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Data in this dataset were collected as a part of the Student Network for Amphibian Pathogen Surveilance (SNAPs) program throughout the United States by undergraduate students in biology or ecology courses as a part of their curriculum throughout 2022. This data was collected in the field by students and sent to the USGS National Wildlife Health Center (NWHC) for testing of two amphibian fungal pathogens, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bs). The dataset includes both the field records of the individual amphibians tested and the results for individuals for Bd and Bsal

Journal of Herpetology, 46(4):658-664

Determining where animals are and if they are persisting across protected landscapes is necessary to implement appropriate management and conservation actions. For long-lived animals and those with boom and bust life histories, perspective across time contributes to discerning temporal trends in occupancy and persistence and potentially in identifying mechanisms affecting those parameters. Long-term data are particularly useful in protected areas where change may be less obvious. We used long-term amphibian data specific to Rocky Mountain National Park in a Bayesian occupancy modeling framework to estimate changes in colonization and persistence of amphibians over three decades and explored mechanisms (e.g., precipitation, drought, visitor use) behind observed changes. Our results indicate that colonization is low and the probability of persistence is declining for Pseudacris maculata, Lithobates sylvaticus and Ambystoma mavortium; and that occupied catchments are increasingly isolated. We found visitor use to be the most influential mechanism, negatively affecting occupancy and persistence of amphibians in RMNP. While these results are sobering, they also provide a way forward where mitigation efforts can target identified drivers.

The first widescale assessment of methylmercury in adult amphibians in the U.S. shows that this toxic compound is common, widespread and, at least for some populations, can reach very high levels. The ARMI-led publication brought together scientists from around the country to test more than 3,200 amphibians representing 14 species from 26 populations. Amphibians are the most endangered group of vertebrates worldwide, but prior to this study, little information was available on mercury bioaccumulation in amphibians across the U.S.

Mercury is a contaminant of global concern that can harm humans and wildlife. In aquatic ecosystems, microbes can convert elemental mercury to methylmercury, which increases risks because methylmercury is more bioavailable, more toxic, and it biomagnifies through food webs.

Study results showed that the amount of methylmercury in amphibians varied widely among sites and by life history characteristics, such as diet, size, and sex. Amphibian methylmercury concentrations ranged from barely detectible at some locations, to levels above wildlife health benchmarks in others. The study also evaluated using dragonfly larvae to estimate bioaccumulation for amphibians that can’t be sampled because they are rare or secretive. Scientists determined that the concentration found in these insects can provide insight into methylmercury bioaccumulation in amphibians.

Despite its toxicity, scientists only have a limited understanding of methylmercury’s effects on amphibians and these results can be used to inform future research on the health effects of methylmercury exposure on amphibians. The study also provides new methods and baseline data that can help scientists and managers assess the risk from mercury for species of management concern, including species listed as threatened and endangered under the Endangered Species Act.

To view the full article click this link: https://pubs.acs.org/doi/10.1021/acs.est.3c05549

As first appeared in USGS NTK:

My late fall trek to Lost Lake in Rocky Mountain National Park to look for evidence of toad breeding is beautiful. The aspen leaves are golden. The air is downright cold at the 7 am start. The ten-mile hike starts downhill but soon angles up and continues up for the next eight miles. That is a lot of time to think about the end of another summer field season and about how few toads we observed. I can’t help but wonder if our field techs somehow overlooked breeding and egg masses? Or was it because it didn’t happen? It was only early October, but I settled in to a decidedly grim and early Halloween-edgy mood that was resistant to the bright blue of the sky and clung to me like a veil the rest of the hike.

Not a soul was camping at Lost Lake. The lake was still with only a few ravens providing their opinions on campers and, no doubt, toad conservation. All senses narrowed to look for a toadlet or an adult toad as I poked through the drying grasses and shrubs around the lake, and hopefully scanned the water’s edge. I could feel, more than see, the daylight dwindling.

On the far side of the lake I saw her, sitting on the shoreline. I stopped short as I saw the stiffness of her body and the blank white stare of her eye. The toad was dead. But hadn’t been dead long. I pulled out the “tools of the trade” and measured her, checked her for an identifying passive integrated transponder tag, and swabbed her to test for the amphibian chytrid fungus. She was not marked, and I only assumed she was a female based on size. I recorded a few bits of environmental data, and although firm-ish, the toad was in no condition to travel for further examination. I felt a chill and realized that the sun was completely gone. I left her on the shore with a quick prayer to the amphibian goddess and a furtive look around for moose.

