Leonardo Vignoli

Flight initiation distance in relation to substratum type, sex, reproductive status and tail condition in two lacertids with contrasting habits

Flight initiation distance in relation to substratum type, sex, reproductive status and tail condition was studied in two lacertid lizards with contrasting habits: the ground-dwelling common lizard Zootoca vivipara and the rupicolous Horvaths rock lizard Iberolacerta horvathi . These species were studied in sympatric populations in a mountain area in North-Eastern Italy, Tarvisio Forest. Mean escape distance was significantly higher in I. horvathi than in Z. vivipara . In both species there were significant differences between sexes, with males escaping at longer distances than females but there were no significant differences between adults and subadults. In both species there were no differences in escape distance of females in different reproductive states. In Z. vivipara specimens with broken tails escaped at a shorter distance than individuals with intact tails. Substratum type had a significant effect on escape distance in both species.

Dietary relationships among coexisting anuran amphibians: a worldwide quantitative review

Anuran amphibians have traditionally been considered suitable model organisms for community ecology studies. In this paper, we review and quantitatively re-analyze the original studies published on dietary relationships among anuran communities worldwide. We re-analyzed 33 independent communities from all continents, including data on prey numbers and/or prey volumes. All datasets underwent null model re-analysis using two randomization algorithms. In addition, logistic regression models were used to identify specific assemblage patterns. We discovered three main patterns: (1) one particular algorithm (RA2, which replaces every cell in the matrix with one randomly chosen, but retains the zero structure of the matrix) performed much better at uncovering community structure; (2) nonrandom structure was more likely to occur in tropical than in nontropical regions; (3) prey volume was a better descriptor of dietary relationships than prey number when attempting to detect nonrandom structure. We showed that: pattern (1) depended on both the overall generalist nature of the anurans in general and on the mathematical properties of RA2; pattern (2) was consistent with theoretical attributes of tropicality; and pattern (3) was due to the intrinsic ecological properties of generalist organisms, which forage more or less opportunistically on prey of very different sizes; hence, when prey number is used as a diet descriptor, there is a risk of approximating different prey taxa that make different relative volume contributions to the overall diet as being of similar relevance .

Modelling Bedriaga's rock lizard distribution in Sardinia: An ensemble approach

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.

Trophic niche of cave populations of Speleomantes italicus

This paper investigates the trophic niche of a poorly studied cave salamander, Speleomantes italicus. We examined Central Appennine hypogean populations that inhabit seven caves situated in three limestone areas in Umbria Region (Italy). Adults displayed feeding activity from May to December and the Vacuity Index analysis revealed a discontinuous trophic activity pattern throughout the year related to prey phenology. According to the qualitative analysis of the trophic spectrum, the populations in question can be defined as euryphagous, while the quantitative analysis (in terms of number and volume of preyed taxa) revealed a specialist strategy with a clear preference towards Diptera Limnobiidae. Both sexes presented similar trophic niche breadth and a high diet overlap, showing no intersexual differences. The hypogean populations of S. italicus, similarly to S. strinatii, showed a narrower trophic niche than epigeans of the same species, probably due to the limited food availability in the cave habitat.

The effects of temperature and pH on the embryonic development of two species of Triturus (Caudata: Salamandridae)

Amphibian populations are especially sensitive to aquatic parameters, in particular during embryonic and larval life. Our aim was to test for an effect of temperature (T = 13°C, 20°C and 25°C at constant pH = 7) and pH (pH = 5.5, 7 and 8.5 at constant T= 20°C) on embryos of two species of Triturus , T. carnifex carnifex and T. italicus (Amphibia, Salamandridae) using GLM procedure. Trend of embryogenesis processes, time to hatching and rate of development have a similar effect in both species in the used range of temperature and pH. Time to hatching decreased significantly with the increasing temperature. The pH experimental conditions had no effect on T. carnifex embryos survival, while the acidic pH condition raised the mortality rate in T. italicus , whose embryos should be more vulnerable than those of T. carnifex to acidification in nature.

Distribution, ecology and conservation of Archaeolacerta bedriagae in Sardinia (Reptilia, Lacertidae)

Arcbaeolacerta bedriagae is a polytypic species endemie to Corsica and Sardinia II represents one of the most peculiar elements of the Italian herpetofauna. This species has a fragmented range in Sardinia. The aim of this paper is to summarise the knowledge on the distribution of this lizard in Sardinia, based both on literature and original records, and to define the conservation status of its populations This research was carried out throughout the entire Sardinian territory, from June 2000 to September 2002. Most of the known sites of occurrence of A. bedriagae were checked, characterised from geomorphologic and florofaunistic points of view and gco-referenced. The surveys carried out explored only the potentially suitable habitats in different hours of the day. Three new localities were discovered, 10 checked sites were confirmed, 12 localities were not confirmed and 43 previously quoted sites were not explored. Two sampling sites were selected for a population study. In the latter two localities, several population parameters, such as density and sex ratio were studied. In the mountain site, a population density twenty limes higher than that found at the sea level site was estimated. Only five species were found to be syntopic with A. bedriagae, Podarcis tiliguerta, Algyroides fitzingeri, Tarentola mauritanica, Chalcides ocellatus and Coluber viridiflavus. The Sardinian subrange includes seven main areas of certain presence, but an underestimation due to their elusivity and the low density of some populations is possible The species generally inhabits areas of scarce interest and difficult for man to reach, though at least in some localities it seems to be disturbed by an increase in tourism. Some conservation actions were proposed.

