Translocation Programs Research Articles

Can recent evolutionary history promote resilience to environmental change?

Principles of social evolution have long been used retrospectively to interpret social interactions, but have less commonly been applied predictively to inform conservation and animal husbandry strategies. We investigate whether differences in developmental environment, facilitated by divergent social conditions, can predict resilience to environmental change. Upon exposure to harsh novel environments, populations that previously experienced more benign social environments are predicted either to suffer fitness losses (the "mutation load hypothesis" and "selection filter hypothesis") or maintain fitness (the "beneficial mutation hypothesis"). We tested these contrasting predictions using populations of burying beetles Nicrophorus vespilloides we had evolved experimentally for 45 generations under contrasting social environments by manipulating the supply of post-hatching parental care. We exposed sexually immature adults from each population to varying heat stress and measured the effect on survival and reproduction. The greater the level of parental care previously experienced by a population, the better its survival under heat stress during sexual maturation. Although this is consistent with the "beneficial mutation hypothesis," it is also possible that populations that had evolved without post-hatching care were simply more prone to dying during maturation, regardless of their thermal environment. Overall, we suggest that stochastic genetic variation, probably due to founder effects, had a stronger influence on resilience. We discuss the implications for translocation and captive breeding programs.

Shared and redundant proteins coordinate signal cross-talk between MAPK pathways in yeast.

All cells must detect, interpret, and adapt to multiple and concurrent stimuli. While signaling pathways are highly specialized, different pathways often share components or have components with overlapping functions. In the yeast Saccharomyces cerevisiae, the high osmolarity glycerol (HOG) pathway has two seemingly redundant branches, mediated by Sln1 and Sho1. Both branches are activated by osmotic pressure, leading to phosphorylation of the MAPKs Hog1 and Kss1. The mating pathway is activated by pheromone, leading to phosphorylation of the MAPKs Fus3 and Kss1. Given that Kss1 is shared by the two pathways, we investigated its role in signal coordination. We activated both pathways with a combination of salt and pheromone, in cells lacking the shared MAPK and in cells lacking either of the redundant branches of the HOG pathway. By systematically evaluating MAPK activation, translocation, and transcription programs, we determined that Sho1 mediates cross talk between the HOG and mating pathways and does so through Kss1. Further, we show that Kss1 initiates a transcriptional program that is distinct from that induced by Hog1 and Fus3. Our findings reveal how redundant and shared components coordinate concurrent signals and thereby adapt to sudden environmental changes.

The Translocation Continuum Framework for context‐specific decision making

Translocations are a critical tool for reversing biodiversity loss but are often characterized by unreasonably high expectations, leading to many translocation programs being brief and terminated before achieving their full potential. To address these issues, we developed the “Translocation Continuum Framework”, an easy‐to‐use tool that clarifies the criteria, strategies, tactics, progress measures, and expected outcomes for five key translocation “phases”: Feasibility Studies, Pilot Studies, Primary Trials, Secondary Experiments, and Tertiary Reinforcements. By accounting for uncertainty, the Framework aims to empower practitioners to design translocation programs that suit their context. We also discuss the limitations of “success” and “failure” labels in translocations, and the importance of parsimonious decision making to maximize learning with the least amount of loss. Only by managing expectations of the likelihood of establishment, growth, and regulation throughout a program's lifetime can we galvanize trust and investment in translocations so they can contribute meaningfully to long‐term restoration.

Captive birds exhibit greater foraging efficiency and vigilance after anti-predator training