Boreal toads, like the one I found, have been on the decline in Rocky Mountain National Park (RMNP), and the southern Rocky Mountain region for a while. One contributor to these declines is the amphibian chytrid fungus that thickens the skin, blocks osmosis (water intake), and eventually leads to heart attack and death. As a research zoologist, my colleagues and I have been working on amphibians in RMNP in northern Colorado for three decades. Our work ranges from questions of immediate interest to the National Park Service, like “how are the wood frogs doing with the hydrological changes on the west side of the park,” or “why are boreal toads declining” to overall management questions like, “what is the status of the amphibian species in the park and what factors may affect persistence?”

Although there are some bad days like my autumn hike to Lost Lake, there are glimmers of hope, or at least of gains in information that we might use towards amphibian conservation. We are currently working on a paper using three decades of data on chorus frogs, salamanders, and wood frogs in RMNP to examine changes in persistence over time across the landscape of the park. This work also considers a variety of mechanisms (e.g., visitor use) that may affect the probability of persistence and thus provides RMNP with information that can contribute to conservation decisions about the management of the park’s amphibians.

Erin Muths is a research zoologist at the Fort Collins Science Center and is a principle investigator for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. Her lab has studied boreal toads and other amphibians in the Rocky Mountains for more than 25 years. She is going to be sorcerer for Halloween.

As first appeared in USGS NTK:

First of all, newts are not the villains, instead, they are often the victims.

Newts are at risk, along with many animals, from climate change and from disease. In fact, they could be poster animals for climate change: In southern California, recent record warm air temperatures along with peak drought conditions are linked with a 20% reduction in mean body condition (e.g., mass) in the California newt (Taricha torosa)*. The disease Batrachochytrium salamadrivorans (Bsal, literally eater of salamanders in Latin) has caused significant devastation to salamander populations in Europe. This fungal disease affects primarily newts and salamanders and the Northeastern U.S. is considered the salamander capital of the world. While Bsal is not present in the United States now**, there is serious potential for the disease to spread from Europe to the U.S. through the pet trade***.

Second, newts are quiet neighbors that contribute to society.

For example, newts eat a variety of insects, and they are eaten by birds, snakes, and some mammals.

Third, newts appreciate Halloween and keep it alive all year!

Newts have three distinct developmental life stages that are in effect, costume changes! They begin as aquatic larva, metamorphose into terrestrial juveniles (sometimes called efts), then metamorphose into adults.

And finally, newts value their eyes.

If you are really looking for some eye of newt, go look in your local grocery, “eye of newt” is actually a very un-scary and easily acquired mustard seed.

Erin Muths is a research zoologist at the Fort Collins Science Center and is a principle investigator for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. Her lab has studied boreal toads and other amphibians in the Rocky Mountains for more than 25 years. She is going to be sorcerer for Halloween.

Michael Adams is a supervisory research ecologist at the Forest and Rangeland Ecosystem Science Center and is the Lead for the Amphibian Research and Monitoring Initiative for the Ecosystems Mission Area. His lab has studied newts and other amphibians in the Pacific Northwest for the past 25 years. His Halloween plans are a mystery to everyone including himself.

References:

*Bucciarelli, G.M., Clark, M.A., Delaney, K.S. et al. Amphibian responses in the aftermath of extreme climate events. Sci Rep 10, 3409 (2020). https://doi.org/10.1038/s41598-020-60122-2

**Waddle, J.H., Grear, D.A., Mosher, B.A., Grant, E.H.C., Adams, M.J., Backlin, A.R., Barichivich, W.J., Brand, A.B., Bucciarelli, G.M., Calhoun, D.L. and Chestnut, T., 2020. Batrachochytrium salamandrivorans (Bsal) not detected in an intensive survey of wild North American amphibians. Scientific reports 10(1), p.13012.

***Connelly, P.J., Ross, N., Stringham, O.C. and Eskew, E.A., 2023. United States amphibian imports pose a disease risk to salamanders despite Lacey Act regulations. Communications Earth & Environment, 4(1), p.351.

