New Publication on Monk Seal!

Valsecchi, E., Tavecchia, G., Boldrocchi, G., Coppola, E., Ramella, D., Conte, L., Blasi, M., Bruno, A., Galli, P., 2023 Playing “hide and seek” with the Mediterranean monk seal: a citizen science dataset reveals its distribution from molecular traces (eDNA). Sci Rep 13, 2610. https://doi.org/10.1038/s41598-023-27835-6

Abstract: Animal conservation relies on assessing the distribution and habitat use of species, but for endangered/elusive animals this can prove difficult. The Monk Seal, Monachus monachus, is one of the world's most endangered species of pinniped, and the only one endemic to the Mediterranean Sea. During recent decades, direct observations have been few and scattered, making it difficult to determine its distribution away from the Aegean Sea (core distribution area of the post-decline relict population). This study relies on environmental DNA (eDNA) analysis to detect the presence of the Monk Seal in 135 samples collected in 120 locations of the central/western Mediterranean Sea, spanning about 1500 km longitudinally and 1000 km latitudinally.

Photo: www.mmc.gov

A recently described species-specific qPCR assay was used on marine-water samples, mostly collected during 2021 by a Citizen Science (CS) project. Positive detections occurred throughout the longitudinal range, including the westernmost surveyed area (Balearic archipelago). The distribution of the positive detections indicated six “hotspots”, mostly overlapping with historical Monk Seal sites, suggesting that habitat-specific characteristics play a fundamental role. We applied single-season occupancy models to correct for detection probability and to assess the importance of site-specific characteristics. The distance from small islets and protected (or access-restricted) areas was correlated negatively with the detection probability. This novel molecular approach, applied here for the first time in an extensive CS study, proved its potential as a tool for monitoring the distribution of this endangered/elusive species.

 

 

GEDA at the 11-F!

GEDA joint the 11F activities for the International Day of Women and Girls in Science . Dr. A. Sanz Aguilar explained the life and work of a scientist. She commented : "Best audience ever!". 😁  

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.

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. 

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 https://doi.org/10.7717/peerj.14511

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

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: https://doi.org/10.1007/s10584-022-03470-4

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 wikipedia.org

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.

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,https://doi.org/10.1111/1365-2656.13842

Abstract:

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.

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.