Persistence and dispersion of an introduced population of Alpine Newt (Triturus alpestris) in the limestone plateau of Larzac (Southern France)

Persistence and dispersion of an introduced population of Alpine Newt (Triturus alpestris) in the limestone plateau of Larzoc (southern France). - The study of introduced populations is interesting to better understand the geographic distribution and adaptability of species in different environments. The recent finding of an Alpine Newt population (Triturus alpestris) in the limestone plateau of Larzac (Department of Herault, France) provides the opportunity to examine the success of this species in the French supra-Mediterranean environment, Indeed, this species is absent from southern France although present in a large part of France and in northern Spain. The introduction site and all water bodies within a 2.5 km radius were surveyed between spring and autumn 2003. Because of the introduction date and the life expectancy of newts, all observed individuals are descendants of the introduced animals. They persist and breed in the study site despite the coexistence with Palmate Newts (Tri-turus helveticus). Body condition decreases in summer in these two species, but was lower in Alpine Newt males than in Palmate Newt males in autumn. Alpine Newts were found in only one of the other nine ponds, indicating a 1.5 km dispersion. Few Alpine Newts were present at this site, but reproduction was effective. These results show that the Alpine Newt can survive in southern France despite the presence of other newt species, but that the dispersion speed and rate towards other ponds are low.Peer reviewe

Distribution and characteristics of aquatic habitats of newts and yellow-bellied toads in the district of Ioannina (Epirus, Greece)

peer reviewedThe study describes the aquatic habitats and distribution of Triturus alpestris veluchiensis Wolterstorff 1935, T. carnifex macedonicus (Karaman, 1922), T. vulgaris graecus (Wolterstorff, 1905) and Bombina variegata scabra (Küster, 1843) in the district (“nomos”) of Ioannina, Northern Greece. Bombina variegata was found to be the most common species, followed by T. alpestris and T. carnifex while T. vulgaris seemed to be rare. The four taxa differed in habitat use and geographic distribution. Records of T. alpestris were limited to the highest sites in the north and east of the district. This species inhabited alpine lakes, but also smaller habitats such as drinking troughs and ponds. Four populations contained paedomorphic individuals. Triturus vulgaris appeared to be restricted to low altitude sites in the centre of the district where it lived in reservoirs, watering basins and drinking troughs. Triturus carnifex and B. variegata had a wider distribution and occupied a broader spectrum of habitats. Bombina variegata was the only species studied which lived in running waters (small brooks). Neither newts nor yellow-bellied toads were found in large rivers and lakes. In the district of Ioannina both habitat variety and distribution range of newts and Yellow-bellied Toads turned out to be greater than previously known. Alpine lakes containing very large populations of paedomorphic individuals should be protected given the rarity of the phenomenon

Polynomial approximation of aerodynamic coefficients based on the statistical description of the wind incidence

peer reviewedIn civil engineering applications, the aerodynamic coefficients are usually measured in wind tunnels for several wind incidences. The measurement results need to be linearized in order to perform the design of the structure. This paper justifies the use of different linearization techniques for different assessments as divergence or buffeting analysis. In this latter context, it is proposed to linearize the aerodynamic coefficient by the least-square method, using the probability density function of the wind incidence as a weighting function. First this probability density function is computed for a 2-D wind flow, as a function of the wind intensities and their correlation. Then, the comparison of results from different linearization techniques provides surprising results indicating that what is usually performed should be considered with care

Facultative paedomorphosis in pond-breeding newts

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Behavioural avoidance of newts in response to an aquatic invader: context dependent patterns and fitness

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Seismic behaviour of storage racks made of thin-walled steel members

peer reviewedThis paper presents an example of rack structure modelling accounting for structural non-linearities and for the possible relative motion between the rack and the stored goods that occurs as soon as the inertial force exceeds the friction resistance. It evidences that the constant reduction factor proposed by the RMI should actually be modulated according to the structural typology (and in particular the first natural frequency of the system) and to the ratio ag/μ between the design acceleration and the friction coefficient of the pallets

Cues from introduced fish alter shelter use and feeding behaviour in adult alpine newts

Amphibians are particularly affected by alien fish introductions and are declining worldwide. However, the behavioural mechanisms behind the observed cases of coexistence and exclusion patterns between adult amphibians and fish are poorly understood. In the present study, we aimed at testing the hypothesis that adult newts display different feeding and space use behaviour in the presence of fish cues (i.e. access less food resources and use more shelters than when fish cues are absent). To achieve this we measured behavioural patterns in 100 adult Alpine newts (Mesotriton alpestris) in a replicated laboratory design (20 tanks × 7 replicates across time). Half of trials involved individuals in indirect (visual and olfactory) contact with goldfish (Carassius auratus), a non-predatory species for adult newts. In the presence of fish, significantly more newts hid under shelters than in their absence, but this difference decreased over time. A lower number of newts fed in comparison with controls. These results show that newts responded to fish presence even in the absence of direct contact, but the differences were small. Newts decreased vital activities such as exploration of open areas and feeding. They also adjusted shelter use over time, suggesting a process of habituation or a risk assessment in the absence of direct risk. These results reveal that exploring behavioural patterns can aid in understanding the causes of exclusion and coexistence patterns between fish and amphibians