Characterisation, prevalence and severity of skin lesions caused by ophidiomycosis in a population of wild snakes.

Ophidiomycosis is an emerging infectious disease affecting wild snakes in the Northern Hemisphere. Recently confirmed in Great Britain, the prevalence, severity and significance of ophidiomycosis has yet to be characterised in free-living snakes at a population level in Europe. Therefore, a population of barred grass snakes (Natrix helvetica) in eastern England was monitored for three seasons (May 2019 to October 2021), to investigate the prevalence (25.5%; 191/750 snakes) and severity of skin lesions and their aetiology. The most frequently observed skin lesion characteristics were changes in scale colour, crusting, and scale margin erosion. The majority of such lesions (96.9%; 185/191 snakes) was observed on the ventral surface along the length of the body. The severity of skin lesions was considered mild in more than half of the cases (53.1%; 98/191 snakes). Predominantly, skin lesions were observed in adult snakes (72.8%; 139/191 snakes). Combined histological examinations and qPCR tests of skin lesions from N. helvetica sloughs and/or carcasses confirmed a diagnosis of ophidiomycosis. Further targeted surveillance, supported by molecular and histological examinations to confirm skin lesion aetiology, is required to determine the extent to which our findings reflect the occurrence of ophidiomycosis in populations within wider landscapes.

Activity patterns and reproductive behavior of the Critically Endangered Bermuda skink (Plestiodon longirostris).

The study of rare or cryptic species in zoos can provide insights into natural history and behavior that would be difficult to obtain in the field. Such information can then be used to refine population assessment protocols and conservation management. The Bermuda skink (Plestiodon longirostris) is an endemic Critically Endangered lizard. Chester Zoo's successful conservation breeding program is working to safeguard, increase and reinforce skink populations in the wild. A key aim of this program is to develop our understanding of the behavior of this species. In this study, using 24 h video recordings, we examined the daily activity patterns, basking behavior and food preferences of four pairs of Bermuda skinks. The skinks displayed a bimodal pattern of activity and basking, which may have evolved to avoid the strength of the midday sun in exposed habitats in Bermuda. Captive Bermuda skinks appear to prefer a fruit-based diet to orthopteran prey. We also documented their reproductive behavior and compared it against two closely related species. Although there were many similarities between the courtship and mating behaviors of the three species, there was a significantly shorter period of cloacal contact in the Bermuda skink. Oophagia was also documented for the first time in this species. This knowledge has enabled the evaluation of the current ex-situ management practices of this species, filled gaps in knowledge that would be challenging to obtain in the field, and enabled the enhancement of both animal husbandry and reproductive success for the conservation breeding program.

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

Reliability of environmental DNA surveys to detect pond occupancy by newts at a national scale.

The distribution assessment and monitoring of species is key to reliable environmental impact assessments and conservation interventions. Considerable effort is directed towards survey and monitoring of great crested newts (Triturus cristatus) in England. Surveys are increasingly undertaken using indirect methodologies, such as environmental DNA (eDNA). We used a large data set to estimate national pond occupancy rate, as well as false negative and false positive error rates, for commercial eDNA protocols. Additionally, we explored a range of habitat, landscape and climatic variables as predictors of pond occupancy. In England, 20% of ponds were estimated to be occupied by great crested newts. Pond sample collection error rates were estimated as 5.2% false negative and 1.5% false positive. Laboratory error indicated a negligible false negative rate when 12 qPCR replicates were used. Laboratory false positive error was estimated at 2% per qPCR replicate and is therefore exaggerated by high levels of laboratory replication. Including simple habitat suitability variables into the model revealed the importance of fish, plants and shading as predictors of newt presence. However, variables traditionally considered as important for newt presence may need more precise and consistent measurement if they are to be employed as reliable predictors in modelling exercises.

Zoos and amphibian conservation: Evaluating the impact of "The Year of The Frog" Campaign.

