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Estimation of the bottleneck size in Florida panthers

We have estimated the extent of genetic variation in museum (1890s) and contemporary (1980s) samples of Florida panthers Puma concolor coryi for both nuclear loci and mtDNA. The microsatellite heterozygosity in the contemporary sample was only 0.325 that in the museum samples although our sample size and number of loci are limited. Support for this estimate is provided by a sample of 84 microsatellite loci in contemporary Florida panthers and Idaho pumas Puma concolor hippolestes in which the contemporary Florida panther sample had only 0.442 the heterozygosity of Idaho pumas. The estimated diversities in mtDNA in the museum and contemporary samples were 0.600 and 0.000, respectively. Using a population genetics approach, we have estimated that to reduce either the microsatellite heterozygosity or the mtDNA diversity this much (in a period of c. 80years during the 20th century when the numbers were thought to be low) that a very small bottleneck size of c. 2 for several generations and a small effective population size in other generations is necessary. Using demographic data from Yellowstone pumas, we estimated the ratio of effective to census population size to be 0.315. Using this ratio, the census population size in the Florida panthers necessary to explain the loss of microsatellite variation was c .41 for the non-bottleneck generations and 6.2 for the two bottleneck generations. These low bottleneck population sizes and the concomitant reduced effectiveness of selection are probably responsible for the high frequency of several detrimental traits in Florida panthers, namely undescended testicles and poor sperm quality. The recent intensive monitoring both before and after the introduction of Texas pumas in 1995 will make the recovery and genetic restoration of Florida panthers a classic study of an endangered species. Our estimates of the bottleneck size responsible for the loss of genetic variation in the Florida panther completes an unknown aspect of this account. ?? 2008 The Authors. Journal compilation ?? 2008 The Zoological Society of London.

Animal Conservation

Translocation and early post-release demography of endangered Laysan teal

In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic post-release monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival and reproduction of all founders, and their first-generation offspring using radio telemetry for 2 years after the first release. Forty-two Laysan teal were sourced directly from the only extant population on Laysan Island and transported 2 days by ship to Midway Atoll. All birds survived the translocation with nutritional and veterinary support, and spent between 4 and 14 days in captivity. Post-release survival of 42 founders was 0.857 (95% CI 0.86-0.99) during 2004-2006 or annualized 0.92 (95% CI 0.83-0.98). Seventeen of 18 founding hens attempted nesting in the first two breeding seasons. Fledgling success was 0.57 (95% CI 0.55-0.60) in 2005 and 0.63 (95% CI 0.62-0.64) in 2006. The effective founding female population (Ne) was 13. We applied these initial demographic rates to model population growth. The nascent population size increased to >100 after only 2 years post-release (?? = 1.73). If this growth rate continues, the size of the Midway population could surpass the source population before 2010. ?? 2008 The Authors. Journal compilation ?? 2008 The Zoological Society of London.

Animal Conservation

Invasive reptiles and amphibians: global perspectives and local solutions

In the annals of invasive species biology, higher taxa such asmammals, plants and insects have received the lion’s shareof research attention, largely because many of these invadershave demonstrated a remarkable ability to degrade ecosys-tems and cause economic harm. Interest in invasive reptilesand amphibians (collectively ‘herpetofauna’, colloquially‘herps’) has historically lagged but is now garnering in-creased scrutiny as a result of their escalating pace ofinvasion. A few herpetofaunal invaders have received con-siderable attention in scientific and popular accounts, in-cluding the brown treesnakeBoiga irregularison Guam,Burmese pythonPython molurusin Florida, Coqu´ıEleutherodactylus coquiin Hawaii and cane toadBufomarinusin Australia. However, relatively few are aware ofmany emerging and potentially injurious herpetofaunalinvaders, such as Nile monitorsVaranus niloticusin Flor-ida, common kingsnakesLampropeltis getulain the CanaryIslands, boa constrictorsBoa constrictoron Aruba andCozumel, or a variety of giant constrictor snakes in PuertoRico. For the vast majority of the most commonlyintroduced species, real or potential impacts to nativeecosystems or human economic interests are poorly under-stood and incompletely explored; major pathways of intro-duction have only recently been elucidated, and effectivemanagement interventions have been limited (Kraus, 2009).

