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Background: For 88 years (1931-present), the Mohonk Preserve's Daniel Smiley Research Center has been collecting data on occupancy and reproductive success of amphibian species, as well as associated water quality of 11 vernal pools each spring (February to May). Though sampling effort has varied over the dataset range, the size of the dataset is unprecedented within the field of amphibian ecology. With more than 2,480 individual species sampling dates and more than 151,701 recorded individual occurrences of the nine amphibian species, the described dataset represents the longest and largest time-series of herpetological sampling with paired water quality data. New information: We describe the novel publication of a paired dataset of amphibian occurrence with environmental indicators spanning nearly 90 years of data collection. As of February 2020, the dataset includes 2,480 sampling dates across eleven vernal pools and 151,701 unique occurrences of egg masses or individuals recorded across nine species of amphibian. The dataset also includes environmental conditions associated with the species occurrences with complete coverage for air temperature and precipitation records and partial coverage for a variety of other weather and water quality measures. Data collection has included species, egg mass and tadpole counts; weather conditions including precipitation, sky and wind codes; water quality measurements including water temperature and pH; and vernal pool assessment including depth and surface vegetation coverage. Collection of data was sporadic from 1931-1991, but data have been collected consistently from 1991 to present. We also began monitoring dissolved oxygen, nitrate concentrations and conductivity of the vernal pools using a YSI Sonde Professional Plus Instrument and turbidity using a turbidity tube in February 2018. The dataset (and periodic updates), as well as metadata in the EML format, are available in the Environmental Data Initiative Repository under package edi.398. [ABSTRACT FROM AUTHOR]

Spring Peeper (Pseudacris crucifer) was first confirmed in Labrador in 1998, when vocalizations were recorded near Happy Valley-Goose Bay. Prior to this, only unsubstantiated reports of Spring Peepers in Labrador existed. In 2006, we visually documented nine Spring Peepers at six locations west of Happy Valley-Goose Bay, in the lower Churchill River valley. In 2014, using auditory surveys, we further documented 1-10 Spring Peepers calling at 13 additional locations in the same general area. These new records support earlier findings and provide additional information on the species at the extreme northeastern edge of its range. [ABSTRACT FROM AUTHOR]

Context. Evaluating the adequacy of created wetlands to replace the functions of lost natural wetlands is important because wetland mitigation is a major tool used to offset wetland losses. However, measurements such as vegetative cover and presence of wildlife may not provide sufficient evidence that created wetlands are functioning properly. Thus, examining the ecology of wetland biota such as that of amphibians may be a more useful surrogate for function. Aims. The objectives of this study were to compare the abundance of amphibian metamorphs and survival and growth of larval amphibians in created wetlands, relative to natural wetlands. Methods. Amphibian metamorphs were trapped in created and natural wetlands during the spring (April-May) and summer (June-August) of 2009 and 2010, and 165 green frog (Lithobates clamitans) larvae were raised during the spring of 2010 in laboratory aquaria containing water from created or natural wetlands. Key results. Abundance of spring peeper (Pseudacris crucifer) metamorphs decreased significantly from 2009 to 2010 and abundance of green frog metamorphs increased with habitat complexity, but both were unaffected by wetland type. Detection probability of metamorphs of both species was low, increased with water temperature and declined with month of observation. Survival, growth curves and mass were similar among green frog larvae raised in created and natural wetland aquaria. Conclusions. Our results suggest that the created and natural wetlands we examined function similarly with respect to providing adequate breeding habitat for green frogs and spring peepers. Implications. Wetlands created to offset the loss of natural wetlands, although generally not designed for the purpose of wildlife habitat, can function as adequate breeding habitat for generalist amphibians such as green frogs and spring peepers. [ABSTRACT FROM AUTHOR]

Amphibian declines have been linked to numerous factors, including pesticide use and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Moreover, research has suggested a link between amphibian sensitivity to Bd and pesticide exposure. We simultaneously exposed postmetamorphic American toads (Anaxyrus americanus), western toads (A. boreas), spring peepers (Pseudacris crucifer), Pacific treefrogs (P. regilla), leopard frogs (Lithobates pipiens), and Cascades frogs (Rana cascadae) to a factorial combination of two pathogen treatments (Bd+, Bd-) and four pesticide treatments (control, ethanol vehicle, herbicide mixture, and insecticide mixture) for 14 d to quantify survival and infection load. We found no interactive effects of pesticides and Bd on anuran survival and no effects of pesticides on infection load. Mortality following Bd exposure increased in spring peepers and American toads and was dependent upon snout-vent length in western toads, American toads, and Pacific treefrogs. Previous studies reported effects of early sublethal pesticide exposure on amphibian Bd sensitivity and infection load at later life stages, but we found simultaneous exposure to sublethal pesticide concentrations and Bd had no such effect on postmetamorphic juvenile anurans. Future research investigating complex interactions between pesticides and Bd should employ a variety of pesticide formulations and Bd strains and follow the effects of exposure throughout ontogeny. [ABSTRACT FROM AUTHOR]

