Studying the movements of organisms that live underground for at least a portion of their life history is challenging, given the state of current technology. Passive integrated transponders (PIT tags) provide a way to individually identify and, more recently, study the movement of smaller animals, including those that make subterranean movements. However, there are widespread assumptions of the use of PIT tags that remain problematic. We tested the effects of PIT-tag implantation on growth and survival, along with the effects of electromagnetic fields for reading PIT tags on behavior, of the smallest salamander that has been PIT-tagged: the Red-Backed Salamander. We found no effect of PIT tags on growth or survival. Using a mesocosm experiment, we also found that electromagnetic effects associated with reading PIT tags, had no effect on salamander behavior. Further, we describe a novel PIT antenna and soil mesocosm experimental arena for studying belowground movements of woodland salamanders. Collectively, these studies suggest that the use of PIT tags do not influence the growth, survival, or behavior of Red-Backed Salamanders. Given the challenges of studying salamanders that live underground and the impending changes in climate and landscapes, this research suggests that PIT tags remain a viable tool for studying the movement ecology of salamanders under global change.

Amphibians and reptiles use caves in different lithologies and biomes. However, the ecological reasons for such behavior have so far not been investigated in a broad scale. We surveyed 945 Brazilian caves in three biomes (Caatinga, Cerrado, and the Amazon), from which 269 had frogs and reptiles. We classified species of amphibians (34) and reptiles (19) according to natural history traits including habit, activity, diet composition, foraging strategy, and developmental mode (anurans). We used IUCN species distribution maps to predict what species occur in the vicinities of the caves but did not use them to test whether specific life history traits were distributed differently between species using and not using caves. We also tested seasonality and occurrence of bodies of water inside caves used by anurans, as well as the area occupied by man-made building and infrastructure around caves as explanatory factors for cave use intensity. Anurans with direct development were more likely to use caves than those with a tadpole stage. Terrestrial anurans were more likely to use caves than arboreal and semiarboreal anurans. No fossorial, semifossorial, or semiaquatic species used caves. Among reptiles, sit-and-wait foragers were more likely to use caves than active foragers. Semiaquatic and terrestrial reptiles were the most likely to use caves. Anurans were most likely to use caves with perennial bodies of water and during the dry season. Our results indicate that species of the herpetofauna are likely to search for resources in the cave habitat as indicated by the relationship between specific life history traits and cave use.

Establishing the social system of a population is key to studying the evolution of behaviors. However, observations of social interactions needed to infer social systems are difficult to obtain for many species. An alternative way of understanding social systems is by studying the space-use pattern of individuals. Along with ecological factors, space use is largely governed by interactions among individuals: typically, competing individuals avoid each other, and individuals benefitting from each other share space. We investigated the social system, specifically the mating system, and the nature of intrasexual interactions between adults, by quantifying space-use patterns of individuals over their adult lifespan in the tropical Psammophilus dorsalis lizard. Males had substantially larger home ranges than females during the mating season, but not during the nonmating season. Female home ranges were small, and showed minimal overlap with other females throughout their lifespan, suggesting consistent intrasexual competition among females. In contrast, males showed minimal overlap with other males in the nonmating season but increased overlap in the mating season, suggesting that males resolve intrasexual competition through other means, like contests, during the mating season. Patterns of overlap between male and female home ranges in the mating season indicated a socially polygynous mating system. Our study provides an initial understanding of home-range patterns and associated inferences of within- and between-sex interactions across the lifespan of a tropical lizard, Psammophilus dorsalis. It highlights the insights into the social structure of a population gained from dispersion patterns of individuals.

Movement data and estimation of home-range sizes provide insight into the types and amount of habitat needed to support wildlife populations, which is critical for conservation planning. Gopher Tortoises, which are important ecosystem engineers and keystone species across the southeastern United States, are experiencing ongoing population declines and warrant additional habitat protection and management throughout their range. Conservation assessments for Gopher Tortoises are currently limited by scant knowledge of the ecology of younger age classes. We implemented a short-term study of immature Gopher Tortoise spatial ecology at Archbold Biological Station (ABS), Florida to determine home-range size, movements, and activity levels of 3–7-yr-old tortoises. We used GPS technology to obtain high-resolution temporal tracking data (approximately 10-fold increase compared with the radio tracking frequency in prior studies). Despite the relatively short duration of our study (≤40 d), immature Gopher Tortoises (n = 6) at ABS had home-range sizes ranging from 0.38 to 1.46 ha, which are approximately 6.6-fold larger than previously reported annual home-range estimates. Tortoises also left their burrows more often (4.0 ± 3.2 SD times per day) and for longer duration (31.5 ± 10.6 SD min per emergence) than in studies conducted elsewhere (1.6 times and 18.8 min, respectively). Our results illustrate the importance of employing new technologies to track previously difficult-to-observe life stages and improve conservation efforts for imperiled species.

