Triturus Cristatus Research Articles

Hybridization and introgression in deeply differentiated salamander species – molecular genetics and a reappraisal of Dr. Louis Vallée’s osteological data

Abstract Two morphologically and genetically distinct salamander species (the crested newt, Triturus cristatus and the marbled newt, T. marmoratus) engage over a large area in the west of France where they hybridize at ca. 4%. The species interaction is characterized by ecological differentiation and limited gene flow beyond the F1 hybrid generation. Incompletely isolated species like these allow to investigate the genetic mechanisms and evolutionary forces that maintain their identity in the face of ongoing gene flow, to which a large mosaic hybrid zone provides excellent opportunities. A reanalysis of published morphological data supports the partial breakdown of the species barrier whereas extensive genetic data show that introgression is low yet asymmetric, in line with the dynamics of species replacement inferred earlier. The current work, with seven diagnostic nuclear markers studied for a large sample, revises the estimates of introgression in both T. cristatus (to 0.24%) and T. marmoratus (to 0.11%). Difficulties remain in the recognition of potential triploid hybrids versus backcross hybrids. Haldane’s rule is partially supported, but deeper analyses require the use of a molecular marker for sex that is not yet available.

Ecological niche variation drives morphological differentiation in tropical stream‐dwelling newts from Indochina

AbstractMorphological diversity within organisms can arise from factors other than genetic diversity alone. Local adaptations and combinations of various factors are also involved in shaping morphology. We investigated the relationship between morphological diversity and ecological niche divergence within two related tropical stream‐dwelling newt species from Indochina: Paramesotriton deloustali and P. guangxiensis. We identified sexual dimorphism within both species and a significantly larger body size in P. deloustali than in P. guangxiensis. Our findings highlighted that climatic variables strongly influence Asian warty newt distribution, indicating the potential effects of climate change on tropical newt populations. Furthermore, we identified significant intra‐ and interspecific morphological and niche differentiation across five populations of the two newt species, suggesting that newt morphology is responsive to environmental factors. A significant negative relationship was observed only between ecological niche similarity and geographic distance among various combinations of factors, indicating that the distinct morphology of the study species mirrors ecological adaptation.

An improved habitat suitability index for the great crested newt Triturus cristatus

An improved habitat suitability index for the great crested newt Triturus cristatus

High genetic diversity but limited gene flow in Flemish populations of the crested newt, Triturus cristatus

Habitat destruction and fragmentation are among the major causes of amphibian decline. We investigated to what extent geographic distance and barriers affect the genetic composition of the crested newt, Triturus cristatus in Flanders (North Belgium), causing inbreeding or loss of genetic diversity. Data from seven microsatellite loci and 170 individuals from seven metapopulations up to 180km apart revealed heterozygosities of 0.53 to 0.67 within populations and moderate levels of genetic divergence between populations (FST values from 0.074 to 0.141, harmonic means of Dest between 0.070 and 0.189). In all Flemish meta-populations, more than 90% of the individuals from a given geographic region were assigned to the same genetic cluster indicating
 little genetic exchange, even in De Panne where the two populations Oosthoek and Westhoek are only a few kilometres apart. Such sub-structuring on a micro-scale has also been described in other amphibians. Unique alleles in most populations further support the probability that genetic drift has already led to some isolation. With the exception of the Oosthoek population, however, we found no significant evidence for bottlenecks. Connectivity within pool clusters seems essential to the maintenance of genetic diversity in crested newts as is indicated by our findings from Tommelen, the population with the largest number of pools in close proximity, which also shows the highest levels of heterozygosity (He and Ho) and the second highest number and richness of alleles. In conclusion, our study indicates that dispersal and migration rates between the Flemish populations of Triturus cristatus are limited at the geographic scale studied here but that habitat fragmentation has not yet led to a significant loss of genetic diversity of the studied Flemish populations, possibly because crested newts are relatively long-lived, fragmentation of their habitat is relatively recent in Flanders, and most investigated pools are still connected at the local scale.

