For ectotherms living in seasonal environments, time available for development and growth is often constrained by the length of the growth season. Declining season length towards higher latitudes often select for latitudinal clines in development and growth rates, exhibiting increasing growth and developmental rates towards the north. However, the physiological and ecological factors enabling these clines are poorly understood. Our study system included eight populations of Rana temporaria along a 1500 km latitudinal gradient. We found increased growth rates in populations at higher latitudes to be the result of higher growth efficiency, partly due to increased relative gut length. Populations with higher growth rates also exhibited lower standard metabolic rates, implying that fast-growing individuals are able to achieve high growth rates by spending less energy on maintenance metabolism under low activity conditions. Predator densities, and antipredatory defenses in prey, are assumed to decrease towards higher latitudes. While all study populations responded to predator presence by decreasing activity and foraging, high latitude populations maintained higher activity levels in the presence of the predator. In trials with a free-ranging predator, high latitude tadpoles experienced higher mortality than those from the low latitudes. The higher activity level in the northern populations increases mortality under predation risk, but is probably needed to maintain high growth and development rates. When competing over resources, tadpoles from the low latitude population were inferior competitors, as indicated by their longer development time when raised together with high latitude tadpoles. We found no effect of latitude on size-corrected burst speed. The general effect of predator presence on burst speed depended on food availability, with well fed tadpoles being faster in the absence, and food restricted being faster in the presence of a predator.

Growth rate is an important life history trait, which impacts fitness indirectly through its effect on the age and size at maturity, as well as directly through costs associated with accelerated growth such as increased predation risk. Genetic variation and plasticity in growth are widespread in nature, and local adaptation of growth rate may evolve due to divergent selection in different environments, for example related to predation risk, temperature or time constraints. I studied local adaptation of larval life history in the moor frog Rana arvalis, in a local network of ponds close to Uppsala. Local adaptation of growth rate and survival was studied in a reciprocal transplant experiment between ponds with different habitat characteristics. Meanwhile, differences among the populations in intrinsic growth, activity and response to predation were studied in a common garden experiment in the laboratory, where tadpoles were raised in the presence or absence of a predator and tested in direct predation trials. In the field, differences in growth among populations were found, independent of which pond the tadpoles were raised in, indicating that the ponds were similar growth environments. Survival differences among the populations depended on the pond, but local populations did not do better than foreign ones. In the laboratory, similar patterns in growth rate were found. All populations were highly plastic in their response to predation, having lower growth and activity in the predator-induced treatment and decreased mortality in the predation trials. Tadpole size was an important factor in escaping predation. One population clearly grew faster than the others in the field and in the lab, which could be explained in terms of its habitat of origin but was most likely related to the relatively late hatching of this population. Future studies are necessary concerning the possible costs of this accelerated growth and the importance of breeding phenology. Apart from the one differential population, I did not find evidence of local adaptation in the field or in the laboratory. The influence of habitat characteristics on tadpole life history was difficult to study, due to the limited number of ponds and many environmental differences among them. However, this thesis was a valuable pilot study concerning the design of experiments to study factors promoting and constraining local adaptation in landscape mosaics. An understanding of local adaptation at the scale at which gene flow occurs is important for the conservation of populations in fragmented landscapes as well as for the study of ecological speciation.

The Caspian region and specifically the Apsheron peninsula of Azerbaijan is known to be polluted with a variety of environmental contaminants, making risk assessment difficult. The wetlands of Sumgayit contain particularly complex mixtures of contaminants. Flow cytometry and the micronucleus assay were used to assess chromosomal damage in aquatic turtles and frogs inhabiting contaminated wetlands in Azerbaijan. By evaluating biomarkers that are indicative of somatic effects, elevated chromosomal damage was documented at several sites in Azerbaijan relative to reference sites. Sediment samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), organochlorines (OCs), and mercury to evaluate contaminant associations with genetic damage. Sediment samples revealed heterogeneous patterns of PAH and mercury concentrations throughout Sumgayit. Significant positive correlations were documented between both PAH and mercury sediment concentrations and chromosomal damage. Population genetic methods were employed to study the effects of long-term chronic contaminant exposure in marsh frogs from Sumgayit. The Sumgayit region has reduced levels of genetic diversity, likely due to environmental degradation. One of the most contaminated sites in Sumgayit, WTP, appears to be a source of new mutations as a result of an increased mutation rate. Finally, the Sumgayit region seems to act as an ecological sink, with levels of gene flow into the region exceeding gene flow out of the region. This study provides not only exposure and biomarker data, but also an integrated method for assessing the cumulative population impacts of contaminant exposure by studying both population genetic and evolutionary effects. The results presented here will be used in conjunction with those of ongoing research involving both wildlife and humans to develop comprehensive ecological and human risk assessments.