Phylogenetic position of the southern rock lizard Australolacerta australis within the Lacertidae radiation : short communication

Abstract The southern rock lizard Australolacerta australis is a rock-dwelling lizard endemic to South Africa. The phylogenetic relationships of this species with other lacertid lizards are still not clear and have never been assessed in any phylogeny of Lacertidae using DNA sequence data. In this study we employed 3 044 base pairs from mitochondrial cytochrome b, 12S and 16S rRNA genes to investigate the phylogenetic position and the evolutionary history of A. australis. We performed phylogenetic analyses under the assumptions of Maximum Likelihood and Bayesian inference and estimated the timing of the cladogenic events related to A. australis by using a relaxed molecular clock method. Our phylogenetic reconstruction clearly placed A. australis within the southern African branch of the tribe Eremiadini including genera Tropidosaura, Meroles, and Pedioplanis. The former genus constitutes with A. australis a clade endemic to southernmost mountains of Africa. The radiation of this southern African clade is estimated to have occurred during the Mid Miocene (14.7–11.5 Mya), and it was likely due to the climate changes that occurred in the South African region at that time.

Spatial niche of the Italian cave salamander, Speleomantes italicus (Dunn, 1923) (Plethodontidae, Amphibia), in a subterranean system of Central Italy

A study was carried out on the population structure and spatial niche of Speleomantes italicus (Dunn, 1923) in a subterranean system of 10 caves in Umbria (Italy). The studied populations revealed a peak of activity from April to July. The relative abundance of salamanders varied throughout the year and the observed frequencies of individuals differed significantly from expected, confirming a seasonal pattern of activity. Both external and internal temperatures positively influenced the abundance of salamanders inside the caves. This relationship may principally be indirect, and presumably salamander cave activity follows prey temporal distribution patterns, which in turn are also linked to temperature. The presence of salamanders was negatively affected by high levels of air moisture both outside and inside the cave. In summer, salamanders find refuge inside caves because the air moisture outside reaches values incompatible with the physiological requirements of the species. Adults showed a significant tendency to use areas inside the cave that were closer to the entrance when the external climate conditions come in the vicinity of those suitable for the species (increased external relative humidity and decreased external temperature), and the external influence on internal micro‐climate is reduced. Comparisons to other Speleomantes species are also provided.

Food habits of Podarcis filfolensis (Reptilia, Lacertidae) on a small Mediterranean island during the dry season

Small islands are typically characterised by simplified ecosystems with low levels of complexity and reduced biodiversity. This condition may determine a scarcity of food resources which in turn can affect several aspects of the ecological features of the species, particularly their trophic niche (e.g., Gorman, 1979; Stephen and Krebs, 1986; Pérez-Mellado and Corti, 1993). Predators are extremely sensitive to the complexity and structure of their ecosystems, and lacertids, which are characterised by small size and generalist habits, usually get over the poverty of resources by in some cases adding vegetal material in their diet (Ouboter, 1981; Sorci, 1990; Pérez-Mellado and Corti, 1993; Van Damme, 1999). The Podarcis species inhabiting the Mediterranean islands are a quite well studied group concerning adaptation to island conditions (e.g., Ouboter, 1981; Valakos, 1987; Pérez-Mellado and Corti, 1993). The rich background on phylogeny (e.g., Lanza and Cei, 1977; Capula, 1990, 1994; Oliverio et al., 1998, 2000; Harris and Arnold, 1999) and autoecology (e.g., Valakos, 1987; Rugiero, 1994; Sorci, 1990; Pérez-Mellado and Corti, 1993; Bombi and Bologna, 2002) of these lizards has stimulated the use of this genus as a model for ecoethological studies. Moreover, this group includes a high number of very common species

Are conservation assessments of threatened species reliable? Updated distribution of the Endangered Sardinian newt Euproctus platycephalus and implications for Red List assessments of Italian amphibians

Assessing and updating the extinction risk and conservation status of species and populations is paramount to guide management strategies. Maintaining up-to-date and realistic geographical distribution maps of individual species is one aspect of this. We report an updated distribution for an Italian island endemic amphibian, the Sardinian newt Euproctus platycephalus , categorized as Endangered on the IUCN global and national Red Lists. The distribution of E. platycephalus was reassessed by means of visual surveys, questionnaires, interviews and scientific literature. The species was found over a geographical range comparable to that used for the IUCN assessment but we recorded a significantly larger number of populations (57 vs 14). There was no appreciable difference in the species’ Extent of Occurrence between 1972–1974 and 2010–2015. Area of Occupancy increased between past (1972–1974 and 1999–2000) and present (2010–2015) distribution records. Based on this updated distribution and considering that several new populations have been found, the distribution of the species may still be underestimated. Given the novel distribution data provided here and the need for new long-term demographic data, we recommend that the conservation status of E. platycephalus be reassessed. In the Italian national Red List a potential overstatement of extinction risk is evident for other amphibian species, possibly because the information used in their assessment is deficient. Considering that monitoring rare and elusive species is costly and time consuming we recommend more extensive use of multiple sources of information for Red List assessments.