Do Active and Passive Antipredator Defences in the Toad Epidalea calamita Differ between Males and Females from Natural Habitats and Agrosystems?

Due to their assumed costs, simultaneous antipredator strategies are expected to face trade-offs, which, however, could be milder in individuals subjected to a more intense predator pressure. In this work, I studied the relationship between locomotion and parotoid glands in the natterjack toad, Epidalea calamita. Specifically, I predicted that individuals with reduced sprint speed would rely more on their chemical defences, having larger and more aposematically coloured parotoid glands. In addition, I expected this trade-off to be more evident in females and toads from pine grove habitats, because, according to previous work, males and toads from agrosystems are under greater predator pressure. However, sprint speed showed no relationship with coloration, but toads with proportionally greater parotoid glands were also proportionally faster. Thus, the costs of these antipredator traits might not be high enough to make them interfere, or the benefits of simultaneous optimisation of sprint speed and parotoid gland size might outweigh the costs of it in some individuals. In any case, habitat and sex did not affect these relationships, so the trends detected are valid across sexes and the habitats studied.

Population genetic structure of the Natterjack toad (Epidalea calamita) in Ireland: implications for conservation management

Molecular methods can play a crucial role in species management and conservation. Despite the usefulness of genetic approaches, they are often not explicitly included as part of species recovery plans and conservation practises. The Natterjack toad (Epidalea calamita) is regionally Red-Listed as Endangered in Ireland. The species is declining and is now present at just seven sites within a highly restricted range. This study used 13 highly polymorphic microsatellite markers to analyse the population genetic diversity and structure. Genetic diversity was high with expected heterozygosity between 0.55 and 0.61 and allelic richness between 4.77 and 5.92. Effective population sizes were small (Ne < 100 individuals), but not abnormal for pond breeding amphibians. However, there was no evidence of historical or contemporary genetic bottlenecks or high levels of inbreeding. We identified a positive relationship between Ne and breeding pond surface area, suggesting that environmental factors are a key determinant of population size. Significant genetic structuring was detected throughout the species’ range, and we identified four genetic entities that should be considered in the species’ conservation strategies. Management should focus on preventing further population declines and future loss of genetic diversity overall and within genetic entities while maintaining adequate local effective population size through site-specific protection, human-mediated translocations and head-start programs. The apparent high levels of genetic variation give hope for the conservation of Ireland’s rarest amphibian if appropriately protected and managed.

Development and validation of a quantitative qPCR assay for detecting Natterjack toad (Epidalea calamita) eDNA samples

The Natterjack toad (Epidalea calamita) is the rarest amphibian species in Ireland, regionally Red-Listed as Endangered. We applied an eDNA approach to detect species presence in breeding pond water samples. We developed a species-specific qPCR assay targeting the cytochrome c oxidase subunit I (COI). The assay was tested in silico, in vitro (DNA extracted from tissue) and in vivo (DNA extracted from water samples). Water samples were collected from five ponds with known Natterjack toad presence or absence to validate the sensitivity and specificity of the assay. The assay was shown to be highly specific to the Natterjack toad and tested positive only against toad tissue samples and eDNA samples from ponds with known species presence. We believe this method can be used for rapid assessment of species occurrence.

