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Roads represent a severe threat to wildlife populations, especially during the rainy season when animals move between habitats to feed and reproduce. We monitored roadkilled amphibians and reptiles in a 2.5-km stretch of a secondary road in the state of Bahia, Brazil, for 47 days from November 2021 to February 2022. Our surveys registered 838 dead individuals of 18 identified species; most were amphibians of the family Leptodactylidae (87.5%), primarily juveniles. We often found individuals close to two extensive swamps at the road's edge. Reptiles (snakes and turtles) represented only 1.3% of all observed roadkill. Our results show that a single spot on a secondary road can significantly impact the local herpetofauna, and we emphasize the need for mitigation measures to avoid further population declines. Collisions with vehicles caused mass mortality and threaten amphibian and reptile populations on a road in Bahia state, Brazil. These populations involved 18 species with terrestrial and aquatic habits. Juveniles of amphibians were the most affected animals. Most roadkill was observed at the edge of the road in a stretch close to two swamps. Mitigation actions are necessary to curb roadkill of amphibians and reptiles at local and regional scales in Brazil. [ABSTRACT FROM AUTHOR]

A persistent 2-month long outbreak of Ranavirus in a natural community of amphibians contributed to a mass die-off of gopher frog tadpoles (Lithobates capito) and severe disease in striped newts (Notophthalmus perstriatus) in Florida. Ongoing mortality in L. capito and disease signs in N. perstriatus continued for 5 weeks after the first observation. Hemorrhagic disease and necrosis were diagnosed from pathological examination of L. capito tadpoles. We confirmed detection of a frog virus 3 (FV3)-like Ranavirus via quantitative PCR in all species. Our findings highlight the susceptibility of these species to Rv and the need for long-term disease surveillance during epizootics. [ABSTRACT FROM AUTHOR]

Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs ( Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg L −1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 μg L −1 atrazine exposed tadpoles ( p <  0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 μg L −1 and 500 μg L −1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 μg L −1 cause significant mortality in tadpoles, while concentrations ≥200 μg L −1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine. [ABSTRACT FROM AUTHOR]

Few hosts have many parasites while many hosts have few parasites. This axiom of macroparasite aggregation is so pervasive it is considered a general law in disease ecology, with important implications for the dynamics of host-parasite systems. Because of these dynamical implications, a significant amount of work has explored both the various mechanisms leading to parasite aggregation patterns and how to infer mechanism from these patterns. However, as many disease mechanisms can produce similar aggregation patterns, it is not clear whether aggregation itself provides any additional information about mechanism. Here we apply a 'constraint-based' approach developed in macroecology that allows us to explore whether parasite aggregation contains any additional information beyond what is provided by mean parasite load. We tested two constraint-based null models, both of which were constrained on the total number of parasites P and hosts H found in a sample, using data from 842 observed amphibian host-trematode parasite distributions. We found that constraint-based models captured ~85% of the observed variation in host-parasite distributions, suggesting that the constraints P and H contain much of the information about the shape of the host-parasite distribution. However, we also found that extending the constraint-based null models can identify the potential role of known aggregating mechanisms (such as host heterogeneity) and disaggregating mechanisms (such as parasite-induced host mortality) in constraining host-parasite distributions. Thus, by providing robust null models, constraint-based approaches can help guide investigations aimed at detecting biological processes that directly affect parasite aggregation above and beyond those that indirectly affect aggregation through P and H. [ABSTRACT FROM AUTHOR]

The objective of this work consists in valuing the carob pods (very rich in sugars and in nourishing elements) as being a medium of culture for growth of Lactobacillus bulgaricus and comparison this natural syrup with MRS medium for lactic acid production curve. By its biochemical composition, the carob syrup is very rich in carbohydrates 16 g/L, protein 0.25 %, ash 0.8 % including potassium (110 mg/100 mL of MF), sodium (80) and calcium (150). Kinetics study of growth of Lactobacillus bulgaricus in MRS and carob pods syrup showed that high biomass and lactic acid were obtained in the end of carob fermentations respectively (5.51 and 13.8) compared to MRS fermentation (4.57 and 10.9). This study clearly showed that carob pods have potential to be used as feedstock for lactic acid production by Lactobacillus bulgaricus using batch culture. [ABSTRACT FROM AUTHOR]