Thyroid hormones (THs) are important hormones involved in developmental processes, including foetal brain maturation. THs are also involved in the maintenance of homeostasis. One in three people in Canada are considered to have some form of thyroid disorder. One reason for the high level of thyroid disorders may be the increasing amount of anthropogenic chemicals released into the environment that affect normal hormone action. Amphibian metamorphosis is completely dependent on TH and provides a model to study such chemicals. This thesis uses the Rana catesbeiana tadpole as a model to study potential TH disrupting chemicals by developing a novel screening assay called the cultured tail fin biopsy assay, or the “C-fin” assay. The C-fin assay uses tail biopsies from premetamorphic tadpoles, Taylor-Kollros stage VI-VIII. The biopsies are cultured in serum-free media along with the test chemical for 48 hours. QPCR is used to measure the mRNA steady-state levels of selected gene transcripts. Two TH-responsive gene transcripts were measured: the up-regulated gene transcript, thyroid hormone receptor β (TRβ) and the down-regulated gene transcript, Rana larval keratin type I (RLKI). Heat-shock protein 30 (HSP30) and catalase (CAT) were used as indicators of cellular stress. Another model system used in this thesis is rat pituitary cells, or GH3 cells. QPCR was used to measure the mRNA steady-state levels of three TH-responsive genes growth hormone (GH), deiodinase I (DIOI), and prolactin (PRL); heat-shock protein 70 (HSP70) was used as an indicator of cellular stress. Nanoparticles, used in various consumer products, were one class of chemicals examined. Using the C-fin assay, nanosilver and quantum dots (QDs) caused perturbations in TH-signalling and also showed signs of cellular stress. There was no overt toxicity observed as was determined by the normalizer, house-keeping gene transcript, ribosomal protein L8. The GH3 cells also detected TH disrupting effects by both nanosilver and QDs; however, nanosilver did not appear to cause cellular stress whereas QDs did. Nitrate and nitrite, major waterway contaminants, were also examined and there were no TH-perturbations observed using the C-fin assay. Finally, two antimicrobials used in many consumer products, triclocarban (TCC), triclosan (TCS) and its metabolite, methyl-TCS (mTCS) were examined using both the C-fin assay and GH3 cells. Both the C-fin assay and the GH3 cells determined mTCS to be more potent than TCS in disrupting TH action. TCC also caused perturbations in TH-signalling as well as causing a significant amount of cellular stress. Overall the C-fin assay and the GH3 cells proved to be excellent models in studying the potential disruptors of the TH axis. The C-fin assay and GH3 cells detected novel TH disruptors and gave further insight into already known disruptors of the TH axis.

Canada is the second highest producer of hydroelectric energy in the world. Nearly 50 of the hydroelectric reservoirs in the country have a capacity larger than 1 billion m3. Despite the great number and extent of hydropower developments in Canada and around the world, relatively little is known about how dams and their operations influence terrestrial and semi-aquatic wildlife. Reservoirs at northern latitudes are characterized by large fluctuations in water level, which create modified shorelines called drawdown zones. To evaluate the impact of these disturbances on amphibians and reptiles, I conducted visual encounter surveys at two sites in the drawdown zone of Kinbasket Reservoir, near Valemount, B.C. From April to August of 2010 and 2011, I documented the habitat use, reproductive phenology, and body condition of two amphibian species (Anaxyrus boreas and Rana luteiventris) as well as the growth, movements, diet, and distribution of one species of garter snake (Thamnophis sirtalis). At two sites in the drawdown zone, A. boreas and R. luteiventris were present for the duration of the summer and utilized several ponds for reproduction. The presence and abundance of Rana luteiventris eggs were generally associated with ponds that had higher mean temperatures, higher mean pH, and the presence of fish. In 2010, there was sufficient time for amphibian breeding and metamorphosis to occur before the reservoir inundated the drawdown zone, but low precipitation levels in that year led to desiccation of many breeding ponds. In 2011, high rainfall and snowmelt led to early inundation of breeding ponds, and thousands of tadpoles were presumably swept into the reservoir. Gravid Thamnophis sirtalis were found at just one of two sites in the drawdown zone, but both sites were frequented by foraging individuals of this species. Anaxyrus boreas appears to be the primary prey of T. sirtalis in the drawdown zone. An improved understanding of how the amphibians and reptiles at Kinbasket Reservoir have persisted in this highly disturbed environment may be vital to their conservation — the activation of a new generating unit at Mica Dam in 2014 will alter the pattern and timing of reservoir inundation for the first time since it was constructed 40 years previously. / Graduate

