Native Amphibians Research Articles

Interspecific variation in the defensive responses of brown frogs to alien predators

AbstractAlien species impact native amphibians through various direct effects, including predation, and pose a significant threat to naïve prey populations. In this study, we exposed tadpoles of three brown frog species (Rana dalmatina, Rana latastei, and Rana temporaria) to the olfactory cues of two alien predators, the pond slider (Trachemys scripta) and red swamp crayfish (Procambarus clarkii), and compared their responses to those induced by the aquatic larvae of a widespread native predator, the Southern hawker (Aeshna cyanea). We recorded two tadpole defensive behaviors, the proportion of time they were active and the number of freezing events. Both agile frog species, R. dalmatina and R. latastei, showed moderate responses to red swamp crayfish kairomones and strong responses to both odonate larvae and pond sliders. In contrast, the common frog (R. temporaria) displayed a less intense response to crayfish with respect to odonate larvae, and a negligible response to pond sliders. Long-lasting coexistence with either European pond turtles or pond sliders may explain the strength of agile frogs’ response toward the alien species; while, the historical range of the white-clawed crayfish (Austropotamobius pallipes) overlapped that of the common frog, enhancing the co-option of alien crayfish cues by this anuran species.

Variation of the stable isotope niches of native amphibians in ponds invaded by the red swamp crayfish

Variation of the stable isotope niches of native amphibians in ponds invaded by the red swamp crayfish

Feral frogs, native newts, and chemical cues: identifying threats from and management opportunities for invasive African Clawed Frogs in Washington state.

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents-including multiple parts of North America-due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa-which produce a powerful neurotoxin tetrodotoxin (TTX)-may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis.

Ranavirus and helminth parasite co-infection in invasive American bullfrogs in the Atlantic forest, Brazil

Emerging infectious diseases threaten amphibian species across the globe. In Brazil, the American bullfrog (Aquarana catesbeiana) is a highly invasive species that can potentially transmit parasites and pathogens to native amphibians. This is the first assessment of co-infection of Ranavirus and helminth macroparasites in invasive populations of bullfrogs in South America. We collected, measured, and euthanized 65 specimens of A. catesbeiana sampled from 9 sites across three states of Brazil in the Atlantic Forest biome. We collected and identified helminth macroparasites and sampled host liver tissue to test for the presence and load of Ranavirus with quantitative PCR. We documented patterns of prevalence, parasite load, and co-infection with generalized linear mixed models, generalized logistic regressions, and randomization tests. Most individual bullfrogs did not exhibit clinical signs of infection, but the overall Ranavirus prevalence was 27% (95% confidence interval, [CI 17–38]). Bullfrogs were infected with helminth macroparasites from 5 taxa. Co-infection of helminth macroparasites and Ranavirus was also common (21% CI [12–31]). Bullfrog size was positively correlated with total macroparasite abundance and richness, and the best-fitting model included a significant interaction between bullfrog size and Ranavirus infection status. We observed a negative correlation between Ranavirus viral load and nematode abundance (slope = −0.22, P = 0.03). Invasive bullfrogs (A. catesbeiana) in Brazil were frequently infected with both Ranavirus and helminth macroparasites, so adult bullfrogs could serve as reservoir hosts for both pathogens and parasites. However, many macroparasites collected were encysted and not developing. Coinfection patterns suggest a potential interaction between Ranavirus and macroparasites because helminth abundance increased with bullfrog size but was lower in Ranavirus infected individuals. Future studies of bullfrogs in the Atlantic Forest should investigate their potential role in pathogen and parasite transmission to native anurans.

Widespread occurrence of the amphibian chytrid panzootic lineage in Uruguay is constrained by climate.