Studies of spawning water bodies in the city of Moscow have shown that the urban populations of common ( Rana temporaria) and moor ( R. arvalis) frogs are small compared with suburban populations, and their individuals lead a hidden mode of life. The recorded increase in the fecundity of females from several populations of the city of Moscow may be accompanied by an increase or the preservation of the diameter of eggs as compared with the same indicator for suburban populations. The populations in which the females produced many small eggs died out during the study period. The most prosperous populations are urban populations of brown frogs whose females spawned eggs of various sizes. We consider the formation of these clutches as a manifestation of the bet-hedging strategy compensating for mortality in adverse and unstable environmental conditions. [ABSTRACT FROM AUTHOR]

Amphibian mortality caused by rail traffic has not attracted much attention in comparison to road mortality. Density of railways in landscape, as well as traffic intensity, is usually much lower than in case of roads. As a consequence, their overall effect on amphibian populations is tacitly assumed to be less negative. To test whether very intensive rail traffic can cause substantial mortality in population of a small amphibian, we investigated a Smooth newt Lissotriton vulgaris population located in the city of Poznań, W Poland, where tram tracks border isolated breeding ponds. We performed controls during the peak of autumn migratory activity along the tracks. Less than 1% of all individuals found during the survey were killed by rail traffic. Observed mortality was very low despite large number of individuals present on the track and intensive tram traffic. As negative effects of traffic are low, rail or tram embankments can provide an important terrestrial habitat for small European newts. [ABSTRACT FROM AUTHOR]

Every spring, many of amphibians are killed by motor vehicles on roads. These road-killed animals can be used as valuable material for non-invasive studies showing the effect of environmental pollution on amphibian populations. The aims of our research were to check whether the phalanges of road-killed toads may be useful as material for histological analysis, and whether various degrees of human impact influence the level in bone abnormalities in the common toad. We also examined whether the sex and age structure of toads can differ significantly depending in the different sites. We chose three toad breeding sites where road-killed individuals had been observed: near the centre of a city, the outskirts of a city, and a rural site. We collected dead individuals during spring migration in 2013. The sex of each individual was determined and the toes were used to determine age using the skeletochronology method. While performing age estimates, we looked for abnormalities in relation to normal bone tissue structure. In urban site, females dominate males (sex ratio 2.6:1), but in populations from rural and semi-urban sites, sex ratio was reverse (1:2.2 and 1:1.4, respectively). However, we did not find any significant differences between age structure of all populations (average age of each population: approximately 4 years). We observed abnormalities in more than 80 % of all toads from the city, compared to approximately 20 % from the rural and semi-urban sites. In particular, we found hypertrophic bone cells, misaligned intercellular substance, and irregular outer edges of bones. We suggest that these malformations are caused by different pollution, e.g. with heavy metals. [ABSTRACT FROM AUTHOR]

There is growing evidence that pathogens play a role in population declines and species extinctions. For small populations, disease-induced extinction may be especially probable. We estimated the susceptibility of two amphibian species of conservation concern (the dusky gopher frog [ Lithobates sevosus] and boreal toad [ Anaxyrus boreas boreas]) to an emerging pathogen (ranavirus) using laboratory challenge experiments, and combined these data with published demographic parameter estimates to simulate the potential effects of ranavirus exposure on extinction risk. We included effects of life stage during pathogen exposure, pathogen exposure interval, hydroperiod of breeding habitat, population carrying capacity, and immigration in simulations. We found that both species were highly susceptible to ranavirus when exposed to the pathogen in water at environmentally relevant concentrations. Dusky gopher frogs experienced 100 % mortality in four of six life stages tested. Boreal toads experienced 100 % mortality when exposed as tadpoles or metamorphs, which were the only life stages tested. Simulations showed population declines, greater extinction probability, and faster times to extinction with ranavirus exposure. These effects were more evident with more frequent pathogen exposure intervals and lower carrying capacity. Immigration at natural rates did little to mitigate effects of ranavirus exposure unless immigration occurred every 2 years. Our results demonstrate that disease-induced extinction by emerging pathogens, such as ranavirus, is possible, and that threat may be especially high for species with small population sizes. For the species in this study, conservation organizations should incorporate ranavirus surveillance into monitoring programs and devise intervention strategies in the event that disease outbreaks occur. [ABSTRACT FROM AUTHOR]

