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Recent Products

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This is an ARMI Product. Potential reduction in terrestrial salamander ranges associated with Marcellus shale development
Authors: Brand, Adrianne B, Wiewel, Amber NM, Grant, Evan H Campbell | Outlet: Biological Conservation
Natural gas production from the Marcellus shale is rapidly increasing in the northeastern United States. Most of the endemic terrestrial salamander species in the region are classified as ‘globally secure’ by the IUCN, primarily because much of their ranges include state- and federally protected lands, which have been presumed to be free from habitat loss. However, the proposed and ongoing development of the Marcellus gas resources may result in significant range restrictions for these and other terrestrial forest salamanders. To begin to address the gaps in our knowledge of the direct impacts of shale gas development, we developed occurrence models for five species of terrestrial plethodontid salamanders found largely within the Marcellus shale play. We predicted future Marcellus shale development under several scenarios. Under scenarios of 10000, 20000, and 50000 new gas wells, we predict 4%, 8%, and 20% forest loss, respectively, within the play. Predictions of habitat loss vary among species, but in general, Plethodon electromorphus and P. wehrlei are predicted to lose the greatest proportion of forested habitat within their ranges if future Marcellus predictions are based on characteristics of the shale play. If predictions are based on current well locations, P. richmondi is predicted to lose the greatest proportion of habitat. Models showed high uncertainty in species’ ranges and emphasize the need for distribution data collected by widespread and repeated, randomized surveys.

This is an ARMI Product. Indicators of the Statuses of Amphibian Populations and Their Potential for Exposure to Atrazine in Four Midwestern U.S. Conservation Areas
Authors: Sadinski W, Roth M, Hayes T, Jones P, Gallant A | Date: 2014-09-12 | Outlet: PLoS ONE 9(9): e107018. doi:10.1371/journal.pone.0107018 | Format: .PDF
Extensive corn production in the midwestern United States has physically eliminated or fragmented vast areas of historical amphibian habitat. Midwestern corn farmers also apply large quantities of fertilizers and herbicides, which can cause direct and indirect effects on amphibians. Limited field research regarding the statuses of midwestern amphibian populations near areas of corn production has left resource managers, conservation planners, and other stakeholders needing more information to improve conservation strategies and management plans. We repeatedly sampled amphibians in wetlands in four conservation areas along a gradient of proximity to corn production in Illinois, Iowa, Minnesota, and Wisconsin from 2002 to 2005 and estimated site occupancy. We measured frequencies of gross physical deformities in recent metamorphs and triazine concentrations in the water at breeding sites. We also measured trematode infection rates in kidneys of recently metamorphosed Lithobates pipiens collected from nine wetlands in 2003 and 2004. We detected all possible amphibian species in each study area. The amount of nearby row crops was limited in importance as a covariate for estimating site occupancy. We observed deformities in <5% of metamorphs sampled and proportions were not associated with triazine concentrations. Trematode infections were high in metamorphs from all sites we sampled, but not associated with site triazine concentrations, except perhaps for a subset of sites sampled in both years. We detected triazines more often and in higher concentrations in breeding wetlands closer to corn production. Triazine concentrations increased in floodplain wetlands as water levels rose after rainfall and were similar among lotic and lentic sites. Overall, our results suggest amphibian populations were not faring differently among these four conservation areas, regardless of their proximity to corn production, and that the ecological dynamics of atrazine exposure were complex.

emergent wetland vegetation at Tamarac National Wildlife Refuge
Mark Roth  
This is an ARMI Product. Detecting Emergence, Growth, and Senescence of Wetland Vegetation with Polarimetric Synthetic Aperture Radar (SAR) Data.
Authors: Gallant AL, Kaya SG, White L, Brisco B, Roth MF, Sadinski W, Rover J | Date: 2014-03-24 | Outlet: Water. 2014; 6(3):694-722 | Format: .PDF
Wetlands provide ecosystem goods and services vitally important to humans. Land managers and policymakers working to conserve wetlands require regularly updated information on the statuses of wetlands across the landscape. However, wetlands are challenging to map remotely with high accuracy and consistency. We investigated the use of multitemporal polarimetric synthetic aperture radar (SAR) data acquired with Canada’s Radarsat-2 system to track within-season changes in wetland vegetation and surface water. We speculated, a priori, how temporal and morphological traits of different types of wetland vegetation should respond over a growing season with respect to four energy-scattering mechanisms. We used ground-based monitoring data and other ancillary information to assess the limits and consistency of the SAR data for tracking seasonal changes in wetlands. We found the traits of different types of vertical emergent wetland vegetation were detected well with the SAR data and corresponded with our anticipated backscatter responses. We also found using data from Landsat’s optical/infrared sensors in conjunction with SAR data helped remove confusion of wetland features with upland grasslands. These results suggest SAR data can provide useful monitoring information on the statuses of wetlands over time.