The status, size, and density of Malaclemys terrapin (Diamondback Terrapin) populations along the Atlantic coast have been reported by most states as unknown or declining. Robust demographic or population data are lacking, with even less information available on their spatial ecology. Spatial capture–recapture (SCR) methods explicitly incorporate spatial processes, providing a formal link between encounter data and space use. Despite the widespread adoption of SCR across ecological disciplines, it has yet to be applied to turtle populations. We present the first application of SCR methods to Diamondback Terrapins by analyzing data collected from two known activity areas in the tidal marsh systems of Wellfleet Bay, Massachusetts. We found that Terrapin detection was positively associated with survey effort at both sites. Detection was also influenced by day of season, tide cycle, the time of tide, survey time relative to the tide, cloud cover, and windspeed. Density and space use differed markedly between the two sites: the estimated density in The Run was 9 individuals/ha with a space use parameter of 309 m, compared to 59 individuals/ha and a space use parameter of 107 m in The Cove. Sex structure was female-biased, with a sex ratio of 0.34 and 0.18 males in The Run and The Cove, respectively. We demonstrate the utility in using SCR methods in turtles, specifically Diamondback Terrapins, to produce comparable estimates of detection and population size and density, while simultaneously providing inference on differential space-use and detection resulting from variation in both behavior and sampling conditions.

Estimates of clutch sizes are essential for modeling population dynamics, yet for many species of amphibian, clutches can be difficult to observe or methodologically problematic to measure. Clutch sizes for direct-developing Plethodontidae are regularly estimated from counts of ovarian follicles. Because many more follicles begin to develop in an ovary than will ultimately reach full size and be deposited, follicle counts change dramatically over an individual female's follicle development cycle, and a high level of subjectivity is inherent in the process of estimating clutch sizes from follicle counts. Many published studies are not transparent in how they determine clutch sizes from follicle counts. Some investigators address this bias using threshold sizes or other characteristics to separate those follicles that will ultimately mature and be deposited from those that will not, but our experience indicates that such approaches still likely overestimate clutch sizes. To move beyond the subjectivity inherent in estimation of final clutch size from follicle counts, we modeled large Plethodon clutch size as a function of female body size (snout–vent length, SVL) and follicle diameter, then used that model to predict the likely number of mature eggs deposited. We propose that this approach provides reasonable estimates of clutch sizes and variances for use in demographic models.

The American Crocodile (Crocodylus acutus) is still considered Vulnerable, with some populations remaining depressed and showing little evidence of recovery. An understanding of the reproductive dynamics and parameters of C. acutus is essential for its conservation and management. Although the knowledge of C. acutus reproductive ecology has greatly increased during recent years, some critical parameters such as breeding effort (i.e., proportion of adult females that nest each year in a population) remain poorly known. Herein we analyzed 14 yr of reproductive data from a C. acutus population in a Mexican atoll to better understand its reproductive dynamics in space and time. We estimated the number of reproductive females in the population and in each nesting area, compared nest characteristics and clutch parameters among nesting areas, and determined female breeding effort and breeding frequency (i.e., proportion of years that an adult female nested). We estimated that 35 reproductive female C. acutus inhabit the main island of the atoll, distributed among 12 nesting areas. The annual female breeding effort ranged from 27.3–60.6% and the breeding frequency of 15 selected females ranged from 57.1–92.3%. Breeding effort depends on the breeding effort in preceding years. We also found significant differences in reproductive attributes (i.e., number of nests, nest–water distance, nest depth, clutch size, and nesting success) among nesting areas that we explain by the quality of those habitats for crocodile nesting and by territorial behavior of females.

More than half of turtle species worldwide are threatened because of habitat loss, invasive species, environmental pollution, disease, unsustainable use, and global climate change. However, some turtles are capable of existing in highly modified habitats, including structures designed to benefit human populations such as reservoirs and canal systems. Examining turtle distributions in large canal systems can inform conservation plans protecting turtle populations within a potential reservoir network and expand our understanding of underlying mechanisms regulating populations. We conducted spatial capture–recapture on turtles inhabiting sections of the Chesapeake and Ohio Canal. We developed a Bayesian spatial capture–recapture model to estimate densities, sex ratios, and associated capture probability parameters for Chrysemys picta (Painted Turtle), Chelydra serpentina (Common Snapping Turtle), Sternotherus odoratus (Eastern Musk Turtle), and Pseudemys rubriventris (Red-Bellied Turtle) captured at 12 sites along 28 km of the canal. We examined the impact of canal depth and forest cover on population densities and the variation in capture probability between sites and sampling days. We found population densities to vary between sites and the associated sex ratios to vary between species, as did the effect of depth and forest cover. Overall capture rates decreased each day, but there was trap-happy behavior from all species except S. odoratus. Our information can set a baseline for understanding turtle populations and inform management in the Chesapeake and Ohio Canal National Historical Park. It is also one of the first studies to establish methods for using new spatial capture–recapture to quantify densities and aquatic space use of turtles.