Orientador: João Francisco Escobedo / Banca: Maeli Dal Pai Silva / Banca: Cláudio Ângelo Agostinho / Banca: Vitalino Dal Pai / Banca: Nilson Augusto Villa Nova / Resumo : No presente trabalho se estuda a produção de rã touro (Rana catesbeiana Shaw, 1802) em baias de fibrocimento dentro de estufas com cobertura de polietileno e em condições de temperatura mínima controlada em laboratório. São feitos estudos fisiológicos (dosagem de Hematócrito e de Triidotiroidina Total - T3 - e de Tiroxina Total - T4), e de alguns aspectos morfofisiológicos da musculatura estriada do músculo adutor magnum (morfologia, freqüência e diâmetro das fibras musculares). Foram construídas três estruturas, cada uma coberta com filme de PVC de 0,1 mm de espessura e de cores diferentes (Verde, Transparente e Branca). A construção das estruturas e das baias foi amplamente detalhada no trabalho. O ambiente interno das estruturas foi estudado através da medição de temperaturas de globo, do ar, do piso, da água e de bulbo molhado, das irradiâncias global e refletida e do saldo de irradiação infravermelha, sendo que, no meio externo, foram feitas medições de irradiância global, da temperatura e da umidade do ar. Foram calculados os índices bioclimáticos: Índice de Temperatura e Umidade (THI), Carga Térmica Radiante (CTR) e Índice de Termômetro de Globo (WBGT). Obtiveram-se correlações para estimativa de variáveis ambientais, no interior das estruturas, a partir de valores medidos no meio externo e a partir de outras, medidas no interior das estruturas. As variáveis que descrevem o ambiente interno das estufas foram correlacionadas com variáveis de desempenho animal (Peso Vivo, Ganho de Peso e Consumo) de forma descritiva, por inferência através de análise multivariada e por análises de regressão. Estas variáveis de desempenho e ambientais, também foram correlacionadas com o rendimento de carcaça,...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bull Frogs ((Rana catesbeiana Shaw, 1802) production in fibercement sheds located inside polyethylene covered structures and under laboratory conditions in a minimum temperature controlled environment, were studied in this work. Physiological analyses (levels of hematocrit, Total Triidothyronine -T3 and Total Thyroxine - T4) were conducted and some morphophysiological aspects of the adutor magnum muscle (morphology, frequency and diameter of the muscle fibers) were described. Three structures were built; each one covered with a 0.1-mm width PVC film with a specific color (green, transparent and white). Structures and shed construction details were fully described. The internal environment inside the structures and sheds was studied and the following environmental variables were measured, in (WBGT) were calculated. The environmental variables inside the structures and sheds were correlated with external ones and estimation equations were found by linear regression analyses. Animal performance (live weight, weight gain and feed intake) was correlated with environmental variables inside the sheds descriptively, and by multivariate and regression analyses. The same was made for carcass dressing, biometry and for diameters and frequencies of the adutor magnum muscle fibers. Conclusions about environmental modeling and about the relative importance of the environmental variables and bioclimatic indexes in the animal performance were presented. This was also made for the morphological and physiological aspects and their relation with the environmental variables and animal performance. / Doutor

The increasing level of the UV-B irradiation due to depleting of the ozone layer is considered to be one of the causes of global amphibian declines. The UV-B radiation causes damage to the DNA in the nuclei of the skin cells and their eventual death. In many amphibian species there was found a negative influence of the UV-B radiation on the hatching success of tadpoles and their subsequent viability. It has been assumed that tadpoles are able to actively avoid places with the higher exposure of the UV-B radiation thanks to their locomotion. In this experiment tadpoles could have chosen between a zone with the UV radiation (UV-B and UV-A) and without the UV radiation. The tadpoles have not been exposed to the UV radiation before the measurement started. The location of the tadpoles during the measurement was recorded by CCD camera. A computer program EthoVision then evaluated the time that these tadpoles spent in each of the zones and the total path length these tadpoles has swum in the zones. The measurements were performed for two groups of tadpoles differing in age to determine whether the level of development may affect the tadpoles' preference to the UV radiation. The tadpoles in both groups spent more time in the zone without the UV radiation. The tadpoles in the more advanced development phase have spent 7 times more time in average in the zone without the UV radiation than in the zone with it. The tadpoles from the second group have spent in average 2.5 times more time in the zone without the UV radiation than in the zone with the UV radiation. The total swimming path length of advanced tadpoles was almost 2.5 times longer in the zone without the UV radiation than in the zone with the UV radiation. Conversely, the total path length of younger tadpoles did not significantly differ between the zones. The total time spent in the zones with / without the UV radiation did not differ between the groups of tadpoles. Also the total path length did not differ between the groups in the zone with the UV-B radiation. However, the total path length of tadpoles had differed between groups in the zone without the UV radiation.