The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a disease among the main causes of amphibian declines worldwide. However, Bd studies on Neotropical amphibians from temperate areas are scarce. We present a comprehensive survey of Bd in Uruguay, in temperate central eastern South America, carried out between 2006 and 2014. Skin swabs of 535 specimens of 21 native and exotic frogs were tested by PCR. We used individual-level data to examine the relationship between infection, climatic variables, and their effects on body condition and the number of prey items found in stomach contents. Infection was widespread in free-ranging anurans with an overall prevalence of 41.9%, detected in 15 native species, wild American bullfrogs Aquarana catesbeiana, and captive specimens of Ceratophrys ornata and Xenopus laevis. Three haplotypes of the Bd ITS region were identified in native amphibians, all belonging to the global panzootic lineage (BdGPL), of which only one was present in exotic hosts. Despite high infection frequencies in different anurans, we found no evidence of morbidity or mortality attributable to chytridiomycosis, and we observed no discernible impact on body condition or consumed prey. Climatic conditions at the time of our surveys suggested that the chance of infection is associated with monthly mean temperature, mean humidity, and total precipitation. Temperatures below 21°C combined with moderate humidity and pronounced rainfall may increase the likelihood of infection. Multiple haplotypes of BdGPL combined with high frequencies of infection suggest an enzootic pattern in native species, underscoring the need for continued monitoring.

Successful eradication of invasive American bullfrogs leads to coextirpation of emerging pathogens

AbstractInterventions of the host–pathogen dynamics provide strong tests of relationships, yet they are still rarely applied across multiple populations. After American bullfrogs (Rana catesbeiana) invaded a wildlife refuge where federally threatened Chiricahua leopard frogs (R. chiricahuensis) were reintroduced 12 years prior, managers launched a landscape‐scale eradication effort to help ensure continued recovery of the native species. We used a before‐after‐control‐impact design and environmental DNA sampling of 19 eradication sites and 18 control sites between fall 2016 and winter 2020–2021 to measure community‐level responses to bullfrog eradication, including for two pathogens. Dynamic occupancy models revealed successful eradication from 94% of treatment sites. Native amphibians did not respond to bullfrog eradication, but the pathogens amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranaviruses were coextirpated with bullfrogs. Our spatially replicated experimental approach provides strong evidence that management of invasive species can simultaneously reduce predation and disease risk for imperiled species.

Uwharrie National Forest—An Ecological Gem in the North Carolina Piedmont

Uwharrie National Forest—An Ecological Gem in the North Carolina Piedmont Hunter Lewis Gold can be found in the Uwharrie River, but the surrounding landscapes of Uwharrie National Forest might be even more precious. This 205 km2 stretch of rugged, mountainous forested terrain (cover photo, Figure 1) between North Carolina's Davidson, Randolph, and Montgomery counties has been described as "a sanctuary of hardwoods, pines, and rocks" (Patterson and Powell 2006). The distinctive topography of these low mountains situated in the southern Piedmont of North Carolina makes Uwharrie National Forest home to a variety of plant and animal species more commonly found elsewhere (USDA Forest Service 2005, Perlmutter 2009, Grissom 2010, Patterson and Knapp 2016, Grissom 2019, Beane 2020). Native American rhyolite quarries, abandoned gold mines, relict populations of eastern white pine (Pinus strobus) (Grissom 2010, Grissom 2019), rare sunflowers (USDA Forest Service 2005), and a population of montane longleaf pine (Pinus palustris) (Patterson and Knapp 2016) make the Uwharrie Mountains a place of unusual inhabitants with an interesting history. Designated by President John F. Kennedy in 1961, Uwharrie National Forest became one of the smallest national forests in the country (USDA Forest Service 2005). Still, despite its size, this forest is full of history and ecological diversity. Found within Uwharrie National Forest is a stretch of mountains that range in elevation from 150 to 350 m. Comprising part of the Carolina Slate Belt, the Uwharrie Mountains are comprised of steep bouldery slopes and narrow ridge crests (Daniel et al. 1996). Metamorphic and igneous rocks including rhyolite and slate are found throughout the Uwharries and evidence of twenty-seven prehistoric Native American rhyolite quarries has been found (Daniel et al. 1996, NCSS 1999). These quarries make the Uwharries a place of archeological significance for the southeastern United States and allow a glimpse into Native Americans' practices and the Indigenous history of the region (Daniel et al. 1996). Gold mines also can be found throughout the Uwharrie Mountains. The first discovery of gold in the United States took place in the nearby Reed Gold Mine, which sparked a hunt for gold in the Uwharries with gold being found in the 1800s. These mines are spread throughout the Uwharries and are no longer in use, but recreational gold panning still occurs (USDA Forest Service 2005). Uwharrie National Forest supports a rich archaeological history, yet the local biodiversity is equally interesting. The Uwharrie Mountains host a variety of rare landforms [End Page 1] such as the Badin Upland Depression Swamp, Roberdo Bog, and the Black Ankle Bog, the latter of which is an example of a hillside seepage bog. The Black Ankle Bog is home to the purple pitcher plant (Sarracennia purpurea) and a large breeding population of native amphibians, which includes the mole salamander (Ambystoma talpoideum) (USDA Forest Service 2005, Perlmutter 2009, Beane 2020). Throughout this national forest, one can also find the endangered Schweinitz's sunflower (Helianthus schweinitzii), the locally rare Carolina thistle (Cirsium carolinianum), and the southern anemone (Anemone berlandieri) (USDA Forest Service 2005). The Uwharrie Mountains stand out compared to most of North Carolina's Piedmont due to the presence of steep slopes which range up to 26 degrees (NCSS 1999). These steep slopes create microclimates that can support populations of plants more commonly found elsewhere. For example, a relict, disjunct population of white pine exists on a humid north-facing slope above the Uwharrie River (Grissom 2010, Grissom 2019). White pine ranged throughout the Piedmont region during the Pleistocene, but as the climate warmed during the Holocene, populations began to contract to only the most favorable habitats (Wendel and Smith 1990, Grissom 2019). The Uwharries are also home to the Gold Mine Branch montane longleaf pine forest, which is a rare forest type for this species, particularly after extensive logging during the 19th and 20th centuries (Peet 2006, Patterson and Knapp 2016). Longleaf pine is more commonly found along the coastal plain forests of the southeastern United States (Grissom 2010, NCFS 2015), yet a stand of around 400 trees exists near the Gold Mine Branch trailhead. Described as "the most atypical ecoregion for longleaf pine to exist" (Peet 2006), the steep slope and well-draining...