Animal Conservation

Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model

Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accounting for (1) spatially explicit variables that we hypothesized might influence abundance; (2) separate sub-models of detection probability for two distinct sampling methods (hair traps and rub trees) targeting different segments of the population; (3) covariates to explain variation in each sub-model of detection; (4) a conditional autoregressive term to account for spatial autocorrelation; (5) weights to identify most important variables. Road density and per cent mesic habitat best explained variation in female grizzly bear abundance; spatial autocorrelation was not supported. More female bears were predicted in places with lower road density and with more mesic habitat. Detection rates of females increased with rub tree sampling effort. Road density best explained variation in male grizzly bear abundance and spatial autocorrelation was supported. More male bears were predicted in areas of low road density. Detection rates of males increased with rub tree and hair trap sampling effort and decreased over the sampling period. We provide a new method to (1) incorporate multiple detection methods into hierarchical models of abundance; (2) determine whether spatial autocorrelation should be included in final models. Our results suggest that the influence of landscape variables is consistent between habitat selection and abundance in this system.

Animal Conservation

Bayesian shared frailty models for regional inference about wildlife survival

One can joke that 'exciting statistics' is an oxymoron, but it is neither a joke nor an exaggeration to say that these are exciting times to be involved in statistical ecology. As Halstead et al. 's (2012) paper nicely exemplifies, recently developed Bayesian analyses can now be used to extract insights from data using techniques that would have been unavailable to the ecological researcher just a decade ago. Some object to this, implying that the subjective priors of the Bayesian approach is the pathway to perdition (e.g. Lele & Dennis, 2009). It is reasonable to ask whether these new approaches are really giving us anything that we could not obtain with traditional tried-and-true frequentist approaches. I believe the answer is a clear yes.

Animal Conservation

Does translocation influence physiological stress in the desert tortoise?

Wildlife translocation is increasingly used to mitigate disturbances to animals or habitat due to human activities, yet little is known about the extent to which translocating animals causes stress. To understand the relationship between physiological stress and translocation, we conducted a multiyear study (2007–2009) using a population of desert tortoises (Gopherus agassizii) near Fort Irwin, California. Blood samples were collected from adult tortoises in three treatment groups (resident, translocated and control) for 1 year prior to and 2 years after translocation. Samples were analyzed by radioimmunoassay for plasma total corticosterone (CORT), a glucocorticoid hormone commonly associated with stress responses in reptiles. CORT values were analyzed in relation to potential covariates (animal sex, date, behavior, treatment, handling time, air temperature, home-range size, precipitation and annual plant production) among seasons and years. CORT values in males were higher than in females, and values for both varied monthly throughout the activity season and among years. Year and sex were strong predictors of CORT, and translocation explained little in terms of CORT. Based on these results, we conclude that translocation does not elicit a physiological stress response in desert tortoises.

California

Priorities for translating goodwill between movement ecologists and conservation practitioners into effective collaboration

Addressing ongoing biodiversity loss requires collaboration between conservation scientists and practitioners. However, such collaboration has proved challenging. Despite the potential importance of tracking animal movements for conservation, reviews of the tracking literature have identified a gap between the academic discipline of movement ecology and its application to biodiversity conservation. Through structured conversations with movement ecologists and conservation practitioners, we aimed to understand whether the identified gap is also perceived in practice, and if so, what factors hamper collaboration and how these factors can be remediated. We found that both groups are motivated and willing to collaborate. However, because their motivations differ, there is potential for misunderstandings and miscommunications. In addition, external factors such as funder requirements, academic metrics, and journal scopes may limit the applicability of scientific results in a conservation setting. Potential solutions we identified included improved communication and better presentation of results, acknowledging each other's motivations and desired outputs, and adjustment of funder priorities. Addressing gaps between science and implementation can enhance collaboration and support conservation action to address the global biodiversity crisis more effectively.

Conservation Science and Practice

Vector control improves survival of three species of prairie dogs ( Cynomys ) in areas considered enzootic for plague

Plague causes periodic epizootics that decimate populations of prairie dogs (PDs) ( Cynomys ), but the means by which the causative bacterium ( Yersinia pestis ) persists between epizootics are poorly understood. Plague epizootics in PDs might arise as the result of introductions of Y. pestis from sources outside PD colonies. However, it remains possible that plague persists in PDs during interepizootic periods and is transmitted at low rates among highly susceptible individuals within and between their colonies. If this is true, application of vector control to reduce flea numbers might reduce mortality among PDs. To test whether vector control enhances PD survival in the absence of obvious plague epizootics, we reduced the numbers of fleas (vectors for Y. pestis ) 96–98% (1 month posttreatment) on 15 areas involving three species of PDs ( Cynomys leucurus , Cynomys parvidens in Utah, and Cynomys ludovicianus in Montana) during 2000–2004 using deltamethrin dust delivered into burrows as a pulicide. Even during years without epizootic plague, PD survival rates at dusted sites were 31–45% higher for adults and 2–34% higher for juveniles compared to survival rates at nondusted sites. Y. pestis was cultured from 49 of the 851 flea pools tested (6882 total fleas) and antibodies against Y. pestis were identified in serum samples from 40 of 2631 PDs. Although other explanations are possible, including transmission of other potentially fatal pathogens by fleas, ticks, or other ectoparasites, our results suggest that plague might be maintained indefinitely in PD populations in the absence of free epizootics and widespread mortality among these animals. If PDs and their fleas support enzootic cycles of plague transmission, there would be important implications for the conservation of these animals and other species.

