Pérez-Mellado, V. & Hernández-Estévez,J.A. & Garcia-Diaz, T. & Terrasa, B. & Ramón, M.M. & Castro, J. & Picornell, A. & Martin-Vallejo, J. & Brown, R. (2008) - Population density in Podarcis lilfordi (Squamata, Lacertidae), a lizard species endemic to small islets in the Balearic Islands (Spain) - Amphibia-Reptilia, 29: 49-60   × he Balearic lizard, Podarcis lilfordi, is present in 43 insular populations in the Cabrera archipelago and around the coasts of Mallorca and Menorca islands (Spain). We studied lizard densities over the entire range of distribution, analyzing observed differences of density in relation to island area, habitat diversity, availability of resources, presence of predators, competitors and human disturbances. The density of the Balearic lizard varies from less than 35 to almost 8000 lizards ha-1, with an average of around 1500 lizards ha-1. In some very small islets we detected no more than 10 individuals. Using a subsample of nine coastal islets (Menorca) we did not find any significant correlation between ground arthropod biomass and lizard density. The combination of island area and its maximal altitude, its so-called biotic capacity, was also uncorrelated with lizard density. In addition, neither degree of island accessibility nor presence/absence of seagull breeding colonies, were able to explain lizard densities.
Islands without ship rats (Rattus rattus) showed a significantly higher lizard density, but islands in which rat eradication programs were launched during the study period, showed lower densities than those with rats but no eradication actions. Genetic variability was significantly higher on bigger lizard populations, lacking a correlation with lizard densities. No single independent variable can explain density differences among populations under study. Our results are discussed in the light of available hypotheses on factors affecting population densities. Berg, M.P. van den & Zawadzki, M. & Kroniger, M. (2014) - 2013 - Herpetological trips to the Balearic Islands (Spain). - L@CERTIDAE, 2014 [3]: 17-34. × More than three decades of fascination for the endemic Balearic sisterspecies Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883), resulted in 30 trips (1980-2013) to the home of these lacertid lizards, in which we studied their ethology as well as their distribution and geographical differences in pattern and coloration. In comparison to prior scientific studies that led to an inflationary description of subspecies, we often found wide variations within populations and their subspecific characteristics. The question “To be distinct, or not to be distinct” is, to our opinion, not answered correctly in most cases. In order to gather data for a future revision of the present subspecific order, we started in 2011 to collect data of these lizards in a structured way, and storing this data in a free accessible database (www.pityusensis.nl). Later in 2011 we enhanced our dataset by gathering tissue samples of the lizards, using the non invasive technique of buccal swabbing, for future accompanied DNA research. Rotger Vallespir, A. (2016) - Evolutionay demography of the Balearic Wall lizard (Podarcis lilfordi). - PhD thesis. Universitat de Barcelona. July 2016. 272 pp. Pérez-Cembranos, A. & Pérez-Mellado, V. & Alemany, I. & Bassitta, M. & Terrasa, B. & Picornell, A. & Castro, J.A. & Brown, R.P. & Ramon, C. (2020) - Morphological and genetic diversity of the Balearic lizard, Podarcis lilfordi (Günther, 1874): Is it relevant to its conservation? - Diversity and Distributions. https://doi. org/10.1111/ddi.13107 × Aims: To characterize the genetic and morphological diversification of the endan- gered Balearic lizard Podarcis lilfordi and to assess the relevance of this diversity, and how it is described, to conservation measures.
Location: This study covers all the populations of the Balearic lizard, Podarcis lilfordi, present in its range of distribution at coastal islets of Menorca, Mallorca and Cabrera Archipelago.
Methods: We analysed genetic and morphological variation across the 43 known extant populations of the Balearic lizard, using mitochondrial and nuclear markers. We examined morphometric and scalation characters using, in some cases, phyloge- netically independent contrasts. We also incorporated the study of dorsal coloration and dorsal colour pattern including the analysis of melanism in several populations. Results: We detected clear genetic divergence between Menorcan populations and populations from Mallorca and Cabrera, in both nuclear and mtDNA markers, but genetic divergence is relatively low among different insular populations within these groups. In contrast, morphological divergence was substantial both between Menorcan and remaining populations and within these groups. Morphological traits, such as dorsal coloration, body size and the number and size of scales, seemed to be linked with differences in climatic conditions between populations. In addition, some traits, as melanism, showed a strong phylogenetic signal.
Main conclusions: The morphological and genetic diversity of the Balearic lizard is incongruent with the subspecies described in the classical taxonomic literature. Moreover, current populations differ not only in some genetic and morphological features, but also in several ecological and ethological characteristics, in many cases unique to one population. Based on our results, we propose abandoning the use of subspecies to describe the extraordinary morphological diversity of the Balearic liz- ard and its replacement with the concept of evolutionary significant units (ESUs). ESUs are particularly suitable to describe and recognize such diversity and, especially, to ensure the continuity of the evolutionary process.
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