022

CMR Workshop ended!

The 2022 Workshop on capture-mark-recapture and- recovery data applied to conservation of animal populations ended today! It has been an interesting and stimulating workshop. This year we had datasets on vultures, trouts, dolphins, sharks, gulls ... We always learn new systems, new challenges, new studies and more important new persons. 

Thanks to all for coming!


Monday, 21 November 2022

"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 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:

Apply here!!

GEDA at the VIII Jornades de Medi Ambients 2023

Dr. A. Sanz-Aguilar joined the VII Jornades de Medi Ambients de les Illes Balears (Ibiza). She presented the results of the study of the Yel...