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Accurate estimates of survival are crucial for many management decisions in translocation programs. Maximizing detection probabilities and reducing sampling biases for released animals can aid in estimates of survival. One important source of sampling bias is an animal’s behavior. For example, individuals that are consistently more exploratory or active may be more likely to be detected visually. Behavioral traits can be related to survival after reintroduction, and because many pre‐release treatments aim to manipulate animal behavior, it is critical to tease apart relationships between behavior and detection probability. Here, we assessed the repeatability (intra‐individual consistency and inter‐individual variation) of behavioral traits for an endangered amphibian, the mountain yellow‐legged frog (Rana muscosa). Because new technological tools offer one potential solution for reducing sampling biases while increasing detection, we also tested whether a long‐range passive integrated transponder (PIT) tag reader could enhance surveys for these individuals after translocation into the wild. After confirming that ex situ bred R. muscosa exhibit repeatable behavioral traits (repeatability = 0.25–0.41) and releasing these frogs (N = 196) into the wild, we conducted post‐release surveys visually and with the long‐range PIT tag reader. Integrating the long‐range reader into surveys improved detection probability four‐fold in comparison to visual surveys alone (~0.09 to ~0.36). Moreover, mark–recapture modeling revealed that tag reader detection probability was not biased toward detecting individuals of specific behavioral types, while visual detection was significantly related to behavioral traits. These results will enable a more accurate understanding of individual differences in post‐release success in translocations. This may be particularly important for amphibian species, which can be difficult to detect and are expected to increasingly be involved in human‐managed breeding and translocation programs due to their vulnerable conservation status.

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1. While ex situ breeding programs are critical tools for species recovery, translocations using animals reared under human care can face low success rates, often related to increased dispersal and reduced survival. These issues may be related to a mismatch between ex situ environments and natural habitats. Natal habitat preference induction, wherein individuals seek out habitat similar to that they experienced during development, may provide one explanation for this phenomenon. While exposure to naturalistic environments and pre-release training can mitigate these issues, there may be developmental windows within which these sorts of experiences are most transformative.2. We characterized the impacts of environmental experience at different developmental stages on morphology, performance and post-translocation dispersal and survival in the endangered mountain yellow-legged frog Rana muscosa. We exposed frogs of different ages (N = 146 one-year-olds, hereafter juveniles; N = 110 two-year-olds, hereafter subadults) to different water flow regimes to mimic stream conditions of reintroduction sites. We measured morphology and swimming performance before and after treatment. Frogs were translocated into the wild and monitored to collect data on movement and survival.3. Stream experience resulted in significantly longer proportional limb lengths and improved swimming performance for juvenile but not subadult frogs. 4. After translocation, stream experienced subadults exhibited significantly lower post-release movement than control subadults. There was no effect of treatment on juvenile movement, which was significantly higher than in subadults.5. Stream experience significantly boosted apparent survival for juveniles but not subadults, but subadults exhibited higher survival overall.6. Synthesis and applications. Our results suggest that early-life experience with naturalistic conditions in ex situ facilities can significantly impact morphology, performance and post-translocation movement and survival, and that the effects are age dependent. Pre-release training is a vital component of

Anurans can display a host of intriguing sexual syndromes, including hermaphroditism and sex reversal. Using a multifaceted approach for diagnosing and characterising hermaphroditism in the endangered anuran species Rana mucosa, we tracked changes in female reproductive status using hormone monitoring, ultrasound examinations, individual life history, fertilisation records and post-mortem findings. Seven individuals originally sexed as females developed secondary male sexual characteristics, behaviour and hormone profiles and, in some cases, had testicular tissue despite having previously laid eggs. Our results suggest that reproductive technologies can shed light on life history patterns and reproductive anomalies that may affect endangered anuran survival.

BackgroundThe non-lethal collection of sperm from live males is an important component for multiple captive-breeding techniques, including assisted reproductive technology (ART) protocols, sperm cryopreservation and in vitro fertilization. However, in amphibians, the type and amount of hormone necessary to induce spermiation can be highly variable, even among closely related species. We are unaware of any studies that have examined the spermiation response to exogenous hormones across highly differentiated populations within a species.MethodsWe examined variation in sperm viability and production in response to the hormone LHRH among four divergent populations of the Red-eyed Treefrog (Agalychnis callidryas). We hypothesized that these highly differentiated populations would show variability in sperm count and viability in response to two dosages, 2 μg/g and 4 μg/g, of the hormone LHRH. We collected spermic urine 3 h post injection (PI). We then examined variation in spermiation at 3, 7, 12, and 24 h PI of LHRH for two allopatric populations that previously showed evidence of premating behavioral isolation.ResultsOne population of Red-eyed Treefrog exhibited reduced sperm viability but not count in response to the hormone LHRH compared to all other populations. In addition, we found peak viability at 3 h PI for the allopatric population comparison. There was no difference in sperm production within or between populations at 3, 7, 12, or 24 h PI. For both studies, intrapopulation variation was high.ConclusionART often focuses on threatened species with small, isolated populations, which could evolve localized differences due to the evolutionary process of drift and selection. The high variation in response and the population-level differences in sperm viability we observed demonstrate that practitioners of ART should consider the possibility of divergent responses to hormones which may affect study design and animal receptivity to ART protocols.Electronic supplementary materialThe online version of this article (doi:10.1186/s12958-016-0216-3) contains supplementary material, which is available to authorized users.

Conservation breeding programs have long been an important management tool for species recovery. Recently, breeding programs have begun to integrate next generation sequencing data into pedigree-based management strategies designed to maximize retention of genetic diversity and minimize inbreeding. The San Diego Zoo Wildlife Alliance established an ex situ breeding program for the endangered southern mountain yellow-legged frog (Rana muscosa), including two separately populations from the San Jacinto and San Bernardino mountain ranges. In this study, we conducted molecular population genetic assessments using double digest restriction site-associated DNA sequencing data to provide improved breeding recommendations for the managed R. muscosa populations. We found that genetic diversity of ex situ populations was relatively low (HO = 0.166–0.245) and population differentiation moderate (FST = 0.29). Patterns of genetic structure of captive frogs supported the evolutionary divergence of individuals by mountain ranges in the wild, with limited gene flow. Relatedness estimates identified close relatives among the founders, and molecularly-derived kinship values were used to determine and rank suitable breeders to minimize population mean kinship. Management recommendations highlight the need for importing additional founders from the wild to enhance genetic diversity in the breeding program, as effective source for genetic restoration.

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