Greater Glasgow pond amphibian surveys 2022

In 2019, Clyde Amphibian and Reptile Group (CARG) decided to organise a spring 2020 common frogspawn (Rana temporaria) survey of the Greater Glasgow area, Scotland. The COVID-19 lockdown postponed this project until 2022. The 2022 survey area was spread across four council districts: Glasgow City, South Lanarkshire, Renfrewshire and East Renfrewshire. The primary aim of the surveys was to collect records of amphibian breeding throughout the Greater Glasgow Area, with secondary aims of: (1) revisiting the ponds to see if the ponds supported the spawn through to tadpole and froglet stages; (2) assessing the condition of the ponds for amphibians; (3) identifying areas for habitat enhancement work; and (4) collecting data on breeding common toads (Bufo bufo) and newts (Lissotriton, Ichthyosaura and Triturus spp.). A total of 45 volunteers participated in the surveys. Surveys were completed between March and May 2022, with a primary focus between March and April in order to capture frog spawning data. Surveyors were asked to record amphibian population data, and habitat data in order to estimate Habitat Suitability Indices. In total 162 ponds were surveyed, with evidence of breeding common frogs found in 66.1% of ponds with 11,478 frogspawn clumps counted on the first set of surveys. Only 12.2% of ponds were found to contain common toads, and small newts (Lissotriton spp.) were identified in only 7.4% of ponds. In relation to the quality of breeding habitat, 24.5% of ponds were assessed as drying out annually, which significantly reduces the suitability of these ponds for breeding. This figure is predicted to increase with anthropogenic climate change reducing the number of breeding ponds available to amphibians in the absence of intervention. Furthermore, the majority of the ponds surveyed were assessed as offering poor or below average suitability for great crested newts (Triturus cristatus) and nearly half of the ponds surveyed were found to have poor or bad water quality, which can increase stress levels for larval amphibians and may adversely affect mortality levels. However, as the analysis of water quality was subjective, these findings should be treated with caution.

Spatial prioritisation for crested newt conservation in Luxembourg: Insights from population genetics and species distribution modelling

Abstract The intensification of agriculture and urbanisation has precipitated the decline of numerous species, including the northern crested newt (Triturus cristatus). To mitigate the impacts of habitat degradation and loss, restoration initiatives depend on evidence‐based decision‐making to identify priority sites for conservation efforts. Here, we employed a multidisciplinary approach, drawing on population genetics, species distribution modelling (SDMs) and landscape genetics to develop a spatial prioritisation framework for the creation and/or restoration of crested newt breeding ponds in Luxembourg. For the genetic analyses, more than 1000 crested newts from 98 ponds across Luxembourg were genotyped at 15 microsatellite loci to assess genetic diversity and spatial clustering. The relationship between newt presence and environmental variables was evaluated using SDMs. Priority restoration areas were identified with PRIORITZR, integrating genetic diversity, habitat suitability and connectivity. The population genetic structure was characterised by spatial clustering, which followed an isolation‐by‐distance pattern. Five sites were identified as significantly differentiated from the remaining populations, warranting targeted conservation efforts. Standing water bodies and proximity to the nearest occupied pond were the most important predictors of crested newt presence. The highest gain in habitat suitability through the creation of new ponds was predicted to occur in southwest Luxembourg. Based on the country‐wide predicted occurrence of crested newts and gains in habitat suitability, areas of highest restoration potential were identified in close proximity to existing crested newt populations. The produced maps of priority restoration areas should inform future conservation efforts of the crested newt in Luxembourg. While the importance of preserving genetic diversity is widely recognised, the theory‐practice gap frequently precludes the incorporation of genetic aspects into in situ conservation measures or management policies. This case study demonstrates the integration of multidisciplinary analyses within an evidence‐based framework to guide species conservation efforts.

New data regarding the distribution and status of the herpetofauna from urban and peri-urban habitats in the city of Pitești, Argeș county (Romania)