Abstract Rearing animals in captivity for conservation translocation is a complex undertaking that demands interdisciplinary management tactics. The maladapted behaviors that captive animals can develop create unique problems for wildlife managers seeking to release these animals into the wild. Often, released captive animals show decreased survival due to predation and their inability to display appropriate anti-predator, vigilance, and risk-analysis behaviors. Additionally, released animals may have poor foraging skills, further increasing their vulnerability to predation. Often conservation translocation programs use anti-predator training to ameliorate these maladapted behaviors before release but find mixed results in behavioral responses. The behavioral scope of analyzing the effect of anti-predator trainings is frequently narrow; the effect of this training on an animal’s risk-analysis competency, or ability to assess the predation risk of a foraging patch and subsequently adjust its behavior, remains unstudied. Using a captive-reared passerine species, the American robin (Turdus migratorius) (46 individuals), we applied an experimental giving up density test (GUD) to analyze the effect of anti-predator training on the robins’ vigilance/risk-analysis behaviors, patch choice, and the GUD of food left behind after one foraging session. Robins moved and foraged freely between 3 foraging patches of differing predation risk before and after a hawk silhouette was presented for 1 min. Results indicate that after anti-predator training, robins displayed increased vigilance across most foraging patches and better foraging efficiency (higher vigilance and latency to forage with simultaneous lower GUD) in the safest patch. These results can have positive survival implications post-release, however, more research on this training is needed because anti-predator training has the potential to elicit indiscriminate increased vigilance to the detriment of foraging gains. Further research is required to standardize GUD’s application in translocation programs with multigenerational captive-bred animals to fully comprehend its effectiveness in identifying and correcting maladaptive behaviors. GUD tests combined with behavioral analysis should be used by conservation translocation managers to examine the need for anti-predator and foraging trainings, the effects of trainings, and a group’s suitability for release.

Species distribution and habitat attributes guide translocation planning of a threatened short-range endemic plant

The success of plant translocations depends on defining habitat attributes critical for establishment and survival, and on locating this habitat in the landscape. We used species distribution modelling, coupled with fine-scale characterisation of local habitat attributes to characterise and identify potential sites for translocation of Tetratheca erubescens J.P.Bull (Elaeocarpaceae), a threatened shrub restricted to cliff faces on one banded ironstone range in semi-arid south-west Western Australia. Here, we 1) constructed a maximum entropy species distribution model (SDM) from known occurrence locations and environmental data, and projected this onto a broader surrounding landscape to seek suitable unoccupied habitat; 2) characterised the local habitat attributes (LHA) of both occupied and predicted but unoccupied habitat (locality types), determining potential characteristics of habitat suitability at the scale of individual plants (microsites) not captured by the landscape-scale models and; 3) assessed unoccupied areas of modelled high habitat suitability to identify ‘potential translocation sites’ that may have the characteristics to support T. erubescens. The SDM resolved two management considerations by identifying suitable habitat outside the known extent of threatened species to locate areas to search for additional natural populations (none found) or to verify as ‘potential translocation sites’ (24 sites identified). Using field surveys to assess LHA at a finer-scale, we detected differences between plant microsites and other random points in occupied habitat. As such, T. erubescens was more likely to grow in wider rock cracks, located in relatively water gaining points in the cliff profile, in soils with organic (rather than mineral) content. Our approach systematically addressed the complex challenges involved in identifying and selecting sites for translocation of a threatened plant species, a first for a semi-arid environment. We used the outcomes of this study to present a conceptual model for practitioners and regulators that outlines our approach for identifying ‘potential translocation sites’ and ranking their suitability within the context of three assessment filters: species requirements; management-operational constraints and regulatory considerations. This application is relevant to translocation programs that seek to return plant species into natural habitat areas.

Range-wide genetic analysis of an endangered bumble bee (Bombus affinis, Hymenoptera: Apidae) reveals population structure, isolation by distance, and low colony abundance.

Declines in bumble bee species range and abundances are documented across multiple continents and have prompted the need for research to aid species recovery and conservation. The rusty patched bumble bee (Bombus affinis) is the first federally listed bumble bee species in North America. We conducted a range-wide population genetics study of B. affinis from across all extant conservation units to inform conservation efforts. To understand the species' vulnerability and help establish recovery targets, we examined population structure, patterns of genetic diversity, and population differentiation. Additionally, we conducted a site-level analysis of colony abundance to inform prioritizing areas for conservation, translocation, and other recovery actions. We find substantial evidence of population structuring along an east-to-west gradient. Putative populations show evidence of isolation by distance, high inbreeding coefficients, and a range-wide male diploidy rate of ~15%. Our results suggest the Appalachians represent a genetically distinct cluster with high levels of private alleles and substantial differentiation from the rest of the extant range. Site-level analyses suggest low colony abundance estimates for B. affinis compared to similar datasets of stable, co-occurring species. These results lend genetic support to trends from observational studies, suggesting that B. affinis has undergone a recent decline and exhibit substantial spatial structure. The low colony abundances observed here suggest caution in overinterpreting the stability of populations even where B. affinis is reliably detected interannually. These results help delineate informed management units, provide context for the potential risks of translocation programs, and help set clear recovery targets for this and other threatened bumble bee species.

