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Consumers employ a variety of foraging strategies, and oftentimes the foraging strategy employed is related to resource availability. As consumers acquire resources, they may interact with their resource base in mutualistic or antagonistic ways—falling along a mutualism‐antagonism continuum—with implications for ecological processes such as seed dispersal. However, patterns of resource use vary temporally, and textbook herbivores may switch foraging tactics to become more frugivorous in periods of greater fleshy fruit availability. In this study, we investigated how fleshy fruit consumption of a generalist herbivore—the gopher tortoise (Gopherus polyphemus)—shifts intra‐annually following seasonal precipitation and subsequently examined how this shift toward increased frugivory influences the suite of plant syndromes dispersed. We noted a clear intra‐annual shift toward a more frugivorous diet which coincided with seasonal precipitation and subsequently observed a marked shift in the plant syndromes dispersed with increasing frugivory. We found that as this generalist herbivore became more frugivorous, it dispersed a greater variety of plant syndromes at low levels of frugivory. However, when the gopher tortoise exhibited high levels of frugivory, the seed load was dominated by those exhibiting the endozoochory syndrome. This study illustrates a functional shift in a seed‐dispersing herbivore toward that of a classical frugivore, suggesting that temporal variation in foraging strategy and the temporal scale in which foraging habits and seed dispersal interactions are quantified have implications for the suite of plant syndromes species disperse. Furthermore, trade‐offs may exist that provide plants with the endozoochory syndrome with a competitive advantage over seeds with contrasting traits, such as the foliage is the fruit syndrome which is expected to experience greater dispersal by classical herbivores. [ABSTRACT FROM AUTHOR]

Globally, vector‐borne diseases are increasing in distribution and frequency, affecting humans, domestic animals, and wildlife. Science‐based management and prevention of these diseases requires a sound understanding of the distribution and environmental requirements of the vectors and hosts involved in disease transmission. Integrated Species Distribution Models (ISDM) account for diverse data types through hierarchical modeling and represent a significant advancement in species distribution modeling. We assessed the distribution of the soft tick subspecies Ornithodoros turicata americanus. This tick species is a potential vector of African swine fever virus (ASFV), a pathogen responsible for an ongoing global epizootic that threatens agroindustry worldwide. Given the novelty of this method, we compared the results to a conventional Maxent SDM and validated the results through data partitioning. Our input for the model consisted of systematically collected detection data from 591 sampled field sites and 12 historical species records, as well as four variables describing climatic and soil characteristics. We found that a combination of climatic variables describing seasonality and temperature extremes, along with the amount of sand in the soil, determined the predicted intensity of occurrence of this tick species. When projected in geographic space, this distribution model predicted 62% of Florida as suitable habitat for this tick species. The ISDM presented a higher TSS and AUC than the Maxent conventional model, while sensitivity was similar between both models. Our case example shows the utility of ISDMs in disease ecology studies and highlights the broad range of geographic suitability for this important disease vector. These results provide important foundational information to inform future risk assessment work for tick‐borne relapsing fever surveillance and potential ASF introduction and maintenance in the United States. [ABSTRACT FROM AUTHOR]

Human‐mediated animal movement can expose wildlife populations to novel environments. Phenotypic plasticity can buffer against the challenges presented by novel environments, while adaptation to local ecosystems may limit resilience in novel ecosystems. Outbreeding depression during the mixing of disparate gene pools can also reduce reproductive success after long‐distance movement. Here, we use a ‘common‐garden’ population of gopher tortoises (Gopherus polyphemus), translocated from numerous sites across the state of Florida, USA, to a mitigation site in the north‐west (panhandle) region to assess whether geographic origin, outbreeding effects, and behavioral plasticity influence reproductive success in this threatened keystone species. We found that females from north‐east Florida produced clutches with lower hatching success than females from other regions. We detected regional differentiation in nest site selection behavior in the common environment of the translocation site, though these differences did not mediate the regional effect on hatching success. We also found evidence for outbreeding depression: hatching success declined with increasing parental geographic and genetic distances, dropping from 93% to 67% across the range of observed parental genetic distances. Together, these results suggest that newly admixed populations may suffer reproductive costs due to historical population differentiation, and that undetected outbreeding depression could significantly hamper conservation efforts for this species and others undergoing a variety of human‐mediated movements. [ABSTRACT FROM AUTHOR]

ABSTRACT Globally, vector‐borne diseases are increasing in distribution and frequency, affecting humans, domestic animals, and wildlife. Science‐based management and prevention of these diseases requires a sound understanding of the distribution and environmental requirements of the vectors and hosts involved in disease transmission. Integrated Species Distribution Models (ISDM) account for diverse data types through hierarchical modeling and represent a significant advancement in species distribution modeling. We assessed the distribution of the soft tick subspecies Ornithodoros turicata americanus. This tick species is a potential vector of African swine fever virus (ASFV), a pathogen responsible for an ongoing global epizootic that threatens agroindustry worldwide. Given the novelty of this method, we compared the results to a conventional Maxent SDM and validated the results through data partitioning. Our input for the model consisted of systematically collected detection data from 591 sampled field sites and 12 historical species records, as well as four variables describing climatic and soil characteristics. We found that a combination of climatic variables describing seasonality and temperature extremes, along with the amount of sand in the soil, determined the predicted intensity of occurrence of this tick species. When projected in geographic space, this distribution model predicted 62% of Florida as suitable habitat for this tick species. The ISDM presented a higher TSS and AUC than the Maxent conventional model, while sensitivity was similar between both models. Our case example shows the utility of ISDMs in disease ecology studies and highlights the broad range of geographic suitability for this important disease vector. These results provide important foundational information to inform future risk assessment work for tick‐borne relapsing fever surveillance and potential ASF introduction and maintenance in the United States.

ABSTRACT Consumers employ a variety of foraging strategies, and oftentimes the foraging strategy employed is related to resource availability. As consumers acquire resources, they may interact with their resource base in mutualistic or antagonistic ways—falling along a mutualism‐antagonism continuum—with implications for ecological processes such as seed dispersal. However, patterns of resource use vary temporally, and textbook herbivores may switch foraging tactics to become more frugivorous in periods of greater fleshy fruit availability. In this study, we investigated how fleshy fruit consumption of a generalist herbivore—the gopher tortoise (Gopherus polyphemus)—shifts intra‐annually following seasonal precipitation and subsequently examined how this shift toward increased frugivory influences the suite of plant syndromes dispersed. We noted a clear intra‐annual shift toward a more frugivorous diet which coincided with seasonal precipitation and subsequently observed a marked shift in the plant syndromes dispersed with increasing frugivory. We found that as this generalist herbivore became more frugivorous, it dispersed a greater variety of plant syndromes at low levels of frugivory. However, when the gopher tortoise exhibited high levels of frugivory, the seed load was dominated by those exhibiting the endozoochory syndrome. This study illustrates a functional shift in a seed‐dispersing herbivore toward that of a classical frugivore, suggesting that temporal variation in foraging strategy and the temporal scale in which foraging habits and seed dispersal interactions are quantified have implications for the suite of plant syndromes species disperse. Furthermore, trade‐offs may exist that provide plants with the endozoochory syndrome with a competitive advantage over seeds with contrasting traits, such as the foliage is the fruit syndrome which is expected to experience greater dispersal by classical herbivores.

