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Crawford BA, Maerz JC, Terrell VC, Moore CT. Population viability analysis for a pond-breeding amphibian under future drought scenarios in the southeastern United States. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Awkerman JA, Greenberg CH. Projected Climate and Hydroregime Variability Constrain Ephemeral Wetland-Dependent Amphibian Populations in Simulations of Southern Toads. ECOLOGIES 2022; 3:235-248. [PMID: 38840846 PMCID: PMC11151813 DOI: 10.3390/ecologies3020018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Amphibian populations are threatened globally by stressors, including diminishing availability of suitable wetland breeding sites, altered hydroregimes driven by changing weather patterns, and exposure to contaminants. Ecological risk assessment should encompass spatial and temporal scales that capture influential ecological processes and demographic responses. Following the PopGUIDE framework of population model development for risk assessment, we used matrix population models, in conjunction with existing hydroregime predictions, under a climate change scenario to evaluate the effects of environmental stochasticity and aquatic pesticide exposure on amphibians that are dependent on ephemeral wetlands. Using southern toads (Anaxyrus terrestris) as an example, we simulated population dynamics with breeding success dependent on hydroregime suitability. Years were defined as optimal, marginal, or insufficient for successful toad recruitment, based on the duration of their potential breeding season and rate of larval development to metamorphosis. We simulated both probabilistic and chronologically specific population projections, including variable annual fecundity, based on hydroregime suitability and reduced larval survival from carbaryl exposure. In our simulations, populations were more negatively impacted by prolonged drought, and consequently multiple sequential years of reproductive failure, than by aquatic pesticide exposure. These results highlight the necessity of reliable climate projections to accurately represent the effects of altered hydroregimes on amphibian populations. Risk assessment approaches could be improved with flexible modifications that allow inclusion of various extrinsic stressors and identification of demographic and ecological vulnerabilities when precise data are lacking.
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Affiliation(s)
- Jill A. Awkerman
- Gulf Ecosystem Measurement and Modeling Division, US EPA, One Sabine Island Drive, Gulf Breeze, FL 32561, USA
| | - Cathryn H. Greenberg
- USDA Forest Service, Southern Research Station, Bent Creek Experimental Forest, 1577 Brevard Rd., Asheville, NC 28806, USA
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Added Value: Gopher Tortoise Surveys Provide Estimates of Gopher Frog Abundance in Tortoise Burrows. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2020. [DOI: 10.3996/jfwm-20-030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
The gopher frog Lithobates capito is one of the most terrestrial frogs in the southeastern United States and often inhabits gopher tortoise burrows Gopherus polyphemus outside of the breeding season. Gopher frog populations have declined, and the species is under review for listing as threatened or endangered under the U.S. Endangered Species Act. Much of our knowledge on the status of gopher frogs is based on detections of larvae at breeding wetlands, which can be challenging because of environmental variability and provides no information on the terrestrial life stages of the species. Therefore, an alternative method is called for. We recorded observations of gopher frogs during gopher tortoise surveys at four conservation lands in Florida and used line-transect distance sampling to estimate frog abundance. We also recorded burrow size, incidence of frog co-occupancy with tortoises, and distance from frog-occupied burrows to breeding wetlands. We observed 274 gopher frogs in 1,097 tortoise burrows at the four sites. The proportion of burrows occupied by gopher frogs among sites ranged from 0.17 to 0.25. Gopher frog abundance in tortoise burrows was 742 (512–1,076 95% CL) at Etoniah Creek State Forest, 465 (352–615) at Ft. White Wildlife Environmental Area, 411 (283–595) at Mike Roess Gold Head Branch State Park, and 134 (97–186) at Watermelon Pond Wildlife Environmental Area. We observed up to four frogs in a single burrow. The proportion of frogs detected in burrows occupied by a gopher tortoise ranged from 0.46 to 0.79 among sites, and overall, gopher frogs preferred burrows occupied by tortoises over unoccupied burrows (χ2 = 15.875; df = 3; P = 0.001). Gopher frogs used burrows from 7 to 43 cm in width; mean width of frog-occupied burrows did not differ from that of unoccupied burrows (F1,3 = 0.049, P = 0.825). Distance from frog-occupied tortoise burrows to the nearest breeding wetland ranged from 141 to 3,402 m. Our data on gopher frogs collected in conjunction with gopher tortoise monitoring efforts using line-transect distance sampling and burrow cameras provided novel information on frog abundance in their terrestrial habitat and required no additional effort. However, the extent to which frogs use tortoise burrows relative to other available refuges (small mammal burrows, stumps, or other structures) is unknown; thus, our estimates should be considered conservative. We suggest that terrestrial abundance estimates for gopher frogs can complement efforts to monitor breeding activity to provide a more comprehensive means of monitoring population trends in this cryptic species.