Deciding where to put them: Sensitivity tests and independent evaluation are critical when using species distribution models to inform conservation translocations

Abstract Conservation translocations are an important tool for combating species declines and population losses. Species distribution models (SDMs) can facilitate the selection of suitable release sites for translocation programs. However, these models can be sensitive to several modelling decisions. In this study, we explore the impacts of three key modelling decisions on Maxent models developed to inform reintroductions of the long‐toed salamander (Ambystoma macrodactylum) in southwestern Alberta. We specifically test the sensitivity of model predictions to (1) the type of environmental variables used to generate models, (2) whether the background points used to calibrate the models reflects the potential bias in the input locality records and (3) the choice of geographic study extent. We use independent presence‐absence data from an extensive field survey to test the accuracy of models based on different decisions. Both model predictions and performance were sensitive to these modelling decisions. Models developed using local study extents were more accurate than those based on range‐wide extents. Both study extent and type of background points impacted model predictions and performance more than the set of environmental variables included in the models for this species. We further demonstrate the impacts of these decisions on the ranking of potential release sites and present a final set of recommendations that accounts for this uncertainty under both current and future climatic conditions. We specifically identify three sites that are expected to be suitable in both present and future time periods as potential release sites for salamander reintroductions in southwestern Alberta. Synthesis and applications: Our study adds to our understanding of how different modelling decisions impact SDMs and the downstream conclusions from these models while simultaneously demonstrating a rigorous approach for the use of SDMs in conservation translocation planning.

Detection of Trypanosoma evansi in jaguars (Panthera onca): insights from the Brazilian Pantanal wetland.

Trypanosoma evansi is a widespread and neglected zoonotic parasite that affects domestic and wild animals, causing a disease commonly known as "surra." The Brazilian Pantanal wetland is recognized as an enzootic area for this protozoan, yet recognizing the importance of reservoir hosts also in order to prevent zoonotic outbreaks. This study aimed to assess the occurrence of T. evansi in jaguars (Panthera onca) from the Brazilian Pantanal wetland and explore associated clinical and hematological manifestations. A total of 42 animals were screened by PCR and sequenced for species identification when positive. Trypanosoma evansi was detected in six free-ranging jaguars (six positive animals of 42 captures and 16 recaptures), representing the first molecular evidence of such infection in this animal species. Our findings suggest that jaguars may act as reservoir hosts of T. evansi in the Brazilian Pantanal wetland. The better understanding of the role of wildlife in the epidemiology of T. evansi is also of importance to future reintroduction and translocation programs toward wildlife conservation efforts.

Identifying predictors of translocation success in rare plant species.

The fundamental goal of a rare plant translocation is to create self-sustaining populations with the evolutionary resilience to persist in the long term. Yet, most plant translocation syntheses focus on a few factors influencing short-term benchmarks of success (e.g., survival and reproduction). Short-term benchmarks can be misleading when trying to infer future growth and viability because the factors that promote establishment may differ from those required for long-term persistence. We assembled a large (n = 275) and broadly representative data set of well-documented and monitored (7.9 years on average) at-risk plant translocations to identify the most important site attributes, management techniques, and species' traits for six life-cycle benchmarks and population metrics of translocation success. We used the random forest algorithm to quantify the relative importance of 29 predictor variables for each metric of success. Drivers of translocation outcomes varied across time frames and success metrics. Management techniques had the greatest relative influence on the attainment of life-cycle benchmarks and short-term population trends, whereas site attributes and species' traits were more important for population persistence and long-term trends. Specifically, large founder sizes increased the potential for reproduction and recruitment into the next generation, whereas declining habitat quality and the outplanting of species with low seed production led to increased extinction risks and a reduction in potential reproductive output in the long-term, respectively. We also detected novel interactions between some of the most important drivers, such as an increased probability of next-generation recruitment in species with greater seed production rates, but only when coupled with large founder sizes. Because most significant barriers to plant translocation success can be overcome by improving techniques or resolving site-level issues through early intervention and management, we suggest that by combining long-term monitoring with adaptive management, translocation programs can enhance the prospects of achieving long-term success.