Made available in DSpace on 2014-06-11T19:31:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-10-05Bitstream added on 2014-06-13T20:02:22Z : No. of bitstreams: 1 teodoro_ms_dr_botfca.pdf: 3390581 bytes, checksum: ee1aefe9d5f6e6c678f22e0db65505fb (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / No presente trabalho se estuda a produção de rã touro (Rana catesbeiana Shaw, 1802) em baias de fibrocimento dentro de estufas com cobertura de polietileno e em condições de temperatura mínima controlada em laboratório. São feitos estudos fisiológicos (dosagem de Hematócrito e de Triidotiroidina Total - T3 - e de Tiroxina Total - T4), e de alguns aspectos morfofisiológicos da musculatura estriada do músculo adutor magnum (morfologia, freqüência e diâmetro das fibras musculares). Foram construídas três estruturas, cada uma coberta com filme de PVC de 0,1 mm de espessura e de cores diferentes (Verde, Transparente e Branca). A construção das estruturas e das baias foi amplamente detalhada no trabalho. O ambiente interno das estruturas foi estudado através da medição de temperaturas de globo, do ar, do piso, da água e de bulbo molhado, das irradiâncias global e refletida e do saldo de irradiação infravermelha, sendo que, no meio externo, foram feitas medições de irradiância global, da temperatura e da umidade do ar. Foram calculados os índices bioclimáticos: Índice de Temperatura e Umidade (THI), Carga Térmica Radiante (CTR) e Índice de Termômetro de Globo (WBGT). Obtiveram-se correlações para estimativa de variáveis ambientais, no interior das estruturas, a partir de valores medidos no meio externo e a partir de outras, medidas no interior das estruturas. As variáveis que descrevem o ambiente interno das estufas foram correlacionadas com variáveis de desempenho animal (Peso Vivo, Ganho de Peso e Consumo) de forma descritiva, por inferência através de análise multivariada e por análises de regressão. Estas variáveis de desempenho e ambientais, também foram correlacionadas com o rendimento de carcaça... / Bull Frogs ((Rana catesbeiana Shaw, 1802) production in fibercement sheds located inside polyethylene covered structures and under laboratory conditions in a minimum temperature controlled environment, were studied in this work. Physiological analyses (levels of hematocrit, Total Triidothyronine -T3 and Total Thyroxine - T4) were conducted and some morphophysiological aspects of the adutor magnum muscle (morphology, frequency and diameter of the muscle fibers) were described. Three structures were built; each one covered with a 0.1-mm width PVC film with a specific color (green, transparent and white). Structures and shed construction details were fully described. The internal environment inside the structures and sheds was studied and the following environmental variables were measured, in (WBGT) were calculated. The environmental variables inside the structures and sheds were correlated with external ones and estimation equations were found by linear regression analyses. Animal performance (live weight, weight gain and feed intake) was correlated with environmental variables inside the sheds descriptively, and by multivariate and regression analyses. The same was made for carcass dressing, biometry and for diameters and frequencies of the adutor magnum muscle fibers. Conclusions about environmental modeling and about the relative importance of the environmental variables and bioclimatic indexes in the animal performance were presented. This was also made for the morphological and physiological aspects and their relation with the environmental variables and animal performance.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-06T18:56:53Z No. of bitstreams: 1 LucasAmaralMachado_DISSERT.pdf: 675823 bytes, checksum: cd1bcc94212045a3a4738ef67078d1cf (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-07T23:51:14Z (GMT) No. of bitstreams: 1 LucasAmaralMachado_DISSERT.pdf: 675823 bytes, checksum: cd1bcc94212045a3a4738ef67078d1cf (MD5) / Made available in DSpace on 2016-06-07T23:51:14Z (GMT). No. of bitstreams: 1 LucasAmaralMachado_DISSERT.pdf: 675823 bytes, checksum: cd1bcc94212045a3a4738ef67078d1cf (MD5) Previous issue date: 2015-03-11 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo deste estudo foi realizar a extra??o ?leo de r?-touro ?leo de r?