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Expert-Informed Habitat Suitability Analysis for At-Risk Species Assessment and Conservation Planning. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2020. [DOI: 10.3996/092019-jfwm-075] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
The U.S. Fish and Wildlife Service (USFWS) is responsible for reviewing the biological status of hundreds of species to determine federal status designations under the Endangered Species Act. The longleaf pine Pinus palustris ecological system supports many priority at-risk species designated for review, including five species of herpetofauna: gopher tortoise Gopherus polyphemus, southern hognose snake Heterodon simus, Florida pine snake Pituophis melanoleucus mugitus, gopher frog Lithobates (Rana) capito, and striped newt Notophthalmus perstriatus. To inform status decisions and conservation planning, we developed habitat suitability models to 1) identify habitat features that best predict species presence and 2) estimate the amount and distribution of suitable habitat across each species' range under current conditions. We incorporated expert judgment from federal, state, and other partners to capture variation in ecological settings across species' ranges, prioritize predictor variables to test in models, mitigate data limitations by informing the selection of pseudoabsence points, qualitatively evaluate model estimates, and improve the likelihood that experts will trust and use model predictions for conservation. Soil characteristics, land cover, and fire interval strongly influenced habitat suitability for all species. Suitable habitat was distributed on known species strongholds, as well as private lands without known species records. Between 4.7% (gopher frog) and 14.6% (gopher tortoise) of the area in a species' range was classified as suitable habitat, and between 28.1% (southern hognose snake) and 47.5% (gopher frog) of suitable habitat was located in patches larger than 1 km2 (100 ha) on publicly owned lands. By overlaying predictions for each species, we identified areas of suitable habitat for multiple species on protected and unprotected lands. These results have direct applications to management and conservation planning: partners can tailor site-level management based on attributes associated with high habitat suitability for species of concern; allocate survey effort in areas with suitable habitat but no known species records; and identify priority areas for management, land acquisitions, or other strategies based on the distribution of species records, suitable habitat, and land protection status. These results can aid regional partners in implementing effective conservation strategies and inform status designation decisions of the USFWS.
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Greenberg C, Johnson S, Owen R, Storfer A. Amphibian breeding phenology and reproductive outcome: an examination using terrestrial and aquatic sampling. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Worldwide amphibian declines highlight the need for programs that monitor species presence and track population trends. We sampled larval amphibians with a box trap at 3-week intervals for 23 months in eight wetlands, and concurrently trapped adults and juveniles with drift fences, to examine spatiotemporal patterns of tadpole occurrence; explore relationships between breeding effort, tadpole abundance, and recruitment; and compare the efficacy of both methods in detecting species presence and reproductive outcome. Intermittent detection of species within and among wetlands suggested high mortality, followed by deposition of new eggs and tadpole cohorts. Breeding effort, tadpole abundance, and juvenile recruitment were generally not correlated. The reasons for this may include differential bias in detecting species or life stages between methods and high incidence of egg or tadpole mortality. Drift fences detected more species than box traps, but each provided insights regarding amphibian presence and recruitment. Our results illustrate shortfalls in the ability of infrequent aquatic sampling to detect local species richness of larval amphibians, as occurrence of many species is spatially and temporally variable. We also show the importance of using different sampling methods to detect species’ presence, as well as difficulties associated with both methods in tracking breeding effort, tadpole occurrence, or reproductive outcome.
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Affiliation(s)
- C.H. Greenberg
- USDA Forest Service, Southern Research Station, Bent Creek Experimental Forest, 1577 Brevard Road, Asheville, NC 28806, USA
| | - S.A. Johnson
- Department of Wildlife Ecology and Conservation, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611-0430, USA
| | - R. Owen
- Florida Park Service, Department of Environmental Protection, 4801 Camp Ranch Road, Gainesville, FL 32641, USA
| | - A. Storfer
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
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Greenberg CH, Zarnoch SJ, Austin JD. Weather, hydroregime, and breeding effort influence juvenile recruitment of anurans: implications for climate change. Ecosphere 2017. [DOI: 10.1002/ecs2.1789] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- C. H. Greenberg
- Bent Creek Experimental Forest; USDA Forest Service; Southern Research Station; Upland Hardwood Ecology and Management RWU-4157; 1577 Brevard Road Asheville North Carolina 28807 USA
| | - S. J. Zarnoch
- USDA; Forest Service; Southern Research Station; 481 Grand Oak Way Moore South Carolina 29369 USA
| | - J. D. Austin
- Department of Wildlife Ecology and Conservation; University of Florida; 110 Newins Ziegler Hall Gainesville Florida 32611 USA
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Hunter EA, Nibbelink NP, Alexander CR, Barrett K, Mengak LF, Guy RK, Moore CT, Cooper RJ. Coastal Vertebrate Exposure to Predicted Habitat Changes Due to Sea Level Rise. ENVIRONMENTAL MANAGEMENT 2015; 56:1528-1537. [PMID: 26163199 DOI: 10.1007/s00267-015-0580-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 07/03/2015] [Indexed: 06/04/2023]
Abstract
Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species' fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species' foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.