Line‐transect distance sampling (LTDS) surveys are commonly used to estimate abundance of animals or objects. In terrestrial LTDS surveys of gopher tortoise (Gopherus polyphemus) burrows, the presence of ground‐level vegetation substantially decreases detection of burrows of all sizes, but no field or analytical methods exist to control for spatially heterogeneous vegetation obstruction as a source of variation in detection. We propose the addition of a simple measurement of ground‐level vegetation that serves as a covariate for the detection function. We present a Bayesian hierarchical model in which covariates burrow width and nearby vegetation height help to account for detection bias and improve precision of estimated density. We investigate the performance of this covariate by simulation and by using real LTDS data collected before and after application of prescribed fire. We collected data in 2018 at the Jones Center at Ichauway in Newton, Georgia, USA. Across all simulations, our model including both covariates produced the most accurate density point estimates of any of the models tested. For our case study, our Bayesian model with vegetation covariates tended to produce similar estimates of density before and after burns. Our study indicates that any level of spatial variation in vegetation obstruction decreases detection of burrows and may lead to underestimation in population size (≤68%) and proportion of individuals with small burrow sizes (≤32%) when not considered during analysis. Our work is extensible to other terrestrial sampling efforts where systematic measurement of a spatially distributed obstructing feature is feasible during the LTDS survey. [ABSTRACT FROM AUTHOR]

Imperiled species face numerous and diverse anthropogenic threats to their persistence, and wildlife managers charged with making conservation decisions benefit from a sound understanding of how populations, species, and ecosystems will respond to future changes in threats to biodiversity. In southeastern North America, the gopher tortoise (Gopherus polyphemus) is a keystone species in upland ecosystems; however, tortoise populations have declined strongly over the last century, and the species is a candidate for increased protection by the United States federal government under the Endangered Species Act (ESA). Here, we sought to support conservation decision making for G. polyphemus by developing a spatially-explicit predictive population model that linked four anthropogenic threats (climate warming, sea-level rise, urbanization, habitat degradation) to demographic vital rates and used the model to estimate future changes in the number of individuals, populations, and metapopulations across the species’ range. Using recent survey data, we projected 457 populations for 80 years into the future under scenarios varying in threat magnitude, management magnitude, and demographic uncertainty. Population projections predicted that the number of individuals, populations, and metapopulations would decline among all simulated scenarios in the next 80 years. Model predictions were more sensitive to variation in adult survival and immigration rates than to variation in threat magnitude. A scenario with decreased habitat management and threat effects from climate warming, sea-level rise, and urbanization predicted geographic variation in persistence probabilities for populations that might result in decreased genetic representation across the species' range. Our results can be used to support conservation listing decisions for the gopher tortoise as part of its federal Species Status Assessment and provide an analytical framework for how to link diverse threats to geographically-varying demographic rates during population viability analyses for wide-ranging imperiled species around the world.

Austwickia (Dermatophilus) chelonae is a filamentous, Gram-positive Actinobacteria in the Dermatophilaceae family. It has caused fatal granulomatous disease in diverse captive reptile species on three continents, but its presence in wild or free-ranging populations was unknown. An adult female gopher tortoise (Gopherus polyphemus) was presented euhydrated, but cachectic and infested with ticks, with two firm, encapsulated masses over the cranioventral neck and right stifle. The tortoise had moderate nonregenerative anemia and evidence of inflammation; plasma biochemistry data was within normal limits. Fine needle aspirate of the neck lesion revealed abundant necrosis and aggregates of cocci. Computed tomography delineated the masses and revealed an additional mass adjacent to the left zygomatic bone. After surgical excision, histology identified chronic granulomas with intralesional filamentous bacteria. Pan-bacterial 16S rRNA PCR and sequencing of the masses identified A. chelonae. Despite treatment with oxytetracycline and ceftazidime, the tortoise deteriorated and was euthanatized. An esophageal lesion consistent with A. chelonae was seen on postmortem examination, although it was determined that the tortoise ultimately succumbed to fungal pneumonia caused by Metarhizium robertsii, an entomopathogenic biotoxin sprayed as insect control. This case reveals A. chelonae is present in free-ranging chelonians in North America. This organism produces a toxin gene similar to diphtheria toxin, one of the most potent known biotoxins, which has not been previously identified outside the genus Corynebacterium. Novel PCR primers were designed for the toxin and rpoB genes, which were amplified and sequenced from two cases and compared with two available genomes. Selection analysis revealed that the toxin gene is under positive selection, which implies it interacts significantly with the immune system, making it a good candidate for immunodiagnostic test development. [ABSTRACT FROM AUTHOR]

ABSTRACT The gopher tortoise (Gopherus polyphemus; hereafter, tortoise), an ecosystem engineer in open pine (Pinus spp.) woodlands of the southeastern United States, often inhabits production pine forests (PPFs), defined here as even‐aged pine forests managed primarily for timber products, which is a common forest type in the tortoise's range. As a result of frequent disturbance from forest management activities, PPFs are characterized by a shifting mosaic of vegetation conditions over time. However, it is unclear how tortoises respond to these shifting conditions, necessitating an understanding of how forest management activities affect tortoise population dynamics and movements in these landscapes. Therefore, we systematically reviewed literature to assess tortoise responses (e.g., survival, demography, movement) to silvicultural activities in PPF landscapes. Although tortoises are often able to persist in PPF landscapes, their burrows may be concentrated along roadsides, powerline rights‐of‐way, and ecotones between recently harvested and older stands. How, and whether, tortoises can effectively move around PPF landscapes to take advantage of shifting habitat conditions is not well‐understood. We discuss research gaps that must be addressed to enhance conservation efforts on PPF landscapes across ownership types. © 2019 The Wildlife Society.

Recovery or sustainable management of wildlife populations often entails management of habitat on which they depend. In this regard, turtles pose unique conservation challenges because of their life histories. The combination of late maturity, low survival when young, and dependence on high adult survival suggests they may be slow to respond demographically to conventional habitat management. Thus, long-term studies are necessary to understand population dynamics and recovery potential in these species. We used 5-11 years of mark-recapture data from 3 populations to evaluate survivorship, demography, and somatic growth of gopher tortoises (Gopherus polyphemus). Green Grove and Wade Tract (southwest GA) are ecological reserves with a history of land management compatible with tortoises. In contrast, Conecuh National Forest (south-central AL) is a closed-canopy pine plantation with prior intensive site preparation but where management intervention improved habitat for tortoises during the study. Apparent survival was high for mature tortoises (87-98%) compared to immature tortoises (70-82%). Adults comprised 57-79% of individuals captured, with Green Grove and Wade Tract populations dominated by larger individuals but Conecuh having a more uniform size distribution. The largest adults captured at Conecuh (297 mm maximum carapace length [CL]) were smaller than the largest adults from Green Grove (337 mm CL) or Wade Tract (341 mm CL), although characteristic growth constants from von Bertalanffy models were similar among sites. We suggest these results indicate a recovering population at Conecuh, where habitat conditions for gopher tortoises have improved despite a legacy of intense predation by humans and reduced habitat quality at the inception of this national forest. Further, we recommend using a combination of short-term and long-term monitoring metrics to assess population recovery in such long-lived species.