ABSTRACT While the use of nanoparticles has dramatically increased in recent years, the ecological consequences are not well known. In particular, little research has been done to investigate the potentially detrimental effects of nanoparticles on amphibians, especially across all life-history stages of salamanders and newts (caudates). To address this dearth in knowledge, we examined the effects of zinc oxide (ZnO) nanoparticles on egg, larval, and adult Rough-skinned Newts ( Taricha granulosa). Chronic toxicity was tested on eggs and larvae, and acute toxicity was tested on eggs, larvae, and adults. For eggs, chronic exposure to ZnO nanoparticles caused higher mortality at 10.0 and 100.0 mg L−1 compared to 0.0, 0.1, and 1.0 mg L−1. When given an acute exposure (24 hr) to 10.0 mg L−1 nanoparticles at a late developmental stage, larvae hatched 5 days early, at a decreased developmental stage, and smaller size compared to the control. Chronic and acute exposure of larvae increased mortality up to 75% at both 10.0 and 100.0 mg L−1 and exhibited sublethal effects, most dramatically, severe gill degradation. These results suggest nanoparticles can have lethal and sublethal effects on all life stages of amphibians. [ABSTRACT FROM AUTHOR]

Habitat suitability is strongly regulated by seasonal conditions and stochastic processes, and this is especially important in temporary aquatic systems that contain organisms with complex life cycles. We investigated the potential for phenotypic plasticity in timing of and size at metamorphosis to mitigate effects of altered habitat conditions, specifically shortened hydroperiod (duration of water in ponds) and altered predator-prey dynamics, in the pond-breeding boreal chorus frog (Pseudacris maculata). We simulated reduced hydroperiod and concentrated predator cue in the laboratory to understand potential benefits and costs of plasticity. Tadpoles developed faster in response to the combined effects of reduced hydroperiod and increased concentration of predator cue, potentially due to reduced conspecific density. In contrast, there was no effect of reduced hydroperiod or predator cue on size at metamorphosis. Alone, this result suggests that phenotypic plasticity may allow P. maculata to escape the negative effects of rapidly drying ponds. However, tadpole survival was significantly lower in reduced hydroperiod treatments relative to all other treatments, suggesting that even if plasticity acts as a buffer against reduced hydroperiod by facilitating metamorphosis, heightened mortality may offset benefits of this rapid response. Our results add to previous studies of plastic responses in amphibians by disentangling the costs and benefits of plasticity in habitats with multiple, simultaneous stressors. We show that while plasticity may accelerate metamorphosis, similar, heightened levels of mortality are experienced regardless of plasticity. This implies that plasticity may not completely buffer populations against the effects of altered habitat conditions, such as those that occur with climate change or urbanization. [ABSTRACT FROM AUTHOR]

In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%), initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad). Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35). Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention. [ABSTRACT FROM AUTHOR]

Recent studies suggest that direct mortality and physiological effects caused by pollutants are major contributing factors to global amphibian decline. However, even sublethal concentrations of pollutants could be harmful if they combined with other factors to cause high mortality in amphibians. Here we show that sublethal concentrations of pollutants can disrupt the ability of amphibian larvae to recognize predators, hence increasing their risk of predation. This effect is indeed much more important since very low amounts of pollutants are ubiquitous, and environmental efforts are mostly directed towards preventing lethal spills. We analyzed the effects of two common contaminants (humic acid and ammonium nitrate) on the ability of tadpoles of the western spadefoot toad ( Pelobates cultripes ) to recognize chemical cues from a common predator, nymphs of the dragonfly Anax imperator . We compared the swimming activity of tadpoles in the presence and absence of water-borne chemical cues from dragonflies at different concentrations of humic acid and ammonium nitrate. Tadpoles reduced swimming activity in response to predator cues in the absence of pollutants, whereas they remained unresponsive to these cues when either humic acid or ammonium nitrate was added to the water, even at low concentrations. Moreover, changes in tadpole activity associated with the pollutants themselves were non-significant, indicating no toxic effect. Alteration of the natural chemical environment of aquatic systems by pollutants may be an important contributing cause for declines in amphibian populations, even at sublethal concentrations. [ABSTRACT FROM AUTHOR]

The article discusses the study on the mortality of amphibians and the outbreaks of ranavirus. This was based on the survey on the areas of Yellowstone National Park, Grand Teton National Park, and National Elk Refuge on diagnostic examinations of dead specimens and amphibian mortalities during visual encounter.