Identifying urban and peri-urban areas inhabited by species of reptiles and amphibians represents the first step in understanding how herpetofauna can adapt to anthropogenic factors. This is particularly true for regions where sampling biases have left significant gaps in our knowledge of fauna distribution, such as Romania. The aim of the study is to show my preliminary observations on the herpetofauna and its use of habitats in the urban and peri-urban environments from the city of Pitești, Argeș County, located in southern Romania. I identified nine species of amphibians (Salamandra salamandra, Lissotriton vulgaris, Triturus cristatus, Bombina variegata, Bufo bufo, Bufotes viridis, Hyla orientalis, Pelophylax ridibundus and Rana dalmatina) and nine species of reptiles (Emys orbicularis, Trachemys scripta, Lacerta agilis, Lacerta viridis, Podarcis muralis, Anguis colchica, Coronella austriaca, Natrix natrix and Natrix tessellata). The most abundent species in urban environments were Podarcis muralis and Bufotes viridis, with other species naturally present in the same habitats being Lacerta viridis, Hyla orientalis and Bufo bufo. In an artificial urban pond there were present Emys orbicularis and the invasive species Trachemys scripta (together with other exotic turtles belonging to other genera) as a result of translocation and releases. When taking into account the peri-urban areas as well, the most abundant species in the study area were Bombina variegata, Rana dalmatina and Bufotes viridis, the first two being limited to the woodland area. The most widespread species were Hyla orientalis, Bufotes viridis, Lacerta viridis, Podarcis muralis and Natrix natrix. These widespread species were present throughout all the study area. I have also recorded some species of reptiles with very few observations in the Argeș County: Natrix tessellata and Trachemys scripta. Finally, I identified anthropogenic factors that negatively impact the herpetofauna, such as habitat loss, direct persecution, road mortality, invasive species and poaching.

Migration strategy of the Great crested newt (Triturus cristatus) in an artificial pond

In animals, migration is an evolutionary adaptation to manage seasonally varying habitats. Often driven by climatic changes or resource availability, amphibians then migrate from their hibernation sites to their breeding grounds. This research focused on the migratory habits of the Great crested newt (Triturus cristatus). The study explored factors like gender, body size, and environmental determinants, noting that immigration and emigration events proved distinct during the year. Results unveiled that males typically reached ponds first, with temperature being pivotal: males preferred up to 5 °C, females around 10 °C, while juveniles moved as temperatures increase. Wind velocity affected larger newts, around 120 mm, prompting them to migrate with stronger winds. Notably, heavy rainfall favored migration of newts of roughly 60 mm size. Humidity displayed gender-based trends: males associated positively with average levels, females showed aversion above 50%, and juveniles leaned towards drier conditions. Emigration patterns mirrored these findings, emphasizing roles of temperature, wind, and humidity. The effect of moonlight is not statistically significant. These findings provide valuable insights into the environmental factors influencing the migration of T. cristatus, which may guide future conservation efforts.

PRELIMINARY OBSERVATIONS REGARDING THE HERPETOLOGICAL FAUNA FROM CORCOVA (MEHEDINȚI COUNTY)

The paper presents preliminary data on amphibian and reptile fauna from Corcova (Mehedinți county). The commune, with an area of 75.32 km2, is located in the south-west of Romania (north-east of the county), on the right bank of the Motru River. Hills prevail in terms of landforms. The study aimed to update the herpetological database with new information resulting from research conducted between March and October 2022. The preliminary list includes: 10 species of amphibians (Urodela - 3 species: Salamandra salamandra, Triturus cristatus, Lissotriton vulgaris and Anura - 7 species: Bombina bombina, Hyla orientalis, Pelobates fuscus, Bufotes viridis, Rana dalmatina, Pelophylax kl. esculentus, P. ridibundus) and 11 species of reptiles (2 species of turtles: Testudo hermanni, Emys orbicularis; 4 species of lizards: Lacerta agilis, L. viridis, Podarcis tauricus, Anguis fragilis; 5 snake species: Dolichophis caspius, Coronella austriaca, Zamenis longissimus, Natrix natrix, N. tessellata). The variety of habitats, the temperate-continental climate with sub-Mediterranean influences, the trophic resource have influenced the diversity of herpetofauna in the area. The highlighted species of amphibians and reptiles are listed on different national protectionist lists (ordinances, laws, etc.). Species that are subject to special habitat conservation measures have drawn our attention: Testudo hermanni, Emys orbicularis, Triturus cristatus, Bombina bombina, Pelobates fuscus (Annex 3 to OUG 57/2007).