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Affiliation(s)
- Elizabeth A Hunter
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA.
| | - Nathan P Nibbelink
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Clark R Alexander
- Skidaway Institute of Oceanography, University of Georgia, Savannah, GA, 31411, USA
| | - Kyle Barrett
- School of Agriculture, Forest, and Environmental Science, Clemson University, Clemson, SC, 29634, USA
| | - Lara F Mengak
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
| | - Rachel K Guy
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Clinton T Moore
- U.S. Geological Survey, Georgia Cooperative Fish and Wildlife Research Unit, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Robert J Cooper
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
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Richter SC, Nunziata SO. Survival to metamorphosis is positively related to genetic variability in a critically endangered amphibian species. Anim Conserv 2013. [DOI: 10.1111/acv.12088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- S. C. Richter
- Department of Biological Sciences; Eastern Kentucky University; Richmond KY USA
| | - S. O. Nunziata
- Department of Biological Sciences; Eastern Kentucky University; Richmond KY USA
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Population and Conservation Genetics of Crawfish Frogs,Lithobates areolatus, at Their Northeastern Range Limit. J HERPETOL 2013. [DOI: 10.1670/12-034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Long Distance Migrations, Landscape Use, and Vulnerability to Prescribed Fire of the Gopher Frog (Lithobates capito). J HERPETOL 2012. [DOI: 10.1670/11-124] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Richter SC, Crother BI, Broughton RE. Genetic Consequences of Population Reduction and Geographic Isolation in the Critically Endangered Frog, Rana sevosa. COPEIA 2009. [DOI: 10.1643/ch-09-070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Chelgren ND, Rosenberg DK, Heppell SS, Gitelman AI. Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran. CAN J ZOOL 2008. [DOI: 10.1139/z08-003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Frogs exhibit extreme plasticity and individual variation in growth and behavior during metamorphosis, driven by interactions of intrinsic state factors and extrinsic environmental factors. In northern red-legged frogs ( Rana aurora Baird and Girard, 1852), we studied the timing of departure from the natal pond as it relates to date and size of individuals at metamorphosis in the context of environmental uncertainty. To affect body size at metamorphosis, we manipulated food availability during the larval stage for a sample (317) of 1045 uniquely marked individuals and released them at their natal ponds as newly metamorphosed frogs. We recaptured 34% of marked frogs in pitfall traps as they departed and related the timing of their initial terrestrial movements to individual properties using a time-to-event model. Median age at first capture was 4 and 9 days postmetamorphosis at two sites. The rate of departure was positively related to body size and to date of metamorphosis. Departure rate was strongly negatively related to time elapsed since rainfall, and this effect was diminished for smaller and later metamorphosing frogs. Individual variation in metamorphic traits thus affects individuals’ responses to environmental variability, supporting a behavioral link with variation in survival associated with these same metamorphic traits.
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Affiliation(s)
- Nathan D. Chelgren
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803, USA
- Department of Statistics, Oregon State University, Corvallis, OR 97331, USA
| | - Daniel K. Rosenberg
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803, USA
- Department of Statistics, Oregon State University, Corvallis, OR 97331, USA
| | - Selina S. Heppell
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803, USA
- Department of Statistics, Oregon State University, Corvallis, OR 97331, USA
| | - Alix I. Gitelman
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331-3803, USA
- Department of Statistics, Oregon State University, Corvallis, OR 97331, USA
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Greenberg CH, Tanner GW. SPATIAL AND TEMPORAL ECOLOGY OF OAK TOADS (BUFO QUERCICUS) ON A FLORIDA LANDSCAPE. HERPETOLOGICA 2005. [DOI: 10.1655/04-89.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Greenberg CH, Tanner GW. SPATIAL AND TEMPORAL ECOLOGY OF EASTERN SPADEFOOT TOADS ON A FLORIDA LANDSCAPE. HERPETOLOGICA 2005. [DOI: 10.1655/04-32] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Breeding Pond Selection and Movement Patterns by Eastern Spadefoot Toads (Scaphiopus holbrookii) in Relation to Weather and Edaphic Conditions. J HERPETOL 2004. [DOI: 10.1670/5-04a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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The Relationship between Breeding by the Gopher Frog, Rana capito (Amphibia: Ranidae) and Rainfall. AMERICAN MIDLAND NATURALIST 2003. [DOI: 10.1674/0003-0031(2003)150[0185:trbbbt]2.0.co;2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Richter SC, Seigel RA. Annual Variation in the Population Ecology of the Endangered Gopher Frog, Rana sevosa Goin and Netting. COPEIA 2002. [DOI: 10.1643/0045-8511(2002)002[0962:avitpe]2.0.co;2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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