Disruptions to the microbiome can impact host health as can exposure to environmental contaminants. However, few studies have addressed how environmental contaminants impact the microbiome. We explored this question for frogs that breed in wetlands contaminated with fly ash, a by-product of coal combustion that is enriched in trace elements. We found differences in the bacterial communities among a fly ash-contaminated site and several reference wetlands. We then experimentally assessed the impacts of fly ash on the skin microbiome of adult spring peepers (Pseudacris crucifer). Frogs were exposed to fly ash in the laboratory for 12 h, the duration of a typical breeding event, and the skin microbiome was assessed after 5 days (experiment 1) or after 5 and 15 days (experiment 2). We examined bacterial community structure using 16S rRNA gene amplicon sequencing and metabolite profiles using high-pressure liquid chromatography-mass spectrometry (HPLC-MS). We found little impact as the result of acute exposure to fly ash on the bacterial communities or metabolite profiles in either experiment, suggesting that the bacterial symbiont communities of adults may be relatively resistant to brief contaminant exposure. However, housing frogs in the laboratory altered bacterial community structure in the two experiments, which supports prior research suggesting that environmental source pools are important for maintaining the amphibian skin microbiome. Therefore, for contaminants like fly ash that may alter the potential source pool of symbionts, we think it may be important to explore how contaminants affect the initial assembly of the amphibian skin microbiome in larval amphibians that develop within contaminated sites. [ABSTRACT FROM AUTHOR]

We document three cases of erythrism in Spring Peeper (Pseudacris crucifer) in New Brunswick and Nova Scotia. Although the source of erythrism in Maritime P. crucifer remains uncertain, the occurrences reported here demonstrate this colour morph to be a widespread, although apparently rare, form in the Canadian Maritimes region. [ABSTRACT FROM AUTHOR]

Acoustic interference can impede effective communication that is important for survival and reproduction of animals. In response to acoustic interference, some animals can improve signalling efficacy by altering the structure of their signals. In this study, we played artificial noise to 46 male spring peepers Pseudacris crucifer, on their breeding grounds, and tested whether the noise affected the duration, call rate, and peak frequency of their advertisement calls. We used two experimental noise treatments that masked either the high- or low-frequency components of an average advertisement call; this allowed us to evaluate whether frogs adaptively shift the peak frequency of their calls away from both types of interference. Our playback treatments caused spring peepers to produce shorter calls, and the high-frequency noise treatment caused them to lower the frequency of their calls immediately after the noise ceased. Call rate did not change in response to playback. Consistent with previous studies, ambient temperature was inversely related to call duration and positively related to call rate. We conclude that noise affects the structure of spring peeper advertisement calls, and that spring peepers therefore have a mechanism for altering signal structure in response to noise. Future studies should test if other types of noise, such as biotic or anthropogenic noise, have similar effects on call structure, and if the observed changes to call structure enhance or impair communication in noisy environments. [ABSTRACT FROM AUTHOR]

The date of first calling (DFC) of Pseudacris crucifer (Spring Peeper) was recorded over 15 years between 1997 and 2012 in a small vernal pond in southeastern New York State. There was no statistically significant trend in temperature or in the DFC over this period. To determine what temperature cues best predicted DFC, 20 potential temperature indices (daily mean, minimum and maximum temperatures averaged over several different time periods, and thermal sums using several different base temperatures) and five precipitation indices (precipitation on the DFC and for four time windows prior to the DFC) were calculated, and predicted DFCs were compared to observed DFCs. The thermal sum with a base of 3 °C (TS3) was the best predictor but overestimated DFC slightly at high values of DFC. In evaluating impacts of climate change on the calling of this frog, the TS3 index may provide a more accurate metric than the daily temperature statistics that have been used in previous studies. In a 63-year record from a nearby weather station, the TS3 index declined significantly, suggesting that Spring Peepers may be calling earlier now than they were in the mid-2Oth century. [ABSTRACT FROM AUTHOR]