Good news from newts: distribution, population size, and dynamics of two protected newt species in the Jiu Gorge National Park, Romania

Long-time monitoring studies recently indicated that newts are in decline in many regions. Motivated by the above-mentioned, in the year 2019, we started monitoring the newt populations from the Jiu Gorge National Park (JGNP) in the Romanian Carpathians, 10 years after the previous study on the same topic. Compared with other areas where newts are in decline, we identified new distribution locations of the two newt species which are present in the park. Also, the previously known populations have greatly increased. Thus, the Lissotriton vulgaris population increased 2.58 times in 10 years, and the Triturus cristatus increased 1.80 times in 10 years. At the same time, in areas from JGNP affected by human activities in the past (abandoned quarry and areas adjacent to the railway), the newts extended their range in the last years and occupied artificial aquatic habitats. In the case of the populations from the natural habitat, the temporal dynamics and the ratio between sexes and species followed the same evolution as in the case of other populations from Romania. The increase of newt populations from JGNP in the last 10 years was most probably a consequence of the reduced human pressure, corroborated with the large surface occupied by native forests in the park. Thus, in natural areas, probably the best management measures for both newt species are not represented by direct (invasive) human interventions but by the conservation of the natural habitats used by the newts. A protected area should maintain the conservation status at least at the present level, and if the region is natural, this fact will maintain and also increase the newt and probably other amphibian populations.

Genetic diversity, gene flow, and landscape resistance in a pond-breeding amphibian in agricultural and natural forested landscapes in Norway.

Genetic diversity is a key part of biodiversity, threatened by human activities that lead to loss of gene flow and reduction of effective population sizes. Gene flow is a result of both landscape connectivity and demographic processes determining the number of dispersing individuals in space and time. Thus, the effect of human impact on processes determining the level of genetic diversity must be interpreted in the context of basic ecological conditions affecting survival and recruitment. When the intensity of human impact and habitat suitability correlate, the effect on genetic diversity and gene flow may be challenging to predict. We compared genetic diversity, gene flow and landscape resistance in two contrasting landscapes in Norway for the pond-breeding amphibian Triturus cristatus: a highly human-impacted, agricultural landscape with ecologically productive habitats, and a forested landscape with less productive habitats and lower levels of human impact. Our results show that genetic diversity was higher and gene flow lower within the forested landscape. Microclimatic moisture conditions and vegetation cover were important determinants of landscape resistance to gene flow within both landscapes. There were indications that landscape resistance was increased by minor roads in the forested landscape, which was not the case for the agricultural landscape, suggesting a higher vulnerability to human interference within the landscape matrix for the populations in less productive habitats. Our findings suggest that the effect of human impact on genetic diversity may not be straightforward but modulated by the ecological conditions underlying local demographic processes. Populations within both landscapes seem to be vulnerable to loss of genetic diversity, but due to different mechanisms. This has implications for the choice of relevant management actions, that is, increasing population stability may be more relevant within an agricultural landscape still permeable for dispersal, while conserving dispersal corridors may be more appropriate in the forested landscape, to avoid isolation and increased genetic drift.

The Great Crested Newt, Triturus cristatus (Laurenti 1768) (Caudata, Salamandridae), near the Eastern Limit of Its Distribution Area in the Middle Urals

The Great Crested Newt, Triturus cristatus (Laurenti 1768) (Caudata, Salamandridae), near the Eastern Limit of Its Distribution Area in the Middle Urals

Robustness of resistance surface optimisations: sampling schemes and genetic distance metrics affect inferences in landscape genetics

ContextLandscape genetics provides powerful tools to quantify the effects of landscape features on population connectivity, but robust results are imperative to inform conservation planning.ObjectivesThe robustness of landscape genetic inferences was assessed using the case of the northern crested newt (Triturus cristatus) in Luxembourg. Specifically, the effect of different study designs and genetic distance metrics was tested in terms of model convergence and misspecification rates (Type I error).MethodsThe optimisation of resistance surfaces was performed in ResistanceGA, using individual- and population-based sampling designs and 16 genetic distance metrics inferred from 897 multilocus genotypes from 85 locations. Empirical results were complemented with simulations to assess Type I error rates and correlation between ‘true’ and optimised resistance surfaces.ResultsIndividual-based optimisations seemed prone to overfitting, with little convergence among empirical resistance surfaces from different sets of individuals. Simulations showed significant differences in performance among population genetic distance metrics. Linear topographical features exhibited higher Type I error rates (83.3%) than continuous features (44.9%), suggesting potential underestimation of road-induced fragmentation effects. Jost’s D, {F}_{ST}, and PCA axes 1–45 were the top three genetic distance metrics for recovering true resistance features. Topographic roughness consistently drove spatial genetic clustering of T. cristatus, but variability existed among conductivity maps derived from optimised resistance surfaces.ConclusionsThese findings underscore the importance of carefully selecting genetic distance metrics and addressing potential sources of uncertainty in resistance surface optimisation. By doing so, we can enhance the effectiveness of conservation planning efforts for T. cristatus and species with similar ecological considerations.