The global reach of zoos has enormous potential to raise awareness of conservation issues such as the amphibian extinction crisis. One mechanism of achieving this is through targeted, time-limited campaigns. However, the longer-term impact of such campaigns on conservation outcomes is rarely evaluated. The goal of this study is to evaluate how zoos view "The Year of The Frog," a campaign launched by zoos in 2008, with the aim of raising awareness of the global amphibian crisis and generating funds to support amphibian conservation initiatives. A questionnaire-based survey of 43 zoos from fourteen countries was used to evaluate how zoo practitioners believed the campaign influenced amphibian conservation some 10 years after its launch. Survey results showed that the campaign not only contributed to the improvement of research into amphibian husbandry in zoos but also increased support of in situ conservation of amphibians. Zoos focused on exotic species, but developed countries led most of the actions of the campaign. The campaign has inspired and encouraged some zoos and other ex situ conservation organizations to embrace amphibian conservation. The next step is to increase collaboration with more organizations through, for example, AArk and IUCN SSC/ASG, particularly in countries that have high amphibian biodiversity.

Survival of climate warming through niche shifts: Evidence from frogs on tropical islands.

How will organisms cope when forced into warmer-than-preferred thermal environments? This is a key question facing our ability to monitor and manage biota as average annual temperatures increase, and is of particular concern for range-limited terrestrial species unable to track their preferred climatic envelope. Being ectothermic, desiccation prone, and often spatially restricted, island-inhabiting tropical amphibians exemplify this scenario. Pre-Anthropocene case studies of how insular amphibian populations responded to the enforced occupation of warmer-than-ancestral habitats may add a valuable, but currently lacking, perspective. We studied a population of frogs from the Seychelles endemic family Sooglossidae which, due to historic sea-level rise, have been forced to occupy a significantly warmer island (Praslin) than their ancestors and close living relatives. Evidence from thermal activity patterns, bioacoustics, body size distributions, and ancestral state estimations suggest that this population shifted its thermal niche in response to restricted opportunities for elevational dispersal. Relative to conspecifics, Praslin sooglossids also have divergent nuclear genotypes and call characters, a finding consistent with adaptation causing speciation in a novel thermal environment. Using an evolutionary perspective, our study reveals that some tropical amphibians have survived episodes of historic warming without the aid of dispersal and therefore may have the capacity to adapt to the currently warming climate. However, two otherwise co-distributed sooglossid species are absent from Praslin, and the deep evolutionary divergence between the frogs on Praslin and their closest extant relatives (~8 million years) may have allowed for gradual thermal adaptation and speciation. Thus, local extinction is still a likely outcome for tropical frogs experiencing warming climates in the absence of dispersal corridors to thermal refugia.

Daily activity profile of the golden mantella in the "Froggotron"-A replicated behavioral monitoring system for amphibians.

Research on threatened species in zoos can provide vital information to inform conservation planning and implementation in the field. This is particularly important for rare and cryptic species with behavior patterns that are difficult to observe in the wild. The Critically Endangered golden mantella (Mantella aurantiaca) is an iconic, endemic frog confined to mid-altitude subhumid forest in Moramanga District, Madagascar. Ecological and behavioral data for this highly threatened species are sparse, and conservation work will need to be informed by both in situ and ex situ research on behavior and habitat preferences. This study utilized environmental information gathered in the field to design a system where behavior and microhabitat use could be measured in captivity. Using replicated climatically controlled chambers (the "Froggotrons"), we analysed the 24-h activity profile of the golden mantella in relation to temperature and humidity. Golden mantellas showed a bimodal pattern of activity during the day with much less activity during the night. Frogs kept at warmer temperatures (20-25°C) were more active than those kept under cooler conditions (16-19°C). However, the bimodal pattern was retained under the different temperatures, although the second peak occurred slightly earlier under warmer conditions. Most activity was observed when humidity levels were above 85%, although less than half of the mantellas were active outside leaf microhabitats during peak periods. These findings can inform ongoing field surveys through determining the optimum times of day to either capture or count golden mantellas for further conservation actions.