In many species of anurans, advertisement calls excite only one of the two inner-ear organs. One prediction of the pre-existing bias hypothesis is that signal innovations that additionally excite the 'untapped' organ will be more behaviorally effective than normal calls. However, recent studies have shown that females of three species with single-peaked calls that stimulate only the basilar papilla (BP) preferred single-peaked synthetic calls with a frequency typical of conspecific calls to two-peaked calls that also stimulated the amphibian papilla (AP). We report that in spring peepers ( Pseudacris crucifer) that also produce single-peaked calls, females did not show a preference in choices between single-peaked and two-peaked synthetic calls. Thus, the addition of energy exciting the AP had a neutral effect on signal attractiveness. Together, these results are unsupportive of the pre-existing bias hypothesis. An alternative hypothesis is that positive fitness consequences of responding to sounds providing extraordinary spectral stimulation are required for a novel call to become established as a mate-attracting signal. Testing these ideas requires a taxonomically broader examination of responses to sounds with novel spectral complexity, and attention to some methodological details will improve the comparability of such studies. [ABSTRACT FROM AUTHOR]

To determine whether the Western Chorus Frog has declined in western Ottawa, we conducted auditory surveys at historical locations as well as at various other wetlands. Western Chorus Frogs were detected at 12 of 18 historical locations. Wetland habi- tat remained at all historical locations where the species was not detected. There was no difference in the year of historical records for sites where Western Chorus Frogs were (median 1987.5) and were not (median 1987.5) detected. In the present study, Western Chorus Frogs were also detected at 30 locations where they had not been previously reported. Historical Sites where Western Chorus Frogs were not detected were not Significantly farther away from known Western Chorus Frog sites (median distance: 2.2 km) than historical sites where Western Chorus Frogs were detected (median distance: 1.4 km). Land use variables for historical sites where Western Chorus Frogs were and were not detected did not vary significantly at any spatial scale from 0.5 to 2.0 km. Western Chorus Frogs were detected in areas with up to 50% forest cover and up to 86% agricultural cover at the 1.0-km radius. The lack of historical data makes it difficult to assess the current status of the Western Chorus Frog in western Ottawa. The species may have declined, remained approximately the same (by shifting to different breeding sites), or even increased its distribution (by colonizing additional sites). [ABSTRACT FROM AUTHOR]

Effective monitoring programs are designed to track changes in the distribution, occurrence, and abundance of species. We developed an extension of Royle and Kéry's (2007) single species model to estimate simultaneously temporal changes in probabilities of detection, occupancy, colonization, extinction, and species turnover using data on calling anuran amphibians, collected from 2002 to 2006 in the Lower Mississippi Alluvial Valley of Louisiana, USA. During our 5-year study, estimates of occurrence probabilities declined for all 12 species detected. These declines occurred primarily in conjunction with variation in estimates of local extinction probabilities (cajun chorus frog [Pseudacris fouquettei], spring peeper [P. crucifer], northern cricket frog [Acris crepitans], Cope's gray treefrog [Hyla chrysoscelis], green treefrog [H. cinerea], squirrel treefrog [H. squirella], southern leopard frog [Lithobates sphenocephalus], bronze frog [L. clamitans], American bullfrog [L. catesbeianus], and Fowler's toad [Anaxyrus fowleri]). For 2 species (eastern narrowmouthed toad [Gastrophryne carolinensis] and Gulf Coast toad [Incilius nebulifer]), declines in occupancy appeared to be a consequence of both increased local extinction and decreased colonization events. The eastern narrow-mouthed toad experienced a 2.5-fold increase in estimates of occupancy in 2004, possibly because of the high amount of rainfall received during that year, along with a decrease in extinction and increase in colonization of new sites between 2003 and 2004. Our model can be incorporated into monitoring programs to estimate simultaneously the occupancy dynamics for multiple species that show similar responses to ecological conditions. It will likely be an important asset for those monitoring programs that employ the same methods to sample assemblages of ecologically similar species, including those that are rare. By combining information from multiple species to decrease the variance on estimates of individual species, our results are advantageous compared to single-species models. This feature enables managers and researchers to use an entire community, rather than just one species, as an ecological indicator in monitoring programs. [ABSTRACT FROM AUTHOR]