A community‐driven captive‐breeding and reintroduction program maintains genetic diversity in a threatened freshwater fish

AbstractCollaborative approaches to conservation management are critical to respond to the ongoing biodiversity crisis. However, local community involvement in many conservation actions is lacking, especially within translocation and reintroduction programs. Similarly, rapid integration of genetic information into collaborative programs with local communities is rarely conducted. Here, we describe a community‐based and collaborative reintroduction program for a threatened Australian freshwater fish, the southern pygmy perch (Nannoperca australis). We integrate on‐the‐ground translocation efforts by volunteers from local communities, captive breeding by a private aquarium business, and genetic analyses done by a research institution to provide a holistic framework for the reintroduction of southern pygmy perch. We evaluated genetic diversity, population structure, relatedness, and inbreeding across the duration of the reintroduction program using data from neutral and adaptive genomic markers. This allowed us to assess the ability of such a program to minimize inbreeding and retain genomic variation, and to promote adaptive potential of the reintroduced population. While genetic variation for the source populations was very low, we found no decrease in genetic diversity or increase in inbreeding across the program. These genetic findings support the efforts made by local communities and will further inform future reintroductions as part of a collaborative conservation framework. We expand on our empirical case study by describing a theoretical framework for integrating conservation genomics research with community‐led conservation management programs and identifying the benefits of such a collaboration. Our study highlights the importance of multifaceted and integrated conservation management approaches to effectively protect and manage threatened species.

Simulation Modeling to Assess Line Transect Distance Sampling Under a Range of Translocation Scenarios

Abstract The accuracy of posttranslocation population monitoring methods is critical to assessing long-term success in translocation programs. Translocation can produce unique challenges to monitoring efforts; therefore, it is important to understand the flexibility and robustness of commonly used monitoring methods. In Florida, USA, thousands of gopher tortoises Gopherus polyphemus have been, and continue to be, translocated from development sites to permitted recipient sites. These recipient sites create a broad range of potential monitoring scenarios due to variability in soft-release strategies, habitat conditions, and population demographics. Line transect distance sampling is an effective method for monitoring natural tortoise populations, but it is currently untested for translocated populations. We therefore produced 3,024 individual-based, spatially explicit scenarios of translocated tortoise populations that differed in recipient site and tortoise population properties, based on real-world examples, literature review, and expert opinion. We virtually sampled simulated tortoise populations by using line transect distance sampling methods and built a Bayesian hierarchical model to estimate the population density for each simulation, which incorporated individual-level covariates (i.e., burrow width and burrow occupancy). Line transect distance sampling was largely appropriate for the conditions that typify gopher tortoise recipient sites, particularly when detection probability on the transect lines was greater than or equal to 0.85. Designing the layout of transects relative to the orientation of soft-release pens, to avoid possible sampling biases that lead to extreme outliers in estimates of tortoise densities, resulted in more accurate population estimates. We also suggest that use of individual-level covariates, applied using a Bayesian framework as demonstrated in our study, may improve the applicability of line transect distance sampling surveys in a variety of contexts and that simulation can be a powerful tool for assessing survey design in complex sampling situations.

The return of the adult Pacific Lamprey offspring from translocations to the Columbia River

AbstractObjectiveThe Pacific Lamprey Entosphenus tridentatus is valuable to tribal culture and to the ecosystem, but its abundance in the interior Columbia River has been highly variable and muted in recent years. Translocation programs have been adopted as a proactive strategy to restore Pacific Lamprey abundance to the interior Columbia River, including the Snake River basin, and these efforts have been largely successful in increasing larval and juvenile abundance in the recipient watersheds and further downstream. We address whether adult translocation offspring from three Columbia River Treaty Tribe programs return to Bonneville Dam in numbers that support previous model predictions; and whether Columbia River origin Pacific Lamprey contribute to adult production widely across the species range.MethodsWe used a genetic data set of unknown origin Pacific Lamprey that returned as adults to Bonneville Dam and broadly distributed locations within and outside of the Columbia River basin. We identified the natal origin of these adults via sibship or parentage to assign individuals to either a precise natal site of volitional production or a set of candidate parents from one of the translocation programs in the Columbia River.ResultWe showed that not only have Snake River translocation offspring returned as adults to Bonneville Dam in numbers that exceeded model projections, but offspring from two other tribal translocation programs in the Umatilla (northeast Oregon) and Yakima (south‐central Washington) rivers were also detected in recent years. Offspring produced across all three translocation programs are estimated at approximately 1065 fish in 2021. Although Pacific Lamprey are known to lack precise natal homing, which may limit the benefits of translocations in the interior Columbia River basin, evidence from detections in this study supports a preference by interior Columbia River Pacific Lamprey to return home and migrate toward their natal basins. However, a portion of Snake River‐origin Pacific Lamprey was estimated to deviate from main‐stem routes into tributaries, including tribal ceded areas where tribal harvest occurs (e.g., Sherars Falls on the Deschutes River).ConclusionThese results indicate benefits from Pacific Lamprey translocation programs that will not only increase abundance to targeted areas but will also increase opportunities for tribal harvest of this culturally important species.

