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Understanding risk factors associated with reintroductions is important for making informed decisions within an adaptive framework. Biosecurity measures minimizing the risk of the introduction or spread of transmissible diseases are a priority when considering the release of captive-reared wildlife. Eastern indigo snake (EIS; Drymarchon couperi) reintroductions have been occurring in Alabama since 2010 and in Florida since 2017. During this effort the pathogen Cryptosporidium serpentis was detected, affecting several of the captive breeding snakes. Infected snakes were quarantined and removed from breeding efforts, which reduced snakes available for the reintroduction projects. To make informed management decisions about future reintroduction strategies, 155 free-ranging snakes were sampled at the two release sites and a third site in Georgia to evaluate the natural occurrence of C. serpentis. Additionally, 72 free-ranging EIS and other species incidentally encountered throughout the EIS range were tested opportunistically. All snakes sampled at the three focal sites tested negative, but one opportunistically tested EIS from South Florida tested positive. These results indicate that C. serpentis is present in the environment in at least one location, but at low levels. Our results suggest that, pending additional surveillance, C. serpentis-positive snakes should not be included in reintroduction efforts, and that maintaining a high level of biosecurity is important in captive breeding programs.

Geographically isolated wetlands (GIWs) have been increasingly recognized for their importance in providing ecosystem services, including support of regional biodiversity. These wetlands serve as valuable foraging and breeding habitat for wetland-dependent species, including wading birds. In certain regions of the U.S. Southeastern Coastal Plain approximately two-thirds of GIWs are impacted by adjacent human land use. We quantified wading bird density in agricultural and natural GIWs to determine the factors influencing their use of these habitats. Using monthly transect surveys, we found that wetland-specific variables, including prey abundance and size, wetland surface area, and dry-down rate, were better predictors of wading bird density than landscape level variables such as wetland density and distance to breeding colony. Bird density was highest in agricultural wetlands early in the hydroperiod, but as GIWs dried down, density dropped in agricultural wetlands and rose in natural wetlands. Collectively, these results suggest that wading birds in the Coastal Plain rely on a matrix of both agricultural and natural wetlands, and their use of wetlands varies temporally, peaking in late spring, to maximize prey availability. The seasonal process of receding water levels in GIWs and subsequent concentration of aquatic fauna provides important food resources for nesting wading birds.

Seasonally inundated wetlands contribute to biodiversity support and ecosystem function at the landscape scale. These temporally dynamic ecosystems contain unique assemblages of animals adapted to cyclically wet–dry habitats. As a result of the high variation in environmental conditions, wetlands serve as hotspots for animal movement and potentially hotspots of biogeochemical activity and migratory transport of nutrient subsidies. Most amphibians are semi-aquatic and migrate between isolated wetlands and the surrounding terrestrial system to complete their life cycle, with rainfall and other environmental factors affecting the timing and magnitude of wetland export of juveniles. Here we used a long-term drift fence study coupled with system-specific nutrient content data of amphibians from two small wetlands in southeastern Georgia, USA. We couple environmental data with count data of juveniles exiting wetlands to explore the controls of amphibian diversity, production and export and the amphibian life-history traits associated with export over varying environmental conditions. Our results highlight the high degree of spatial and temporal variability in amphibian flux with hydroperiod length and temperature driving community composition and overall biomass and nutrient fluxes. Additionally, specific life-history traits, such as development time and body size, were associated with longer hydroperiods. Our findings underscore the key role of small, isolated wetlands and their hydroperiod characteristics in maintaining amphibian productivity and community dynamics.

Open pine ecosystems of the southern United States are a conservation priority for many agencies, organizations, and private landowners. These woodlands, characterized by moderately-stocked overstories, low cover of midstory, and grass-dominated herbaceous groundcover, provide important habitat for a suite of rare and declining wildlife species. To provide guidance for land managers engaged in habitat restoration in open pine ecosystems, ranges of desired conditions for elements of vegetation structure have been developed using literature survey and expert opinion. We compared empirical data on habitat occupancy for 17 wildlife species from second-growth longleaf pine woodlands in southwestern Georgia with recommended ranges for basal area (BA) of all pine, BA of pine ≥ 35.5 cm dbh, percent canopy cover, percent herbaceous cover, and percent shrub cover. Vegetation data were taken from 864 monitoring plots and Mahalanobis distance models were used to develop habitat suitability indices from the wildlife data. Recommendations for shrub cover and BA of pines ≥ 35.5 cm fit well with model predictions for all wildlife species. However, mean BA of all pines at sites used by wildlife were at the low end of the recommended range. Herbaceous cover at sites used by wildlife was well below the recommended range, whereas canopy cover was well above recommendations, suggesting these ranges should be expanded. These modifications could provide managers of open pine ecosystems greater flexibility, allowing them to incorporate a broader suite of objectives in their management while still providing habitat for wildlife species of concern. Moreover, our models suggest that monitoring presence of open pine indicator bird species may be an efficient method to assess restoration or management progress of open canopy pine systems.