Ideal disease mitigation measures for wildlife are safe and benign for target species, non-target organisms, humans, and the environment. Identifying unintended collateral effects is a key consideration. Insecticides are commonly used to control flea (Siphonaptera) vectors of the plague bacterium Yersinia pestis to protect prairie dogs (Cynomys spp.) and their plague-susceptible obligate predators, endangered black-footed ferrets (Mustela nigripes). Currently, deltamethrin dust and fipronil baits are used in this context. A variety of animals use prairie dog burrows as nesting habitat or as refuge, which potentially exposes them to deltamethrin, and to fipronil (and metabolites) in prairie dog feces. Western tiger salamanders (Ambystoma mavortium) use prairie dog burrows and have permeable skin. We used western tiger salamanders to assess the effects of deltamethrin and fipronil, at realistic concentrations in “burrow” mesocosms, on salamander survival, physiology, and behavior. Treatments included (1) deltamethrin dust, (2) prairie dog feces containing fipronil and fipronil sulfone metabolite, and (3) appropriate controls. All 29 salamanders survived the 63-d post-treatment period. Over 28 d post-treatment, salamander body mass increased and there were no differences in body mass changes among the experimental groups. We did not detect insecticide residues in tissues from 8 control salamanders and only detected fipronil sulfone in tissues from 3 of 10 salamanders tested in mesocosms with fipronil feces. Deltamethrin was detected in tissues from 9 of 11 salamanders tested in deltamethrin mesocosms. Salamanders were detected outside of burrows, via photographs taken at 15 min intervals, more frequently after (than before) treatments, particularly in the deltamethrin mesocosms. For the deltamethrin group, photograph detection rates were highest 1-day post-treatment (suggesting the salamanders may have attempted to avoid deltamethrin by spending more time outside burrows) and declined by about 1% every 10 d post-treatment, down to pre-treatment patterns. Deltamethrin concentrations in whole body samples correlated positively with the amount of time the salamanders were undetected in photographs (a proxy for time spent in burrows). Experimentation is recommended to evaluate the potential effects of deltamethrin, in particular, on herpetofauna occupying prairie dog colonies under natural conditions.

The Arizona Toad (Anaxyrus microscaphus) is restricted to riverine corridors and adjacent uplands in the arid southwestern United States. As with numerous amphibians worldwide, populations are declining and face various known or suspected threats, from disease to habitat modification resulting from climate change. The Arizona Toad has been petitioned to be listed under the U.S. Endangered Species Act and was considered “warranted but precluded” citing the need for additional information – particularly regarding natural history (e.g., connectivity and dispersal ability). The objectives of this study were to characterize population structure and genetic diversity across the species’ range. We used reduced-representation genomic sequencing to genotype 3,601 single nucleotide polymorphisms in 99 Arizona Toads from ten drainages across its range. Multiple analytical methods revealed two distinct genetic groups bisected by the Colorado River; one in the northwestern portion of the range in northwestern Arizona, southwestern Utah, and eastern Nevada and the other in the southeastern portion of the range in central and eastern Arizona and New Mexico. We also found subtle substructure within both groups, particularly in central Arizona where toad populations in lower elevations were less connected than those at higher elevations. The northern and southern parts of the Arizona Toad range are not well connected genetically and could be managed as separate units. Further, these data could be used to identify source populations for assisted migration or translocations to support small or potentially declining populations.

Biodiversity is generally reduced when non-native species invade an ecosystem. Invasive crayfish, Procambarus clarkii, populate California freshwater streams, and in the Santa Monica Mountains (Los Angeles, USA), their introduction has led to trophic cascades due to omnivorous feeding behavior and a rapid rate of population growth. The native California newt, Taricha torosa, possesses a neurotoxin, tetrodotoxin (TTX), that affects freshwater animal behavior. Given P. clarkii has a limited evolutionary history with TTX, we hypothesized that TTX may affect crayfish feeding behaviors. To determine if TTX affects P. clarkii behavior, we measured cumulative movement and various feeding behaviors of P. clarkii exposed to (i) waterborne, ecologically realistic concentrations of TTX (~?3.0?×?10??8 moles/L), (ii) an anuran chemical cue to account for intraguild cues, or (iii) a T. torosa chemical cue with quantitated TTX in it (~?6.2?×?10??8 moles/L).