The ongoing global decline in the species diversity of amphibians and reptiles, and limited resources to study natural history, reinforce the need for the adequate sampling of all the different information pertaining to biological diversity that characterizes these organisms. Decision-making processes by conservationists should be based on reliable knowledge, and the analysis of the scientific literature guarantees access to the available biological information. We assessed the major herpetology journals and described the patterns and trends in the publication of natural history notes on amphibians and reptiles on a global scale over the past decade. Our results show that there is considerable geographic and taxonomic bias in the studies reported in the notes, with the United States, Brazil, and Mexico representing the top countries, and Bufonidae, Craugastoridae, Agamidae, and Colubridae the top families in publications. Research efforts were not influenced systematically by the conservation status target species, and we recorded more studies related to nonendangered species than to endangered ones. Overall, natural history notes have great potential for reducing knowledge shortfalls in herpetology studies.

A existência de um padrão global de declínio de espécies de anfíbios e répteis, e os recursos limitados para o estudo da história natural, reforçam a necessidade de representar suficientemente todos os gradientes da diversidade biológica que caracteriza esses grupos. As decisões conservacionistas devem ser baseadas em conhecimentos confiáveis, sendo a análise da produção científica uma estratégia eficiente, permitindo o uso de informações biológicas disponíveis. Avaliamos as revistas da área de herpetologia e descrevemos os padrões e as tendências na publicação de notas científicas relacionadas aos anfíbios e répteis, em escala global na última década. Nossos resultados demonstram que há uma considerável propensão geográfica e taxonômica nos estudos reportados pelas notas científicas, sendo os Estados Unidos, Brasil e México os principais países e Bufonidae, Craugastoridae, Agamidae e Colubrida as principais famílias nas publicações. Além disso, identificamos que as publicações de notas científicas são enviesadas taxonomicamente, sendo observado maior número de notas científicas por espécies de répteis do que de anfíbios. O esforço de pesquisa não foi motivado pela categoria de ameaça, sendo que, espécies não ameaçadas de extinção foram consideravelmente mais estudadas do que aquelas classificadas como ameaçadas. Dentre as principais lacunas de conhecimento, as notas científicas, se compiladas, podem contribuir para a redução de lacunas de conhecimento.

Shasta salamanders (collectively, Hydromantes samweli, H. shastae, and H. wintu; hereafter, Shasta salamander) are endemic to northern California in the general vicinity of Shasta Lake reservoir. Although generally associated with limestone, they have repeatedly been found in association with other habitats, calling into question the distribution of the species complex. Further limiting our knowledge of the species' distributions is that they are only active or available for sampling on the soil surface for a small portion of the year, and detection probabilities for the species have never been estimated. We developed and implemented a survey protocol designed to estimate detection, availability, and occurrence probabilities from December 2019 through March 2020. We provide inference on Shasta salamander occurrence in portions of their range that have received little survey effort. We found that Shasta salamander occurrence was positively associated with the percent cover of embedded rock, and the species' availability (i.e., probability of being active on the soil surface during sampling) was positively related to relative humidity. The probability of occurrence of Shasta salamanders in our study area was low, and our winter-to-spring survey protocol was effective for estimating detection, availability, and occurrence probabilities in the study area and at specific sites. We suggest that conducting replicate surveys that quantify animal availability and detection probabilities will facilitate a better understanding of the habitat associations of Shasta salamanders and other rare species that might often be unavailable for detection.

A long-standing question regarding the evolution of the snake body plan is to what extent does axial regionalization and organ position correspond with that of generalized tetrapod vertebrates. Here, we evaluated the position of shifts in vertebral morphology with respect to heart location in 2 species and 13 specimens of garter snakes (Thamnophis). From dissections, geometric morphometrics, and segmented regressions on principal component scores describing shape of the cranial aspect of vertebrae, we determined a consistent morphological transition at approximately 17% of the pre-cloacal vertebral column. The transition was strongly coincident with the position of the heart, suggesting a developmental link between the first major transition in vertebral regions and the longitudinal position of the heart in garter snakes. Our novel discovery has implications for further recognizing the pre-cloacal vertebral column of snakes as regionalized, and that these regions are positionally linked with organogenesis of the viscera.