Vector-Borne and Zoonotic Diseases

An integrated path for spatial capture–recapture and animal movement modeling

Ecologists and conservation biologists increasingly rely on spatial capture–recapture (SCR) and movement modeling to study animal populations. Historically, SCR has focused on population-level processes (e.g., vital rates, abundance, density, and distribution), whereas animal movement modeling has focused on the behavior of individuals (e.g., activity budgets, resource selection, migration). Even though animal movement is clearly a driver of population-level patterns and dynamics, technical and conceptual developments to date have not forged a firm link between the two fields. Instead, movement modeling has typically focused on the individual level without providing a coherent scaling from individual- to population-level processes, whereas SCR has typically focused on the population level while greatly simplifying the movement processes that give rise to the observations underlying these models. In our view, the integration of SCR and animal movement modeling has tremendous potential for allowing ecologists to scale up from individuals to populations and advancing the types of inferences that can be made at the intersection of population, movement, and landscape ecology. Properly accounting for complex animal movement processes can also potentially reduce bias in estimators of population-level parameters, thereby improving inferences that are critical for species conservation and management. This introductory article to the Special Feature reviews recent advances in SCR and animal movement modeling, establishes a common notation, highlights potential advantages of linking individual-level (Lagrangian) movements to population-level (Eulerian) processes, and outlines a general conceptual framework for the integration of movement and SCR models. We then identify important avenues for future research, including key challenges and potential pitfalls in the developments and applications that lie ahead.

Ecology

Northward migrations of nonbreeding Bald Eagles from Arizona, USA.

Knowledge of the spatiotemporal patterns of migratory and nonbreeding-season movements by animals is critical for conservation, but can be difficult to obtain if animals move far from known breeding territories and across administrative and country borders. To understand the migratory movements of Bald Eagles ( Haliaeetus leucocephalus ) originating from a demographically closed population in Arizona, USA, we deployed GPS transmitters on 24 juveniles and 2 nonbreeding adult eagles between 2017 and 2023. We identified common migration routes, stopover locations, and migration phenology. Eagles moved north from Arizona during the population's post-breeding period in the boreal spring and summer, and returned south in autumn in advance of the breeding season. Eagles migrated along two primary routes: (1) along the Wasatch Mountains in Utah and extending into the Rocky Mountains of southern Idaho, and (2) through eastern Nevada and along the Rocky Mountains in western and northern Idaho. Stopover locations were frequently near lakes and rivers. Recent fledglings began migration later than older individuals and 15 of 16 of these juveniles that survived until the following breeding season returned to Arizona. The individual that did not return showed evidence of permanent emigration to northern California. Our results contribute to a growing understanding of avian migration routes within the Pacific Flyway and the diverse migration strategies, including northward migration following the breeding season, exhibited across raptor populations. We highlight that explicit studies of juveniles, subadults, and nonbreeding adults are key to understanding avian migration dynamics and identifying opportunities for conservation.

Arizona

A metapopulation strategy to support long term conservation of genetic diversity in Department of the Interior bison