Long‐term datasets are required to understand the response of long‐lived organisms (e.g., gopher tortoises [Gopherus polyphemus]) to management actions, such as prescribed burns. Our objective was to estimate the effects of prescribed burning on gopher tortoise population dynamics over decadal time frames at Fort Stewart Army Reserve, southeastern Georgia, USA. We captured and marked adult tortoises from 1994–2020. In addition, since the early 1990s, managers at Fort Stewart collected spatial records of prescribed burns; thus, we could compare demography of the population to prescribed burning. We used a Bayesian hierarchical model (open population Jolly‐Seber model) to estimate population parameters (emigration and survival, immigration and recruitment, and adult abundance) and their relationships with years since burn. We observed opposing responses to years since burn at 2 sites: abundance and the probability of staying (survival plus not emigrating) increased within 1 site when it had been more recently burned (F zones), but abundance and probability of staying in a second site increased when it had been longer since the site was burned (E zones). Some of these effects were weak but indicative of different responses to burning between the sites. Although the sites experienced similar burning regimes, they differed substantially in other habitat features: the F zones had almost twice the tree cover and lower soil sand composition, indicating that tortoise population responses to burning depend on habitat context. We inferred that the primary mechanism for demographic responses to years since burn was likely emigrating adults, which indicates the need for more detailed movement data. Our results demonstrate that gopher tortoise population responses to prescribed burning are complex, context dependent, and primarily influenced by tortoise movements. Therefore, prescribed burn plans may best accommodate spatially dynamic tortoise populations when they create spatial heterogeneity in burn ages within the range of typical tortoise movements. © 2021 The Wildlife Society. Gopher tortoises at 2 sites exhibited opposing population responses to prescribed burning, with differences likely attributable to habitat differences between the 2 sites. Tortoise populations likely responded to burning through increases or decreases in emigration; therefore, prescribed burn plans should be designed to accommodate spatially dynamic tortoise populations, allowing tortoises to select burn ages that are the most beneficial given other habitat conditions. [ABSTRACT FROM AUTHOR]

Gopher tortoises (Gopherus polyphemus) are among the most commonly translocated reptiles. Waif tortoises are animals frequently of unknown origin that have been displaced from the wild and often held in human possession for various reasons and durations. Although there are risks associated with any translocation, waif tortoises are generally excluded from translocation projects because of heightened concerns of introducing pathogens and uncertainty about the post‐release survival of these individuals. If these risks could be managed, waif tortoises could have conservation value because they can provide the needed numbers to stabilize populations. In the early 1990s, the discovery of an isolated population of gopher tortoises (≤15 individuals) near Aiken, South Carolina, USA, prioritized establishment of the Aiken Gopher Tortoise Heritage Preserve (AGTHP). Because of the population's need for augmentation and the site's isolation from other tortoise populations, the AGTHP provided the opportunity to evaluate the post‐release survival of translocated waif tortoises without compromising a viable population. Since 2006, >260 waif tortoises have been introduced to the preserve. Using a Cormack‐Jolly‐Seber modeling framework to analyze release records and capture histories from trapping efforts in 2017 and 2018, we estimated the long‐term apparent survival and site fidelity of this population composed largely of waif tortoises. We estimated annual apparent survival probabilities to be high (≥0.90) for subadult, adult male, and adult female tortoises, and these rates were similar to those reported for wild‐to‐wild translocated gopher tortoises and those from unmanipulated populations. Of the tortoises recaptured within the boundaries of the preserve, 75% were located within 400 m of their release location. These results suggest that waif tortoises could be an important resource in reducing the extirpation risk of isolated populations. © 2021 The Wildlife Society. Released waif gopher tortoises—formerly captive individuals or those of unknown provenance—exhibited high long‐term site fidelity and annual apparent survival rates similar to survival reported for unmanipulated populations and wild‐to‐wild translocated tortoises. Provided that risks can be managed, waif gopher tortoises can contribute to recovery of isolated populations in need of augmentation. [ABSTRACT FROM AUTHOR]

Population manipulations such as translocation and head‐starting are increasingly used as recovery tools for chelonians. But evaluating success of individual projects can require decades of monitoring to detect population trends in these long‐lived species. Furthermore, there are often few benchmarks from stable, unmanipulated populations against which to compare demographic rates, particularly for the immature stages. We used 8 years of mark‐recapture data to estimate apparent survival of immature gopher tortoises (Gopherus polyphemus) recruited into an introduced population of gopher tortoises first established on St. Catherines Island, Georgia, USA, in 1987. During 2006–2013, we conducted targeted trapping of immature gopher tortoises and compared survival of the hatchling, juvenile and subadult stages among treatments: individuals released shortly after hatching from eggs obtained from gravid female founders (direct releases), individuals reared in captivity for 6–9 months following hatching (head‐starts), and individuals first encountered as free‐ranging, wild‐recruited offspring (wild recruits). Among the candidate models we examined, the best fit model included additive effects of tortoise stage and treatment; however, overlapping 95% credible intervals among treatments (CrI) suggested that survival did not vary significantly among treatments. Annual apparent survival increased over the immature period, highlighting the importance of calculating separate estimates for the different immature stages. Across all treatments, the additive model estimated annual apparent survival probability to be 0.37 (CrI = 0.25–0.48) for hatchlings, 0.71 (CrI = 0.61–0.81) for juveniles, and 0.83 (CrI = 0.74–0.94) for subadults. Our study, in combination with previous monitoring efforts at St. Catherines Island, provides strong evidence that the translocation and subsequent population augmentation efforts have been successful in establishing a robust population of gopher tortoises. Additionally, our results provide estimates of demographic rates for life stages that are poorly understood but critical to understanding population dynamics of this imperiled species. © 2020 The Wildlife Society. Eight years of mark‐recapture targeting immature life stages provided survival estimates for hatchling, juvenile, and subadult gopher tortoises recruited following translocation. These results, in combination with other monitoring of the population, provide strong evidence that the translocation and subsequent population augmentation efforts have been successful in establishing a robust population of gopher tortoises. [ABSTRACT FROM AUTHOR]

Multimodal signalling reinforces specific messages in communication. In gopher tortoises, similar to other reptilian species, visualization of conspecific and chemical exudates from the skin may serve as a multimodal display advertising information about conspecific species, sex, or individual qualities, but this has not been fully elucidated. For gopher tortoises, one such possible source of chemical cues could be secretions from seasonally enlarged mental glands (MG). Here, we used both sexes of gopher tortoises in a paired choice presentation of MG secretions vs. distilled (DI) water on resin tortoise models to assess visual presence with tortoise-specific secretions. We examined behaviours to treatments to examine if MG secretions are recognizable olfactory cues and if visual cues alone are sufficient to maintain social interactions using a simple visual presentation vs. a complex visual and olfactory presentation. Tortoises of both sexes spent more total time (p < 0.001) and performed a greater number of behaviours (p < 0.001) towards the MG-treated model, relative to the neutral control (DI-treated model), suggesting that olfactory MG secretions are also required, along with visual presence of a tortoise, to engage in social behaviours. Our results are among the first for this species suggesting that pheromone usage may drive social interactions in social behaviours. [ABSTRACT FROM AUTHOR]