Empirical evidence for effects of invasive American Bullfrogs on occurrence of native amphibians and emerging pathogens.

Invasive species and emerging infectious diseases are two of the greatest threats to biodiversity. American Bullfrogs (Rana [Lithobates] catesbeiana), which have been introduced to many parts of the world, are often linked with declines in native amphibians via predation and the spread of emerging pathogens such as amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]) and ranaviruses. Although many studies have investigated the potential role of bullfrogs in the decline of native amphibians, analyses that account for shared habitat affinities and imperfect detection have found limited support for clear effects. Similarly, the role of bullfrogs in shaping the patch-level distribution of pathogens is unclear. We used eDNA methods to sample 233 sites in the southwestern USA and Sonora, Mexico (2016-2018) to estimate how the presence of bullfrogs affects the occurrence of four native amphibians, Bd, and ranaviruses. Based on two-species, dominant-subordinate occupancy models fitted in a Bayesian context, federally threatened Chiricahua Leopard Frogs (Rana chiricahuensis) and Western Tiger Salamanders (Ambystoma mavortium) were eight times (32% vs. 4%) and two times (36% vs. 18%), respectively, less likely to occur at sites where bullfrogs occurred. Evidence for the negative effects of bullfrogs on Lowland Leopard Frogs (Rana yavapaiensis) and Northern Leopard Frogs (Rana pipiens) was less clear, possibly because of smaller numbers of sites where these native species still occurred and because bullfrogs often occur at lower densities in streams, the primary habitat for Lowland Leopard Frogs. At the community level, Bd was most likely to occur where bullfrogs co-occurred with native amphibians, which could increase the risk to native species. Ranaviruses were estimated to occur at 33% of bullfrog-only sites, 10% of sites where bullfrogs and native amphibians co-occurred, and only 3% of sites where only native amphibians occurred. Of the 85 sites where we did not detect any of the five target amphibian species, we also did not detect Bd or ranaviruses; this suggests other hosts do not drive the distribution of these pathogens in our study area. Our results provide landscape-scale evidence that bullfrogs reduce the occurrence of native amphibians and increase the occurrence of pathogens, information that can clarify risks and aid the prioritization of conservation actions.