Once numbering in the tens of millions, plains bison ( Bison bison bison ) were nearly driven to extinction with only a few hundred individuals remaining by the late 19th century. Plains bison have since recovered to approximately 20,000 animals managed in conservation herds throughout North America, yet substantial challenges to their recovery remain. The Department of the Interior (DOI) is working with diverse partners to steward approximately 11,000 bison in 18 conservation herds across 12 states. Most herds exist in areas without native predators, and removals are required to keep herd sizes at or below carrying capacity. The loss of genetic diversity within bison, and the fact that most DOI herds are relatively small and isolated from each other with no opportunity for natural gene flow, raises concerns about maintaining genetic diversity over the long term. Connecting populations through gene flow (i.e., creating a metapopulation) can minimize loss of genetic diversity, both within and across populations. Management of DOI bison conservation herds has historically varied across bureaus and conservation units. Adopting a national perspective on bison conservation was identified as a priority in the 2008 Department of the Interior Bison Conservation Initiative (BCI). The concept of metapopulation management as a potential tool to maximize the conservation of genetic diversity among DOI herds was first described in this 2008 Initiative and was specifically encouraged in the 2010 DOI Bison Conservation Genetics Workshop report (Dratch and Gogan 2010). In the 2020 BCI, the DOI re-affirmed its commitment to conserving bison as native, North American wildlife. This document establishes a framework for a nationally coordinated strategy for bison managed by the DOI to support the genetic conservation goals outlined in the 2020 BCI. This is a decisionmaking framework that guides managers through the process of determining when and how to consider translocations. Decisions and actions within the framework are informed by analysis and interpretation of data housed in an integrated, relational database that will be initially populated with the most current data and updated annually thereafter. It provides science-based guidance on how to conserve DOI bison genetic diversity through strategic translocations, while also considering cattle introgression and bison health. We illustrate how this Strategy can be used to guide the establishment of new conservation herds and discuss what it means to be a DOI partner. Finally, this is intended to be used as a living document that will evolve as needs and technologies change.

Science Report

The WOAH global wildlife health collaborating centre network (WOAH-WildNet): A coordinated and transformative approach to global wildlife health challenges

Wildlife health is integral to functioning, complex ecosystems [ 1 ], directly and indirectly influencing the health of people, animals, plants, and the environment [ 2 – 4 ]. Healthy wildlife populations are essential for ecosystem services and are at the heart of the One Health approach [ 3 , 4 ], which aims to sustainably balance and optimize the health of people, animals, and ecosystems through multisectoral and transdisciplinary collaboration [ 5 ]. Despite its importance, wildlife health initiatives often operate in silos, limiting capacity to address transboundary threats such as emerging diseases, pollution, and environmental changes. Anthropogenic changes, including habitat loss, degradation, fragmentation, and unsustainable harvesting, exacerbate wildlife health challenges [6–9]. These pressures disrupt species biology and alter host-pathogen dynamics [10–12], underscoring the importance of coordinated collective action in addressing harmful effects on the health of wild animals. While local conservation efforts are vital, long-term success in safeguarding biodiversity requires a unified, global network. For instance, without harmonized surveillance and response systems, individual institutions cannot effectively track pathogens across borders or share diagnostic capabilities. The World Organisation for Animal Health (WOAH) Collaborating Centre Network for Wildlife Health—WOAH-WildNet—was established to bridge these gaps. By fostering global collaboration, sharing resources, and enabling data exchange, WOAH-WildNet provides a transformative, systems-based approach to wildlife health, managing risks, and enhancing ecosystem resilience. Central to this mission is breaking down silos to promote intersectoral coordinated responses to complex wildlife health challenges.

PLOS Sustainability and Transformation

Integrating growth and survival models for flexible estimation of size-dependent survival in a cryptic, endangered snake

Estimates of demographic rates for animal populations and individuals have many applications for ecological and conservation research. In many animals, survival is size-dependent, but estimating the form of the size–survival relationship presents challenges. For elusive species with low recapture rates, individuals’ size will be unknown at many points in time. Integrating growth and capture–mark–recapture models in a Bayesian framework empowers researchers to impute missing size data, with uncertainty, and include size as a covariate of survival, capture probability, and presence on-site. If there is no theoretical expectation for the shape of the size–survival relationship, spline functions can allow for fitting flexible, data-driven estimates. We use long-term capture–mark–recapture data from the endangered San Francisco gartersnake ( Thamnophis sirtalis tetrataenia ) to fit an integrated growth–survival model. Growth models showed that females reach longer asymptotic lengths than males and that the magnitude of sexual size dimorphism differed among populations. The capture probability and availability of San Francisco gartersnakes for capture increased with snout–vent length. The survival rate of female snakes exhibits a nonlinear relationship with snout–vent length (SVL), with survival flat between 300 mm and 550 mm SVL before decreasing for females between 550 mm and 700 mm SVL. For male snakes, survival decreased for adult males >550 mm SVL. The survival rates of the smallest and largest San Francisco gartersnakes were highly uncertain because recapture rates were very low for these sizes. By integrating growth and survival models and using penalized splines, we found support for size-dependent survival in San Francisco gartersnakes. Our results have applications for devising management activities for this endangered subspecies, and our methods could be applied broadly to the study of size-dependent demography among animals.