Optimising sampling and analysis protocols in environmental DNA studies.

Ecological surveys risk incurring false negative and false positive detections of the target species. With indirect survey methods, such as environmental DNA, such error can occur at two stages: sample collection and laboratory analysis. Here we analyse a large qPCR based eDNA data set using two occupancy models, one of which accounts for false positive error by Griffin et al. (J R Stat Soc Ser C Appl Stat 69: 377-392, 2020), and a second that assumes no false positive error by Stratton et al. (Methods Ecol Evol 11: 1113-1120, 2020). Additionally, we apply the Griffin et al. (2020) model to simulated data to determine optimal levels of replication at both sampling stages. The Stratton et al. (2020) model, which assumes no false positive results, consistently overestimated both overall and individual site occupancy compared to both the Griffin et al. (2020) model and to previous estimates of pond occupancy for the target species. The inclusion of replication at both stages of eDNA analysis (sample collection and in the laboratory) reduces both bias and credible interval width in estimates of both occupancy and detectability. Even the collection of > 1 sample from a site can improve parameter estimates more than having a high number of replicates only within the laboratory analysis.

Using GPS-enabled decoy turtle eggs to track illegal trade.

The insatiable human appetite for wildlife products drives species to extinction, spreads disease and has negative consequences for the economies of source countries [1,2]. As a major transnational enterprise, illegal wildlife trade is valued between eight and 26.5 billion US dollars annually [3,4]. Because law enforcement is often only reactive, information on trafficking routes is key to disrupting trade and curtailing wildlife crime. In our efforts to uncover trade routes of trafficked sea turtle eggs, we developed and field-tested the InvestEGGator, a 3D-printed decoy turtle egg embedded with a GPS-GSM transmitter (Supplemental Information). Illegally collected clutches of turtle eggs containing a decoy transmitter enabled us to track the movements of traffickers, and thus gain a better understanding of illegal trade routes. The decoys, set to emit a signal once an hour, provided five tracks, the most detailed of which identified an entire trade chain, covering 137 km. Using data provided by the decoys, we identified trafficking routes and on two occasions properties of potential interest to law enforcement. Decoys also yielded anecdotal information, furthering our understanding of trafficking routes.

Drivers of amphibian population dynamics and asynchrony at local and regional scales.

Identifying the drivers of population fluctuations in spatially distinct populations remains a significant challenge for ecologists. Whereas regional climatic factors may generate population synchrony (i.e. the Moran effect), local factors including the level of density dependence may reduce the level of synchrony. Although divergences in the scaling of population synchrony and spatial environmental variation have been observed, the regulatory factors that underlie such mismatches are poorly understood. Few previous studies have investigated how density-dependent processes and population-specific responses to weather variation influence spatial synchrony at both local and regional scales. We addressed this issue in a pond-breeding amphibian, the great crested newt Triturus cristatus. We used capture-recapture data collected through long-term surveys in five T. cristatus populations in Western Europe. In all populations-and subpopulations within metapopulations-population size, annual survival and recruitment fluctuated over time. Likewise, there was considerable variation in these demographic rates between populations and within metapopulations. These fluctuations and variations appear to be context-dependent and more related to site-specific characteristics than local or regional climatic drivers. We found a low level of demographic synchrony at both local and regional levels. Weather has weak and spatially variable effects on survival, recruitment and population growth rate. In contrast, density dependence was a common phenomenon (at least for population growth) in almost all populations and subpopulations. Our findings support the idea that the Moran effect is low in species where the population dynamics more closely depends on local factors (e.g. population density and habitat characteristics) than on large-scale environmental fluctuation (e.g. regional climatic variation). Such responses may have far-reaching consequences for the long-term viability of spatially structured populations and their ability to respond to large-scale climatic anomalies.