Abstract Mycoplasma agassizii is one of the known causative agents of upper respiratory tract disease (URTD) in Mojave desert tortoises (Gopherus agassizii) and in gopher tortoises (Gopherus polyphemus). We sequenced the genomes of M. agassizii strains PS6T (ATCC 700616) and 723 (ATCC 700617) isolated from the upper respiratory tract of a Mojave desert tortoise and a gopher tortoise, respectively, both with signs of URTD. The PS6T genome assembly was organized in eight scaffolds, had a total length of 1,274,972 bp, a G + C content of 28.43%, and contained 979 protein-coding genes, 13 pseudogenes and 35 RNA genes. The 723 genome assembly was organized in 40 scaffolds, had a total length of 1,211,209 bp, a G + C content of 28.34%, and contained 955 protein-coding genes, seven pseudogenes, and 35 RNA genes. Both genomes exhibit a very similar organization and very similar numbers of genes in each functional category. Pairs of orthologous genes encode proteins that are 93.57% identical on average. Homology searches identified a putative cytadhesin. These genomes will enable studies that will help understand the molecular bases of pathogenicity of this and other Mycoplasma species.

College/university campuses comprise a distinct type of urban interface, with their generally expansive spatial pattern of alternating permanent structures, parking lots, and green spaces. The campus of the University of West Florida (UWF) in Pensacola, Florida, was constructed among second-growth longleaf pine stands recovering from extensive logging in the western-most extent of the Panhandle, with the original campus design deliberately carried out to maintain original contours and minimize tree removal. The extended campus includes a fire-excluded, longleaf-dominated landscape with active gopher tortoise populations confined to power line right-of-ways. This study (1) examined burrowing effects on soils and plant communities, and (2) estimated the age of longleaf pine stems (trees) around campus to assess the influence of human activity on population structure. Gopher tortoise sampling was confined to three discrete areas (types) for each burrow: apron (redistributed soil outside burrow), burrow (soil above burrowed cavity), and matrix (unaltered surrounding area). Within one 0.1 m2 quadrat/sample type for each of 16 burrows, density was determined for all vascular species; mineral soil was taken to a 5-cm depth. Air-dried soil was analyzed for pH, organic matter (OM), cation exchange capacity (CEC), extractable macro- and micronutrients, and extractable aluminum. All longleaf stems >2.5 cm diameter at breast height (DBH) were measured for DBH. Stem age was estimated with an allometric equation. Plant density was reduced by burrowing 7-fold on apron versus burrow and matrix sites, which did not vary between each other. Soil variables did not vary between burrow and matrix samples. Apron soils were significantly lower in pH, OM, CEC, and cations. Soil NO3− was ~3-fold higher in apron soils. Age structure of longleaf pine on campus revealed that nearly 2/3 of all stems are between 75 and 125 years old, consistent with the cessation of extensive logging of longleaf in this region. [ABSTRACT FROM AUTHOR]

Inbreeding depression, the reduction in fitness due to mating of related individuals, is of particular conservation concern in species with small, isolated populations. Although inbreeding depression is widespread in natural populations, long‐lived species may be buffered from its effects during population declines due to long generation times and thus are less likely to have evolved mechanisms of inbreeding avoidance than species with shorter generation times. However, empirical evidence of the consequences of inbreeding in threatened, long‐lived species is limited. In this study, we leverage a well‐studied population of gopher tortoises, Gopherus polyphemus, to examine the role of inbreeding depression and the potential for behavioural inbreeding avoidance in a natural population of a long‐lived species. We tested the hypothesis that increased parental inbreeding leads to reduced hatching rates and offspring quality. Additionally, we tested for evidence of inbreeding avoidance. We found that high parental relatedness results in offspring with lower quality and that high parental relatedness is correlated with reduced hatching success. However, we found that hatching success and offspring quality increase with maternal inbreeding, likely due to highly inbred females mating with more distantly related males. We did not find evidence for inbreeding avoidance in males and outbred females, suggesting sex‐specific evolutionary trade‐offs may have driven the evolution of mating behaviour. Our results demonstrate inbreeding depression in a long‐lived species and that the evolution of inbreeding avoidance is shaped by multiple selective forces. [ABSTRACT FROM AUTHOR]

Hepatozoon prevalence (occurrence) and parasitemia (intensity) levels were documented in 67 individuals of the threatened gopher tortoise (Gopherus polyphemus) for the first time in four South Florida, US, locations: Jonathan Dickinson State Park (JDSP), Pine Jog Preserve (PJP), Florida Atlantic University Preserve (FAUP), and Blazing Star Preserve (BSP). Sex ratios (males:females) per site were 0.44 at JDSP, 0.72 at PJP, 1.42 at FAUP, and 0.40 at BSP, but no significant differences in the carapace length were found between the two sexes (independent t-test; P=0.101). Hepatozoon sp. was found in 13% (9/67) of tortoises. Percentages of infected tortoises were 22% (5/23) males and 6% (2/33) females. Prevalence and parasitemia were low or nonexistent within sampled tortoises at each of the study sites, although the highest prevalence and parasitemia values were found in gopher tortoises at JDSP (23%, 4/17) which also harbored the highest infection levels, reaching 349/10,000 erythrocytes. No infection was detected within sampled gopher tortoises at PJP. [ABSTRACT FROM AUTHOR]

Gopher tortoise Gopherus polyphemus populations have declined by as much as 80% over the past century, primarily as a result of habitat loss. In 2006, the eastern population of the gopher tortoise was petitioned for federal listing as threatened. In response, a Candidate Conservation Agreement was developed for the gopher tortoise. A Candidate Conservation Agreement is a voluntary agreement between the U.S. Fish and Wildlife Service and other interested parties to address the conservation needs of a species before it becomes federally listed and to enact measures to preclude the need to list the species. The gopher tortoise Candidate Conservation Agreement identified an assessment of the status of populations on protected lands as a priority and line transect distance sampling (LTDS) was adopted as the standardized survey methodology. Surveys with LTDS rely on detection of gopher tortoise burrows because tortoises are fossorial. However, gopher tortoise burrows vary greatly in size and small burrows of juveniles are rarely detected. Although LTDS is statistically robust and allows for imperfect detection, few studies have examined how detection varies with tortoise burrow size and whether habitat structure may influence detection of gopher tortoise burrows. Both factors could affect the accuracy of population estimates using LTDS and interpretation of demographic parameters needed for the Candidate Conservation Agreement. Therefore, we conducted surveys for burrows using LTDS before (28 March–13 April 2016) and after (9–18 May 2016) a prescribed burn, which reduced vegetation cover. We detected significantly more burrows (P < 0.001, n = 651) of all sizes after the burn, and the burrow abundance estimate was 64% higher postburn. Our study showed that conducting gopher tortoise surveys after a prescribed burn increased detections and provided a more accurate population estimate. We therefore recommend conducting surveys immediately after a burn. However, varying burn cycles on large sites may make it difficult to survey following a prescribed burn and because the effects of a burn on habitat structure may vary within a site, methods to account for variation in detection due to habitat structure are needed. Population estimates for gopher tortoises using LTDS that do not account for variation in detection due to habitat structure likely underestimate population size. [ABSTRACT FROM AUTHOR]