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1. Understanding the trophic relationships of consumers is central to ecology, but constructing meaningful food webs is often difficult because of a lack of detailed information on consumption versus assimilation and high degrees of omnivory. 2. We used fatty acid analyses to examine the trophic relationships of three common larval anurans ( Pseudacris crucifer, Lithobates catesbeianus and Lithobates clamitans) that are often classified as grazers or detritivores. Tadpoles and potential food sources were sampled in four ponds in southern Illinois and analysed for fatty acid composition. Single linkage cluster analysis was then used to compare fatty acid profiles among tadpole gut contents, tadpole muscle tissues and available food resources. 3. Diets varied among species and within species among ponds, but organic sediments consistently contributed most to the fatty acid composition of the gut contents of all species. Fatty acid profiles also indicated that larval insects and phytoplankton were consumed by both L. catesbeianus and L. clamitans in one pond, while L. clamitans and P. crucifer consumed mainly periphyton along with sediments in another pond, and these diet differences appeared linked to physical differences among ponds, with periphyton and/or phytoplankton contributing more to tadpole diets in less shaded ponds. 4. The fatty acid composition of muscle tissues of L. clamitans, the dominant tadpole in these systems, indicated that plant detritus and bacteria, which were the dominant components of organic sediments in the ponds, were common components of the assimilatory diet. 5. Results demonstrate the utility of fatty acid analyses for assessing both consumption and assimilation. The tadpole assemblages we examined derive much of their energy from heterotrophic and allochthonous sources and exhibit high dietary plasticity. This information will allow for more accurate and comprehensive assessments of trophic interactions in freshwater habitats, as well as aid in amphibian conservation, management and captive propagation efforts. [ABSTRACT FROM AUTHOR]

Frog choruses are dynamic social environments in which males must balance the conflicting demands of attracting a female and defending their calling site. The optimal trade-off is probably one that adaptively tracks temporal and spatial changes in the local social environment. Previous studies have indicated that a male frog''s propensity to interact aggressively with its nearby neighbours reflects patterns of plasticity that could allow for such tracking. We presently do not know the mechanisms underlying plasticity in aggressive signalling in frogs, nor do we understand how plasticity depends on variation in social context. In this field playback experiment with spring peepers, Pseudacris crucifer, we investigated how differences in the type of signalling interactions (a form of social context) experienced by calling males influence the plasticity of aggression directed towards nearby neighbours in the chorus. We used the habituation–discrimination experimental paradigm to present males with calls simulating a new neighbour that was initially either aggressive (producing a mixture of advertisement and aggressive vocalizations) or nonaggressive (producing only advertisement calls). We found that interacting with an initially aggressive versus nonaggressive neighbour had negligible effects on the plasticity of a male''s aggressive response, but that subsequent changes in social context (e.g. a switch to aggressive calling by a previously nonaggressive neighbour) greatly influenced a male''s aggressive responsiveness. We discuss our results in terms of short-term habituation as a mechanism for the plasticity and specificity of aggressive signalling behaviour in frog choruses. [Copyright &y& Elsevier]

The dynamics of ecological communities emerge from the interplay of local and regional processes, but there are few long-term data on multiple interacting species across multiple sites to evaluate these processes. We report the population dynamics of two species of treefrogs, the spring peeper (Pseudacris crucifer) and the chorus frog (P. triseriata), in 37 ponds over 11 years. We examined the relation between larval traits of these species and responses to environmental change (a severe drought) at the local (pond) level, and the consequences to regional dynamics of the species. Consistent with experimental evidence, predators limited abundances of both species, competitive effects were undetectable, and pond hydroperiod and forest canopy cover affected species' presences and population sizes. The drought caused strong reductions in pond hydroperiods and predator densities, which led to increases in colonization probability and decreases in extinction probability for the chorus frog. These habitat dynamics resulted in the colonization of 15 new ponds and exponential growth in regional population size of the chorus frog. Colonization probability was positively related to pond connectivity. Pond occupancy rates for the spring peeper were relatively constant, but important source ponds on the landscape changed with the drought. Ponds with extensive forest canopy cover were sink habitats for both species, and high pond connectivity appeared to be necessary to maintain species' presences in these habitats. Landscape dynamics were responsible for changes in the fundamental spatial structure of species' populations, e.g., the chorus frog transitioned between approximations of a classic metapopulation and a patchy population over the course of the study. Many of these results were driven by the interplay of climate variation and spatial food web structure, indicating the importance of incorporating this interaction into metacommunity theory. Our results further indicate the crucial role of habitat (pond) heterogeneity to species persistence, i.e., moderating the potential Moran effects of spatially correlated weather conditions. Overall this study illustrates: (I) how natural systems constantly transition between metapopulation/metacommunity states typically treated as static in the literature, (2) the extensive interconnection of phenomena at different scales in ecology, and (3) the importance of habitat heterogeneity and landscape context for amphibian conservation strategies. [ABSTRACT FROM AUTHOR]