A comparison of understanding of the amphibian crisis by zoo visitors across three countries.

Despite the global declines in the rate of amphibians, evaluation of public understanding of the crisis has not yet been carried out. We surveyed visitors (n = 1,293) at 15 zoos in Brazil, New Zealand, and the United Kingdom, using a certainty-based assessment method to compare visitor knowledge of the global amphibian crisis. We further analyzed zoo educational material about amphibians to explore its potential to raise awareness through amphibian-focused environmental education. Visitors in the three countries had relatively little understanding of amphibians and the global amphibian crisis. When the degree of confidence in answering the questions (high, medium, and low) is accounted for, correct answers varied between 28% and 39%. This compared to scores of between 58% and 73% when the degree of confidence in responding was not accounted for. However, specific areas of knowledge (e.g., biology, conservation, biogeography, and conceptual ideas) varied significantly across the countries. Visitors had a weaker grasp of biogeographical and conservation issues than general amphibian biology. Zoo visitors in Brazil knew less about amphibian conservation than those in New Zealand or the United Kingdom. There was less amphibian-focused content in educational materials in zoos in Brazil than there was in the United Kingdom. Improving information about the global amphibian crisis may increase support for future conservation actions. Outreach education is one of the most important approaches in any strategic planning for conservation of species. Amphibian-focused environmental education at institutions such as zoos and aquaria can be a crucial intervention to support amphibian conservation worldwide.

Reservoir frogs: seasonality of Batrachochytrium dendrobatidis infection in robber frogs in Dominica and Montserrat.

Emerging infectious diseases are an increasingly important threat to wildlife conservation, with amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis, the disease most commonly associated with species declines and extinctions. However, some amphibians can be infected with B. dendrobatidis in the absence of disease and can act as reservoirs of the pathogen. We surveyed robber frogs (Eleutherodactylus spp.), potential B. dendrobatidis reservoir species, at three sites on Montserrat, 2011-2013, and on Dominica in 2014, to identify seasonal patterns in B. dendrobatidis infection prevalence and load (B. dendrobatidis genomic equivalents). On Montserrat there was significant seasonality in B. dendrobatidis prevalence and B. dendrobatidis load, both of which were correlated with temperature but not rainfall. B. dendrobatidis prevalence reached 35% in the cooler, drier months but was repeatedly undetectable during the warmer, wetter months. Also, B. dendrobatidis prevalence significantly decreased from 53.2% when the pathogen emerged on Montserrat in 2009 to a maximum 34.8% by 2011, after which it remained stable. On Dominica, where B. dendrobatidis emerged seven years prior to Montserrat, the same seasonal pattern was recorded but at lower prevalence, possibly indicating long-term decline. Understanding the dynamics of disease threats such as chytridiomycosis is key to planning conservation measures. For example, reintroductions of chytridiomycosis-threatened species could be timed to coincide with periods of low B. dendrobatidis infection risk, increasing potential for reintroduction success.

Removal models accounting for temporary emigration.

Removal of protected species from sites scheduled for development is often a legal requirement in order to minimize the loss of biodiversity. The assumption of closure in the classic removal model will be violated if individuals become temporarily undetectable, a phenomenon commonly exhibited by reptiles and amphibians. Temporary emigration can be modeled using a multievent framework with a partial hidden process, where the underlying state process describes the movement pattern of animals between the survey area and an area outside of the study. We present a multievent removal model within a robust design framework which allows for individuals becoming temporarily unavailable for detection. We demonstrate how to investigate parameter redundancy in the model. Results suggest the use of the robust design and certain forms of constraints overcome issues of parameter redundancy. We show which combinations of parameters are estimable when the robust design reduces to a single secondary capture occasion within each primary sampling period. Additionally, we explore the benefit of the robust design on the precision of parameters using simulation. We demonstrate that the use of the robust design is highly recommended when sampling removal data. We apply our model to removal data of common lizards, Zootoca vivipara, and for this application precision of parameter estimates is further improved using an integrated model.