A 35-year (1967-2002) demographic study was conducted on the gopher tortoise (Gopherus polyphemus) from two different habitats on Archbold Biological Station located on the southern end of the Lake Wales Ridge in south-central Florida. We found geographic, habitat, and human-mediated effects on several aspects of its biology. Our findings underscore the necessity of long-term demographic data to more accurately answer ecological questions concerning long-lived species, such as how the gopher tortoise detectably might be affected by habitat quality and human activities. [ABSTRACT FROM AUTHOR]

Mammalian herbivores often alter plant species richness and diversity, but such impacts have not been much investigated in reptiles. This study examined the effects of gopher tortoise (Gopherus polyphemus) herbivory on species richness, Gini-Simpson diversity, and dominance, plant abundance, and biomass. Tortoise herbivory was eliminated in five areas through the use of exclosure plots for a period of two years and was compared to five similar areas where tortoises were allowed to feed. Cafeteria feeding trials were also used to quantify dietary preference. Tortoise exclosure plots had lowered species richness, and significantly lowered diversity, but significantly higher dominance than in controls. Heliotropium polyphyllum, the most highly preferred local species by tortoises, was the most dominant plant in exclosure and control plots and became even more dominant in exclosure plots. The abundance and biomass of the next two most common plant species, Fimbristylis cymosa and Polypremum procumbens, which are not preferred by tortoises, were reduced in the exclosures, probably due to increased competition with Heliotropium. Several rare plant species were eliminated in the exclosure plots. We conclude that tortoise herbivory may directly influence plant community assembly by reducing preferred plant species and promoting the growth of non-preferred species. [ABSTRACT FROM AUTHOR]

Highlights • Thinned pine stands have structural conditions consistent with open pine woodlands. • Prescribed fire and herbicide applied after thinning can extend open pine condition. • Duration of open pine condition is influenced by site index and planting density. • Connectivity of open pine patches can facilitate movement for many open pine species. • Gopher tortoises have an even flow of habitat in regenerating and thinned stands. Abstract Pine forests managed for economic return comprise 19% of southeastern U. S. forests and can provide vegetation structure and composition necessary for many wildlife species adapted to open pine conditions. However, in the absence of frequent fire and other disturbance in southeastern pine (Pinus spp.) forests, midstory hardwoods create closed canopy conditions limiting value of pine stands for many endemic, disturbance-adapted wildlife species. Limitations of past research investigating exact mechanisms for producing and maintaining open pine conditions in managed pine systems have led to a paucity of information regarding ecoregion applications and outcomes. This study evaluated (1) to what extent managed pine stands replicate open pine structural conditions and (2) to what extent managed pine stands provide habitat for the gopher tortoise, an open pine keystone species. We used summary statistics from existing literature to identify structural metrics provided by managed loblolly pine (P. taeda) stands and compared them to disturbance-maintained open pine woodlands. We used spatially-explicit forest management simulations to determine amount and configuration of open pine woodland conditions within two large (>9000 ha), economically-feasible managed pine landscapes in the East and West Gulf Coastal Plains ecoregions. As a case study, we estimated availability and connectivity of gopher tortoise (Gopherus polyphemus) habitat, in managed pine stands of the East Gulf Coastal Plains. Pine stands planted at ≤1310 stems/ha (≤530 stems/ac) provide up to four years of "excellent" open pine condition for wildlife following commercial thinning, based on desired conditions for southern pine forests, with temporal availability depending on site quality. Mid-rotation applications of prescribed fire and selective herbicide can extend "excellent" open pine condition initiated by commercial thinning up to an additional four years. Landscape metrics indicated that, under typical management practices, open pine stands can be spatially and temporally connected to the extent necessary to facilitate among-patch movement for many open pine-adapted species of conservation concern. Our landscape analyses indicated tortoises using primarily regenerating and thinned stands potentially can have a relatively even flow of suitable habitat conditions and opportunities to move to adjacent or nearby open stands when currently-occupied stands reach canopy closure. The disturbance regimes inherent in pine plantation management create diverse landscapes that conserve plant and wildlife biodiversity while meeting economic objectives. Therefore, pine plantations may complement current conservation efforts for open pine woodland species dependent on or tolerant of large-scale disturbance and shifting habitat conditions while offering refuge for high vagility species. [ABSTRACT FROM AUTHOR]

ABSTRACT Red imported fire ants (Solenopsis invicta; fire ants) are predators of turtle (Testudine) eggs and hatchlings, but little information is available indicating how and when fire ants detect turtle nests during incubation. Therefore, during 2014, we compared fire ant presence at gopher tortoise (Gopherus polyphemus) nests in burrow aprons in early and late incubation with paired burrow aprons that did not contain eggs. To determine whether fire ants were attracted to soil disturbance associated with nesting, we compared fire ant presence at physically disturbed burrow aprons without eggs (i.e., simulated empty nests) with paired burrow aprons with no disturbance or eggs at Ichauway, Georgia, USA. We found fire ants more frequently at nests than at paired aprons early in incubation, but not late in incubation. Additionally, we found no difference in fire ant presence between simulated empty nests and paired sites. Our results indicate that fire ants are attracted to gopher tortoise nests because of a factor other than the initial soil disturbance that accompanies nest deposition, possibly the mucous and moisture released by the female as eggs are laid. © 2016 The Wildlife Society.

Gopher Tortoise (Gopherus polyphemus) burrows support diverse commensal invertebrate communities that may be of special conservation interest. We investigated the impact of red imported fire ants (Solenopsis invicta) on the invertebrate burrow community at 10 study sites in southern Mississippi, sampling burrows (1998–2000) before and after bait treatments to reduce fire ant populations. We sampled invertebrates using an ant bait attractant for ants and burrow vacuums for the broader invertebrate community and calculated fire ant abundance, invertebrate abundance, species richness, and species diversity. Fire ant abundance in gopher tortoise burrows was reduced by >98% in treated sites. There was a positive treatment effect on invertebrate abundance, diversity, and species richness from burrow vacuum sampling which was not observed in ant sampling from burrow baits. Management of fire ants around burrows may benefit both threatened gopher tortoises by reducing potential fire ant predation on hatchlings, as well as the diverse burrow invertebrate community. Fire-ant management may also benefit other species utilizing tortoise burrows, such as the endangered Dusky Gopher Frog and Schaus swallowtail butterfly. This has implications for more effective biodiversity conservation via targeted control of the invasive fire ant at gopher tortoise burrows.