California

Seasonal productivity in a population of migratory songbirds: why nest data are not enough

Population models for many animals are limited by a lack of information regarding juvenile survival. In particular, studies of songbird reproductive output typically terminate with the success or failure of nests, despite the fact that adults spend the rest of the reproductive season rearing dependent fledglings. Unless fledgling survival does not vary, or varies consistently with nest productivity, conclusions about population dynamics based solely on nest data may be misleading. During 2007 and 2008, we monitored nests and used radio telemetry to monitor fledgling survival for a population of Ovenbirds ( Seiurus aurocapilla ) in a managed-forest landscape in north-central Minnesota, USA. In addition to estimating nest and fledgling survival, we modeled growth for population segments partitioned by proximity to edges of non-nesting cover types (regenerating clearcuts). Nest survival was significantly lower, but fledgling survival was significantly higher, in 2007 than in 2008. Despite higher nest productivity in 2008, seasonal productivity (number of young surviving to independence per breeding female) was higher in 2007. Proximity to clearcut edge did not affect nest productivity. However, fledglings from nests near regenerating sapling-dominated clearcuts (7–20 years since harvest) had higher daily survival (0.992 ± 0.005) than those from nests in interior forest (0.978 ± 0.006), which in turn had higher daily survival than fledglings from nests near shrub-dominated clearcuts (≤6 years since harvest; 0.927 ± 0.030) in 2007, with a similar but statistically non-significant trend in 2008. Our population growth models predicted growth rates that differed by 2–39% ( x¯ = 25%) from simpler models in which we replaced our estimates of first-year survival with one-half adult annual survival (an estimate commonly used in songbird population growth models). We conclude that nest productivity is an inadequate measure of songbird seasonal productivity, and that results based exclusively on nest data can yield misleading conclusions about population growth and clearcut edge effects. We suggest that direct estimates of juvenile survival could provide more accurate information for the management and conservation of many animal taxa.

Ecosphere

Wild Burmese python nest site selection, thermogenesis, and brooding behaviors in the Greater Everglades Ecosystem

Invasive Burmese pythons ( Python bivittatus ) are extremely cryptic animals. Although their conservation status in their native range is Vulnerable, in the Greater Everglades Ecosystem (Florida, USA) they have become a dominant destructive force and usually are immediately removed whenever found. This poses a paradox where removals are occurring, yet the study and understanding of python ecology is needed to inform removal methods. An important component of life history includes the nesting season, but little is known about python nest site selection, nest brooding, thermogenesis, or hatching success in the wild. Here, we present the first complete and most detailed report of oviposition and brooding for this biologically significant time period of a female Burmese python. We describe anthropogenic nest site selection, document the extent of shivering thermogenesis, describe brooding behaviors, and provide photo-documentation of complete hatching of the largest python clutch on record.

Florida

Protection from UV light is an evolutionarily conserved feature of the haematopoietic niche

Haematopoietic stem and progenitor cells (HSPCs) require a specific microenvironment, the haematopoietic niche, which regulates HSPC behaviour . The location of this niche varies across species, but the evolutionary pressures that drive HSPCs to different microenvironments remain unknown. The niche is located in the bone marrow in adult mammals, whereas it is found in other locations in non-mammalian vertebrates, for example, in the kidney marrow in teleost fish. Here we show that a melanocyte umbrella above the kidney marrow protects HSPCs against ultraviolet light in zebrafish. Because mutants that lack melanocytes have normal steady-state haematopoiesis under standard laboratory conditions, we hypothesized that melanocytes above the stem cell niche protect HSPCs against ultraviolet-light-induced DNA damage. Indeed, after ultraviolet-light irradiation, unpigmented larvae show higher levels of DNA damage in HSPCs, as indicated by staining of cyclobutane pyrimidine dimers and have reduced numbers of HSPCs, as shown by cmyb (also known as myb ) expression. The umbrella of melanocytes associated with the haematopoietic niche is highly evolutionarily conserved in aquatic animals, including the sea lamprey, a basal vertebrate. During the transition from an aquatic to a terrestrial environment, HSPCs relocated into the bone marrow, which is protected from ultraviolet light by the cortical bone around the marrow. Our studies reveal that melanocytes above the haematopoietic niche protect HSPCs from ultraviolet-light-induced DNA damage in aquatic vertebrates and suggest that during the transition to terrestrial life, ultraviolet light was an evolutionary pressure affecting the location of the haematopoietic niche.

Nature