06. Diet of the recently introduced white-lipped frog Leptodactylus fragilis from a suburban ecosystem in western Cuba

ABSTRACT - Diet and trophic interactions are essential for understanding aspects of the natural history of a species and evaluating its role within the ecosystem. A successful coloniser often has the ability to exploit a wide variety of prey during its establishment and may generate negative impacts due to competition with the local fauna. During both the dry and rainy seasons of 2019, in a suburban ecosystem in western Cuba, we analysed the diet of the recently introduced white-lipped frog Leptodactylus fragilis. Captured frogs were measured and stomach-flushed and released 24 h after analysis at the site of capture. Ninety-one L. fragilis were captured, 73 of them (80.2 %) had prey in the stomach. The most consumed prey were beetles, followed by spiders, and crickets. No difference was observed in prey consumption between seasons. This frog may change its foraging strategy according to the habitat it occupies. In this study, we observed high values of food niche breadth, which may imply a greater competition of L. fragilis for food resources with the native syntopic anurans in Cuba. Studies on temporal and spatial dynamics are needed to understand the possible competitive interaction with native amphibians in this area.

Marbled crayfish Procambarus virginalis invades a nature reserve: how to stop further introductions?

We hereby provide the first documented data on the occurrence of a viable Procambarus virginalis population in a nature reserve in Poland and the steps that were taken to prevent further introductions of the species in the country. To date, Poland represents the most north-eastward distribution area in Europe, where the species occurs in ecosystems with natural water temperature regimes. The ecological plasticity of P. virginalis and its obligate parthenogenetic reproduction make this crayfish an exceptional invader. The crayfish may have detrimental effects on the native invertebrates, amphibians, and fish, and alter the state of the entire ecosystem. Therefore, we investigated the presence of the species in the nature reserve of Pojezierze Łęczyńskie Landscape Park after a suspected P. virginalis individual was found by a local citizen. The nature reserve also includes an area designated to protect native amphibians and turtles. Our study revealed the presence of a thriving population of P. virginalis in the protected area and clear indications of its impact on native and invasive species, both in aquatic and terrestrial environments. If no action is taken, the species will likely expand to other water bodies across the country. An extensive sensibilization campaign allowed us to find additional invaded areas and significantly contribute to the effective ban of this and other invasive crayfish species from private and commercial online trade. Raising public awareness and banning invasive crayfish species trade is essential for successfully detecting and preventing further introductions.

Artificial aquatic habitats impoverish amphibian diversity in agricultural landscapes of central Argentina

Abstract In central Argentina, agro‐ecosystems constitute the dominant landscape, representing the replacement of extensive grassland areas by crops and pastures. Agriculture has caused the loss of extensive areas of Pampean inland wetlands through drainage and the construction of artificial aquatic habitats such as ditches and ponds. This study evaluated the availability and amphibian breeding use of 194 natural and artificial open water habitats and identified those attributes that affect amphibian diversity (richness, abundance and species occurrence). Interviews with farmers revealed that all artificial ditches, drainage channels and ponds were constructed directly or indirectly to support agricultural activities, and 61.5% of them were created at the expense of natural wetlands. The results from generalized linear mixed models) indicated a significant decrease (P < 0.05) in amphibian richness (14.2–35.7%) and abundance (35.3–86.6%) in artificial habitats compared with natural habitats. Overall, vegetation cover, average depth and edge slope emerged as the most important attributes affecting amphibian diversity in artificial open water habitats. Vegetation cover had a significant (P < 0.05) positive influence on species richness and abundance, whereas average depth and edge slope had the opposite effect. Given the substantial modification of inland wetlands in central Argentina, natural aquatic habitats should be considered top priorities for conservation, and law enforcement is urgently needed to control the drainage and levelling of lagoons, ponds and low‐lying areas. The appropriate design and planning of constructed wetlands, including shallow depth and slightly sloping edges, could greatly improve the ability of artificial wetlands to favour native amphibians in these altered landscapes. Artificial wetlands could offer complementary habitats to natural habitats for amphibians and aquatic wildlife if actions leading to sustainable management and territorial planning are applied.