An animal’s spatial ecology may provide insight into how resources are distributed or potentially limiting across its home range. Some species with broad geographic distributions may exhibit intraspecific variation in space use among populations given the spectrum of available habitat across their range. Animals may need to move further in habitats with limited resources thereby lowering survival. Species, like the eastern rat snake (Pantherophis alleghaniensis), occur throughout the eastern USA and are thought to be strongly tied to hardwood forests. However, their occurrence in pine-dominated forests in the southeastern USA suggests they have broader habitat requirements than previously noted. Our objective was to investigate patterns of habitat use and spatial ecology for eastern rat snakes across multiple pine-dominated forests in Southern Georgia and Northern Florida to capture regional differences in eastern rat snake resource use. We examined home range and habitat use at multiple spatial scales for 30 radio-telemetered snakes from three sites; one in Georgia (Pebble Hill) and Florida (Tall Timbers) during 2004–2005 and one more northern site in Georgia (Ichauway) during 2010–2012. Snakes tracked on Ichauway had a mean home range size that was 3.9 times larger (95% Mean Convex Polygon [MCP], 13.6 ± 8.2 ha) than the estimate for Tall Timbers (3.5 ± 3.2 ha) and 2.6 times larger than the estimate for Pebble Hill (5.3 ± 3.2 ha). Snakes at all three sites selected primarily open edge and pine habitat at the landscape scale and were most likely to be found in large, mature oak trees (Quercus spp.). At Ichauway, hardwood removal activities associated with longleaf pine (Pinus palustris) restoration reduced the number of hardwood trees per hectare by 33% in hardwood removal areas from 1998 to 2014. This management approach included limiting suitable large oak trees that rat snakes use and may help explain the variation in home range size and the number of snakes captured at Ichauway (n = 14) compared to the other two sites (Tall Timbers, n = 154, Pebble Hill, n = 127).

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.

International demand for wood and other forest products continues to grow rapidly, and uncertainties remain about how animal communities will respond to intensifying resource extraction associated with woody bioenergy production. We examined changes in alpha and beta diversity of bats, bees, birds, and reptiles across wood production landscapes in the southeastern United States, a biodiversity hotspot that is one of the principal sources of woody biomass globally. We sampled across a spatial gradient of paired forest land-uses (representing pre and postharvest) that allowed us to evaluate biological community changes resulting from several types of biomass harvest. Short-rotation practices and residue removal following clearcuts were associated with reduced alpha diversity (-14.1 and -13.9 species, respectively) and lower beta diversity (i.e., Jaccard dissimilarity) between land-use pairs (0.46 and 0.50, respectively), whereas midrotation thinning increased alpha (+3.5 species) and beta diversity (0.59). Over the course of a stand rotation in a single location, biomass harvesting generally led to less biodiversity. Cross-taxa responses to resource extraction were poorly predicted by alpha diversity: correlations in responses between taxonomic groups were highly variable (-0.2 to 0.4) with large uncertainties. In contrast, beta diversity patterns were highly consistent and predictable across taxa, where correlations in responses between taxonomic groups were all positive (0.05-0.4) with more narrow uncertainties. Beta diversity may, therefore, be a more reliable and information-rich indicator than alpha diversity in understanding animal community response to landscape change. Patterns in beta diversity were primarily driven by turnover instead of species loss or gain, indicating that wood extraction generates habitats that support different biological communities.Conservación de la Diversidad Alfa y Beta en Paisajes de Producción Maderera Resumen La demanda internacional de madera y otros productos forestales sigue creciendo rápidamente mientras permanecen las incertidumbres sobre cómo responderán las comunidades animales a la intensificación de la extracción de recursos asociada con la producción de bioenergía leñosa. Examinamos los cambios en la diversidad alfa y beta de murciélagos, abejas, aves y reptiles en los paisajes de producción maderera en el sureste de los Estados Unidos, un punto caliente de biodiversidad y una de las fuentes principales de biomasa leñosa a nivel mundial. Muestreamos a lo largo de un gradiente espacial de usos de suelo forestales emparejados (representando la pre- y postcosecha) que nos permitió evaluar los cambios en las comunidades biológicas resultantes de varios tipos de recolección de biomasa. Las prácticas de corta rotación y de eliminación de residuos después de la tala estuvieron asociadas con la reducción de la diversidad alfa (−14.1 y −13.9 especies, respectivamente) y una diversidad beta más baja (es decir, diferencia de Jaccard) entre los pares de uso de suelo (0.46 y 0.50, respectivamente), mientras que el raleo de rotación media incrementó la diversidad alfa (+3.5 especies) y beta (0.59). Durante la duración de una rotación permanente en una sola ubicación, la cosecha de biomasa generalmente derivó en menos biodiversidad. La respuesta de los taxones a la extracción de recursos estuvo muy mal pronosticada por la diversidad alfa: la correlación de las respuestas entre los grupos taxonómicos fue altamente variable (−0.2 a 0.4) con muchas incertidumbres. Como contraste, los patrones de diversidad beta fueron fuertemente coherentes y predecibles en todos los taxones, mientras que la correlación de las respuestas entre los grupos taxonómicos siempre fue positiva (0.05 a 0.4) con incertidumbres más limitadas. Por lo tanto, la diversidad beta puede ser un indicador más confiable y rico en información que la diversidad alfa para entender las respuestas de la comunidad animal a los cambios en el paisaje. Los patrones de la diversidad beta estuvieron impulsados principalmente por la rotación en lugar de la pérdida o ganancia de especies, lo que indica que la extracción de madera genera hábitats que mantienen a diferentes comunidades biológicas.【摘要】国际上对木材和其它森林产品的需求在持续快速增长, 而动物群落如何应对与木质生物能源生产相关的日益加剧的资源开采, 仍然存在不确定性。美国东南部是生物多样性的热点地区, 也是全球木质生物质的主要来源之一, 本研究分析了该地区木材生产景观中蝙蝠、蜜蜂、鸟类和爬行动物 α 多样性和 β 多样性的变化。我们沿空间梯度对森林土地利用情况两两取样 (代表采伐前和采伐后), 以评估几种生物质采伐造成的生物群落变化。短期轮伐和皆伐后清除残留物都与成对的土地利用样方之间 α 多样性降低, (分别为 −14.1 个物种和 −13.9 个物种) 及 β 多样性 (即 Jaccard 异质性) 降低 (分别为 0.46 和0.50) 有关, 而中期轮伐间苗则可以增加 α 多样性 (+3.5 种) 和 β 多样性 (0.59) 。在单一地点的林分轮换过程中, 生物质采伐一般会导致较低的生物多样性。 α 多样性很难预测对资源开采的跨类群响应, 表现为类群之间响应的相关性高度可变 (−0.2 到 0.4), 有很大的不确定性。相比之下, 各类群之间的 β 多样性格局则具有高度的一致性和可预测性, 类群之间的响应都是正相关关系 (0.05 至 0.4), 不确定性较小。因此, 在理解动物群落对景观变化的响应方面, β 多样性可能是比 α 多样性更可靠、信息更丰富的指标。β多样性的格局主要是由周转而非物种丧失或增加所驱动的, 表明木材生产可以产生支持不同生物群落的生境。【翻译: 胡怡思; 审校: 聂永刚】.

