Search Results


E Muths
Papers & Reports Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians
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Authors: Cayuela H, Valenzuela-Sanchez A, Teulier L, Martinez-Solano I, Lena JP, Merila J, Muths E, Shine R, Quay L, Denoel M, Clobert J, Schmidt BR | Date: 2020-02 | Outlet: The Quarterly Review of Biology | Format: .PDF
Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations and affects evolutionary processes by shaping patterns of gene flow. For these reasons, dispersal has received considerable attention from ecologists, evolutionary biologists, and conservationists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades researchers have taken an ever-increasing interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography, genetic, and the conservation of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal.
Sampling for stream salamanders
Sampling for stream salamanders
EHC Grant
Papers & Reports A National-Scale Assessment of Mercury Bioaccumulation in United 2 States National Parks Using Dragonfly Larvae As Biosentinels 3 through a Citizen-Science Framework
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Authors: Eagles-Smith CA, Willaker JJ, Nelson SJ, Flanagan CM, Krabbenhoft DP, Chen CY, Ackerman JT, Grant EHC, Pilliod D | Outlet: Environmental Science and Technology
ABSTRACT: We conducted a national-scale assessment of mercury (Hg) bioaccumulation in aquatic ecosystems using dragonfly
larvae as biosentinels by developing a citizen-science network to facilitate biological sampling. Implementing a carefully designed
sampling methodology for citizen scientists, we developed an effective framework for a landscape-level inquiry that might otherwise
be resource limited. We assessed the variation in dragonfly Hg concentrations across >450 sites spanning 100 United States National
Park Service units and examined intrinsic and extrinsic factors associated with the variation in Hg concentrations. Mercury
concentrations ranged between 10.4 and 1411 ng/g of dry weight across sites and varied among habitat types. Dragonfly total Hg
(THg) concentrations were up to 1.8-fold higher in lotic habitats than in lentic habitats and 37% higher in waterbodies, with
abundant wetlands along their margins than those without wetlands. Mercury concentrations in dragonflies differed among families
but were correlated (R2 > 0.80) with each other, enabling adjustment to a consistent family to facilitate spatial comparisons among
sampling units. Dragonfly THg concentrations were positively correlated with THg in both fish and amphibians from the same
locations, indicating that dragonfly larvae are effective indicators of Hg bioavailability in aquatic food webs. Collectively, this
continental-scale study demonstrates the utility of dragonfly larvae for estimating the potential mercury risk to fish and wildlife in
aquatic ecosystems and provides a framework for engaging citizen science as a component of landscape Hg monitoring programs.
Researcher measures the length of a Gulf Coast Waterdog
Researcher measures the length of a Gulf Coast Waterdog
Lindy Muse
Data Release Data from a 2015 trapping survey targeting the Gulf Coast Waterdog, Necturus beyeri, in Saint Tammany Parish, Louisiana
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Authors: Glorioso BM, Waddle JH | Date: 2020-06-05 | Format: URL
This dataset provides the data associated with a 2015 project to examine factors affecting the occupancy of Gulf Coast Waterdogs along Bayou Lacombe, Saint Tammany Parish, Louisiana. Data include site locations and distance from headwaters, water data (pH, turbidity, salinity, and depth), and capture data from trap checks. For Necturus beyeri captures, the datatset provides the sex of captures and length and mass measurements. The dataset states whether eggs were visible in females, whether each animal was swabbed for disease and whether tissue was clipped for genetics.
Data Release Seasonal median daily water depths for study wetlands in the St. Croix National Scenic Riverway, the North Temperate Lakes Long-term Research area, and the Upper Mississippi River study area from 2013-2018
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Authors: Sadinski Walt, Roth F Mark | Date: 2020-05-20 | Outlet: U.S. Geological Survey data release, https://doi.org/10.5066/P9H4VLEM | Format: .XLSX
To relate water levels in our study wetlands to temperature, precipitation, wetland water depth, and amphibian calling activity, we installed one pressure logger in the deepest spot we could find in each wetland. Soon after thawing conditions allowed, we drove a plastic pipe (anchor pipe) into the sediments at the deepest location and secured another pipe to it that contained one pressure logger (Onset Computer Corporation Model U20-001-04 [Bourne, MA, USA]) suspended approximately 2.5 cm above the sediments. We installed additional individual pressure loggers in the upper part of the logger pipes (in air) at select locations to measure barometric pressure for calibrating the submerged loggers’ readings. We measured pressure once per hour and used software supplied by the logger manufacturers to upload and convert data to depth at the end of each season.
Papers & Reports Estimation of metademographic rates and landscape connectivity for a conservation-reliant anuran
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Authors: Duarte A, Peterson JT, Pearl CA, Rowe JC, McCreary B, Galvan SK, Adams MJ | Outlet: Landscape Ecology
Context Amphibian conservation efforts commonly assume populations are tied to waterbodies that collectively function as a metapopulation. This assumption is rarely evaluated, and there is a need to understand the degree of connectivity among patches to appropriately define, manage, and conserve biological populations.

Objectives Our objectives were to quantify local persistence, colonization, and recruitment (metademographic rates) in relation to habitat attributes, evaluate the influence of the spatial arrangement of patches on landscape-scale population dynamics, and estimate the scale at which metapopulation dynamics are occurring for the Oregon spotted frog (Rana pretiosa).

Methods We collected R. pretiosa detection/non-detection data and habitat information from 93 sites spread throughout the species’ core extant range in Oregon, USA, 2010–2018. We developed a spatial multistate dynamic occupancy model to analyze these data.