Zur Bedeutung der ‚Grünbrücke Kiebitzholm‘ (Schleswig-Holstein) für Amphibien

In den Jahren 2006 bis 2010 wurde die Amphibienfauna auf der Grünbrücke bei Kiebitzholm (Schleswig-Holstein, Norddeutschland), an den angrenzenden Straßensäumen beidseitig der Bundesautobahn (BAB) A21 sowie an Stillgewässern im 1,5 km Radius um die Grünbrücke untersucht. Im Untersuchungsgebiet konn- ten sieben Amphibienarten festgestellt werden, darunter Knoblauchkröte (Pelo- bates fuscus), Kreuzkröte (Epidalea calamita) und Moorfrosch (Rana arvalis), die landes- oder bundesweit als bestandsgefährdet gelten. Bei Knoblauchkröte und Moorfrosch handelt es sich zudem um bundesweit bedeutsame Zielarten für den Biotopverbund. Teichmolch (Lissotriton vulgaris), Erdkröte (Bufo bufo), Grasfrosch (Rana temporaria) und Moorfrosch wurden im Untersuchungszeitraum auf der Grünbrücke nachgewiesen. Der Kammmolch (Triturus cristatus) konnte nur auf der östlichen Rampe festgestellt werden. Die Grünbrücke diente den er- fassten Individuen offenbar in erster Linie zur Querung der BAB A21 und nur zum Teil auch als Sommerhabitat. Eine auf der östlichen Rampe angelegte Wildtränke wurde im Jahr 2010 erstmals von Teichmolch, Kammmolch und Moorfrosch als Laichgewässer genutzt. Knoblauchkröte und Kreuzkröte waren im Untersuchungsgebiet besonders selten. Sie traten in einem bzw. zwei Untersuchungsgewässern auf. Während die Kreuz- kröte auf beiden Seiten der Autobahn gefunden wurde, wurde die Knoblauchkröte nur westlich der Straße erfasst. Die übrigen festgestellten Amphibienarten traten in teilweise größeren Populationen auf beiden Seiten der BAB A21 auf. Die Funde dieser Arten auf der Grünbrücke zeigen, dass bereits ein Verbund zwischen diesem Que- rungsbauwerk und den Populationen in der Umgebung realisiert war.

Distribución, uso del hábitat y fenología de los anfibios en las Bardenas Reales de Navarra

Se actualiza la composición y distribución de las especies de anfibios en la Zona Especial de Conservación de las Bardenas Reales (Navarra), a partir de un seguimiento realizado en la primavera y verano de 2012 en 444 humedales potenciales para su reproducción. Se constata la presencia de siete especies de anfibios y la reproducción otoñal de Epidalea calamita (Laurenti, 1768), Pelodytes punctatus (Daudin, 1802) y Pelobates cultripes (Cuvier, 1829) en ciertos años, dependiente de precipitaciones producidas a finales de verano y principios de otoño. Otras tres especies presentes en decenios anteriores (Lissotriton helveticus (Razoumowsky, 1789), Discoglossus galganoi Capula, Nascetti, Lanza, Bullini y Crespo, 1985, y Hyla molleri Bedriaga, 1889) no fueron encontradas en los muestreos de 2012.

Telomere attrition with age in a wild amphibian population

Telomere shortening with age has been documented in many organisms, but few studies have reported telomere length measurements in amphibians, and no information is available for growth after metamorphosis, nor in wild populations. We provide both cross-sectional and longitudinal evidence of net telomere attrition with age in a wild amphibian population of natterjack toads ( Epidalea calamita ). Based on age-estimation by skeletochronology and qPCR telomere length measurements in the framework of an individual-based monitoring programme, we confirmed telomere attrition in recaptured males. Our results support that toads experience telomere attrition throughout their ontogeny, and that most attrition occurs during the first 1–2 years. We did not find associations between telomere length and inbreeding or body condition. Our results on telomere length dynamics under natural conditions confirm telomere shortening with age in amphibians and provide quantification of wide telomere length variation within and among age-classes in a wild breeding population.

The importance of long-term genetic monitoring of reintroduced populations: inbreeding in the natterjack toad (Epidalea calamita)

Genetic monitoring is an important, but frequently lacking, component of management actions to support long-term persistence in reintroduced populations. Populations that remain small, due to demographic processes and genetic diversity, are more likely to experience a second extinction event. The natterjack toad (Epidelea calamita) is legally protected in Britain and was the subject of a reintroduction programme in the 1990s. However, subsequent genetic assessment has been mostly lacking. The aim of this study was to assess the genetic diversity of two reintroduced populations of natterjack toads in order to inform conservation management. Adults were sampled and nine microsatellites amplified to assess neutral genetic variation within each site and for comparison with the source population. Inbreeding was observed at the reintroduction sites, as evidenced by high FIS values (0.43 and 0.72), low observed compared to expected heterozygosities, and significant deviation from Hardy-Weinberg equilibrium. Observed heterozygosity is currently lower in the reintroduction sites than it was in the source population at the time of the reintroductions (Red Rocks: 0.15±0.20; Talacre: 0.12±0.20; Ainsdale (source): 0.29). Evidence for a bottleneck was not found, although this is likely a result of sampling overlapping generations. No withinsite population structuring was observed. Such low genetic diversity has not previously been recorded in any natterjack population. Genetic rescue, combined with pool creation, is the most viable option for safeguarding the species at these sites into the future. Our work highlights the importance of ongoing genetic monitoring, in collaboration with conservation organisations, to support conservation management.