Ecological stoichiometry provides a framework to predict how animals regulate nutritional balances within their tissue and, as a result, how animal biomass affects ecosystem processes through nutrient cycling. However, most interspecific and developmental stoichiometric studies in animals focus on invertebrates, and the few vertebrate studies are largely fish‐centric. Larval anurans are ideal vertebrates to test predictions of developmental and interspecific stoichiometry as they undergo a complex development, exhibit broad arrays of life‐history traits, and can constitute high animal biomass in wetlands, implying major roles in wetland nutrient storage and cycling. We examined (1) patterns of body stoichiometry across larval developmental stages within multiple anuran species, (2) whether key predictors of stoichiometric change, specifically body size, developmental period, and breeding season, influence interspecific stoichiometric variation, and (3) natural magnitudes and fluctuations of larval anuran nutrient storage in geographically isolated wetlands (GIWs). We measured carbon (C), nitrogen (N), and phosphorus (P) tissue content in larval anurans across five developmental stages within 11 species collected from four GIWs to examine patterns of developmental and interspecific stoichiometry. Within species, we found broad developmental stoichiometric patterns in which later developmental stages were lower in %N, but higher in %P than earlier stages. Patterns in %C were inconsistent but were generally lower in later stages, while tissue C:N ratios increased, and C:P and N:P decreased in later developmental stages. Interspecific stoichiometric variation was partially explained by body size and developmental period which positively affected %C and C:N ratios. We observed spatial and temporal fluctuations in species‐specific biomass which dictated nutrient storage patterns within larval anuran assemblages, though stoichiometric identity played a major role. Our estimated magnitudes of larval anuran areal nutrient storage also greatly exceeded that of other wetland fauna with the maximum estimated areal P storage reaching over 200 times that of a similar‐density co‐occurring invertebrate group. These results highlight stoichiometric patterns of development and interspecific variation in a diverse group of amphibians while providing critical baseline information for elucidating the role of anurans in wetland nutrient dynamics.

Barbour's map turtle (Graptemys barbouri) is the species of map turtle with the highest degree of sexual dimorphism, with females attaining larger body sizes and having much greater head widths than males. Accordingly, females and males also feed on different riverine prey, with females historically feeding on native gastropods and bivalves and males predominantly feeding on soft-bodied macroinvertebrates. Here, we report on a diet shift in female Barbour's map turtle from native prey to an invasive mollusk, the Asian clam (Corbicula fluminea), in southwestern Georgia.