Learn more about Florida Gopher Tortoises! The Wildlife of Florida Factsheet series was created to provide the public with a quick accurate introduction to Florida’s wildlife, including both native and invasive. We hope these factsheets inspire people to investigate wildlife in their own backyard and communities and understand the amazing biodiversity of wildlife in the state of Florida.

Gopherus polyphemus populations are diminishing throughout their range due to urbanization, fragmentation, and poor habitat management. Increased population densities, poor habitat quality, and lack of fire may influence disease transmission. Parasite roles within wild tortoise populations are largely unknown; despite evidence these pathogens may pose significant health risks. This study provides a baseline of gopher tortoise intestinal parasites across South Florida and reports on how varying environmental and tortoise characteristics may affect intestinal parasite species prevalence and approximate loads. Tortoise fecal samples were taken from six tortoise populations across five South Florida sites. Seven species of intestinal parasites were discovered from 123 tortoises. Identified parasites include endohelminths such as cyathostomes, pinworms, ascarids, flukes, and protozoans including Eimeria, Cryptosporidium, and Amoeba species. Significant differences in parasite prevalence and loads were seen between sites, while parasitism among sex, size class, and habitat type remained relatively ubiquitous. [ABSTRACT FROM AUTHOR]

In many vertebrates, body size is an important driver of variation in male reproductive success. Larger, more fit individuals are more likely to dominate mating opportunities, skewing siring success and resulting in lower effective population sizes and genetic diversity. The mating system of the gopher tortoise (Gopherus polyphemus) has been characterized as both female-defense and scramble-competition polygyny. Mating systems are typically not fixed and can be influenced by factors such as population density, demographic structure, and environmental conditions; however, most populations will have a predominant strategy that results from local conditions. We assessed how male body size influences patterns of paternity and reproductive success in a natural population of gopher tortoises in Florida, United States. Using microsatellites, we assigned parentage of 220 hatchlings from 31 nests collected during 2 reproductive seasons. Larger males were significantly more likely to sire offspring and sired more offspring than smaller males; however, the likelihood of a clutch being multiply sired was unrelated to male body size. We also found evidence of mate fidelity across years. Although paternity patterns in this high-density population are more consistent with defense polygyny, female monopoly by males was incomplete, with both large and small males contributing to multiply sired clutches. Additional behavioral data are needed to clarify the role of female mate selection in paternity outcomes. The context-dependence of mating systems underscores the need to compare parentage patterns across populations and to recognize the potential for more than 1 strategy to be employed within a single population. [ABSTRACT FROM AUTHOR]

ABSTRACT: Gopher tortoise (Gopherus polyphemus) populations are declining throughout their range and recovery requires management intervention to alleviate losses. Population augmentation strategies may prove useful in recovery of depleted populations once threats are mitigated. We head‐started and soft‐released hatchlings produced from robust donor populations and evaluated their post‐release survivorship and movement for the first year following their release. During 2014 and 2015, we head‐started and released 145 tortoises, of which we radio‐tracked a subset of 41 individuals, from 2 cohorts at 2 release areas within Yuchi Wildlife Management Area in Burke County, Georgia, USA. Movement and mortality of gopher tortoises was highest in the first month after release but declined soon after. Estimated annual survivorship of our first cohort was 60.6%. Annual survivorship of our second cohort was low (7.1%) at the southeast release area but much higher (75.0%) at the northwest release area because of spatial variation in predation. Although survivorship was variable, site fidelity remained high throughout the study and no tortoise moved >122.0 m from its release location. Initial results suggest that head‐starting could prove effective as a population recovery tool, but that release strategy and predator mitigation, especially within the first month, are critical to success. © 2018 The Wildlife Society. [ABSTRACT FROM AUTHOR]

The lack of sensitive and specific markers of inflammation poses a diagnostic challenge in sick or injured reptile patients. The objective of this study was to investigate the diagnostic performance of blood analytes associated with inflammation in healthy (n = 24) and sick (n = 38) gopher tortoises (Gopherus polyphemus). Receiver operating characteristic analysis identified the following as the best-performing diagnostic tests: erythrocyte sedimentation rate (area under the curve [AUC] = 0.812; 95% confidence interval [CI] = 0.693, 0.900), absolute mature heterophils (AUC = 0.771; 95% CI = 0.646, 0.869), total leukocytes (AUC = 0.767; 95% CI = 0.642, 0.866), lactate (AUC = 0.766; 95% CI = 0.641, 0.864), and absolute immature heterophils (AUC = 0.755; 95% CI = 0.628, 0.856). These results support the clinical application of additional tools for the diagnosis and monitoring of inflammatory disease in gopher tortoises. Clinicians may consider adding erythrocyte sedimentation rate and lactate to the minimum database for this species. [ABSTRACT FROM AUTHOR]

Currently available tests for the diagnosis of inflammatory disease in reptiles are limited and poorly sensitive. However, a number of hematological and plasma biochemical analytes are validated in the diagnosis of inflammation in mammals. The objective of this study was to establish reference intervals for erythrocyte sedimentation rate, lactate, heat-precipitated fibrinogen, hematology, and plasma protein electrophoresis based on total protein by biuret method in 23 clinically healthy, captive gopher tortoises (Gopherus polyphemus) after successful rehabilitation and to determine differences by age, sex, and season. In order to investigate biological differences, samples were collected in April, July, and November. There were no sex differences in any measured analyte; however, there were significant differences by age and season. Immature animals (<2 kg) had significantly higher total protein, albumin : globulin ratio, pre-albumin, albumin, and α-1 globulin than adults. Tortoises sampled in the spring season had significantly higher total solids (refractometer) and lower eosinophils compared with animals sampled in the summer. Further investigation is required to determine the clinical utility of these analytes in the diagnosis of inflammation in this species. [ABSTRACT FROM AUTHOR]

Gopherus polyphemus (Gopher Tortoise) populations historically occurred throughout much of the southeastern Coastal Plain, and burrows created by this species provide refugia for a large suite of commensal species. Our objective was to evaluate the physical degradation of Gopher Tortoise burrows over time. We provide burrow-status information from initial and follow-up surveys of a low-density population of Gopher Tortoises across Eglin Air Force Base (Eglin), FL, a large landscape with very deep, sandy soils. Approximately 63% (n = 79) of active and/or inactive burrows were collapsed, filled in, or substantially degraded after 2 y, 82% (n = 65) after 3 y, and 100% (n = 19) after 5 y. Compared to results from a similar study with different soils, burrows degraded more quickly on Eglin. Our results on burrow longevity can inform interpretation of Gopher Tortoise surveys and aid in predicting temporal availability of burrows for commensals. [ABSTRACT FROM AUTHOR]