The article discusses the study on chytrid fungus Batrachochytrium dendrobatidis that can cause chytridiomycosis diseases to amphibians resulting to mortalities and population declines in species. The survey focused on biodiversity assessment and not on surveillance based on samples collected. Tables presented on the summary of samplings.

The article discusses the ranavirus, viruses within the family Iridoviridae found in amphibians which is considered as the cause of mortality on species. Amphibians infected with can display both physical and behavioral signs of infections. The virus was first detected at Nebraska, U.S. This has been detected on some countries such as Iowa, Nebraska, and South Dakota.

The article discusses the North American response to Batrachochytrium salamandrivorans (Bsal), a fungal pathogen that has caused deaths of native salamanders in Europe. The concern over the associated risk of Bsal to native salamanders in North America is noted. A call for the creation of a North American Bsal Strategic Plan to prevent the spread of the pathogen is also mentioned.

The size structure of a larval population facilitates interaction asymmetries that, in turn, influence the dynamics of size-structure. In species that exhibit conspicuous aggressive interactions, the competitive effects of the smaller individuals may be overlooked. We manipulated initial size differences between two larval cohorts and young-cohort density of Salamandra infraimmaculata in mesocosms to determine: (1) whether young individuals function primarily as prey or as competitors of older and larger individuals; (2) the resulting dynamics of size variation; and (3) recruitment to the postmetamorph population. Intercohort size differences generally remained constant over time at low young-cohort densities, but reduced over time at high densities due to retardation of the old-cohort growth rate. This suggests a competitive advantage to the young cohort that outweighs the interference advantage of older cohorts previously documented in this species. The increase in mortality from desiccation due to high young-cohort density was an order of magnitude greater in the old cohort than in the young-cohort, further indicating size-dependent vulnerability to competition. However, the conditions least favorable to most of the old-cohort larvae (large size difference and high young-cohort density) promoted cannibalism. Among cannibals, mortality and time to metamorphosis decreased and sizes at metamorphosis increased substantially. Thus, a balance between the competitive advantage to young cohorts, and the interference and cannibalism advantage to old cohorts shapes larval size-structure dynamics. Larval densities and individual expression of cannibalism can shift this balance in opposite directions and alter relative recruitment rates from different cohorts. [ABSTRACT FROM AUTHOR]

Animal populations that normally fluctuate in size in response to stochastic environmental events might be subject to unsustainably high mortality rates in the face of progressive habitat loss or degradation. This should perturb the population's age-structure in predictable ways if the increase in mortality is age- or stage-specific (i.e., a decline in recruitment should result in a progressively older adult population, whereas a decline in adult survivorship should result in a progressively younger adult population). We used skeletochronology to ascertain the ages of adult individuals in a population of Fowler's Toads, Anaxyrus ( = Bufo) fowleri, over 20 yr, spanning a period of regulated population fluctuation from 1992 to 2002 and a period of sustained population decline thereafter until 2011. Age structure was similar between sexes, but was highly variable during both periods. Although there was no temporal trend detected in average age among 420 toads during the predecline period, 1992-2000, there was an increase in average age among 469 toads during the decline period, 2002-2011, with no significant change in adult survivorship. This evidence of an aging population is consistent with a reduction in recruitment in the population, related to the progressive loss of breeding habitat caused by an invasive plant, demonstrating that amphibian populations may be threatened with decline even when mortal threats to adults have not increased. [ABSTRACT FROM AUTHOR]

Roads have many detrimental effects on natural habitats and their fauna, ranging from altered microclimate to road kills. Animals which move slowly or are attracted to the road surface are particularly threatened. We studied herpetofauna road mortality in a Cerrado ecosystem in central Brazil. We sampled 51 km of state roads during 26 days distributed between dry and wet seasons in 2010 and recorded 109 dead individuals of 34 species of amphibians and reptiles. Including animals found alive on the road, we recorded 159 individuals across 39 species (estimated richness: 48). This number represents about 50% of the herpetofauna species richness expected to occur in a Cerrado site in central Brazil based on a concomitant species inventory. Our study indicates that roads can cause high mortality rates for the Cerrado herpetofauna. We consider that this problem requires urgent attention since economic growth is largely based on agriculture in the Cerrado and construction of more roads is planned to improve harvest transport. [ABSTRACT FROM AUTHOR]