Human demand for food, fiber, and space is accelerating the rate of change of land cover and land use. Much of the world now consists of a matrix of natural forests, managed forests, agricultural cropland, and urbanized plots. Expansion of domestic energy production efforts in the United States is one driver predicted to influence future land-use and land management practices across large spatial scales. Favorable growing conditions make the southeastern United States an ideal location for producing a large portion of the country's renewable bioenergy. We investigated patterns of bat occurrence in two bioenergy feedstocks commonly grown in this region (corn, Zea mays, and pine, Pinus taeda and P. elliottii). We also evaluated potential impacts of the three major pathways of woody biomass extraction (residue removal following clearcut harvest, short-rotation energy plantations, and mid-rotation forest thinning) to bat occurrence through a priori land-use contrasts. We acoustically sampled bat vocalizations at 84 sites in the Southeastern Plains and Southern Coastal Plains of the southeastern United States across three years. We found that mid-rotation thinning resulted in positive effects on bat occurrence, and potential conversion of unmanaged (reference) forest to managed forest for timber and/or bioenergy harvest resulted in negative effects on bat occurrence when effects were averaged across all species. The effects of short-rotation energy plantations, removal of logging residues from plantation clearcuts, and corn were equivocal for all bat species examined. Our results suggest that accelerated production of biomass for energy production through either corn or intensively managed pine forests is not likely to have an adverse effect on bat communities, so long as existing older unmanaged forests are not converted to managed bioenergy or timber plantations. Beyond bioenergy crop production, mid-rotation thinning of even-aged pine stands intended for timber production, increases to the duration of plantation rotations to promote older forest stands, arranging forest stands and crop fields to maximize edge habitat, and maintaining unmanaged forests could benefit bat communities by augmenting roosting and foraging opportunities.

Many sympatric species use Gopherus polyphemus (Gopher Tortoise) burrows as refugia from predators, extreme temperatures, and fire. As part of an ongoing project involving trail-camera monitoring at Gopher Tortoise burrows, we observed a Sciurus niger (Eastern Fox Squirrel) sheltering in an occupied burrow twice in a single day. Eastern Fox Squirrels primarily forage on the ground, and Gopher Tortoise burrows likely offer refuge from avian predators but could expose Eastern Fox Squirrels to increased predation risk from mammalian and reptilian predators. Alternatively, the squirrel may have been seeking refuge from higher-than-average temperatures. Our observation further demonstrates the importance of Gopher Tortoise burrows to vertebrate fauna in the southeastern United States.

Population genetic diversity is widely accepted as important to the conservation and management of wildlife. However, habitat features may differentially affect evolutionary processes that facilitate population genetic diversity among sympatric species. We measured genetic diversity for two pond‐breeding amphibian species (Dwarf salamanders, Eurycea quadridigitata; and Southern Leopard frogs, Lithobates sphenocephalus) to understand how habitat characteristics and spatial scale affect genetic diversity across a landscape. Samples were collected from wetlands on a longleaf pine reserve in Georgia. We genotyped microsatellite loci for both species to assess population structures and determine which habitat features were most closely associated with observed heterozygosity and rarefied allelic richness. Both species exhibited significant population genetic structure; however, structure in Southern Leopard frogs was driven primarily by one outlier site. Dwarf salamander allelic richness was greater at sites with less surrounding road area within 0.5 km and more wetland area within 1.0 and 2.5 km, and heterozygosity was greater at sites with more wetland area within 0.5 km. In contrast, neither measure of Southern Leopard frog genetic diversity was associated with any habitat features at any scale we evaluated. Genetic diversity in the Dwarf salamander was strongly associated with land cover variables up to 2.5 km away from breeding wetlands, and/or results suggest that minimizing roads in wetland buffers may be beneficial to the maintenance of population genetic diversity. This study suggests that patterns of genetic differentiation and genetic diversity have associations with different habitat features across different spatial scales for two syntopic pond‐breeding amphibian species.

Concerns over energy demands and climate change has led the United States to set ambitious targets for bioenergy production in the coming decades. The southeastern U.S. has had a recent increase in biomass woody pellet production and is projected to produce a large portion of the nation's cellulosic biofuels. We conducted a large-scale, systematic comparison of potential impacts of two types of bioenergy feedstocks–corn (Zea mays) and pine (Pinus spp.)–on bird communities across the southeastern U.S. In addition, we evaluated three biomass alternatives for woody biomass from pine plantations: thinning, residue harvest, and short-rotation energy plantations (SREPs). We conducted transect counts for birds in eight different land-uses across the region (85 sites), including corn fields, reference and plantation forests, 2013-2015. We then used hierarchical occupancy models to test the effect of these biomass alternatives on 31 species. Across all species, birds had lower rates of occupancy in corn fields compared to pine stands. Thinning had positive effects on the average occupancy across species, while residue harvest and the potential conversion of conventional plantations to SREPs had negative effects. Cavity nesters and species with bark-gleaning foraging strategies tended to show the strongest responses. These results highlight the potential negative effects of corn as an energy crop relative to the use of pine biomass. In addition, harvesting biomass via thinning was a bird-friendly harvest method in comparison to other alternatives. While SREPs may negatively impact some bird species, previously reported yields emphasize that they may provide an order of magnitude greater yield per unit area than other alternatives considered, such that this land-use practice may be an important alternative to minimize the bioenergy impacts across the landscape. This article is protected by copyright. All rights reserved.

Gopher Tortoise (Gopherus polyphemus) burrows are used by more than 60 vertebrate species, but the frequency with which species use burrows and the extent to which other vertebrates use the mound of sand at the burrow entrance, called the burrow apron, has not been quantitatively assessed. Between 2 June and 9 October 2014, we monitored active and inactive adult Gopher Tortoise burrows with motion-triggered trail cameras to identify and enumerate vertebrate burrow visitors. We recorded 12,238 video clips during 2299 trap nights, of which 10,151 (83%) contained a Gopher Tortoise and 1732 (14%) contained other vertebrate species. We reduced multiple videos of a single burrow visitation to 1 observation, resulting in 929 observations of 14 vertebrate species (not including the Gopher Tortoise) using tortoise burrows and 34 species on burrow aprons. Mammals were the most commonly recorded taxa (54%), followed by birds (32%), amphibians (9%), and reptiles (5%). Active burrows were visited more frequen...