Results
We found that the presence of TTX in any form significantly reduced crayfish movement and decreased the amount of food consumed over time. Crayfish responses to the anuran treatment did not significantly differ from controls.

Conclusion
Our laboratory results show that naturally occurring neurotoxin from native California newts limits invasive crayfish foraging and feeding rates, which may play a role in preserving local stream ecosystems by limiting invasive crayfish behaviors that are detrimental to biodiversity.

Recent ARMI-led research showed the removal of invasive American bullfrogs from livestock ponds and small lakes in southern Arizona also resulted in the apparent local extirpation of two pathogens associated with the bullfrogs. The American bullfrog is native eastern North America but has become widespread in the West, where it preys on many native species of conservation concern. Other recent ARMI-led research from the area suggested that American Bullfrogs could act as reservoirs for pathogens like amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) and ranaviruses, which are often lethal to native amphibians, but less so to American Bullfrogs.

In the early 2000s, American bullfrogs were eradicated from ponds in the Buenos Aires National Wildlife Refuge near the Arizona-Mexico border to assist with the reintroduction efforts for the federally threatened Chiricahua Leopard Frog. In 2015, the bullfrog reinvaded the refuge and was once again removed. This reinvasion from outside the refuge motivated funding for a multi-year, landscape-scale eradication program. In the fall-winter of 2016 and the winter of 2020-2021, the research team tested the water at bullfrog eradication and control (no eradication efforts occurred) sites for the DNA (environmental DNA or eDNA) of invasive bullfrogs, federally threatened Chiricahua Leopard Frogs, and Bd and ranaviruses.

Results from the eDNA sampling showed American Bullfrogs were eradicated successfully from most sites, and where bullfrogs were eradicated, the pathogens were also no longer detected. Chiricahua Leopard Frogs did not increase in occurrence after eradicating bullfrogs, possibly due to an exceptional drought that could have limited the ability of native amphibians to colonize sites.

To our knowledge, this is one of the few studies to link eradication of an invasive species to co-eradication of emerging pathogens. Our spatially replicated experimental approach provides strong evidence that management of invasive species can simultaneously reduce predation and disease risk for imperiled species.

To view the full article click this link: https://doi.org/10.1111/conl.12970

Aquatic invasive species (AIS) present major ecological and economic challenges globally, endangering ecosystems and human livelihoods. Managers and policy makers thus need tools to predict invasion risk and prioritize species and areas of concern, and they often use native range climate matching to determine whether a species could persist in a new location. However, climate matching for AIS often relies on air temperature rather than water temperature due to a lack of global water temperature data layers, and predictive power of models is seldom evaluated. We developed 12 global lake (water) temperature-derived “BioLake” bioclimatic layers for distribution modeling of aquatic species and compared “climatch” climate matching predictions (from climatchR package) from BioLake with those based on BioClim temperature layers and with a null model. We did this for 73 established AIS in the United States, training the models on their ranges outside of the United States and Canada. Models using either set of climate layers outperformed the null expectation by a similar (but modest) amount on average, but some species were occasionally found in locations with low climatch scores. Mean US climatch scores were higher for most species when using air temperature. Including additional climate layers in models reduced mean climatch scores, indicating that commonly used climatch score thresholds are not absolute but can be context specific and may require calibration based upon climate data used. Although finer resolution global lake temperature data would likely improve predictions, our BioLake layers provide a starting point for aquatic species distribution modeling. Climate matching was most effective for some species that originated at low latitudes or had small ranges. Climatch scores remain useful but limited for predicting AIS risk, perhaps because current ranges seldom fully reflect climatic tolerances (fundamental niches). Managers could consider climate matching as one of a suite of tools that can be used in AIS prioritization.