In recent studies, habitat traits have emerged as stronger predictors of species occupancy, abundance, richness and diversity than competition. However, in many cases, it remains unclear whether habitat also mediates processes more subtle than competitive exclusion, such as growth, or whether intra- and interspecific interactions among individuals of different species may be better predictors of size., To test whether habitat traits are a stronger predictor of abundance and body size than intra- and interspecific interactions, we measured the density and body size of three species of larval salamanders in 192 ponds across a landscape., We found that the density of larvae was best predicted by models that included habitat features, while models incorporating interactions among individuals of different species best explained the body size of larvae. Additionally, we found a positive relationship between focal species density and congener density, while focal species body size was negatively related to congener density., We posit that salamander larvae may not experience competitive exclusion and thus reduced densities, but instead compensate for increased competition behaviourally (e.g. reduced foraging), resulting in decreased growth. The discrepancy between larval density and body size, a strong predictor of fitness in this system, also highlights a potential shortcoming in using density or abundance as a metric of habitat quality or population health. [ABSTRACT FROM AUTHOR]

We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease. Standardized population monitoring of key amphibian and reptile species should be established with urgency to enable early detection of potential impacts of disease emergence in this global biodiversity hotspot. [ABSTRACT FROM AUTHOR]

The chytrid fungus Batrachochytrium dendrobatidis ( Bd ) is notorious amongst current conservation biology challenges, responsible for mass mortality and extinction of amphibian species. World trade in amphibians is implicated in global dissemination. Exports of South African Xenopus laevis have led to establishment of this invasive species on four continents. Bd naturally infects this host in Africa and now occurs in several introduced populations. However, no previous studies have investigated transfer of infection into co-occurring native amphibian faunas. A survey of 27 U.K. institutions maintaining X . laevis for research showed that most laboratories have low-level infection, a risk for native species if animals are released into the wild. RT-PCR assays showed Bd in two introduced U.K. populations of X . laevis , in Wales and Lincolnshire. Laboratory and field studies demonstrated that infection levels increase with stress, especially low temperature. In the U.K., native amphibians may be exposed to intense transmission in spring when they enter ponds to spawn alongside X . laevis that have cold-elevated Bd infections. Exposure to cross-infection has probably been recurrent since the introduction of X . laevis , >20 years in Lincolnshire and 50 years in Wales. These sites provide an important test for assessing the impact of X . laevis on Bd spread. However, RT-PCR assays on 174 native amphibians ( Bufo , Rana , Lissotriton and Triturus spp.), sympatric with the Bd -infected introduced populations, showed no foci of self-sustaining Bd transmission associated with X . laevis . The abundance of these native amphibians suggested no significant negative population-level effect after the decades of co-occurrence. [ABSTRACT FROM AUTHOR]

Polymorphic species provide an excellent system to study population divergence because different phenotypes often face diverse selection pressures within their shared environment. Previous studies have demonstrated that different color morphs of P lethodon cinereus (striped and unstriped), which vary in their degree of melanin-based coloration, vary temporally in their seasonal activity and differ in metrics associated with stress physiology. Despite the known association between melanin-based coloration and disease resistance among vertebrates, few studies have examined this relationship in amphibians. In a laboratory experiment, we exposed juvenile and adult P . cinereus to the pathogenic chytrid fungus [ B atrachochytrium dendrobatidis ( B d)] and tested the hypothesis that the different color morphs would differ in their response to B d. If the degree of melanization is positively associated with immune traits in this species, we predicted that unstriped salamanders would be more resistant to B d and would exhibit higher survival rates compared to striped salamanders. Our results suggest that unstriped salamanders have a higher prevalence of infection when they do not behaviorally avoid B d. Unstriped salamanders also exhibited higher rates of B d-induced mortality compared to striped salamanders. These results conflict with our initial predictions and with general findings suggesting that individuals with higher levels of melanin production are more resistant to disease. Behavioral traits of the unstriped morph, including responses to predators and interactions with territorial opponents, may contribute to increased levels of stress and reduced resistance to infection. Future studies that directly manipulate glucocorticoid levels and/or temperature are needed to better understand the differences in B d resistance in this species. [ABSTRACT FROM AUTHOR]