Reducing Populations of an Invasive Ant Influences Survival, Growth, and Diet of Southern Toads (Anaxyrus terrestris)

The southeastern United States supports some of the greatest levels of amphibian diversity in North America, and several species are in decline. Invasive species in the southeastern United States, such as the red imported fire ant (Solenopsis invicta; hereafter RIFA), may be a factor in amphibian declines via depredation, injury of, and/or competition with native amphibians for arthropod prey. Our objective was to assess the influence of RIFAs and RIFA reductions on the diet, growth, and survival of Southern Toads (Anaxyrus terrestris). In 2013 and 2014 we randomly assigned juvenile toads into enclosures either treated with an insecticide, hydramethylnon, to reduce RIFAs (hereafter RIFA treatment) or maintained with ambient levels of RIFAs (hereafter control; n = 4 enclosures per treatment). The mean proportion of recaptured toads was 9.5 and 21 times greater in the RIFA treatment compared to the control in 2013 and 2014, respectively. Toads in the control enclosures were 23% larger at the end of the study than toads recaptured in the RIFA treatment enclosures, though this was driven largely by differences in toad densities. Toad diets in the control and RIFA treatment enclosures overlapped 94%. When considering the dietary overlap of different ant genera only, the dietary overlap was 44%. Our study provides evidence RIFAs alter amphibian populations and may be contributing to amphibian declines in the southeastern United States. Given the high mortality rates we observed, RIFAs should be considered when developing conservation plans for any amphibian species found in areas where RIFAs are present.

Presence of invasive American bullfrogs may reduce infectious disease in a native frog species.

Amphibians breeding in aquatic environments may encounter a myriad of threats during their life cycle. One species known to prey on native amphibians in aquatic habitats is the invasive North American bullfrog Lithobates catesbeianus, which, besides being a voracious predator and competitor, often acts as a pathogen carrier and disease superspreader because it tolerates high infection loads of the frog-killing fungus Batrachochytrium dendrobatidis (Bd). Here, we hypothesized that the presence of the bullfrogs in microcosms should either (1) decrease Bd disease severity in native frog species by discouraging them from using the aquatic environment, or (2) increase the mortality of the native species. We tested these 2 mutually exclusive hypotheses by co-housing the snouted treefrog Scinax x-signatus (native to our study area) with L. catesbeianus in the laboratory, exposing them to Bd, and using qPCR analysis to quantify the resulting Bd infection loads in the native frogs. Our experiment had the following replicated treatments: (1) native-only treatment (3 individuals of S. x-signatus), (2) native-predominant treatment (2 S. x-signatus + 1 L. catesbeianus), and (3) exotic-predominant treatment (1 S. x-signatus + 2 L. catesbeianus). We found that Bd infection loads in the native S. x-signatus were highest in the native-only treatment, and lowest in the exotic-predominant treatment, indicating that bullfrogs may discourage native frogs from occupying the aquatic habitat, thus reducing encounter rates between native frogs and the waterborne pathogen. This effect could be driven by the bullfrogs' predatory behavior and their high philopatry to aquatic habitats. Our results highlight that predation risk adds to the complexity of host-species interactions in Bd epidemiology.

High fungal pathogen loads and prevalence in Baja California amphibian communities: The importance of species, elevation, and historical context

Amphibians are declining globally, and the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been the culprit in many of these declines. In the Mediterranean region of Baja California, Mexico—a biodiversity hotspot—native amphibians are also in decline, and Bd is present. To determine which factors best predict Bd infection prevalence and intensity in Baja California anurans, we conducted Bd sampling at three disparate sites at varying elevations. We observed an overall Bd prevalence of 68%, and found that species was an important predictor of pathogen prevalence and burden (load) both across and within sites. Pathogen prevalence and load increased positively with elevation. The highest Bd load we detected was 139,188 zoospore equivalents (ZE) in a western toad ( Anaxyrus boreas )—more than 10 times the pathogen burden at which chytridiomycosis is lethal in some species. We observed high Bd prevalence (84 – 99%) and Bd loads (> 44,000 ZE) in the California red-legged frog ( Rana draytonii )—a cause for concern in this threatened anuran, especially at La Grulla—the highest elevation (2050 m) site for this species across its range. We sampled museum specimens to determine how long Bd has been present in the region, and detected the pathogen as early as 1932. Contemporary Bd prevalence and load in Baja California are considerably higher than would be expected given similar habitats and the same community composition as in southern California, USA. We therefore highlight the importance of historical context and comparative analyses in examining contemporary Bd dynamics, as well as adhering to strict biosecurity measures when implementing reintroductions and translocations.