Macrochelys temminckii (Alligator Snapping Turtle) was petitioned for federal listing as threatened under the Endangered Species Act in 2012 as a result of population declines attributable in part to harvest for human consumption. The species was listed as threatened in 1992 in Georgia, where all harvest of the species was closed. Because little is known about how Alligator Snapping Turtle populations respond to protection, we surveyed Georgia's Flint River, which had originally been surveyed in 1989, to assess whether abundance of Alligator Snapping Turtles increased following close of commercial harvest. Our survey, conducted in 2014 and 2015 yielded captures of 52 Alligator Snapping Turtles with an overall catch per unit effort (CPUE) of 0.09 turtles/trap-night, as compared to 62 captures and a CPUE of 0.08 turtles/trap-night in the 1989 survey. Although CPUE was similar between the two studies, we observed differences among the lower, middle, and upper reaches of the river; CPUE increased in ...

Upper respiratory tract disease (URTD) in North American tortoises (Gopherus) has been the focus of numerous laboratory and field investigations, yet the prevalence and importance of this disease remains unclear across many tortoise populations. Furthermore, much research has been focused on understanding diagnostic biomarkers of two known agents of URTD, Mycoplasma agassizii and Mycoplasma testudineum, yet the reliability and importance of these diagnostic biomarkers across populations is unclear. Gopher Tortoises (Gopherus polyphemus) have experienced significant declines and are currently protected range wide. Geographically, Alabama represents an important connection for Gopher Tortoise populations between the core and periphery of this species' distribution. Herein, we systematically sampled 197 Gopher Tortoises for URTD across seven sites in south-central and south-eastern Alabama. Plasma samples were assayed for antibodies to M. agassizii and M. testudineum; nasal lavage samples were assayed for the presence of viable pathogens as well as pathogen DNA. Lastly, animals were scored for the presence of external symptoms and nasal scarring consistent with URTD. External symptoms of URTD were present in G. polyphemus in all sites sampled in Alabama. There was no relationship between active symptoms of URTD and Mycoplasma antibodies, however the presence of URTD nasal scarring was positively related to M. agassizii antibodies (P = 0.032). For a single site that was sampled in three sequential years, seroprevalence to M. agassizii significantly varied among years (P < 0.0001). Mycoplasma agassizii DNA was isolated from four of the seven sites using quantitative PCR, yet none of the samples were culture positive for either of the pathogens. An analysis of disease status and condition indicated that there was a significant, positive relationship between the severity of URTD symptoms and relative body mass (P < 0.05). This study highlights the need for continued monitoring of disease in wild populations. Specifically, focus must be placed on identifying other likely pathogens and relevant biomarkers that may be important drivers of URTD in North American tortoises. Special consideration should be given to environmental contexts that may render wild populations more susceptible to disease.

Prescribed fire is an essential tool for the restoration and maintenance of the longleaf pine (Pinus palustris) ecosystem. This type of management benefits wildlife species that are frequently associated with open canopy pine forests in the Southeastern U.S., including upland snakes. But few studies have examined the long term effects of prescribed fire (i.e., fire frequency over time) on snake occurrences at local and landscape scales. Likewise, comprehensive data are lacking on the response of snakes to individual prescribed burns (i.e., how long after a fire does a snake occupy a location). To investigate snake responses to these two factors, we used radio-telemetry data for five species of snakes, including three species of open-canopied forest specialists and two species that occur more broadly in upland forests (i.e., generalists), on a large site managed with prescribed fire. We hypothesized that open-canopied forest specialists, eastern diamondback rattlesnake (Crotalus adamanteus), Florida pine snake (Pituophis melanoleucus), and eastern coachwhip (Coluber flagellum) would select more frequently burned locations over less frequently burned locations and would occupy locations sooner after a fire than generalist species, eastern kingsnake (Lampropeltis getula) and gray ratsnake (Pantherophis allegheniensis). We used spatial data collected from previous snake radio-telemetry studies conducted over a nine year period (2003–2012) and annual burn data from 1994 to 2012. We used compositional analysis to evaluate snake use (selection) versus availability of locations based on fire frequency at different spatial scales (home range and landscape). As predicted, open-canopied forest specialists selected locations with more frequent fire (≤2.5 y return interval) significantly more often than locations with less frequent fire (≥3.3 y return interval; F7, 18 = 9.06, p