Common Toads Bufo bufo are declining in Britain and other areas of their range and road mortality is thought to be a contributing factor. In some areas, particularly in Europe and North America, 'toad patrols' have been set up to transport toads across roads during the breeding migration with the aim of reducing road mortality. This study measured body sizes of toads at two sites in Cambridgeshire, England, one with a long term toad patrol and one without, to determine whether the population at the patrolled site had a larger mean size because some individuals had been enabled to survive for longer. No significant difference in body size was found between the two sites, suggesting that mortality induced by factors other than traffic kill may be operating on the population and/or growth and that ultimate body size may be constrained by other environmental factors, which are not affected by toad patrols. [ABSTRACT FROM AUTHOR]

For more than 20 years, conservationists have agreed that amphibian populations around the world are declining. Results obtained through laboratory or mesocosm studies and measurement of contaminant concentrations in areas experiencing declines have supported a role of contaminants in these declines. The current study examines the effects of contaminant exposure to amphibians in situ in areas actually experiencing declines. Early larval Pseudacris regilla were translocated among Lassen Volcanic, Yosemite and Sequoia National Parks, California, USA and caged in wetlands in 2001 and 2002 until metamorphosis. Twenty contaminants were identified in tadpoles with an average of 1.3-5.9 (maximum = 10) contaminants per animal. Sequoia National Park, which had the greatest variety and concentrations of contaminants in 2001, also had tadpoles that experienced the greatest mortality, slowest developmental rates and lowest cholinesterase activities. Yosemite and Sequoia tadpoles and metamorphs had greater genotoxicity than those in Lassen during 2001, as determined by flow cytometry. In 2001 tadpoles at Yosemite had a significantly higher rate of malformations, characterized as hemimelia (shortened femurs), than those at the other two parks but no significant differences were observed in 2002. Fewer differences in contaminant types and concentrations existed among parks during 2002 compared to 2001. In 2002 Sequoia tadpoles had higher mortality and slower developmental rates but there was no difference among parks in cholinesterase activities. Although concentrations of most contaminants were below known lethal concentrations, simultaneous exposure to multiple chemicals and other stressors may have resulted in lethal and sublethal effects. [ABSTRACT FROM AUTHOR]

Wildlife passages are widely used mitigation measures designed to reduce the adverse impacts of roads on animals. We investigated whether road kills of small and medium-sized terrestrial vertebrates can be reduced by constructing dry paths adjacent to streams that pass under road bridges. The study was carried out in southern Finland during the summer of 2008. We selected ten road bridges with dry paths and ten bridges without them, and an individual dry land reference site for each study bridge on the basis of landscape and traffic features. A total of 307 dead terrestrial vertebrates were identified during the ten-week study period. The presence of dry paths decreased the amount of road-killed terrestrial vertebrates (Poisson GLMM; p < 0.001). That was true also when considering amphibians alone ( p < 0.001). The evidence on road-kills on mammals was not such clear. In the mammal model, a lack of dry paths increased the amount of carcasses ( p = 0.001) whereas the number of casualties at dry path bridges was comparable with dry land reference sites. A direct comparison of the dead ratios suggests an average efficiency of 79% for the dry paths. When considering amphibians and mammals alone, the computed effectiveness was 88 and 70%, respectively. Our results demonstrate that dry paths under road bridges can effectively reduce road-kills of small and medium-sized terrestrial vertebrates, even without guiding fences. Dry paths seemed to especially benefit amphibians which are a threatened species group worldwide and known to suffer high traffic mortality. [ABSTRACT FROM AUTHOR]