Demographic and ecological niche dynamics of the Vietnam warty newt, Paramesotriton deloustali: Historical climate influences.

Quaternary climatic cycles strongly affected the genetic diversification and ranges of organisms, shaping current genetic structures and distribution patterns. Urodeles provide ideal examples for exploring these dynamics over time and across space. In this study, we integrated a phylogeographic approach and ensemble species distribution modeling (eSDM) to infer the historical demography and distribution patterns of the Vietnam warty newt, Paramesotriton deloustali. Mitochondrial data revealed two groups, West and East, which diverged approximately 1.92 million years ago (Mya). Diversification was likely driven by change in the climate during early stages of the Pleistocene, with increasing monsoon and drought intensities. Biogeographic analysis indicated that the newt's current distribution formed as a result of vicariance events. In addition, the two groups occupy distinct ecological niches. Demographic reconstruction showed signs of expansion in the effective population sizes of the two major groups beginning around 0.11 and 0.15 Mya, respectively. However, eSDM showed fluctuating predicted distributions during the last interglacial, last glacial maximum, mid-Holocene, and present. Mountain systems in northern Vietnam are likely to have served as climatic refuges and to have played a crucial role in safeguarding species from the effects of climate change.

Using eDNA to understand predator–prey interactions influenced by invasive species

Invasive predatory species may alter population dynamic processes of their prey and impact biological communities and ecosystem processes. Revealing biotic interactions, however, including the relationship between predator and prey, is a difficult task, in particular for species that are hard to monitor. Here, we present a case study that documents the utility of environmental DNA analysis (eDNA) to assess predator–prey interactions between two invasive fishes (Lepomis gibbosus, Pseudorasbora parva) and two potential amphibian prey species, (Triturus cristatus, Pelobates fuscus). We used species-specific TaqMan assays for quantitative assessment of eDNA concentrations from water samples collected from 89 sites across 31 ponds during three consecutive months from a local amphibian hotspot in Germany. We found a negative relationship between eDNA concentrations of the predators (fishes) and prey (amphibians) using Monte-Carlo tests. Our study highlights the potential of eDNA application to reveal predator–prey interactions and confirms the hypothesis that the observed local declines of amphibian species may be at least partly caused by recently introduced invasive fishes. Our findings have important consequences for local conservation management and highlight the usefulness of eDNA approaches to assess ecological interactions and guide targeted conservation action.

Amphibians and reptiles in North Sweden: distribution, habitat affinities, and abundance (Classes: Amphibia and Reptilia).

North Sweden ('Norrland' in Swedish) covers 243000 km2 and lies mainly in the boreal biome. The herpetofauna comprises five amphibian and four reptile species: Lissotriton vulgaris, Triturus cristatus, Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, Anguis fragilis, Natrix natrix, and Vipera berus. Successful conservation and management of amphibians and reptiles depend on accurate information about distribution, habitat affinities, and abundance. Such knowledge is also essential as a benchmark to assess changes in distribution and abundance that may come about as a result of climate change and human habitat alteration. This paper aims to present accurate distribution maps, describe habitat affinities, and provide abundance estimates for the herpetofauna of North Sweden for the period 1970-2022. Distribution data are presented by traditional faunistic provinces, as well as by biotic regions and alpine life zones. Separate sections address post-glacial colonization and a herpetological perspective on anthropogenic changes in relation to species´ present status. Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, and Vipera berus are widely distributed throughout the boreal sub-regions. Rana temporaria, Zootoca vivipara, and Vipera berus also extend into the alpine region. Triturus cristatus, Anguis fragilis, and Natrix natrix occur mainly in the coastal parts of the Southern Boreal region. There are no signs of recent changes in distribution range, but Lissotriton vulgaris, Triturus cristatus, and Rana arvalis have been largely overlooked in the past and have a much wider occurrence than previously recognized. Most species are found in habitats usually not described in all-European field guides. Nearly all anurans hibernate in water. Abundance estimates suggest that some species are more common in the boreal than thought, supporting the notion that a large share of their total European population occurs there. Although local extinctions and declines are known, there are no signs of widespread population decline for any species during the study period.

An experimental assessment of detection dog ability to locate great crested newts (Triturus cristatus) at distance and through soil.