In the fire maintained longleaf pine (Pinus palustris) ecosystem, underground refugia such as gopher tortoise (Gopherus polyphemus) burrows and stump holes may be important for animals to escape fire and extreme temperatures. Despite being documented as refugia for several species of concern including the black pine snake (Pituophis melanoleucus lodingi) and eastern diamondback rattlesnake (Crotalus adamanteus), longleaf pine stumps are commonly removed and harvested for rosin, eliminating associated underground habitats. We used trail cameras to examine the use of stump holes by vertebrates from September 2018 – May 2019. Each of 35 stump holes was paired with a nearby gopher tortoise burrow, a documented high value refugium type, to serve as a reference. We used Shannon Diversity Index to investigate species diversity differences and non-metric multidimensional scaling to investigate species composition differences between stump holes and tortoise burrows. We developed multi-season occupancy models to investigate reptile, amphibian, bird, and small mammal occupancy differences between tortoise burrows and stump holes. We documented 13 taxa unique to stump holes, 14 taxa unique to tortoise burrows, and 26 shared taxa. Although overall species diversity was similar between tortoise burrows and stump holes, species composition differed, with more reptile species associated with stump holes and more bird species associated with gopher tortoise burrows. Reptile, amphibian, bird, and small mammal occupancy was similar between stump holes and tortoise burrows and among stumps of varying decay states. Our research underscores the collective importance of tortoise burrows and stump holes as refugia and foraging sites for wildlife in the longleaf pine ecosystem. Additionally, our study demonstrates the importance of developing best management practices for stump removal such as retaining a proportion of stumps of different decay classes.

Bioenergy produced from woody biomass in managed forest systems represents a substantial portion of the global supply of renewable energy. As societies transition to renewable energy and demand for wood-based bioenergy increases, timber-producing forests and other agricultural and marginal lands may transition to bioenergy management regimes. Limited empirical information exists regarding how wildlife communities will respond to bioenergy intensification. We investigated herpetofaunal occurrence across 75 study sites located in two types of bioenergy feedstocks (corn and pine) to evaluate effects of bioenergy alternatives in a global biodiversity hotspot in the southeastern United States: the North American Coastal Plain. We found that removing harvest residue following clearcut management in pine forests as a source of woody biomass resulted in either neutral or positive effects for six of the seven herpetofaunal species examined. Other bioenergy alternatives, such as mid-rotation thinning and short-rotation practices, resulted in highly variable effects among individual species and generally contrasting effects between amphibians and reptiles. Similarly high variability was observed when comparing species occurrence patterns between corn and managed pine bioenergy feedstocks. Our study suggests herpetofaunal community responses to changing land-use practices in the era of bioenergy may be taxa- and species-specific. Some land-use practices (e.g., residue removal following clearcuts) may be generally compatible with conservation of most species examined, but conserving herpetofaunal diversity within the Southeast as bioenergy production increases may involve promoting heterogeneous managed landscapes in which a diversity of harvest approaches are used.

Partial support by CEAUL (funded by Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2013) (TAM). 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. Publisher PDF

Lethal control of coyotes (Canis latrans) is a mechanism for increasing white-tailed deer (Odocoileus virginianus) recruitment but can be difficult to implement and may be ineffective on small parcels of land because of coyote immigration. In 2003, we constructed 4 40-ha mesopredator exclosures with the objective of quantifying the influence of mesopredators, including coyotes, on select wildlife populations and communities. Camera trapping indicated neonate/adult female white-tailed deer ratios were approximately 2 times greater inside predator exclosures than in control plots. Hunter success data provided further evidence of increased recruitment associated with exclosures relative to the remainder of the study site. Because exclosures were located on the boundary of our study area and off-site white-tailed deer harvest records were not available, we used estimates of deer density, sex ratios, reproductive rates, relative use of exclosures, and neonate survival inside and outside of exclosures to parameterize a Monte Carlo simulation model to estimate the impact of our 4 exclosures on neonate recruitment into the start of the firearms hunting season on a 1,600-ha area. After 1,000 iterations, we estimated that predator exclusion provided an additional 18 ± 0.13 (x¯ ± SE; median = 15, interquartile range [IQR] = 9–24) recruits/year above that expected without exclusion. Simulated neonate/adult female ratio was 0.74 ± 0.03 (median = 0.72, IQR = 0.52–0.93) with exclosures and 0.41 ± 0.008 (median = 0.39, IQR = 0.21–0.58) without. Simulated exclosure impact on recruitment was most sensitive to white-tailed deer relative use of exclosures and was least sensitive to neonate survival inside exclosures. We suggest that predator exclusion may be an effective mechanism for reducing neonate mortality and increasing white-tailed deer recruitment in areas where neonate survival is affected by predation. Exclosures may be particularly valuable on small parcels of land where predator removal would be offset by immigration. Finally, exclosures provide refuge from predators throughout the year, and we hypothesize exclosures may also contribute to adult survival and reduce impacts of predation risk that may also affect white-tailed deer population dynamics. Additional research incorporating variation in exclosure size and white-tailed deer density is needed to better evaluate predator exclosures for creating neonate refugia and mitigating sub-lethal impacts of predation. © 2015 The Wildlife Society.