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This is an ARMI Product. Pesticide concentrations in frog tissue and wetland habitats in a landscape dominated by
Authors: Smalling KL, Reeves R, Muths E, Vandever M, Battaglin WA, Hladik ML, Pierce CL | Date: 2014 | Outlet: Science of the Total Environment | Format: .PDF
Among the multiple stressors potentially affecting the presence of amphibians across agricultural landscapes, habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline. Conservation efforts have attempted to restore wetlands lost through landscape modifications with the aim of reducing contaminant loads in surface waters and providing quality habitat to wildlife. However, the benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the accumulation of pesticides in tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The herbicide atrazine was detected in 100% of the water samples and in some instances at concentrations high enough to potentially cause reproductive effects in leopard frogs. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought to cause lethality in frogs. Seventeen pesticides were detected in tissue samples with concentrations ranging from 0.08 to 1,500 µg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and implementing conservation and management actions for these and similar wetlands in agriculturally dominated landscapes.

Common Toad
J Bosch  
This is an ARMI Product. Demography of common toads after local extirpation of
Authors: Bosch J, Fernandez-Beaskoetxez S, Scherer R D, Amburgey S M, Muths E | Date: 2014-09 | Outlet: Amphibia-Reptilia | Format: .PDF
Estimating demographic parameters like survival or recruitment provides insight into the state and trajectory of populations, but understanding the contexts influencing those parameters, including both biotic and abiotic factors, is particularly important for management and conservation. At a high elevation national park in Central Spain, common toads (Bufo bufo) are apparently taking advantage of the near-extirpation of the midwife toad (Alytes obstetricans), as colonizationinto new breeding ponds is evident.Within this scenario, we expected demographic parameters of common toad populations to be affected favorably by the putative release from competition. However, we found the population growth rate was negative in 4 of 5 years at the long-standing population; survival probability at the long-standing population and newly-colonized breeding ponds was lower than reported for other toads living at high elevations and the probability of recruitment was inadequate to compensate for the survival rate in maintaining a positive trajectory for either of the breeding ponds. We assessed weather covariates and disease for their contribution to the context thatmay be limiting the common toad’s successful use of the niche vacated by the midwife toad.

This is an ARMI Product. Partitioning the non-consumptive effects of predators on prey with complex life histories
Authors: Davenport M, Hossack BR, Lowe WH | Date: 2014-08 | Outlet: Oecologia 176:149–155
Non-consumptive effects (NCE) of predators on prey can be as strong as consumptive effects and may be driven by numerous mechanisms, including predator characteristics. Previous work has highlighted the importance of predator characteristics in predicting NCEs, but has not addressed how complex life histories of prey could mediate predator NCEs. We conducted a meta-analysis to compare the effects of predator gape limitation (gape-limited or not) and hunting mode (active or sit-and-pursue) on the activity, larval period, and size at metamorphosis on larval aquatic amphibians and invertebrates. Larval prey tended to reduce their activity and require more time to reach metamorphosis in the presence of all predator functional groups, but the responses did not differ from zero. Prey metamorphosed at smaller size in response to non-gape-limited, active predators, but counter to expectations, prey metamorphosed larger when confronted by non-gape-limited, sit-and-pursue predators. These results indicate NCEs on larval prey life history can be strongly influenced by predator functional characteristics. More broadly, our results suggest that understanding predator NCEs would benefit from greater consideration of how prey life-history attributes mediate population and community-level outcomes.

Age specific mortality rates for three ectotherm species.
 
This is an ARMI Product. Biodemography of Ectothermic Tetrapods Provides Insights into the Evolution and Plasticity of Mortality Patterns
Authors: Miller DAW, Janzen FJ, Fellers GM, Kleeman PM, Bronikowski AM | Date: 2014 | Outlet: Sociality, Hierarchy, Health: Comparative Biodemography: Papers from a Workshop: 295-313. | Format: .PDF
In this paper we examine the biodemography of wild populations of three species (a turtle, a frog, and a snake). All are ectotherms, an understudied subset of the vertebrate taxa for understanding aging. Employing a comparative perspective by examining wild populations of relatively long-lived ectothermic vertebrates, we found that (1) across all three species, there was strong evidence for mortality senescence and (2) environmental factors, including stress, influence age-specific patterns of mortality both in current and later years and therefore produces plastic variation in the shapes of mortality trajectories.

