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Tidwell K.S.,Oregon Zoo | Shepherdson D.J.,Oregon Zoo | Hayes M.P.,Habitat Program
Journal of Herpetology | Year: 2013

Few data exist that quantify evasive behavior in postmetamorphic anurans. On the basis of our casual observations that Oregon Spotted Frogs (Rana pretiosa) from one of two different populations appeared to exhibit a more pronounced evasive response, we used a pseudopredator stimulus to quantify the evasive response of juveniles from the two populations. We drew test animals from a pool of animals for each population that were captive-reared under identical conditions. Using latency to initial response, we compared the distribution of response times between the two populations at two sequential intervals over the rearing period. In both experiments, the Conboy Lake population had shorter latency-to-response times than the Black River population. However, we also found that latency-to-response times were shorter during the second test interval than during the first test interval for each population. The basis of population differences in response times may reside in differences in the predator set influencing each population, contaminants differentially influencing the Black River population in a negative manner, or some combination of both. Explanation for the faster latency-to-response times in the second experiment is unclear since both maturation and the length of the captive rearing interval may contribute to the effect, but they are confounded in this study. Copyright 2013 Society for the Study of Amphibians and Reptiles. Source


Barbour A.B.,University of Florida | Adams A.J.,Center for Fisheries Enhancement | Yess T.,Northern Kentucky University | Behringer D.C.,University of Florida | Wolfe R.K.,Habitat Program
Fisheries Research | Year: 2012

Studies of fish ecology are enhanced by precise and accurate knowledge of survival, which can be estimated from capture-recapture/resighting based survival probabilities. We conducted a cost-benefit analysis of resighting by an array of 11 autonomous PIT tag antennae and recapture by seine netting, and compared the effectiveness of the two methods for recapturing/resighting marked fish in an estuarine environment. During three separate marking periods, we marked a total of 2109 fish with PIT tags, recapturing 106 by seine (5.0%) and resighting 1700 by antennae (80.6%). Antennae resulted in precise monthly survival estimates while seine netting did not, but antennae did not collect ancillary data (e.g., growth) and their use was limited to areas where fish used constricted passes <10-30. m in width. Despite a reliance on seine nets to capture fish for marking and high initial construction costs, the cost-effectiveness of PIT tag antennae (US$45-$57 per unique fish resighted) exceeded that of seine netting (US$167-$934). Considering physical capture was required to mark fish, the use of PIT tag antennae is a dual-method approach incorporating both physical captures and telemetry. This dual-method approach can collect cost-effective and highly detailed data that could enhance our ability to make informed management and conservation decisions. © 2012 Elsevier B.V. Source


Conlon J.M.,United Arab Emirates University | Reinert L.K.,Vanderbilt University | Mechkarska M.,United Arab Emirates University | Prajeep M.,United Arab Emirates University | And 6 more authors.
Journal of Chemical Ecology | Year: 2013

Population declines due to amphibian chytridiomycosis among selected species of ranid frogs from western North America have been severe, but there is evidence that the Oregon spotted frog, Rana pretiosa Baird and Girard, 1853, displays resistance to the disease. Norepinephrine-stimulated skin secretions were collected from a non-declining population of R. pretiosa that had been exposed to the causative agent Batrachochytrium dendrobatidis. Peptidomic analysis led to identification and isolation, in pure form, of a total of 18 host-defense peptides that were characterized structurally. Brevinin-1PRa, -1PRb, -1PRc, and -1PRd, esculentin-2PRa and -PRb, ranatuerin-2PRa, -2PRb, -2PRc, and -2PRe, temporin-PRb and -PRc were identified in an earlier study of skin secretions of frogs from a different population of R. pretiosa known to be declining. Ranatuerin-2PRf, -2PRg, -2PRh, temporin-PRd, -PRe, and -PRf were not identified in skin secretions from frogs from the declining population, whereas temporin-PRa and ranatuerin-2PRd, present in skin secretions from the declining population, were not detected in the current study. All purified peptides inhibited the growth of B. dendrobatidis zoospores. Peptides of the brevinin-1 and esculentin-2 families displayed the highest potency (minimum inhibitory concentration = 6.25-12.5 μM). The study provides support for the hypothesis that the multiplicity and diversity of the antimicrobial peptide repertoire in R. pretiosa and the high growth-inhibitory potency of certain peptides against B. dendrobatidis are important in conferring a measure of resistance to fatal chytridiomycosis. © 2013 Springer Science+Business Media New York. Source


Wilhere G.F.,Habitat Program
Conservation Biology | Year: 2012

Policy advocacy is an issue regularly debated among conservation scientists. These debates have focused on intentional policy advocacy by scientists, but advocacy can also be unintentional. I define inadvertent policy advocacy as the act of unintentionally expressing personal policy preferences or ethical judgments in a way that is nearly indistinguishable from scientific judgments. A scientist may be well intentioned and intellectually honest but still inadvertently engage in policy advocacy. There are two ways to inadvertently engage in policy advocacy. First, a scientist expresses an opinion that she or he believes is a scientific judgment but it is actually an ethical judgment or personal policy preference. Second, a scientist expresses an opinion that he or she knows is an ethical judgment or personal policy preference but inadvertently fails to effectively communicate the nature of the opinion to policy makers or the public. I illustrate inadvertent advocacy with three examples: recovery criteria in recovery plans for species listed under the U.S. Endangered Species Act, a scientific peer review of a recovery plan for the Northern Spotted Owl (Strix occidentalis caurina), and the International Union for Conservation of Nature's definition of threatened. In each example, scientists expressed ethical judgments or policy preferences, but their value judgments were not identified as such, and, hence, their value judgments were opaque to policy makers and the public. Circumstances suggest their advocacy was inadvertent. I believe conservation scientists must become acutely aware of the line between science and policy and avoid inadvertent policy advocacy because it is professional negligence, erodes trust in scientists and science, and perpetuates an ethical vacuum that undermines the rational political discourse necessary for the evolution of society's values. The principal remedy for inadvertent advocacy is education of conservation scientists in an effort to help them understand how science and values interact to fulfill the mission of conservation science. © 2011 Society for Conservation Biology. Source


Yahnke A.E.,University of Washington | Grue C.E.,U.S. Geological Survey | Hayes M.P.,Habitat Program | Troiano A.T.,University of Washington
Environmental Toxicology and Chemistry | Year: 2013

Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5L/ha) and high-volume (7.0L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs. © 2012 SETAC. Source

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