Gopher tortoises (Gopherus polyphemus) occur in open-canopy pine habitat on well-drained soils in the southeastern United States, where they construct burrows that offer protection from thermal extremes, fire, and predators. Gopher tortoise populations have declined over the past 50 y, primarily as a result of habitat loss and degradation. Southeastern pine forests require active management with prescribed fire, mechanical thinning, or removal of hardwoods to maintain suitable habitat for gopher tortoises. In addition, many pine forests in the Southeast that support gopher tortoise populations are managed for multiple uses including intensive silviculture. Heavy equipment associated with these activities used in proximity to gopher tortoise burrows can cause them to collapse, potentially causing harm to tortoises or other imperiled organisms that use their burrows. Hence, there is a need for practical guidelines for use of heavy equipment for timber harvest, management, and other activities around gopher tortoise burrows to minimize risk to tortoises. We conducted a field study to determine the distance at which heavy equipment caused gopher tortoise burrows to collapse using a feller buncher, rubber-tire front-end loader, and an agricultural tractor with a tree-mower attachment in sandy clay loam (15 burrows) and undifferentiated deep sand (15 burrows) soils at a site in southwestern Georgia. All burrows were confirmed to be unoccupied by tortoises or other vertebrate commensal species using a camera scope before collapse. The greatest mean distance to collapse across all vehicles tested in sandy clay loam and undifferentiated deep sand was 2.19 ± 0.56 m and the maximum distance to collapse was 3 m. Given the variation in collapse distance, we recommend a buffer that extends 4 m in radius from the entrance of the gopher tortoise burrow to minimize risk of collapse from heavy equipment.

We used the imported red-fire ant (Solenopsis invicta; hereafter fire ant) and hispid cotton rat (Sigmodon hispidus) as model species to address the population-level effects of an invasive ant on a semiprecocial small mammal. We stocked cotton rats into 8 enclosures, implementing a 2-way factorial design with predator (ambient or excluded) and fire ant (ambient or reduced) treatments as factors. We trapped monthly from June 2012 to June 2013 and calculated monthly recruitment and survival. Rats in enclosures with ambient predators had a risk of mortality approximately 2 times greater than rats in enclosures with predators excluded. The risk of mortality was 3 and 4.5 times greater for female and male cotton rats, respectively, in enclosures with ambient fire ants and predators compared to enclosures with reduced fire ants and excluded predators. We found no effects on recruitment. Our results indicate that native predators had the greatest influence on cotton rat populations. Nevertheless, in the absence ...

We used the southern toad (Anaxyrus terrestris) as a model species to explore how an invasive species, the red-imported fire ant (Solenopsis invicta; hereafter RIFA), influences amphibian predator avoidance and movement behaviors. Our objective was to determine if toads spent less time near and moved more frequently in the presence of RIFAs compared to pyramid ants by comparing behavioral reactions of toads to RIFAs versus a control and pyramid ants versus a control. Laboratory experiments involved three treatments including no ants, RIFAs, and native pyramid ants (Dorymyrmex bureni) within an experimental arena. We randomly placed ants into one of two containers located at each end of the arena. For each trial we placed a toad into the experimental arena, allowed the toad to acclimate and then recorded its behavior. We calculated the proportion of time the toad spent near ants and the number of movements completed by each toad. Comparing the RIFA treatment to the pyramid ant treatment, toads spent 35 % less time on the half of the experimental arena near RIFAs (P = 0.0304). Toad movements were 1.5 times more frequent in trials with RIFAs than pyramid ants (P = 0.0488). We propose that southern toads associate RIFAs either with increased predation risk or risk of injury compared to pyramid ants. Although the behaviors we observed might lessen the direct effects of RIFAs on southern toads via predation and injury, the indirect effects of increased movement and avoidance of RIFAs could also influence toad fitness by decreasing reproductive and foraging success.

Governments worldwide do not adequately protect their limited freshwater systems and therefore place freshwater functions and attendant ecosystem services at risk. The best available scientific evidence compels enhanced protections for freshwater systems, especially for impermanent streams and wetlands outside of floodplains that are particularly vulnerable to alteration or destruction. New approaches to freshwater sustainability - implemented through scientifically informed adaptive management - are required to protect freshwater systems through periods of changing societal needs. One such approach introduced in the US in 2015 is the Clean Water Rule, which clarified the jurisdictional scope for federally protected waters. However, within hours of its implementation litigants convinced the US Court of Appeals for the Sixth Circuit to stay the rule, and the subsequently elected administration has now placed it under review for potential revision or rescission. Regardless of its outcome at the federal level, policy and management discussions initiated by the propagation of this rare rulemaking event have potential far-reaching implications at all levels of government across the US and worldwide. At this timely juncture, we provide a scientific rationale and three policy options for all levels of government to meaningfully enhance protection of these vulnerable waters. A fourth option, a 'do-nothing' approach, is wholly inconsistent with the well-established scientific evidence of the importance of these vulnerable waters.