We reassessed the type-series of Amphisbaena ibijara and Amphisbaena frontalis to evaluate the characters used to diagnose and distinguish them, and compared these data with additional specimens of A. ibijara. We found broadly overlapping ranges of the quantitative diagnostic characters, and no differences between the qualitative characters, that could support differences between A. frontalis and A. ibijara. Based on our morphological results, and the geographic proximity of the distribution ranges of both species, we consider A. ibijara as a junior synonym of A. frontalis. We provide updated data on intraspecific variation in the diagnostic characters of A. frontalis.

Nós reanalisamos as séries-tipo de Amphisbaena ibijara e Amphisbaena frontalis para avaliar os caracteres usados para diagnosticar e distinguir essas espécies, e nós comparamos estes dados com espécimes adicionais de A. ibijara. Nós encontramos ampla sobreposição entre os caracteres quantitativos diagnósticos, e nenhuma diferença entre os caracteres qualitativos que poderiam suportar diferenças entre A. frontalis e A. ibijara. Baseados nos nossos resultados morfológicos, e na proximidade geográfica da distribuição de ambas espécies, nós consideramos A. ibijara como sinônimo júnior de A. frontalis. Nós fornecemos também dados atualizados da variação intraespecífica dos caracteres diagnósticos de A. frontalis.

Gekko (Rhacogekko) sorok is a small gecko species that was described in 2008 based on a single specimen from Borneo. We rediscovered multiple specimens of this species in the Lambir Hills National Park, Malaysian Borneo. The specimens constitute the second record of the species and the first record from Sarawak State. We describe the specimens and validate the taxonomic status of the species, which was formerly treated as Luperosaurus until recently and is now placed within the genus Gekko (Rhacogekko). Molecular phylogenetic analysis revealed that G. sorok is nested within a clade that includes Luperosaurus sensu stricto and is strongly supported as the sister lineage to L. joloensis. We tentatively propose that this species not be treated as Gekko (Rhacogekko) sorok, but rather as Luperosaurus sorok. We also comment on the natural history of this rare species and suggest that it is a high canopy dweller.

The Gopher Frog (Rana capito) is a threatened species native to the southeastern longleaf pine ecosystem. Although once much more widespread across the southeastern United States, they now occur in North Carolina at only a handful of disjunct sites in the Coastal Plain and Sandhills regions of the state. The long-term persistence of these populations is thus a concern, as is a loss of genetic variation over time. We used mitochondrial and microsatellite markers to better understand the spatial structure of genetic variation and levels of genetic variability across these remaining populations in order to inform conservation and management decisions. Eight unique mitochondrial haplotypes were found, but these were all genetically similar to one another. Levels of genetic diversity based on the microsatellite analyses were similar across populations, but inbreeding coefficients in two populations were significant, suggesting a potential vulnerability to inbreeding depression. All disjunct populations showed significant genetic differentiation, which was not related to geographic distance. Conversely, within populations, the genetic relatedness of individuals between ponds decreased as distance between ponds increased. This kinship pattern is likely driven by strong breeding philopatry (individuals returning to the same ponds across years) and indicates that conservation actions at the scale of <1 km would primarily affect kin groups of Gopher Frogs, whereas conservation actions at scales ‡1.5 km would be needed to capture more distantly related individuals. Management efforts should thus focus on local metapopulation dynamics by maintaining multiple breeding ponds at each location, and by enhancing connectivity between these breeding ponds.

Turtle populations around the world are continually confronted with changing environments that affect their ecology and conservation status. Among freshwater turtles, population dynamics are thought to be mediated by complex yet often cryptic causes. One recent direction of focus in addressing these causes is the turtle-associated microbiota. In turtles, the gut-associated microbiota is of exceptional interest due to its continual association with host species under changing conditions. Diet-based fluctuations and changes in microbial diversity may correspond to varying external environments at both the individual and population level. Environmental responses are of particular interest due to the anthropogenic changes that may underlie them. Pollutants, disruption of climatic patterns, and habitat fragmentation all have the potential to affect turtle-associated microbiota and subsequent population and species conservation. To better understand potential human-induced changes, the diversity of turtle-associated microbiota over local spatial gradients must be better understood. We examined microbial community α- and β-diversity among 30 adult False Map Turtles (Graptemys pseudogeographica) at three sites within the lower Missouri River, United States. Our results indicate significant microbial community centroid differences among sites (β-diversity), which are likely mediated by various local environmental factors. Such factors will have to be carefully considered in any future attribution of anthropogenic determinants on turtle-associated microbiota as it relates to turtle population dynamics.