A Simple Conservation Tool to Aid Restoration of Amphibians following High-Severity Wildfires: Use of PVC Pipes by Green Tree Frogs (Hyla cinerea) in Central Texas, USA

Amphibians are the most threatened vertebrate class based on the IUCN Red List. Their decline has been linked to anthropogenic activities, with wildfires being among the most conspicuous agents of habitat alterations affecting native amphibians. In 2011, the most destructive wildfire in Texas history occurred in the Lost Pines ecoregion of central Texas, USA, burning 39% of the 34,400 ha forest and drastically decreasing available habitats for many native wildlife species, including the green tree frog (Hyla cinerea). We investigated use of PVC pipes as artificial refuges for green tree frogs in different habitats within this post-fire pine forest. We monitored green tree frog use of small (diameter 38.1-mm, 1.5 inch) and large (diameter 50.8-mm, 2 inch) pipes located adjacent to, and 5 m from, ponds in burned and unburned areas over a 5-month period. We caught 227 frogs, 101 (24 adults and 77 juveniles) in burned and 126 (61 adults, 63 juveniles, and 2 unknown) in unburned areas. A relationship between pipe use by adults and/or juveniles and pipe location in burned versus unburned areas was found, but pipe use by adults and/or juveniles and pipe size were independent. Pipe use by adults and/or juveniles and pipe size were also independent. Juveniles were more frequently observed in pipes located adjacent to ponds. Our results confirmed that PVC pipes merit consideration as a simple, inexpensive, conservation tool to aid in restoration of green tree frog populations after high-severity wildfires. Such artificial refuges may be particularly important for survival of juveniles in severely altered post-fire habitats.

Predation Pressure of Invasive Marsh Frogs: A Threat to Native Amphibians?

Anurans have been introduced in many parts of the world and have often become invasive over large geographic areas. Although predation is involved in the declines of invaded amphibian populations, there is a lack of quantitative assessments evaluating the potential risk posed to native species. This is particularly true for Pelophylax water frogs, which have invaded large parts of western Europe, but no studies to date have examined their predation on other amphibians in their invaded range. Predation of native amphibians by marsh frogs (Pelophylax ridibundus) was assessed by stomach flushing once a month over four months in 21 ponds in southern France. Nine percent of stomachs contained amphibians. Seasonality was a major determinant of amphibian consumption. This effect was mediated by body size, with the largest invaders ingesting bigger natives, such as tree frogs. These results show that invasive marsh frogs represent a threat through their ability to forage on natives, particularly at the adult stage. The results also indicate that large numbers of native amphibians are predated. More broadly, the fact that predation was site- and time-specific highlights the need for repeated samplings across habitats and key periods for a clear understanding of the impact of invaders.

Amphibians of the equatorial seasonally dry forests of Ecuador and Peru.

Seasonally dry forests (SDFs) are one of the most challenging ecosystems for amphibians, fueling the diversity of this group of vertebrates. An updated inventory of native amphibians present in the Equatorial SDF is provided, which extends along the Pacific coast of Ecuador and northwestern Peru. The study is based on an extensive field sampling (two thirds of the total records) carried out throughout the Equatorial SDF, along with a compilation of the available information on distribution of amphibians in the region from published scientific papers, museum collections and on-line databases. The final dataset included 2,032 occurrence records for 30 amphibian species, belonging to eight anuran families. Additionally, data regarding conservation status, habitat use, spawn deposition site, reproductive mode, and body size, along with an identification key for all encountered species are provided. The results indicate a strong sampling bias with a deficit in the Peruvian part of the study area, and a need for urgent inventories targeted at under-sampled areas, using modern taxonomic methods. The study emphasizes the conservation priorities in the Equatorial SDF, based on the distribution, conservation status and life-history data. This information should be useful for the local authorities and institutions involved in the management and conservation of biodiversity in SDF.

