Sardinian populations of the snake Hemorrhois (= Coluber) hippocrepis are likely the most endangered populations of snakes in Italy. Major threats to survivorship are the anthropogenic habitat alteration and the extremely low population density, while nothing is known about the potential effects that climate change could exert on this species. The main goal of this paper is to provide helpful instruments for the short- and long-term conservation of H. hippocrepis in Sardinia. By means of an ecological modeling approach, we derived the Sardinian whip snake habitat suitability map, and we compared the potential range extent under present condition and future climatic scenarios. Results clearly show an alarming trend for H. hippocrepis conservation: changing climate conditions will cause a dramatic reduction on suitable surface since 2020, with a further collapse by 2050 (down to 11 km2). We also identified areas of species potential persistence up till 2050, where prospective management initiatives could have the greatest probability of success in this region. In particular, only one existing protected area will likely still keep suitable habitats for H. hippocrepis. Therefore, we suggest that very careful management of this relictual area should be implemented by now if we really want to save these exceedingly threatened snake populations.
Studies of the ecological characteristics of sympatric species are important for developing and testing ecological theory, but may be of interest also for conservation biology research when the study species are threatened, endemic and with narrow distribution. Here, we studied a particular aspect of the ecology (i.e. microhabitat use) of two sympatric lizards (Archaeolacerta bedriagae, Podarcis tiliguerta) endemic to Sardinia and Corsica (Tyrrhenian islands). We studied this issue by modelling procedures, using field data collected at six study areas in both Sardinia and Corsica. We recorded 18 microhabitat variables for each lizard spot. The variables were entered as independent variables in logistic regression analysis with the presence/absence data for the lizards as the dependent variable, and Akaike Information Criterion was applied to select the best models describing the ecological equation of each study species. In total, we based our modelling approach on 296 individuals of A. bedriagae and 182 of P. tiliguerta. The general logistic regression models revealed that five distinct variables were significantly correlated to the presence/absence of A. bedriagae, and six to that of P. tiliguerta. We found that three variables were important for only P. tiliguerta, two for only A. bedriagae, and three for both species and with an identical sign. We also found some similarities in microhabitat choice between species. Indeed, some variables were always present in the best models of both A. bedriagae and P. tiliguerta. In general, A. bedriagae was more related to spots with large stones and low vegetation than P. tiliguerta, which, on the contrary, choose spots relatively closer to vegetation. The various reasons explaining the observed similarities and differences between species were examined. It is suggested that our modelling procedure may be widely used for studies of lizard community ecology, because it easy to use and allows a more-in-depth analysis than normal 'count approaches'.
Demographic and morphological aspects of two nearby subpopulations of the common wall lizard (Podarcis muralis) were studied, by a capture-mark-recapture procedure, at an archaeological site in the surroundings of Rome, central Italy. In both sites, the births peak was observed in September. Adult sex-ratio was skewed towards males in one subpopulation, but was close to equality in the other. Morphological characteristics were consistent in the two sites, with males always exhibiting larger snout-vent-length and head size. Population size and density, computed by a Jolly-Seber index applied by using POPAN model revealed differences between subpopulations, with lizard density being much higher in the site with higher habitat heterogeneity and shelter availability. Tail condition was similar between sites. The general implications of these data are discussed.
Many techniques for predicting species potential distribution were recently developed. Despite the international interest for these procedures, applications of predictive approaches to the study of Italian fauna distribution are exceptionally rare. This paper aimed at: (a) detecting climatic exigencies of A. bedriagae in Sardinia; (b) predicting the Archaeolacerta bedriagae Sardinian potential distribution; (c) identifying the most vulnerable Italian populations of the species. Literature and field data were utilized as presence records. Six modelling procedures (BIOCLIM, DOMAIN, ENFA, GAM, GLM, and MAXENT) were adopted. The species climatic requirements were defined using the WorldClim databank for deriving the environmental predictors. AUC and Kappa values were calculated for models validation. AUC values were compared by using Anova Monte Carlo. The best four models were combined through the weighted average consensus method for producing a univocal output. GAM and MAXENT had the best performances (respectively: AUC = 0.93 ± 0.03, Kappa = 0.77 ± 0.08; AUC = 0.93 ± 0.03, Kappa = 0.78 ± 0.07). Good results were also obtained by GLM and DOMAIN (respectively: AUC = 0.89 ± 0.04, Kappa = 0.72 ± 0.05; AUC = 0.88 ± 0.04, Kappa = 0.69 ± 0.07). BIOCLIM and ENFA gained relatively low performances (respectively: AUC = 0.78 ± 0.07, Kappa = 0.57 ± 0.14; AUC = 0.75 ± 0.06; Kappa = 0.49 ± 0.10). In Sardinia A. bedriagae is mainly influenced by seasonality, which causes the evidenced range fragmentation. Moreover, the general importance of multi-methods approaches and consensus techniques in predicting species distribution was highlighted.
Archaeolacerta bedriagae is a rock lizard endemic to Corsica and Sardinia. Four subspecies have been recozied to date on the basis of morphological traits. Previous allozyme investigations revealed high genetic differentiation among populations of the species. Based on these results some authors hypothesized that more than one species of Archaeolacerta may occur on Corsica and Sardinia. In this paper we investigated allozyme variation at 19 gene loci in 5 populations belonging to all subspecies of A. bedriagae in order to study genetic differentiation among populations from Corsica and Sardinia, and to compare our results with those obtained in previous studies carried out on allozyme variation and taxonomy of the species. Low levels of genetic differentiation (average Nei's D = 0.026) and heterogeneity (mean FST = 0.147) were found comparing the A. bedriagae populations, and there was no evidence of interruption or restriction of gene flow. This is in agreement with the available molecular and morphometric data, while it is not in accordance with allozyme data reported in the previous studies. Our data do not support the hypothesis of an unrecognized criptic species of Archaeolacerta in Corsica and Sardinia, and indicate that the definitive assessment of the taxonomic status of the A. bedriagae populations requires further investigation.