Enteric bacterial communities from Southern Toads (Bufo terrestris) and Spring Peepers (Pseudacris crucifer) were quantified during larval development and metamorphosis to examine relationships between development and enteric microflora. Higher levels of enteric Gram-negative bacteria were observed during metamorphosis in each species' intestines. Gut content had no effect on bacterial levels in B. terrestris. Much higher bacterial levels were recorded in smaller metamorphs. The results of this research suggest that enteric microflora may play an ecological role in anuran development and metamorphosis. [ABSTRACT FROM AUTHOR]

We studied the interactive effect of ultraviolet-B radiation and the heavy metal copper on the tadpole fitness of the Spring Peeper (Pseudacris crucifer). Many studies have identified UV-B effects on amphibian survival while others have examined the effects of heavy metals, such as copper; however, few studies have investigated the possibility of interactive effects between UV-B and heavy metals on amphibian fitness. Tadpoles were reared in laboratory containers and tested to ascertain whether UV-B and Cu had interactive effects on P. crucifer fitness. Exposure to UV-B and Cu individually and interactively significantly affected P. crucifer survival. This suggests that in some areas amphibian survival could be impacted due to abiotic interactions. [ABSTRACT FROM AUTHOR]

A central question to the usefulness of surveys for estimating population trends is whether the surveys adequately represent the biological communities that are being monitored. There are two approaches to address this issue; the first is to statistically adjust site occupancy using species detection probabilities, and the second is to determine the minimum sampling effort required to adequately represent the communities. We focused on the latter approach, using data from two anuran monitoring programs, the Ontario Backyard Frog survey (1992–2001) and the Ontario Bait Frog survey (2001–2003). We determined the minimum sampling effort required to adequately represent the anuran community, and demonstrated the pitfalls of examining population trends when detection probabilities are less than one and vary either temporally or spatially. We found that approximately 12 and 24 randomly sampled nights were required to detect 80% and 90% of species richness, respectively. Detection probabilities varied among species, and were highest for spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans), and lowest for wood frogs (Rana sylvatica) and northern leopard frogs (Rana pipiens). Variation in detection probabilities is likely associated with species specific differences in calling strategies and breeding periods. Anuran monitoring programs that use three stratified sampling periods require site occupancies to be adjusted using detection probabilities in order to adequately represent anuran communities. Failing to account for differences in detection probabilities may result in false significant differences in site occupancy rates. The issues raised here are not limited to monitoring anurans, but are suitable for surveys of many taxa. [Copyright &y& Elsevier]

Freeze tolerance exists among a few species of terrestrially hibernating North American frogs such as the wood frog (Rana sylvatica) and the spring peeper (Pseudacris crucifer). We investigated jump distance and swimming speed of these two frog species during postfreeze recovery because impaired performance, even if reversible, could have adverse ecological consequences for these frogs. Following a nonlethal freeze at –1.5 °C, R. sylvatica returned to the prefreeze level of both modes of locomotion sooner than P. crucifer (54 h vs. 11 d or longer). Wood frogs recovered slowly following more intense freezes: a –4.0 °C treatment group failed to reach the prefreeze level after 11 d, and a –3.0 °C treatment group took 54 h to reach 50% of the prefreeze level. As a result of their diminished locomotive performance, frogs recovering from natural freezes may be temporarily less able to exploit environmental resources and less able to escape predators active in winter. Nevertheless, given the massive biochemical and physiological disturbances accompanying tissue freezing, the recovery dynamics in these frogs seem sufficiently rapid to minimize most ecological risks and to permit early spring breeding. The faster recovery of locomotion in R. sylvatica compared with P. crucifer is consistent, however, with its greater northward distribution. [ABSTRACT FROM AUTHOR]

We sampled a population of two species of hylid treefrogs using 90 vertical ground-placed PVC pipes of 3 diameters positioned along a 1500-m transect at a forest-open pond ecotone in north-central Florida in order to identify potential capture biases. We recorded 1,981 treefrog observations (778 unmarked, 1,203 recaptures) in 8 months. Our results identified species-specific seasonal and weather-related variation in capture by pipe diameter and pipe location. These biases may limit the usefulness of this sampling technique when monitoring long-term treefrog population status and trends. [ABSTRACT FROM AUTHOR]