From 2011-12, we studied a gopher tortoise (Gopherus polyphemus) population with a historically high prevalence of antibodies to Mycoplasma agassizii to assess long-term effects of upper-respiratory-tract disease (URTD) on tortoise behavior. We radiotracked 30 adult tortoises (16 males, 14 females) from a long-term study site with the use of mark-recapture methods to determine site fidelity and to compare home-range size to that of a study in 1997. An additional 10 tortoises (six males, four females) with severe clinical signs of URTD from elsewhere in the study area were radiotracked and compared to tortoises that were asymptomatic or had only mild clinical signs. We also monitored thermoregulatory behavior of tortoises with the use of data loggers affixed to the carapace. There was no significant difference in home-range size between the asymptomatic tortoises and those with mild symptoms. Home ranges of tortoises with severe URTD were significantly larger than asymptomatic or mildly affected tortoises. Tortoises with severe clinical signs moved long distances over short periods, contradicting a hypothesis that chronically infected tortoises are less likely to emigrate. Prevalence of M. agassizii antibodies was similar among the three groups (98% overall), but prevalence of antibodies to a second pathogen associated with URTD, Mycoplasma testudineum, was lower in the asymptomatic (n=14, 7%) and mild-symptoms (n=7, 14%) groups than the severe-symptoms group (n=8, 50%). Variation in the average carapacial temperatures of tortoises with severe URTD was significantly different from carapacial temperatures of mild and asymptomatic tortoises, suggesting differences in thermoregulatory behavior of severely ill tortoises. Our 15-yr recapture data suggest that, despite high prevalence of M. agassizii, population density has not decreased over time. However, emigration, especially of tortoises with severe clinical disease, may play an important role in dispersal and persistence of pathogens.

Upper respiratory tract disease (URTD) in the gopher tortoise (Gopherus polyphemus) is highly contagious and has been implicated in the reduction of populations throughout the range. With the exception of a few limited studies, the prevalence of URTD in Georgia, USA tortoise populations is poorly known. We found that exposure to Mycoplasma agassizii and Mycoplasma testudineum, associated with URTD, varied geographically among 11 Georgia tortoise populations. The prevalence of antibodies to M. agassizii in individual populations was either very low (0-3%, n=7 populations) or very high (96-100%, n=4 populations), whereas there was variation in the prevalence of antibodies to M. testudineum among populations (20-61%, n=10) with only one site being negative. Five sites had tortoises with antibodies to both pathogens, and these were the only sites where we observed tortoises with clinical signs consistent with URTD. We did not find tortoises with clinical signs of URTD at sites with tortoises with antibodies only to M. testudineum, which provides evidence that this organism may be of limited pathogenicity for gopher tortoises. Collectively, these data indicate that both M. agassizii and M. testudineum are present in Georgia populations of gopher tortoises and that clinical disease is apparent in populations where both pathogens are present. Additional research is needed to better understand the role of these two pathogens, and other potential pathogens, in the overall health of tortoise populations, especially if future conservation efforts involve translocation of tortoises.

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.

Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions. We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then examined a large-scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models. For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond-backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions. Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was affected by landscape-scale habitat features. Furthermore, we suggest that current interspecific interactions may influence snake occupancy, challenging the paradigm that contemporary patterns of snake co-occurrence are largely a function of diet partitioning that arose over evolutionary time.

Six-lined racerunner (Aspidoscelis sexlineata) is an indicator species of frequently burned Longleaf pine (Pinus palustris) forests. To evaluate how the species responded to forest restoration, we conducted a mark-recapture study in formerly fire-suppressed Longleaf pine forests exposed to prescribed fire or fire surrogates (i.e. mechanical or herbicide-facilitated hardwood removal) as well as in firesuppressed control sites and reference sites, which represented the historic condition. After initial treatment, all sites were exposed to over a decade of prescribed burning with an average return interval of approximately 2 years. We used population-level response of A. sexlineata as an indicator of the effectiveness of the different treatments in restoring habitat. Specifically, we compared mean numbers of marked adults and juveniles at treatment sites to that of reference sites. After 4 years, restoration objectives were met at sites treated with burning alone and at sites treated with mechanical removal of hardwoods followed by fire. After over 10 years of prescribed burning, restoration objectives were met at all treatments. We conclude that prescribed burning alone was sufficient to restore fire-suppressed Longleaf pine sandhills for A. sexlineata populations.

The ecological restoration of fire-suppressed habitats may require a multifaceted approach. Removal of hardwood trees together with reintroduction of fire has been suggested as a method of restoring fire-suppressed longleaf pine (Pinus palustris) forests; however, this strategy, although widespread, has not been evaluated on large spatial and temporal scales. We used a landscape-scale experimental design to examine how bird assemblages in fire-suppressed longleaf pine sandhills responded to fire alone or fire following mechanical removal or herbicide application to reduce hardwood levels. Individual treatments were compared to fire-suppressed controls and reference sites. After initial treatment, all sites were managed with prescribed fire, on an approximately two- to three-year interval, for over a decade. Nonmetric multidimensional scaling ordinations suggested that avian assemblages on sites that experienced any form of hardwood removal differed from assemblages on both fire-suppressed sites and reference sites 3-4 years after treatment (i.e., early posttreatment). After10 years of prescribed burning on all sites (i.e., late posttreatment), only assemblages at sites treated with herbicide were indistinguishable from assemblages at reference sites. By the end of the study, individual species that were once indicators of reference sites no longer contributed to making reference sites unique. Occupancy modeling of these indicator species also demonstrated increasing similarity across treatments over time. Overall, although we documented long-term and variable assemblage-level change, our results indicate occupancy for birds considered longleaf pine specialists was similar at treatment and reference sites after over a decade of prescribed burning, regardless of initial method of hardwood removal. In other words, based on the response of species highly associated with the habitat, we found no justification for the added cost and effort of fire surrogates; fire alone was sufficient to restore these species.