Data release of Bd and Bsal detection results from the ARMI funded Student Network for Amphibian Pathogen Surveillance network. Includes 40+ institutions from the U.S. and Mexico as of calendar year 2022

Infectious diseases are a major driver of the global amphibian decline. In addition, many factors, from genetics and stress to pollution and climate change, can influence the response to pathogens. Therefore, it is important to be able to evaluate amphibian immunity in the field and in the laboratory. The phytohemagglutinin (PHA) assay is an inexpensive and relatively non-invasive tool that has been used extensively to assess immunocompetence, especially in birds, and more recently in amphibians. However, there is substantial variation in experimental methodology among amphibian PHA studies in terms of species and life stages, PHA doses and injection sites, and use of experimental controls. Here, we compile and compare all known PHA studies in amphibians in order to identify knowledge gaps and develop best practices for future work. We found that research has only been conducted on a limited number of species, which may not reflect the diversity of amphibians as a whole. There is also a lack of validation studies in most species, so that doses and timing of PHA injection and subsequent swelling measurements may not effectively evaluate immunocompetence. Based on these and other findings, we put forward a set of recommendations to make future PHA studies more consistent and improve the ability to utilize this assay in wild populations, where immune surveillance is greatly needed.

Introduction: Designs for safe and effective road crossing structures for small animals are typically under-road microtunnels and culverts which have varying levels of effectiveness reported in the scientific literature. Many species, particularly migratory amphibians, may have limited ability to find and use passages if they are too far apart, resulting in substantial barrier effects.

Methods: We designed a novel open elevated passage (elevated road segment: ERS), similar to a low terrestrial bridge, that could theoretically be built to any length based upon species needs and movement characteristics. A 30 m length prototype ERS was installed along a forest road with a history of amphibian road mortality in Sierra National Forest, Fresno County, CA, USA. From 2018 to 2021, we monitored small animal activity under the ERS in relation to surrounding roadside and forest habitats using active infrared cameras.

Results: We documented a total of 8,815 unique use events, using species specific independence criteria, across 22 species of amphibians (3), reptiles (4), and small mammals (15). Poisson regression modeling of taxonomic group activity under the ERS, roadside and forest, showed that amphibian activity was highest in the forest habitat, no differences were observed for reptiles, and small mammal activity was highest under the ERS. However, mean activity estimates under the ERS were equal to or greater than the open roadside habitat for all 22 species, suggesting that adding cover objects, such as downed logs and vegetation may further enhance passage use.

Discussion: Overall, results showed that the design of the ERS crossing has potential to provide high connectivity for a wide range of amphibian, reptile, and small mammal species while reducing road mortality. ERS systems can also be used in areas with challenging terrain and other hydrological and environmental constraints. Incorporating current road ecology science, we provide supplemental ERS concept designs for secondary roads, primary roads and highways to help increase the options available for road mitigation planning for small animals.

To view the full article click this link: https://doi.org/10.3389/fevo.2023.1145322

This is one of many research studies USGS is conducting to inform safe and effective road crossing systems for amphibians and reptiles. See https://www.usgs.gov/centers/werc/science/reptile-and-amphibian-road-ecology for more information.

Geographic distribution parish record for this snake species

Turtles are one of the most imperiled vertebrate groups in the world. With habitat destruction unabated in many places, urban and suburban greenspaces may serve as refugia for turtles, at least those species able to tolerate heavily altered landscapes. In south-central Louisiana, we have conducted a turtle capture-mark-recapture effort in two ponds in an urban greenspace for 13 years to understand species composition, survival, and individual growth rates. We had 574 total captures of 251 individuals of five species from 2009–2021, with Trachemys scripta elegans (Red-eared Sliders) and Sternotherus odoratus (Eastern Musk Turtles) being most common. Apparent annual survival for T. scripta (0.79) was similar to estimates reported in other studies in altered habitats, whereas apparent annual survival for S. odoratus (0.89) was slightly or much higher than other published studies. Growth rates of T. scripta were comparable to other studies and showed both sexes have similar rates of growth until maturity, which is earlier and at a smaller size in males. The two ponds showed marked differences in captures by size, with significantly more juvenile T. scripta captured in the pond with more vegetation, depth, and a softer bottom. Most T. scripta (78.5%) that were recaptured came from the same pond they were originally captured. The basic demographic data gained in this study can serve as a starting point for broader questions on urbanization effects and as a comparison to more natural populations.

