The Herpetological Journal

https://doi.org/10.33256/31.2.6169

pp. 61-69

Authors: Zoltán Tóth, Fanni Mihók & Edina Nemesházi

Abstract: Understanding the distribution of genetic variation is central for both population biology and conservation genetics. Genetic population structure can be primarily affected by the species’ dispersal ability, which is assumed to be limited in many amphibians. In this study, we estimated allelic differentiation metrics and FST indices to investigate genetic variation among natural breeding ponds of smooth newts (Lissotriton vulgaris) over a small spatial scale. Based on six microsatellite loci,
we found a small, but significant allelic differentiation among clusters of natural breeding ponds (i.e. ‘local regions’), which result was in line with the calculation of corresponding hierarchical FST values. Analysis of molecular variance also indicated significant between-region variation in the study area. Pairwise estimations showed that only the furthermost regions differed from each other in both differentiation measures, but this difference was not attributable to geographic distances between ponds. Our results provide evidence that hierarchical genetic structure can be characteristic to breeding ponds of smooth newts on a small spatial scale in their natural breeding habitat, but dispersal distance may be less limited than previously thought in these philopatric caudates.

Authors: Zoltán Tóth, Fanni Mihók & Edina Nemesházi

https://doi.org/10.33256/hj31.2.7076

pp. 70-76

Authors: Yole Caruso, Daniele Macale, Luca Luiselli & Leonardo Vignoli

Abstract: Lizard thermoregulation is costly and is largely behavioural. Podarcis raffonei, endemic of few islets of the Aeolian archipelago (southern Italy), is one of the most threatened lizards in Europe, its survival being under threat also due to the presence of the congeneric P. siculus, a successful invader characterised by behavioural plasticity and effectiveness and precision at regulating body temperature (Tb). We tested whether thermoregulation behaviour diverges between the two species by analysing (i) the heating rates under a standard thermal condition, and (ii) the temperature at which lizards ended basking (T_final) along a thermal gradient. Overall, we found behavioural differences between the two lizards (i.e. P. siculus exhibited lower T_final), although both species had comparable heating rates and thermoregulated in the same thermal conditions. The invasive P. siculus had lower T_final and, since heating rates were similar between species, it expended less time basking than native P.
raffonei. We speculate that the observed thermal ecology differences could provide a selective advantage to P. siculus in the harsh island environment.

Keywords: Podarcis raffonei, Podarcis siculus, lizard, biological invasion, competition

Authors: Yole Caruso, Daniele Macale, Luca Luiselli & Leonardo Vignoli

https://doi.org/10.33256/31.2.7784

pp. 77-84

Authors: Marta Biaggini & Claudia Corti

Abstract:  Agriculture intensification is among one of the major threats affecting terrestrial reptiles worldwide. There is however a lack of information available on the ecology of these vertebrates in agricultural landscapes. Basic information like the pattern of occurrence in cultivated fields is key to assess the probability of an animal being affected by threats driven by agricultural managing. Focussing on the Italian wall lizard (Podarcis siculus), we performed a field study to assess in detail its distribution and abundance in two cultivations, vineyards and cereal fields. Lizard distribution and abundance significantly varied among land uses, regardless of the arthropod fauna composition and diversity (analysed in the same fields), and the management activities. In the cereal fields, lizards were present exclusively along the field margins while in the vineyards
they also occurred in the inner portions of the cultivated areas, even if they were more abundant next to the borders. The widespread presence of lizards in the vineyards suggest that P. siculus can likely adapt to such cultivated areas. This partly lowers the effect of habitat loss due to vineyard planting but exposes animals to the risks related to management activities, including mechanical practices and chemical application. In contrast, the presence of sowed lands, as extremely simplified habitats, results primarily in a definitive loss of habitat for lizards that are unable to settle within them, while the exposure to threats driven by management is less direct than in vineyards.

Keywords: agriculture, Podarcis, reptiles, wildlife protection

https://doi.org/10.33256/31.2.8590

pp. 85-90

Authors: Geoffrey R. Smith & Jessica E. Rettig

Abstract: Amphibians often select oviposition sites based on a variety of cues that indicate the level of risk in the oviposition habitat. Surprisingly, the role of aquatic vegetation or habitat structure/complexity in anuran oviposition site selection has not been extensively studied even though it might affect perceived risk. We examined the effects of free-ranging invasive western mosquitofish (Gambusia affinis) and artificial vegetation/habitat structure on colonisation of experimental pools by gray treefrogs (Hyla versicolor). Hyla versicolor avoided ovipositing in mesocosms with G. affinis. The presence of artificial vegetation/habitat structure had no effect on oviposition site selection by H. versicolor, whether alone or in interaction with G. affinis. Our experiment provides evidence for the avoidance of fish, and more specifically G. affinis, by ovipositing H. versicolor; but provides no evidence for a role of vegetation/habitat structure.