The Science Underlying Giant Panda Conservation Translocations.

The giant panda (Ailuropoda melanoleuca) is the flagship species of animal conservation worldwide, and the number of captive pandas reached 673 in 2021. According to the Fourth National Survey Report on the Giant Panda, there are 1864 wild pandas, segregated into 33 local populations, and 25 of these populations are too small to be self-sustaining. In addition to the conservation and restoration of panda habitats, conservation translocations, an approach that has been shown to be effective in slowing or reversing biodiversity loss, are highly desirable for panda conservation. The captive-bred panda population has grown rapidly, laying the foundation for releasing captive-bred pandas into the wild. This paper reviews the scientific advances in conservation translocations of pandas. Studies have shown that before translocation conservation programs are implemented, we should determine what factors are causing the depletion of the original population at the release site. The selection of suitable release sites and individuals will help to improve the survival rate of released individuals in the wild. Pre-release training and post-release monitoring are essential to ensure successful releases. We also see the great potential for increasing applications of Adaptive Management to improve the success of giant panda conservation translocation programs. This review provides theoretical guidance for improvement of the success rate in conservation translocations for captive pandas, and uses the panda as a model species to provide a global reference for the conservation translocations of rare and endangered species.

Genetic mixing in conservation translocations increases diversity of a keystone threatened species, Bettongia lesueur.

Translocation programmes are increasingly being informed by genetic data to monitor and enhance conservation outcomes for both natural and established populations. These data provide a window into contemporary patterns of genetic diversity, structure and relatedness that can guide managers in how to best source animals for their translocation programmes. The inclusion of historical samples, where possible, strengthens monitoring by allowing assessment of changes in genetic diversity over time and by providing a benchmark for future improvements in diversity via management practices. Here, we used reduced representation sequencing (ddRADseq) data to report on the current genetic health of three remnant and seven translocated boodie (Bettongia lesueur) populations, now extinct on the Australian mainland. In addition, we used exon capture data from seven historical mainland specimens and a subset of contemporary samples to compare pre-decline and current diversity. Both data sets showed the significant impact of population founder source (whether multiple or single) on the genetic diversity of translocated populations. Populations founded by animals from multiple sources showed significantly higher genetic diversity than the natural remnant and single-source translocation populations, and we show that by mixing the most divergent populations, exon capture heterozygosity was restored to levels close to that observed in pre-decline mainland samples. Relatedness estimates were surprisingly low across all contemporary populations and there was limited evidence of inbreeding. Our results show that a strategy of genetic mixing has led to successful conservation outcomes for the species in terms of increasing genetic diversity and provides strong rationale for mixing as a management strategy.

IOI’S EXPERIENCE OF TRANSLOCATING EASTERN BARN OWLS FROM PENINSULAR MALAYSIA TO SABAH

The eastern barn owl (Tyto javanica javanica) has proven to be an effective biological control agent for rodent pest populations in Malaysian oil palm plantations. To establish self-sustaining populations of barn owls in areas where their numbers are low or absent, a translocation programme was implemented. This paper discusses the process of translocating barn owls from Peninsular Malaysia to Sabah. The study provides valuable insights into the factors that contribute to the success of translocation programmes, such as careful planning, monitoring, and preparation, including the construction of an aviary, installation of barn owl boxes, and adherence to export and import procedures, permit applications, and quarantine processes for barn owls from Peninsular Malaysia to Sabah based on IOI’s perspective and experience. Overall, the translocation of barn owls to Sabah is a commendable initiative that not only helps conserve this natural pest controller but also demonstrates the feasibility of translocation as a means of species conservation. Keywords: Barn owl, biological control, translocation, permit application, import-export process.