National parks and other protected areas are important for preserving landscapes and biodiversity worldwide. An essential component of the mission of the United States (U.S.) National Park Service (NPS) requires understanding and maintaining accurate inventories of species on protected lands. We describe a new, national-scale synthesis of amphibian species occurrence in the NPS system. Many park units have a list of amphibian species observed within their borders compiled from various sources and available publicly through the NPSpecies platform. However, many of the observations in NPSpecies remain unverified and the lists are often outdated. We updated the amphibian dataset for each park unit by collating old and new park-level records and had them verified by regional experts. The new dataset contains occurrence records for 292 of the 424 NPS units and includes updated taxonomy, international and state conservation rankings, hyperlinks to a supporting reference for each record, specific notes, and related fields which can be used to better understand and manage amphibian biodiversity within a single park or group of parks.

Forest harvest is a primary landscape-scale management action affecting riparian forests. Although concerns about impacts of forest harvest on stream amphibians is generally limited to areas adjacent to harvest, there is a paucity of information regarding potential downstream effects of forest harvest on these species. We designed a before-after, control-impact (BACI) experiment to quantify potential impacts of clearcut logging that included 12-m buffers or smaller variable-width buffers on the distribution and abundance of headwater stream amphibians in adjacent and downstream areas. We sampled larval coastal tailed frogs (Ascaphus truei), coastal giant salamanders (Dicamptodon tenebrosus), and Columbia torrent salamanders (Rhyacotriton kezeri) across 3,915 sampling occasions that spanned 13 study reaches in 2008–2011 (pre-harvest) and 2013–2016 (post-harvest) as part of the Trask River Watershed Study in the Oregon Coast Range, U.S.A. We analyzed these data using occupancy models to estimate occupancy and (when possible) relative abundance, while accounting for various sources of imperfect detection. All species exhibited reduced occupancy adjacent to clearcuts with variable-width buffers (odds ratios [ORs] ranged = 0.24–0.48), and these negative impacts were not always diminished when increasing the buffer size to 12 m (ORs ranged = 0.20–3.56). Dicamptodon tenebrosus was the only species to have occupancy impacted in downstream areas, and this negative impact was related to clearcut logging with uniform 12-m buffers (OR = 0.60). This species was also the only species to have abundance negatively impacted by forest harvest in downstream areas (OR = https://0.41 with uniform 12-m buffers, OR = https://0.38 with variable-width buffers), albeit impacts to abundance were not evaluated for R. kezeri. Ascaphus truei abundance increased in areas downstream of clearcut logging with uniform 12-m buffers (OR = 2.92). Although we found the direction and magnitude of responses varied by species, our study confirms that clearcut logging can have negative impacts on amphibians that inhabit the adjacent stream areas. Perhaps more importantly, we also found that forest harvest can have negative effects on stream amphibians downstream of the harvested area and that increasing the buffer size to 12 m did not necessarily diminish these impacts in adjacent and downstream areas. Altogether, our study provides a nuanced picture of adjacent and downstream effects of forest harvest on three endemic headwater stream amphibians, and our findings demonstrate that forest management practices should consider downstream effects on aquatic taxa when assessing the impact of harvesting trees near headwater streams.

The decline of amphibian populations is one of the starkest examples of the biodiversity crisis. For stream-breeding amphibians, alteration of natural flow regimes by dams, water diversions, and climate change have been implicated in declines and extirpations. Identifying drivers of amphibian declines requires long time series of abundance data because amphibian populations can exhibit high natural variability. Multiple population viability analysis (MPVA) models integrate abundance data and share information from different populations to estimate how environmental factors influence population growth. Flow alteration has been linked to declines and extirpations in the Foothill Yellow-Legged Frog (Rana boylii), a stream-breeding amphibian native to California and Oregon. To date, no study has jointly analyzed abundance data from populations throughout the range of R. boylii in an MPVA model. We compiled time series of egg mass counts (an index of adult female abundance) from R. boylii populations in 36 focal streams and fit an MPVA model to quantify how streamflow metrics, stream temperature, and surrounding land cover affect population growth. We found population growth was positively related to stream temperature and was higher in the years following a wet year with high total annual streamflow. Density-dependence was weakest (i.e., carrying capacity was highest) for streams with high seasonality of streamflow and intermediate rates of change in streamflow during the spring. Our results highlight how altered streamflow can further increase the risk of decline for R. boylii populations. Managing stream conditions to better match natural flow and thermal regimes would benefit the conservation of R. boylii populations.