Seasonal variation in environmental DNA detection in sediment and water samples.

The use of aquatic environmental DNA (eDNA) to detect the presence of species depends on the seasonal activity of the species in the sampled habitat. eDNA may persist in sediments for longer than it does in water, and analysing sediment could potentially extend the seasonal window for species assessment. Using the great crested newt as a model, we compare how detection probability changes across the seasons in eDNA samples collected from both pond water and pond sediments. Detection of both aquatic and sedimentary eDNA varied through the year, peaking in the summer (July), with its lowest point in the winter (January): in all seasons, detection probability of eDNA from water exceeded that from sediment. Detection probability of eDNA also varied between study areas, and according to great crested newt habitat suitability and sediment type. As aquatic and sedimentary eDNA show the same seasonal fluctuations, the patterns observed in both sample types likely reflect current or recent presence of the target species. However, given the low detection probabilities found in the autumn and winter we would not recommend using either aquatic or sedimentary eDNA for year-round sampling without further refinement and testing of the methods.

Species identification by conservation practitioners using online images: accuracy and agreement between experts.

Emerging technologies have led to an increase in species observations being recorded via digital images. Such visual records are easily shared, and are often uploaded to online communities when help is required to identify or validate species. Although this is common practice, little is known about the accuracy of species identification from such images. Using online images of newts that are native and non-native to the UK, this study asked holders of great crested newt (Triturus cristatus) licences (issued by UK authorities to permit surveying for this species) to sort these images into groups, and to assign species names to those groups. All of these experts identified the native species, but agreement among these participants was low, with some being cautious in committing to definitive identifications. Individuals' accuracy was also independent of both their experience and self-assessed ability. Furthermore, mean accuracy was not uniform across species (69-96%). These findings demonstrate the difficulty of accurate identification of newts from a single image, and that expert judgements are variable, even within the same knowledgeable community. We suggest that identification decisions should be made on multiple images and verified by more than one expert, which could improve the reliability of species data.

The biorhythm of human skeletal growth.

Evidence of a periodic biorhythm is retained in tooth enamel in the form of Retzius lines. The periodicity of Retzius lines (RP) correlates with body mass and the scheduling of life history events when compared between some mammalian species. The correlation has led to the development of the inter-specific Havers-Halberg oscillation (HHO) hypothesis, which holds great potential for studying aspects of a fossil species biology from teeth. Yet, our understanding of if, or how, the HHO relates to human skeletal growth is limited. The goal here is to explore associations between the biorhythm and two hard tissues that form at different times during human ontogeny, within the context of the HHO. First, we investigate the relationship of RP to permanent molar enamel thickness and the underlying daily rate that ameloblasts secrete enamel during childhood. Following this, we develop preliminary research conducted on small samples of adult human bone by testing associations between RP, adult femoral length (as a proxy for attained adult stature) and cortical osteocyte lacunae density (as a proxy for the rate of osteocyte proliferation). Results reveal RP is positively correlated with enamel thickness, negatively correlated with femoral length, but weakly associated with the rate of enamel secretion and osteocyte proliferation. These new data imply that a slower biorhythm predicts thicker enamel for children but shorter stature for adults. Our results develop the intra-specific HHO hypothesis suggesting that there is a common underlying systemic biorhythm that has a role in the final products of human enamel and bone growth.

Practitioner and scientist perceptions of successful amphibian conservation.