Investigating scent communication and latrine use to inform translocation of the Tasmanian devil

Translocation programs for endangered mammalian carnivores face numerous challenges, including the potential for lethal interactions between releasees and resident conspecifics. Here we evaluate whether familiarizing residents with the scent of releasees might be an effective strategy for reducing aggression following Tasmanian devil (Sarcophilus harrisii) translocation. Tasmanian devils live in loose social networks in which residents have overlapping home ranges and use communal latrines. In a controlled ex situ experiment, we first found that devils readily distinguished between the feces of familiar and unfamiliar conspecifics. Next, we swapped feces between devils slated for release and wild resident devils, seeding a random half of communal latrines in the wild with the feces of releasee prior to their release, and used motion-activated video cameras to record devil visits. Wild resident devil visitation frequency and olfactory communication behaviors initially increased at experimental latrine sites where feces were deposited but not at control sites. After release, the translocated devils used both types of latrine sites and spent more time investigating experimental sites, but investigatory and scent-marking behaviors of the wild resident devils decreased, suggesting that they had become familiar with the releasees through scent. We further show that Tasmanian devil latrine sites are strongly associated with ecotones and the presence of shrubs. These findings contribute to our understanding of Tasmanian devil scent ecology and suggest that devil translocations conducted into existing populations would benefit from familiarization through latrine scent manipulation. More broadly, our results suggest an important role for scent ecology in carnivore translocation programs.Significance statementA conservation management action that is being trialed for endangered Tasmanian devils is to breed devils in human care and reinforce dwindling small resident populations through translocation. However, with limited social interactions, unfamiliar devils may interact aggressively, increasing injury and reducing translocation success. Scent communication is nearly ubiquitous in mammals and may be a prerequisite for management of social aggression. Almost nothing is known about devil scent ecology. Our discovery that devils become familiarized with conspecifics through feces, combined with findings that wild devils that are exposed to translocated devil scent in advance of release show reduced interest in scent-seeded latrines, even after new devils are released, suggests that devils familiarized through scent in advance of relocation may exhibit reduced aggression. These results provide an avenue for improving the success of translocations for devils and other at-risk solitary mammalian carnivores.

Translocation and long-term monitoring of threatened thin-spined porcupines (Chaetomys subspinosus) on the Brazilian coast

With increasing infrastructural development along Brazil’s coast, environmental regulation measures are becoming increasingly necessary in the face of the damage caused by large projects that impact tropical forests. Brazilian legislation supports implementation of translocation programs for impacted fauna, especially threatened species such as the thin-spined porcupine Chaetomys subspinosus (Rodentia, Erethizontidae). Thus, we present a case study of a pioneer translocation program for the thin-spined porcupine in southeastern Brazil. We aimed to analyze the home-range and habitat selection of three translocated porcupines and one resident individual. In addition, we analyzed the success of the translocations. The porcupines were monitored by radiotelemetry for 3–16 months from October 2015 to March 2017 in a mosaic landscape of restinga forests (sandbank forest vegetation) within a eucalyptus matrix. The translocated porcupines had considerably larger home-ranges (14.29–18.36 ha, minimum convex polygon method – MCP) than did the resident animal (1.22 ha – MCP). We observed stabilization in the home-range size curves of the translocated females in the 7th − 9th month of monitoring. All translocated individuals achieved permanence within a preselected area, indicating adaptation to the new area. In addition, individuals showed a clear preference for restinga forests over drained eucalyptus plantations. Thus, our results demonstrate the feasibility of thin-spined porcupine translocations and the importance of maintaining restinga forest remnants outside of protected areas for the conservation and permanence of viable populations of this rodent.