The authors formally investigated a major international wildlife wholesaler and subsequently confiscated more than 26,400 nonhuman animals of 171 species and types. Approximately 80% of the nonhuman animals were identified as grossly sick, injured, or dead, with the remaining in suspected suboptimal condition. Almost 3,500 deceased or moribund animals (12% of stock), mostly reptiles, were being discarded on a weekly basis. Mortality during the 6-week “stock turnover” period was determined to be 72%. During a 10-day period after confiscation, mortality rates (including euthanasia for humane reasons) for the various taxa were 18% for invertebrates, 44.5% for amphibians, 41.6% for reptiles, and 5.5% for mammals. Causes of morbidity and mortality included cannibalism, crushing, dehydration, emaciation, hypothermic stress, infection, parasite infestation, starvation, overcrowding, stress/injuries, euthanasia on compassionate grounds, and undetermined causes. Contributing factors for disease and injury included poor hygiene; inadequate, unreliable, or inappropriate provision of food, water, heat, and humidity; presumed high levels of stress due to inappropriate housing leading to intraspecific aggression; absent or minimal environmental enrichment; and crowding. Risks for introduction of invasive species through escapes and/or spread of pathogens to naive populations also were identified. [ABSTRACT FROM PUBLISHER]

The habitat in the vicinity of Kurupukari, on the Essequibo River in central Guyana, is tall evergreen lowland forest. The area has suffered some human disturbance from agriculture, road construction and ferry activity. The area was sampled for 10 days in 1990 and 12 days in 1997; seven days in rainy season and 15 in dry season. During this sampling 23 anuran and 17 reptile species were collected. Some differences exist between species collected on either side of the river. Comparisons are made with collections from other locations in Guyana. [ABSTRACT FROM AUTHOR]

Abstract: Malformations and increased mortality due to infection by the digenetic trematode, Riberioa ondatrae have been reported for many species of amphibians. Severe malformations have also been reported in the Common Hourglass Tree Frog, Polypedates cruciger induced by pleurolophocercous cercariae in Sri Lanka in addition to the changes in the behaviour, development and survival of the host. We exposed pre-limb bud stage tadpoles (Gosner stages 25–26) of the Asian Common Toad, Duttaphrynus melanostictus to the same pleurolophocercous type cercariae under laboratory conditions. Molecular and morphological identification showed that these cercariae belonged Acanthostomum burminis infecting freshwater snakes as definitive hosts. These cercariae induced malformations (27.8%) and reduced survival to metamorphosis (53.8%). The magnitude of the effects increased with the dose of cercariae. Types of malformations were mainly axial, such as scoliosis and kyphosis. Severe limb malformations such as extra or missing limbs as reported for amphibians exposed to R. ondatrae were not observed in the D. melanostictus. Same authors reported a higher percentage of malformations previously when P. cruciger was exposed to the cercariae A. burminis compared to D. melanostictus. However, tadpoles of D. melanostictus, which are smaller compared to those of P. cruciger, experienced higher mortality than P. cruciger tadpoles. Trematode induced malformations and mortality in amphibians are highly variable and depend on multiple factors such as host species differences such as resistance to infection and tolerance, life-history characteristics such as size at metamorphosis and length of the metamorphosis period, and other factors such as size of the amphibian at the time of trematode exposure. [Copyright &y& Elsevier]

The amphibian chytrid fungus, Batrachochytrium dendrobatidis ( Bd), has been linked to amphibian declines and extinctions worldwide. The pathogen has been found on amphibians throughout eastern North America, but has not been associated with mass die-offs in this region. In this study, we conducted laboratory experiments on the effects of Bd infection in a putative carrier species, Lithobates pipiens, using two estimators of fitness: jumping performance and testes morphology. Over the 8-week study period, peak acceleration during jumping was not significantly different between infected and uninfected animals. Peak velocity, however, was significantly lower for infected animals after 8 weeks. Two measures of sperm production, germinal epithelium depth, and maximum spermatic cyst diameter, showed no difference between infected and uninfected animals. The width, but not length, of testes of infected animals was significantly greater than in uninfected animals. This study is the first to show effects on whole-organism performance of Bd infection in post-metamorphic amphibians, and may have important long-term, evolutionary implications for amphibian populations co-existing with Bd infection. [ABSTRACT FROM AUTHOR]