Resilience of native amphibian communities following catastrophic drought: Evidence from a decade of regional-scale monitoring

The increasing frequency and severity of drought may exacerbate ongoing global amphibian declines. However, interactions between drought and coincident stressors, coupled with high interannual variability in amphibian abundances, can mask the extent and underlying mechanisms of drought impacts. We synthesized a decade (2009–2019) of regional-scale amphibian monitoring data (2273 surveys, 233 ponds, and seven species) from across California's Bay Area and used dynamic occupancy modeling to estimate trends and drivers of species occupancy. An extreme drought during the study period resulted in substantial habitat loss, with 51% of ponds drying in the worst year of drought, compared to <20% in pre-drought years. Nearly every species exhibited reduced breeding activity during the drought, with the occupancy of some species (American bullfrogs and California newts) declining by >25%. Invasive fishes and bullfrogs were also associated with reduced amphibian occupancy, and these taxa were locally extirpated from numerous sites during drought, without subsequent recovery– suggesting that drought may present an opportunity to remove invaders. Despite a historic, multi-year drought, native amphibians rebounded quickly to pre-drought occupancy levels, demonstrating evidence of resilience. Permanent waterbodies supported higher persistence of native species during drought years than did temporary waterbodies, and we therefore highlight the value of hydroperiod diversity in promoting amphibian stability.

Multi-method biodiversity assessments from wetlands in Grand Teton National Park

A cost-efficient approach to long-term monitoring is to focus on one species or group of organisms as indicators of ecological condition. Through the use of autonomous monitoring technologies, monitoring programs can efficiently expand the biological community surveyed and inferences made. Amphibians have been monitored in Yellowstone and Grand Teton national parks by the Greater Yellowstone Inventory and Monitoring Network (GRYN) since 2006, yet other taxa dependent on wetlands have not been systematically studied. Our main aim was to explore what additional insights we could gain about wetland biodiversity by combining GRYN’s amphibian surveys with multiple autonomous technologies. We deployed wildlife cameras and acoustic recorders (for audible and ultrasonic sounds) at 4 permanent wetlands in Grand Teton National Park, WY during early and late summer 2017 and used descriptive metrics to summarize our findings. During GRYN’s surveys, 3 of 4 native amphibians were detected. With autonomous monitoring tools, we also documented avian and mammalian communities and detected changes in the degree of activity over the summer. Combining multiple, complementary technologies with field-based surveys provides a more comprehensive picture of wetland biodiversity and enhances insights about ecological condition and change.

Distribution and Genetic Diversity of the Amphibian Chytrid in Japan.

While research on frog chytrid fungus Batrachochytrium dendrobatidis (Bd), an infectious disease that threatens amphibian diversity, continues to advance worldwide, little progress has been made in Japan since around 2010. The reason for this is, which we pointed out in 2009, that the origin of frog chytrid fungus may be in the East Asian region, including Japan based on the Bd ITS-DNA variation, and as few cases of mass mortality caused by this fungus have been observed in wild amphibian populations in Japan, the interest of the Japanese government and the general public in Bd has waned. However, we believe that organizing the data obtained so far in Japan and distributing the status of frog chytrid fungus in Japan to the world will provide useful insight for future risk management of this pathogen. We collected more than 5500 swab samples from wild amphibians throughout Japan from 2009 to 2010. Then, we investigated the infection status using the Nested-PCR method. We sequenced the obtained DNA samples and constructed a maximum-parsimony (MP) tree to clarify the phylogenetic diversity of Bd. We detected Bd infection in 11 (nine native and two alien) amphibian species in Japan and obtained 44 haplotypes of Bd ITS-DNA. The MP tree showed a high diversity of Bd strains in Japan, suggesting that some strains belong to Bd-GPL and Bd-Brazil. Except for local populations of the Japanese giant salamanders Andrias japonicus in Honshu Island and the sword tail newts Cynops ensicauda in Okinawa Island, the Bd infection prevalence in native amphibian species was very low. The alien bullfrog Aquarana catesbeiana had high Bd infection rates in all areas where they were sampled. No Bd infection was detected in other native amphibians in the areas where giant salamanders, sword tail newts, and bullfrogs were collected, suggesting that many native amphibians are resistant to Bd infection. The sword tail newt of Okinawa Island had both the highest infectious incidence and greatest number of haplotypes. The giant salamanders also showed relatively high infection prevalence, but the infected strains were limited to those specific to this species. These two Caudata species are endemic to a limited area of Japan, and it was thought that they may have been refugia for Bd, which had been distributed in Japan Islands for a long time.