Early life experience with predators impacts development, behavior, and post‐translocation outcomes in an endangered amphibian

AbstractPre‐release training is becoming a standard practice in conservation breeding and translocation programs for mammals and birds, but is still relatively neglected for herpetofauna, likely stemming from widespread beliefs that amphibians are “hard‐wired” and are thus predicted to benefit little from experiential learning. However, experience during development can drive both morphological and behavioral modifications that could benefit post‐translocation survival. Here, we developed an anti‐predator training program for the endangered mountain yellow‐legged frog Rana muscosa and evaluated its impact on morphometrics, developmental rates, behavior, and post‐release outcomes. Using a controlled, balanced factorial experimental design, we exposed individuals at two developmental stages (tadpoles and post‐metamorphic) to visual and olfactory cues from one of its principal predators, the two‐striped garter snake Thamnophis hammondii. We found that exposure to predators during the tadpole stage impacted tadpole development, morphology, and behavior. However, we found no evidence that post‐metamorphic behavior or post‐release outcomes were influenced by tadpole predator exposure, either on its own or in interaction with post‐metamorphic training treatments. Training of post‐metamorphic frogs, however, yielded evidence of learning, with downstream effects on behavior and apparent survival after release into the wild. Our findings produce novel insights on the value of anti‐predator training in amphibian conservation translocation programs, bolster recent evidence re‐evaluating the importance of learning and developmental experience for amphibian species, and provide guidance for selecting optimal developmental windows for training.

Viability analysis for population reinforcement of Grauer's gorillas at Mount Tshiaberimu, Democratic Republic of the Congo

AbstractReintroduction and translocation programs have been sparingly used for the management of endangered primate populations. Mount Tshiaberimu in eastern Democratic Republic of the Congo (DRC) contains 6 Grauer's gorillas (Gorilla beringei graueri) with only 2 adult females. Without intervention, this population is at high risk of extinction. We designed population viability analysis models to compare different release scenarios of wild‐born captive female gorillas housed at the Gorilla Rehabilitation and Conservation Education (GRACE) Center in the DRC. We identified the minimum number of females needed to maintain a viable population in this habitat. We used a stochastic Leslie matrix model and a more complex individual‐based model to project population growth. We used published demographic parameters for mountain gorillas (Gorilla b. beringei) corresponding to a 3.2% annual growth rate, and then applied a correction factor to female fertility to obtain parameters consistent with 1% and 2% growth rates. We ran each scenario over a 50‐year time period (1,000 simulations) to determine the final population size and risk of local extinction. Results from our optimistic (3.2% growth) and conservative (1% growth) individual‐based model projections indicated that the extinction risk dropped below 1% with the release of at least 2 or 3 females, respectively. Both approaches predicted similar extinction risks for all scenarios; however, the variance in final population size was higher with the individual‐based model. For long‐lived mammals like primates, we recommend the use of individual‐based models, which can incorporate life‐history parameters such as long gestation and nursing periods. Our analysis suggests a translocation of ≥3 females to rescue the Tshiaberimu gorilla population in the short term. Factors such as inbreeding depression, habitat quality, disease risks, and anthropogenic pressures will need to be evaluated in later stages of population reinforcement planning.

Assessing genetic diversity patterns at neutral and adaptive loci to inform population reinforcement of an endangered migratory vulture

One of the primary goals of conservation translocation programs should be the maintenance of both population demographic stability and genetic diversity. Here, we provide genetic management recommendations to inform a population reinforcement of the declining Egyptian Vulture population in the Balkans. Specifically, we examined whether the number of released individuals is sufficient to prevent genetic diversity loss due to random genetic drift and what the origin of the individuals should be that comprise the captive breeding pool. To this aim, we estimated and assessed genetic diversity levels and genetic structure of Egyptian Vulture populations across much of the species’ range using both neutral and non-neutral candidate loci involved in migration. We then evaluated the effects of the currently proposed population management scheme and candidate source populations on retaining allelic diversity. Our results show low differentiation values among populations and absence of genetic structure which point to past high gene flow. Furthermore, there was no predicted significant impact of different source populations on the genetic diversity of the recipient Balkan population. We also found that the declining Egyptian Vulture population in the Balkans still retains high levels of genetic diversity and therefore genetic diversity restoration is not currently needed. However, without any management, diversity is likely to decrease fast because of increased genetic drift as the population size continues to decline. Population reinforcement with nine birds per year for 20 years would provide sufficient demographic support for the population to retain > 85% of rare allelic diversity. Birds originating from the Balkans would ensure ecological and behavioral similarity and thus would be the best option for reinforcement. Nevertheless, our results demonstrate that to prevent further population contraction and loss of adaptive alleles, releasing individuals of different origin would also be appropriate.