Animal mortality caused by vehicle collisions is one of the main ecological impacts of roads. Amphibians are the most affected group and road fatalities have a significant impact on population dynamics and viability. Several studies on Iberian amphibians have shown the importance of country roads on amphibian road mortality, but still, little is known about the situation in northern Portugal. By being more permeable to amphibian passage, country roads represent a greater source of mortality than highways, which act as barriers. Thus, mitigation measures should be applied, but due to the extensive road network, the identification of precise locations (hotspots) and variables related to animal-vehicle collision is needed to plan these measures successfully. The aim of the study was to analyse the spatial occurrence and related factors linked to amphibian mortality on a number of country roads in northern Portugal, using spatial statistics implemented in GIS and applying a binary logistical regression. We surveyed 631 km of road corresponding to seven transects, and observed 404 individual amphibians: 74 (18.3%) alive and 330 (81.7%) road-killed. Bufo bufo represented 80% of the mortality records. Three transects showed clustered distribution of road-kills, and broadleaved forests and road ditches were the most important factors associated with hotspots of road-kill. Logistic regression models showed that habitat quality, Bufo bufo's habitat preferences, and road ditches are positively associated with amphibians' road mortality in northern Portugal, whereas average altitude and length of walls were negatively associated. This study is a useful tool to understand spatial occurrence of amphibian road-kills in the face of applying mitigation measures on country roads from northern Portugal. This study also considers the necessity of assessing the condition of amphibian local populations to understand their road-kills spatial patterns and the urgency to apply mitigation measures on country roads. [ABSTRACT FROM AUTHOR]

The article offers information on the study which focuses on the patterns of road-kills of various amphibians in the region of Vendée, Western France. It states that most amphibians that suffered road-kills are Bufo bufo toad and Rana dalmatina, an agile frog. It says that Pelophylax lessonae posted 4% of road-kills because of its sedentary lifestyles on ponds. It mentions that road-kills of amphibians could be attributed to its migratory movements and road-kills are found on low traffic roads that is bordered by woodland and wetlands.

Ranaviruses have caused die-offs of amphibians across the globe. In North America, these pathogens cause more amphibian mortality events than any other pathogen. Field observations suggest that ranavirus epizootics in amphibian communities are common during metamorphosis, presumably due to changes in immune function. However, few controlled studies have compared the relative susceptibility of amphibians to ranaviruses across life stages. Our objectives were to measure differences in mortality and infection prevalence following exposure to ranavirus at four developmental stages and determine whether the differences were consistent among seven anuran species. Based on previous studies, we hypothesized that susceptibility to ranavirus would be greatest at metamorphosis. Our results did not support this hypothesis, as four of the species were most susceptible to ranavirus during the larval or hatchling stages. The embryo stage had the lowest susceptibility among species probably due to the protective membranous layers of the egg. Our results indicate that generalizations should be made cautiously about patterns of susceptibility to ranaviruses among amphibian developmental stages and species. Further, if early developmental stages of amphibians are susceptible to ranaviruses, the impact of ranavirus epizootic events may be greater than realized due to the greater difficulty of detecting morbid hatchlings and larvae compared to metamorphs. [ABSTRACT FROM AUTHOR]

There are many anthropogenic obstacles faced by amphibians in the urban environment. An example of one of these is roads between habitat features such as hibernation sites and breeding ponds; this leads to traffic mortalities. In urban settings, cycle paths may be as busy as-roads and present similar dangers; we report this in the case of smooth newts (Lissotriton vulgaris) attempting to cross a cycle path in central Cambridge. We also explore a potential solution, a drift fence, which we wish to implement in the future to prevent further declines. [ABSTRACT FROM AUTHOR]

The fungus Batrachochytrium dendrobatidis (Bd) is a pathogen associated with global declines of amphibians. We used qPCR to detect Bd in 255 samples from 10 Polish populations of 8 species. We found Bd infection in 3 species (Bombina variegata, Pelophylax lessonae, P. esculentus). The infection intensity in P. lessonae reached a maximum of 58400 genomic equivalents of zoospores (GE), and the 2 most heavily infected individuals died. Previous observations of the populations that included infected individuals showed reduced body size, failure to reproduce, and mortalities of adults. These data highlight the importance of emerging diseases, and the need to recognize them as an important factor in conservation of the genus Pelophylax in Poland and Central and Eastern Europe.

A reprint of the article "Early-Life Exposure of Frogs to Herbicide Increases Mortality From Fungal Diseases," which appeared in the October 29, 2013 issue of "HerpDigest" is presented. The article presents the result of a study conducted by Jason Rohr, Taegan McMahon and Neal Halstead and colleagues, which examined the effect of herbicide atrazine and a fungal disease on frogs. Other variables include number of days of exposure, recovery from atrazine exposure and effects of other stressors.