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.

New Publication on Lizard Body size differences!

Rotger, A., Igual, J.M., Genovart, M., [...], Tavecchia, G. 2021.  Contrasting Adult Body-Size in Sister Populations of the Balearic Lizard, Podarcis lilfordi (Günther 1874) Suggests Anthropogenic Selective Pressures. Herpethological Monograph  35: 53-64. https://doi.org/10.1655/HERPMONOGRAPHS-D-19-00005 

Summary: Recently isolated populations offer a good biological model to infer the evolutionary forces responsible for the current divergences across populations. We coupled genetic, morphometric, ecological, and demographic analyses from three island populations of the endemic Balearic Wall Lizard, Podarcis lilfordi, (Balearic archipelago, Spain) to infer the mechanisms underlying the observed differences in body size. For each population, we described plant community structure, derived a biotic capacity index, and used individual-based data on 1369 lizards captured and released during 6 yr (2009–2015) to estimate population density and body growth patterns.

We used genetic data collected on 80 individuals (∼27 for each population) to infer genetic divergences across islets and population history. Body size divergences cannot be explained by the ecological or population characteristics. Individual growth was slower in the smallest island, where lizards reached the largest average body size. In addition to having the highest density, results suggested that resource availability does not constrain asymptotic body size, but the speed at which individuals reach it does. The Approximate Bayesian Computation used to infer population history from genetic data supported the occurrence of two bottlenecks in the islet with the highest anthropogenic footprint. We emphasize the need to integrate ecological and genetic data and the importance of considering the effects of past human disturbance as an additional force in being able to model present island fauna.

Fieldwork at the Cabrera National Park

GEDA has monitored lizard density in a small area of the Cabrera National Park. The campaign is part of the extension of the monitoring program in the southern islands of Mallorca, financed by the Government of Balearic Islands (code: PRD2018/25). 

A big 'thank' to the Park who helped with the logistic.

Whole genome sequencing!

The GEDA is taking part in the Whole-genome Sequencing Project of the endemic Podarcis lilfordi, in collaboration with the Evolutionary Ecology Lab of the University of Barcelona. The project is supported by the Biogenoma of the IRBio-UB within the Earth BioGenome project. 

More about the project, here.

 

Lizard campaign just started!

 The first island has been sampled. Likely we had good weather and animals were collaborating. Looking forward to calculate an estimate of population size from the CMR data collected.Only five to go!

Lizard autumn campaign ended!

Lizard autumn campaign ended this week. Still need to bring back the boat and process the nearly five hundred photos (!). This year there has been a good recruitment of young lizards (photo).

Lizard autumn campaign just started

Lizard autumn campaign just started. Safety first!  

Good news: animals seem to collaborate.

Spring lizard campaign 2018: first day!

The spring lizard campaign 2018 has began with a first sunny day and 58 individuals caught, photographed and released. Nearly all were old firends.