Detection dogs are increasingly used to locate cryptic wildlife species, but their use for amphibians is still rather underexplored. In the present paper we focus on the great crested newt (Triturus cristatus), a European species which is experiencing high conservation concerns across its range, and assess the ability of a trained detection dog to locate individuals during their terrestrial phase. More specifically, we used a series of experiments to document whether a range of distances between target newts and the detection dog (odour channelled through pipes 68 mm in diameter) affects the localisation, and to assess the ability and efficiency of target newt detection in simulated subterranean refugia through 200 mm of two common soil types (clay and sandy soil, both with and without air vents to mimic mammal burrows, a common refuge used by T. cristatus). The detection dog accurately located all individual T. cristatus across the entire range of tested distances (0.25 m- 2.0 m). The substrate trials revealed that the detection dog could locate individuals also through soil. Contrary to existing studies with detection dogs in human forensic contexts, however, detection was generally slower for T. cristatus under sandy soil compared to clay soil, particularly when a vent was absent. Our study provides a general baseline for the use of detection dogs in locating T. cristatus and similar amphibian species during their terrestrial phase.

Pollutant accumulation in road mitigation tunnels for amphibians: A multisite comparison on an ignored but important issue

Underpasses or road tunnels are increasingly installed to reconnect habitats and ensure safe wildlife passage, thus preventing habitat fragmentation caused by roads and mortality from collisions with vehicles. In the UK, such underpasses are regularly implemented for amphibians and especially the protected great crested newt, Triturus cristatus. However, roads are also a key source of environmental pollutants including trace metals, road salt, petroleum and diesel hydrocarbons and these might impact road mitigation structures where amphibians are funnelled to, yet the extent and implications of such pollutants are almost never quantified in relation to this aspect, despite the recognised sensitivity of amphibians to chemical pollutants. Sediments were analysed from four amphibian road mitigation tunnel sites across the UK and compared to natural soil formations at local reference sites to determine whether contaminants were indeed accumulating within the tunnels. Three potential contaminants (copper, lead, and total petroleum hydrocarbons) were found in greater concentrations in the underpass sediments than respective reference sites at three of four locations, while one (zinc) was found in greater concentrations at all four studied underpasses compared to reference sites. Aggregated sediment pH value was significantly greater in the underpass sediment than the respective reference sites at all four study sites and in several instances the contaminants reached values that exceeded the thresholds of environmental concern. Despite the large geographic area covered and the significant site differences the absolute values of potential pollutants in tunnels were similar across sites, thus suggesting similar pollution sources and pathways. These results suggest road tunnels installed for ecological mitigation could be a significant pathway for pollutants from road surfaces to amphibians and it is recommended that focussed monitoring and maintenance of the underpasses is enacted given that their short or long-term impacts on amphibians are currently unknown. Potential management options could include regular jet-washing of the underpasses, or alternatively, pre- or post-implementation modifications of mitigation designs should aim to minimise the pollution pathway from road surfaces.

Comparing trap and bait efficiency to record the great crested newts (Triturus cristatus)

A crucial aspect of conservation management for endangered newt species is the establishment of a monitoring methodology and the evaluation of trap efficacy to ensure the accuracy of data collection. In this study, we assessed three funnel trap types (prism shape, umbrella shape, and Ortmann's trap) to capture great crested newts (Triturus cristatus). We also tested three baits (chicken liver, chemical lights in glow sticks, and control traps without bait) and determined the optimal trap control time within a 12 h period. Our findings showed that the umbrella shape trap was most effective, catching five times more newts than the Ortmann's and prism shape traps. Surprisingly, the commonly used prism shape trap performed poorly. Bait type did not significantly impact newt captures compared to control traps. During the 12 h experiment, newts spent the longest time in the chicken liver-baited Ortmann's trap (averaging 4.5 h), while the umbrella shape trap with chicken liver bait had the highest turnover of individuals. We observed no behavioural response from “trap-shy” individuals. This study emphasizes the importance of selecting appropriate traps, considering bait choice, and trap control time for effective monitoring of endangered newt populations.

Great Crested Newts (Triturus cristatus Laurenti 1768) found trapped in an abandoned car tire at Litcham Common, Norfolk

Great Crested Newts (Triturus cristatus Laurenti 1768) found trapped in an abandoned car tire at Litcham Common, Norfolk