Keywords: Eggs, Gambusia affinis, habitat complexity, Hyla versicolor, oviposition, vegetation

https://doi.org/10.33256/31.2.9198

pp. 91-98

Authors: Leroy Soria-Díaz, Claudia C. Astudillo-Sánchez, Yuriana Gómez-Ortiz, Javier Manjarrez, Víctor Mundo-Hernández, Tamara Rubio-Blanco & Hublester Domínguez-Vega

Abstract:  Human activities have caused several changes in biotic communities all over the world. Some species maintain viable populations in altered environments through different adaptations, however, knowledge in this regard is scarce for certain taxa, including reptiles. We analysed the detectability and habitat selection of the rattlesnake Crotalus triseriatus to contribute to our knowledge about how this species responds to anthropogenic landscape change. Rattlesnakes were monitored for two years in two anthropized landscapes using visual encounter surveys. We analysed detectability in relation to climatic factors and human activity, and habitat selection was analysed in native and non-native vegetation. Our study shows that detectability of C. triseriatus is differentially affected in anthropized landscapes; human activity may be determinant in
landscapes such as agricultural fields, whilst climatic factors may be determinant in landscapes where people are less active such as the protected areas within urban parks. The analyses of habitat selection shows that native vegetation is crucial for the persistence of C. triseriatus in the studied landscapes. Several strategies may allow rattlesnakes to persist in different anthropized landscapes; nonetheless, native habitat remnants should be protected in anthropized areas to conserve wildlife.

Keywords: Anthropized landscapes, behavioural adaptations, Mexico, native habitat remnants, urban herpetology

https://doi.org/10.33256/31.2.99110

pp. 99-110

Authors: Manon Dalibard, Laëtitia Buisson, Olivier Calvez, Morgan Nguyen-Hong, Audrey Trochet & Pascal Laffaille

Abstract: Individual recognition of animal species is a prerequisite for capture-mark-recapture (CMR) studies. For amphibians, photoidentification of body pattern is a non-invasive and less expensive alternative than classical marking methods (e.g. passive integrated transponder). However, photo-identification is effective only if the patterns are (i) sufficiently variable between individuals, and (ii) stable over time. This method also depends on the observer’s judgment. In the present study, we assessed the effectiveness of an automatic algorithm (AmphIdent) to recognise ventral colour patterns of the Pyrenean brook newt (Calotrion asper), endemic to the Pyrenees Mountains of France. To assess the performance of the tested method, 113 individuals from two different streams were marked with passive integrated transponders (PIT-tags). We used false rejection rate (FRR), false acceptance rate (FAR) and true acceptance rate (TAR) as metrics to evaluate performances of photoidentification. Mean FRR was 7.3 %, FAR was 5.2 %, and TAR was 92 % across both streams, both sexes and all the observers. FAR was significantly different between sexes, while FRR and TAR were significantly influenced by the interaction between the sex and the stream. Despite these differences, our error rates are among the lowest values found in the literature for both amphibian and non-amphibian computer-assisted photo-identification. We found that poor-quality reference pictures could lead to an increasing difficulty to achieve a correct match when time since first capture rose. Consequently, individual photo-identification using AmphIdent software is a reliable tool to aid in the monitoring the Pyrenean brook newts, provided that pictures are taken with care, reference images are regularly updated and observers are properly trained to use the software and interpret images.

Keywords: AmphIdent, natural marking, computer recognition, amphibian monitoring, pattern changes

https://doi.org/10.33256/31.2.111117

pp. 111-117

Authors: Andrew S. Buxton, Hannah Tracey & Nick C. Downs

Abstract: The application of a habitat suitability index (HSI) assessment to predict the use of ponds by great crested newts (Triturus cristatus) is commonly used in association with distribution and monitoring projects. Such projects are often used to inform development and planning decision making. However, this type of assessment is frequently misused, and misinterpreted. We used a large, commercially collected environmental DNA (eDNA) survey for great crested newt pond occupancy (489 ponds) to; (1) assess whether it is appropriate to use low HSI scores to rule out occupancy, (2) discuss the use of high HSI scores to identify ponds of high importance for the species and, (3) explore the eDNA detection method. We conclude that there is no evidence to support ruling out pond occupancy based on low HSI scores. However, the conventional view that ponds with HSI scores above 0.7 are of high importance to great crested newts is somewhat supported by the data. Both eDNA and direct observational survey methodologies suffer from sampling error and these need to be acknowledged in the analysis of large data sets.

Keywords: Great crested newt, habitat suitability index, HSI, Triturus cristatus, environmental DNA, presence absence survey