Conservation requires successful outcomes. However, success is perceived in many different ways depending on the desired outcome. Through a questionnaire survey, we examined perceptions of success among 355 scientists and practitioners working on amphibian conservation from over 150 organizations in more than 50 countries. We also sought to identify how different types of conservation actions and respondent experience and background influenced perceptions. Respondents identified 4 types of success: species and habitat improvements (84% of respondents); effective program management (36%); outreach initiatives such as education and public engagement (25%); and the application of science-based conservation (15%). The most significant factor influencing overall perceived success was reducing threats. Capacity building was rated least important. Perceptions were influenced by experience, professional affiliation, involvement in conservation practice, and country of residence. More experienced practitioners associated success with improvements to species and habitats and less so with education and engagement initiatives. Although science-based conservation was rated as important, this factor declined in importance as the number of programs a respondent participated in increased, particularly among those from less economically developed countries. The ultimate measure of conservation success-population recovery-may be difficult to measure in many amphibians; difficult to relate to the conservation actions intended to drive it; and difficult to achieve within conventional funding time frames. The relaunched Amphibian Conservation Action Plan provides a framework for capturing lower level processes and outcomes, identifying gaps, and measuring progress.

Optimising monitoring efforts for secretive snakes: a comparison of occupancy and N-mixture models for assessment of population status.

A fifth of reptiles are Data Deficient; many due to unknown population status. Monitoring snake populations can be demanding due to crypsis and low population densities, with insufficient recaptures for abundance estimation via Capture-Mark-Recapture. Alternatively, binomial N-mixture models enable abundance estimation from count data without individual identification, but have rarely been successfully applied to snake populations. We evaluated the suitability of occupancy and N-mixture methods for monitoring an insular population of grass snakes (Natrix helvetica) and considered covariates influencing detection, occupancy and abundance within remaining habitat. Snakes were elusive, with detectability increasing with survey effort (mean: 0.33 ± 0.06 s.e.m.). The probability of a transect being occupied was moderate (mean per kilometre: 0.44 ± 0.19 s.e.m.) and increased with transect length. Abundance estimates indicate a small threatened population associated to our transects (mean: 39, 95% CI: 20-169). Power analysis indicated that the survey effort required to detect occupancy declines would be prohibitive. Occupancy models fitted well, whereas N-mixture models showed poor fit, provided little extra information over occupancy models and were at greater risk of closure violation. Therefore we suggest occupancy models are more appropriate for monitoring snakes and other elusive species, but that population trends may go undetected.

The power of monitoring: optimizing survey designs to detect occupancy changes in a rare amphibian population.

Biodiversity conservation requires reliable species assessments and rigorously designed surveys. However, determining the survey effort required to reliably detect population change can be challenging for rare, cryptic and elusive species. We used a tropical bromeliad-dwelling frog as a model system to explore a cost-effective sampling design that optimizes the chances of detecting a population decline. Relatively few sampling visits were needed to estimate occupancy and detectability with good precision, and to detect a 30% change in occupancy with 80% power. Detectability was influenced by observer expertise, which therefore also had an effect on the sampling design - less experienced observers require more sampling visits to detect the species. Even when the sampling design provides precise parameter estimates, only moderate to large changes in occupancy will be detected with reliable power. Detecting a population change of 15% or less requires a large number of sites to be surveyed, which might be unachievable for range-restricted species occurring at relatively few sites. Unless there is high initial occupancy, rare and cryptic species will be particularly challenging when it comes to detecting small population changes. This may be a particular issue for long-term monitoring of amphibians which often display low detectability and wide natural fluctuations.

Future of keeping pet reptiles and amphibians: towards integrating animal welfare, human health and environmental sustainability.

The keeping of exotic pets is currently under debate and governments of several countries are increasingly exploring the regulation, or even the banning, of exotic pet keeping. Major concerns are issues of public health and safety, animal welfare and biodiversity conservation. The keeping of reptiles and amphibians in captivity encompasses all the potential issues identified with keeping exotic pets, and many of those relating to traditional domestic pets. Within the context of risks posed by pets in general, the authors argue for the responsible and sustainable keeping of reptile and amphibian pets by private persons, based on scientific evidence and on the authors' own expertise (veterinary medicine, captive husbandry, conservation biology).