Anuran reproduction is influenced by various biotic and abiotic factors, of which temperature and rainfall are the best studied. Here we examine the relationship between multiple abiotic environmental variables – specifically, air and water temperature, rainfall, barometric pressure, relative humidity and wind velocity – and the calling activity of five species (Rana sylvatica, Pseudacris crucifer, Bufo americanus, Rana clamitans, and Rana catesbeiana) in an anuran community in New Brunswick, Canada. Acoustical and environmental data were sampled hourly for 4 months during the breeding season in 1997. Logistic regression analyses indicated that each species responded to a unique combination of meteorological variables, even when calling concurrently. Calling in the spring breeding species, R. sylvatica, P. crucifer, and B. americanus, was most associated with the time of day (i.e., they called primarily at night), while calling in the summer breeding species, R. clamitans and R. catesbeiana, was associated primarily with high water temperature. Species with short breeding periods (i.e., explosive breeders; R. sylvatica, B. americanus) responded to fewer environmental variables than did species with prolonged breeding periods (P. crucifer, R. clamitans, R. catesbeiana). Prolonged breeding species responded differently to climatic variables throughout the breeding season: during the latter half of their calling periods, the time of day and a variable that predicts rain, i.e., barometric pressure, became more important, and water temperature became less important. [ABSTRACT FROM AUTHOR]

In an eastern North American tree frog, the spring peeper (Pseudacris crucifer), calling rate has been correlated with reproductive success in the field. To determine the sources of individual variation in calling rate in this species, I analyzed males calling at rates greater than and less than the chorus average throughout one breeding season. Compared to low-rate callers, high-rate callers were relatively larger, heavier, older, and in better body condition, and their muscles used in calling had higher activities of the enzymes citrate synthase and beta-hydroxyacyl- CoA dehydrogenase. This muscle profile is functionally matched by cardiovascular correlates, as indicated by the larger ventricles and higher blood hemoglobin concentrations in high-calling rate males. These cardiovascular features are much less developed in females and may result from the fact that females do not engage in vigorous calling behavior. In P. crucifier, a male's calling rate may function as an indicator of the presence of a suite of functionally interrelated traits responsible for the maintenance of this sexually selected display behavior. [ABSTRACT FROM AUTHOR]

The metabolic effects of evaporative water loss at 5 °C were assessed for both fall- and spring-collected spring peepers Psuedacris crucifer. Frogs readily endured the loss of 50% of total body water. During dehydration organ water content was defended with no change in water content in skeletal muscle, gut, and kidney of 50% dehydrated frogs and reduced water content in liver, brain and heart. Dehydration stimulated a rapid and massive increase in liver glucose production. In fall-collected frogs liver glucose rose by 120-fold to 2690±400 nmol · mg protein or 220 μmol · g ww in 50% dehydrated frogs and glucose in other organs increased by 2.6- to 60-fold. Spring-collected frogs showed the same qualitative response to dehydration although absolute glucose levels were lower, rising maximally by 8.4-fold in liver. Glucose synthesis was supported by glycogenolysis in liver and changes in the levels of glycolytic intermediates in liver indicated that an inhibitory block at the phosphofructokinase locus during desiccation helped to divert hexose phosphates into the production of glucose. Liver energy status (ATP, total adenylates, energy charge) was maintained even after the loss of 35% of total body water but at 50% dehydration all parameters showed a sharp decline; for example, energy charge fell from about 0.85 to 0.42. Severe dehydration also led to an accumulation of lactate in four organs, probably hypoxia-induced the to impaired circulation. The hyperglycemic response of P. crucifer to dehydration mimics the cryoprotectant synthesis response seen during freezing of this freeze-tolerant frog, suggesting that these share a common regultory mechanism and that the cryoprotectant response may have arisen out of pre-existing volume regulatory responses of amphibians. The hyperglycemic response to dehydration might also be utilized during winter hibernation to help retard body water loss by raising the osmolality of the body fluids in situations where hibernaculum conditions become dry. [ABSTRACT FROM AUTHOR]

The article presents a study focusing on sudden mass die-off of a large population of Wood Frog (Lithobates sylvaticus) tadpoles in Maine due to ranavirus. The findings include during the die-off no obvious stressors other than possible overcrowding found, no other species of amphibian or reptile appeared diseased or experienced noticeable mortality, and densities of adult and larval Green Frogs, Grey Treefrogs and Spring Peepers appeared to be unaffected.