Results Results indicated the proportion of sites occupied by R. pretiosa was relatively stable despite regular turnover in site occupancy. Connectivity was highest when the distance between sites was within 4.49–7.70 km, and populations within 1 km are at the appropriate spatial scale for effective population management. Rana pretiosa metademographic rates were strongly tied to water availability, vegetation characteristics, and beaver dams.

Conclusions Our analysis provides critical information to identify the appropriate spatial scale for effective population management, estimates the distance at which populations are connected, and quantifies the effects of hypothesized threats to species at a landscape scale. We believe this type of model can inform conservation and management strategies for multiple species.
Wolf spider feeding on a Blanchard's Cricket Frog
Wolf spider feeding on a Blanchard's Cricket Frog
Brad M. Glorioso
Papers & Reports ACRIS BLANCHARDI (Blanchard's Cricket Frog). Predation.
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Authors: Maldonado BR, Glorioso BM, Kidder RP | Date: 2020-06 | Outlet: Herpetological Review 51(2):296 | Format: .PDF
A natural history note describing predation of a Blanchard's Cricket Frog by a wolf spider at an elevated height.
A Cuban Treefrog ([I]Osteopilus septentrionalis[/I]) with striking green coloration
A Cuban Treefrog (Osteopilus septentrionalis) with striking green coloration
Brad M. Gloriso
Papers & Reports OSTEOPILUS SEPTENTRIONALIS (Cuban Treefrog)
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Authors: Glorioso BM, Vanbergen P, Roy J, Walter M, Leonpacher L, Freistak M | Date: 2018 | Outlet: Herpetological Review 49(1):70-71 | Format: .PDF
A note on the geographic distribution of the Cuban Treefrog (Osteopilus septentrionalis), describing new parish records in East Baton Rouge Parish and Lafayette Parish.
Hatchling western pond turtle found in the stomach of an invasive bullfrog in the San Luis Rey River, San Diego Co., CA
Hatchling western pond turtle found in the stomach of an invasive bullfrog in the San Luis Rey River, San Diego Co., CA
U.S. Geological Survey
Papers & Reports Historical museum collections and contemporary population studies implicate roads and introduced predatory bullfrogs in the decline of western pond turtles
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Authors: Nicholson E G, Manzo S, Devereux Z, Morgan T, Fisher R N, Brown C W, Dagit R, Scott P A, Shaffer H B | Date: 2020-06-12 | Outlet: PeerJ 8:e9248 DOI 10.7717/peerj.9248 | Format: .PDF
The western pond turtle (WPT), recently separated into two paripatrically distributed species (Emys pallida and Emys marmorata), is experiencing significant reductions in its range and population size. In addition to habitat loss, two potential causes of decline are female-biased road mortality and high juvenile mortality from non-native predatory bullfrogs (Rana catesbeiana). However, quantitative analyses of these threats have never been conducted for either species of WPT. We used a combination of historical museum samples and published and unpublished field studies shared with us through personal communications with WPT field researchers (B Shaffer, P Scott, R Fisher, C Brown, R Dagit, L Patterson, T Engstrom, 2019, personal communications) to quantify the effect of roads and bullfrogs on WPT populations along the west coast of the United States. Both species of WPT shift toward increasingly male biased museum collections over the last century, a trend consistent with increasing, female-biased road mortality. Recent WPT population studies revealed that road density and proximity were significantly associated with increasingly male-biased sex ratios, further suggesting female-biased road mortality. The mean body size of museum collections of E. marmorata, but not E. pallida, has increased over the last 100 years, consistent with reduced recruitment and aging populations that could be driven by invasive predators. Contemporary WPT population sites that co-occur with bullfrogs had significantly greater average body sizes than population sites without bullfrogs, suggesting strong bullfrog predation on small WPT hatchlings and juveniles. Overall, our findings indicate that both species of WPT face demographic challenges which would have been difficult to document without the use of both historical data from natural history collections and contemporary demographic field data. Although correlational, our analyses suggest that female-biased road mortality and predation on small turtles by non-native bullfrogs are occurring, and that conservation strategies reducing both may be important for WPT recovery.
Southern California slender salamander ([I]Batrachoseps major[/I]).
Southern California slender salamander (Batrachoseps major).
Chris Brown, U.S. Geological Survey
Papers & Reports Changes in capture rates and body size among vertebrate species occupying an insular urban habitat reserve
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Authors: Stanley TR, Clark RW, Fisher RN, Rochester CJ, Root SA, Lombardo KJ, Ostermann-Kelm SD | Date: 2020-06-29 | Outlet: Conservation Science and Practice 2020;e245. | Format: .PDF
Long-term ecological monitoring provides valuable and objective scientific information to inform management and decision making. In this paper we analyze 22 years of herpetofauna monitoring data from the Point Loma Ecological Conservation Area (PLECA), an insular urban reserve near San Diego, California. Our analysis showed that counts of individuals for one of the four most common terrestrial vertebrates declined, whereas counts for other common species increased or remained stable. Two species exhibited declines in adult body length, whereas biomass pooled over the five most common species increased over time and was associated with higher wet season precipitation. Although the habitat and vegetation at PLECA have remained protected and intact, we suspect that changes in arthropod communities may be driving changes in the abundance, growth, and development of insectivorous lizards. This study underscores the value of long-term monitoring for establishing quantitative baselines to assess biological changes that would otherwise go undetected.
An ornate chorus frog ([I]Pseudacris ornata[/I]) with brown coloration
An ornate chorus frog (Pseudacris ornata) with brown coloration
Peter Paplanus
Papers & Reports Pseudacris ornata
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Author: Glorioso BM | Date: 2010 | Outlet: Catalogue of American Amphibians and Reptiles | Format: .PDF
An in-depth species account of the ornate chorus frog (Pseudacris ornata).