Small populations resulting from the impacts of habitat fragmentation are prone to increased risks of extinction because of a lack of population connectivity. Roads increase habitat fragmentation, but properly managed roadsides may be able to function as wildlife corridors. Here we use radiotelemetry to observe movement patterns of Gopher Tortoises (Gopherus polyphemus) along potential roadside corridors at the John F. Kennedy Space Center (KSC) in Florida, USA, to determine if tortoises use roadsides as movement pathways between larger habitat patches or as residential habitat. Additionally, we translocated tortoises to study the feasibility of roadsides to function as movement corridors. We found that roadsides are not used as a movement pathway but rather as an apparent long-term residential habitat. Only one tortoise was observed exiting the roadside corridor, and minimum convex polygon (MCP) home range sizes and distances traveled remain similar to those exhibited by tortoises in larger habitat patches. Following translocation, we observed a failure to return home, either by direct paths or by corridor use, for all but one tortoise. Instead, most tortoises remained along roadsides after only a brief period of exploration. Overall, we find that roadsides act as independent, residential habitat instead of as a movement corridor. Future studies should focus on understanding the actual suitability of roadsides, as they may function as ecological traps given their attractiveness but high risk of mortality. While we urge caution, current management should treat roadsides as residential locations for Gopher Tortoises and focus on reducing road mortality. [ABSTRACT FROM AUTHOR]

In southern Florida, USA, Gopher Tortoises (Gopherus polyphemus) primarily occupy habitats that are considered suboptimal or unsuitable in other parts of the range. The dominant habitat is mesic flatwoods, which has abundant forage but has high water tables that might hinder burrowing and nesting. In contrast, Florida scrub assemblages on inland ridges have suitable soils but scarce forage. We used radio telemetry to monitor 22 male and 23 female Gopher Tortoises in mesic flatwoods and scrub habitats of southern Florida. Compared to mesic flatwoods, we predicted larger home ranges and more frequent movement among burrows in scrub because of the scarcity of forage, and we predicted possible shifts in home ranges (e.g., from wetter to drier habitats) in response to seasonal rainfall. We found that home ranges in our study area were larger than is typical for higher-quality habitats (e.g., sandhill) in other parts of the range, but we observed little movement between habitats. Male home ranges and burrow use patterns were similar in flatwoods and scrub, with males making frequent excursions to court females. Females in scrub were sedentary, contradicting our prediction of frequent movement attributable to scarce forage, and we did not observe feeding forays by either sex to adjacent food-rich habitats. Compared to females in scrub, females in flatwoods had larger home ranges, used more burrows, and moved more frequently among them. High levels of movement in flatwoods might have been influenced by the high water table and frequent burrow flooding. Nonetheless, we saw no evidence of large-scale shifts to drier habitats for nesting or during peak rains. Further research is needed to investigate mechanisms that enable persistence of Gopher Tortoises under apparently suboptimal conditions. [ABSTRACT FROM AUTHOR]

Background: Infectious disease is the single greatest threat to taxa such as amphibians (chytrid fungus), bats (white nose syndrome), Tasmanian devils (devil facial tumor disease), and black-footed ferrets (canine distemper virus, plague). Although understanding the genetic basis to disease susceptibility is important for the long-term persistence of these groups, most research has been limited to major-histocompatibility and Toll-like receptor genes. To better understand the genetic basis of infectious disease susceptibility in a species of conservation concern, we sequenced all known/ predicted immune response genes (i.e., the immunomes) in 16 Florida gopher tortoises, Gopherus polyphemus. All tortoises produced antibodies against Mycoplasma agassizii (an etiologic agent of infectious upper respiratory tract disease; URTD) and, at the time of sampling, either had (n = 10) or lacked (n = 6) clinical signs. Results: We found several variants associated with URTD clinical status in complement and lectin genes, which may play a role in Mycoplasma immunity. Thirty-five genes deviated from neutrality according to Tajima's D. These genes were enriched in functions relating to macromolecule and protein modifications, which are vital to immune system functioning. Conclusions: These results are suggestive of genetic differences that might contribute to disease severity, a finding that is consistent with other mycoplasmal diseases. This has implications for management because tortoises across their range may possess genetic variation associated with a more severe response to URTD. More generally: 1) this approach demonstrates that a broader consideration of immune genes is better able to identify important variants, and; 2) this data pipeline can be adopted to identify alleles associated with disease susceptibility or resistance in other taxa, and therefore provide information on a population's risk of succumbing to disease, inform translocations to increase genetic variation for disease resistance, and help to identify potential treatments. [ABSTRACT FROM AUTHOR]

In the Wanderings of Odysseus in Books 9 to 12 of the Odyssey (the Apologue), success is garnered by acts of trickery which help the hero overcome foes / surpass obstacles, while victims of tricks are depicted in helpless, supplicative, soporific, or weakened states. In tandem with this, I observe how the absence of polymetic prowess, demonstrated either through a focus on isolated bie (physical strength) or through what is otherwise represented as a certain mindlessness or foolishness, leads to failure in the interactions. The Wanderings in Odyssey 9 to 12 have the important function in the Odyssey of solidifying Odysseus' outstanding quality as a polymetic hero, acting as a proving ground for this means of heroic achievement. [ABSTRACT FROM AUTHOR]

ABSTRACT Adult gopher tortoises (Gopherus polyphemus) are difficult to physically restrain, particularly for examination of the upper respiratory tract and oral cavity—areas important for biological sample collection during disease surveillance studies. Collection of nasal lavage is required for determining the status of Mycoplasma infection in tortoises. Anesthesia is often necessary to provide full relaxation in order to gain access to the head and mouth for nasal lavage. Therefore, deep sedation or general anesthesia are required both for the welfare of the tortoise and to maximize the usefulness of biological samples collected. The objective of this study was to assess the utility and safety of a novel field‐anesthetic combination of dexmedetomidine–ketamine–morphine (75 mc/kg; 8 mg/kg; 1 mg/kg, respectively), followed by reversal with atipamezole (0.02 mg/kg). Between May and October 2009 at the Joseph W. Jones Ecological Research Center in Baker County, Georgia, USA, 128 tortoises were captured and anesthetized with this protocol. Average time to first effects was 9.7 minutes, to induction was 21.6 minutes, to total recovery after administration of reversal was 92.7 minutes, and the mean time from administration of anesthesia through complete recovery for adult tortoises was 129 minutes but ranged from 40 minutes to 300 minutes. Clinical signs of upper respiratory tract disease significantly reduced the induction time such that tortoises with clinical signs lost consciousness faster than healthy tortoises. Study month significantly influenced the time to induction and time to recovery, such that as the study progressed, both parameters decreased. This anesthetic protocol proved to be an effective, reliable, repeatable, and safe method to collect quality biological samples from gopher tortoises. © 2013 The Wildlife Society.