Loading headstarted tadpoles into backpacks
E. Muths  
This is an ARMI Product. Animal reintroductions: an innovative assessment of survival
Authors: Muths E, Bailey LL, Watry MK | Date: 2014-06 | Outlet: Biological Conservation xx:xxx-xxx
Quantitative evaluations of reintroductions are infrequent and assessments of milestones reached before a project is completed, or abandoned due to lack of funding, are rare. However, such assessments, which are promoted in adaptive management frameworks, are critical. Quantification can provide defensible estimates of biological success, such as the number of survivors from a released cohort, with associated cost per animal. It is unlikely that the global issues of endangered wildlife and population declines will abate, therefore, assurance colonies and reintroductions are likely to become more common. If such endeavors are to be successful biologically or achieve adequate funding, implementation must be more rigorous and accountable. We use a novel application of a multistate, robust design capture-recapture model to estimate survival of reintroduced tadpoles through metamorphosis (i.e., the number of individuals emerging from the pond) and thereby provide a quantitative measure of effort and success for an “in progress” reintroduction of toads. Our data also suggest that tadpoles released at later developmental stages have an increased probability of survival and that eggs laid in the wild hatched at higher rates than eggs laid by captive toads. We illustrate how an interim assessment can identify problems, highlight successes, and provide information for use in adjusting the effort or implementing a Decision-Theoretic adaptive management strategy.

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This is an ARMI Product. ARMI 2013 Annual Update
Authors: Halstead BJ, Adams MJ, Grant ECH, Hossack BR, Smalling KL, Ball LC | Date: 2014-02-17 | Format: .PDF
Welcome to the 2013 Annual ARMI Update, which provides highlights and significant milestones of this innovative program. This was an especially notable year for ARMI with the release of a landmark publication “Trends in amphibian occupancy in the United States.” Our synthesis and scaling up of 9 years of monitoring data produced the first-ever estimate of how fast frogs, toads and salamanders in the United States are disappearing from their habitats. Our findings received international attention and rekindled the discussion about global amphibian declines. This was not the only topic we addressed this year, as ARMI’s total publication count rose to 460 papers representing our latest research findings on the effects of climate change, land use, diseases, pesticides, and management on amphibian populations.

Full text: armi.usgs.gov/docs/ARMI%202013%20Annual%20Update.pdf

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Adam Backlin  
This is an ARMI Product. Population declines lead to replicate patterns of internal range structure at the tips of the distribution of the California red-legged frog (Rana draytonii)
Authors: Richmond JQ, Backlin AR, Tatarian PJ, Solvesky BG, Fisher RN | Date: 2014 | Outlet: Biological Conservation | Format: .PDF
Demographic declines and increased isolation of peripheral populations of the threatened California red-legged frog(Rana draytonii)have led to the formation of internal range boundaries at opposite ends of the species’ distribution. While the population genetics of the southern internal boundary has been studied in some detail, similar information is lacking for the northern part of the range. In this study, we used microsatellite and mtDNA data to examine the genetic structuring and diversity of some of the last remaining R. draytonii populations in the northern Sierra Nevada, which collectively form the northern external range boundary. We compared these data to coastal populations in the San Francisco Bay Area, where the species is notably more abundant and still exists throughout much of its historic range. We show that ‘external’ Sierra Nevada populations have lower genetic diversity and are more differentiated from one another than their ‘internal’ Bay Area counterparts. This same pattern was mirrored across the distribution in California, where Sierra Nevada and Bay Area populations had lower allelic variability compared to those previously studied in coastal southern California. This genetic signature of northward range expansion was mirrored in the phylogeography of mtDNA haplotypes; northern Sierra Nevada haplotypes showed greater similarity to haplotypes from the south Coast Ranges than to the more geographically proximate populations in the Bay Area. These data cast new light on the geographic origins of Sierra Nevada R. draytonii populations and highlight the importance of distinguishing the genetic effects of contemporary demographic declines from underlying signatures of historic range expansion when addressing the most immediate threats to population persistence. Because there is no evidence of contemporary gene flow between any of the Sierra Nevada R. draytonii populations, we suggest that management activities should focus on maintaining and creating additional ponds to support breeding within typical dispersal distances of occupied habitat.


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