Ectotherms frequently thermoregulate behaviorally to improve physiological processes such as digestion and growth, but basking and other thermoregulatory activities can also increase predation risk. Organismal and environmental characteristics can, in some species, influence predation risk associated with thermoregulation and thereby relax or tighten constraints on thermoregulatory behavior, physiological performance, and, ultimately, life history traits. Providing one of the first such investigations in turtles, we examine whether behavior and thermal environment modulate a thermoregulation-predation risk trade-off in juvenile gopher tortoises ( Gopherus polyphemus). Young gopher tortoises experience very high predation pressure, and their declining species faces many challenges, including human-induced increased shading of its environment. We hypothesized that in response to simulated predator approach, basking hatchling and juvenile tortoises would: (i) hide inside burrows; (ii) hide for shorter durations in cooler burrows presumably due to greater constraints on physiological performance; and (iii) spend greater time at the surface following disturbance in cool environments because individuals would need to bask more to maintain preferred body temperatures. Basking tortoises always hid inside burrows when approached and exhibited very long flight initiation distances ( [ABSTRACT FROM AUTHOR]

The United States Department of Defense (DoD) has a dual mission of maintaining military readiness and stewardship of its natural resources. The DoD invests more than $334 million on land and species management on their properties, which support high levels of biodiversity and harbor a disproportionate number of threatened, endangered, and atrisk species. The gopher tortoise (Gopherus polyphemus) occurs on 28 DoD installations in the southeastern United States. Because more than 350 species have been documented to use their burrows, the gopher tortoise is considered a keystone species. However, few species of birds have previously been documented as burrow associates. In this study, we compare bird species richness, visitation frequency, and behaviors at gopher tortoise burrows at two Department of Navy properties (Santa Rosa County, Florida) that differed in size, training intensity, habitat diversity, and proportion of habitat suitable for gopher tortoises. We detected a total of 33 species of birds and documented previously unreported behaviors of foraging, dust bathing, and wing-flashing display behaviors at tortoise burrows. Although species richness between sites was not significantly different, frequency of visitation was greater at the site with less military training activity. Our findings underscore the importance of even small military installations in supporting local biodiversity and the need to further explore gopher tortoise burrows as a potential resource for avifauna. [ABSTRACT FROM AUTHOR]

Department of Defense lands are essential for providing important habitat for threatened, endangered, and at-risk species (TER-S). However, there is little information on the effects of military-related contaminants on TER-S on these lands in field situations. Thus, this study examined genotoxicity and oxidative stress in gopher tortoises ( Gopherus polyphemus) on Camp Shelby, MS-the largest known population of this species, which is listed as an 'endangered species' in Mississippi and a 'threatened species' by the U.S. government. Blood was collected from tortoises at 19 different sites on the base with different levels of habitat quality (high-quality and low-quality habitat) and military activity (high, low, and no military activity). Oxidative stress was quantified as lipid peroxidation and GSSG/GSH ratios, while DNA damage was determined using flow cytometry. Our results suggest that: (1) for tortoises residing in low-quality habitats, oxidative stress and DNA damage increased with increasing military activity, while in high-quality habitats, oxidative stress and DNA damage decreased with increasing military activity; (2) in the absence of military activity, tortoises in high-quality habitat had higher levels of oxidative stress and DNA damage than those in low-quality habitat, and (3) there were interactions between military activity, habitat quality, and landuse in terms of the amount of observable DNA damage and oxidative stress. In particular, on high-quality habitat, tortoises from areas with high levels of military activity had lower levels of oxidative stress and DNA damage biomarkers than on reference sites. This may represent a compensatory or hormetic response. Conversely, on low-quality habitats, the level of oxidative stress and DNA damage was lower on the reference sites. Thus, tortoises on higher-quality habitats may have a greater capacity for compensatory responses. In terms of management implications, it is suggested that low quality habitats should be a higher priority for remediation, and lower priority for conducting military activities. [ABSTRACT FROM AUTHOR]

The gopher tortoise (G opherus polyphemus) has experienced dramatic population declines throughout its distribution in the southeastern United States and is federally listed as threatened in the area west of the Tombigbee and Mobile rivers. While there is molecular support for recognizing the listed portion of the range as genetically distinct, other research has suggested that additional population structure exists at both range-wide and regional scales. In this study, we sought to comprehensively define genetic population structure at both spatial scales by doubling the data available in terms of the number of sampling sites, individuals, and microsatellite loci compared to previously published work. We also compared patterns of genetic diversity, gene flow, and demographic history across the range. We collected 933 individuals from 47 sampling sites across the range and genotyped them for 20 microsatellite loci. Our range-wide analyses supported the recognition of five genetic groups (or regions) delineated by the Tombigbee and Mobile rivers, Apalachicola and Chattahoochee rivers, and the transitional areas between several physiographic province sections of the Coastal Plains (i.e., Eastern Gulf, Sea Island, and Floridian). We found genetic admixture at sampling sites along the boundaries of these genetically defined groups. We detected some degree of additional genetic structure within each of the five regions. Notably, within the range listed as threatened under the Endangered Species Act, we found some support for two additional genetic groups loosely delineated by the Pascagoula and Chickasawhay rivers, and we detected four more genetic groups within the Florida region that seemed to reflect the influence of the local physiography. Additionally, our range-wide analysis found the periphery of the range had lower levels of genetic diversity relative to the core. We suggest that the five main genetic groups delineated in our study warrant recognition as management units in terms of conservation planning. Intraregional population structure also points to the potential importance of other barriers to gene flow at finer spatial scales, although additional work is needed to better delineate these genetic groups. [ABSTRACT FROM AUTHOR]

Gopher tortoises ( Gopherus polyphemus) are candidates for range-wide listing as threatened under the U.S. Endangered Species Act. Reliable population estimates are important to inform policy and management for recovery of the species. Line transect distance sampling has been adopted as the preferred method to estimate population size. However, when tortoise density is low, it can be challenging to obtain enough tortoise observations to reliably estimate the probability of detection, a vital component of the method. We suggest a modification to the method based on counting usable tortoise burrows (more abundant than tortoises) and separately accounting for the proportion of burrows occupied by tortoises. The increased sample size of burrows can outweigh the additional uncertainty induced by the need to account for the proportion of burrows occupied. We demonstrate the method using surveys conducted within a 13,118-ha portion of the Gopher Tortoise Habitat Management Unit at Fort Gordon Army Installation, Georgia. We used a systematic random design to obtain more precise estimates, using a newly developed systematic variance estimator. Individual transects had a spatially efficient design (pseudocircuits), which greatly improved sampling efficiency on this large site. Estimated burrow density was 0.091 ± 0.011 burrows/ha (CV = 12.6%, 95% CI = 0.071-0.116), with 25% of burrows occupied by a tortoise (CV = 14.4%), yielding a tortoise density of 0.023 ± 0.004 tortoise/ha (CV = 19.0%, 95% CI = 0.016-0.033) and a population estimate of 297 tortoises (95% CI = 210-433). These techniques are applicable to other studies and species. Surveying burrows or nests, rather than animals, can produce more reliable estimates when it leads to a significantly larger sample of detections and when the occupancy status can reliably be ascertained. Systematic line transect survey designs give better precision and are practical to implement and analyze. [ABSTRACT FROM AUTHOR]

Gopher tortoises (Gopherus polyphemus) have declined across their range. Understanding genetic structure of remaining populations is important for their conservation and management. Until recently, little was known about genetic structure of gopher tortoises in the Florida Panhandle. DNA samples from 81 Florida Panhandle gopher tortoises and 30 from the Peninsula were analyzed using species-specific microsatellites. Results suggest that tortoises in counties east and west of the Suwannee River form a genetically intermediate cluster between tortoises in the Panhandle and Peninsula. We propose that a broad region of unsuitable habitat between the Suwannee and Saint Marks rivers constitutes a genetic boundary between Panhandle and Peninsula gopher tortoise populations. [ABSTRACT FROM AUTHOR]