-touro e desenvolver uma emuls?o adequada para uso t?pico do mesmo. Duas amostras de ?leo fora obtidas por diferentes m?todos, sendo uma por extra??o a quente e outra utilizando solvente org?nico. As amostras foram fisioquimicamente caracterizadas por t?cnicas de titula??o e seus compostos identificados atrav?s de cromatografia gasosa acoplada a espectrometria de massas (GC/EM). O equil?brio hidrif?lico-lipof?lico requerido (EHLr) do ?leo de r?-touro foi determinado e em seguida um diagrama de fases constru?do. A estabilidade da emuls?o de uso t?pico contendo diferentes adjuvantes farmac?uticos foi determinada. A an?lise de citotoxicidade do ?leo de r?-touro in natura e na emuls?o de uso t?pico foi realizada atrav?s do ensaio de MTT, utilizando linhagem de fibroblastos normais (3T3) e de melanoma (B16F10). O rendimento da extra??o a quente foi de 60,6%. Os principais compostos insaturados encontrados foram o ?cido eicosapentaen?ico (17,6%) e ?cido araquid?nico (8,4%). O estudo de EHLr demonstrou a presen?a de sistemas est?veis com EHL entre 12 e 13,5 e o diagrama de fases revelou a predomin?ncia de sistemas caracterizados como emuls?o (62%). A emuls?o t?pica apresentou tamanho de got?cula igual a 390 nm, polidispers?o de 0,05, potencial zeta -25 mV e manteve-se est?vel durante os 90 dias avaliados. O ?leo de r?-touro e a emuls?o t?pica n?o apresentaram citotoxicidade frente ? linhagem de c?lulas 3T3. No entanto, estes sistemas inviabilizaram significativamente (p > 0,05) o crescimento das c?lulas B16F10. Em conclus?o, o ?leo de r?-touro apresenta caracter?sticas qu?micas desej?veis para o desenvolvimento de sistemas terap?uticos de uso farmac?utico e/ou cosm?tico. / The skin is one of the largest organs of the human body and accounts for about 16% of body weight. The body protection against the external environment microorganisms is one of its most important functions, however is necessary that the skin remain intact for this function be exercised, so that when there is an injury on the skin, the process of restructuring needs to be starts, however this restructuration may also be compromised due to some diseases, justifying even more the need for the development of topical products that promote or accelerate the skin healing. Thus the aim of this study was to extract bullfrog oil and to develop a suitable topical emulsion. Two different oil samples were extracted by hot or organic solvent process. Titration techniques and gas chromatography- mass spectrometry were used to characterize the bullfrog oil. The required hydrophile-lipophile balance (HLBr) of bullfrog oil was determined and a pseudo-ternary phase diagram was constructed. The stability of the topical emulsion was evaluated. Then, cellular viability was determined by MTT assay using normal fibroblasts (3T3) and melanoma (B16F10) cells lines. The hot extraction yield was 60.6%. The major polyunsaturated compounds found were Eicosapentaenoic acid (17.6%) and Arachidonic acid (8.4%). HLBr study demonstrated the presence of stable systems with HLB ranging from 12.1 to 13.5 and the pseudo-ternary phase diagram showed mainly emulsion systems (62%). Topical emulsion showed 390 nm, polydispersity 0.05, zeta potential -25 mV and remained stable for ninety days. The bullfrog oil and topical emulsion did not showed citotoxicity in normal fibroblasts cells. However, these systems showed significantly inhibition of melanoma cells growth. In conclusion, the bullfrog oil presented desirable chemical characteristics required to be used for the development of a pharmaceutical and cosmetic products.

AN ABSTRACT OF THE DISSERTATION OF GRETCHEN ELIZABETH PADGETT-FLOHR for the Doctor of Philosophy degree in Zoology, presented on March 5, 2009 at Southern Illinois University of Carbondale. TITLE: BATRACHOCHYTRIUM DENDROBATIDIS IN CENTRAL CALIFORNIA AMPHIBIANS MAJOR PROFESSOR: Eric Schauber Amphibian chytridiomycosis has been identified as a disease responsible for the decline and extinction of many amphibian taxa world wide, but little research has been conducted on the disease in Mediterranean climates. To address this gap in the data I studied the amphibian assemblage present across a ~6,475 ha site in central California and investigated the occurrence of the etiological agent, Batrachochytrium dendrobatidis (BD) from organismal, community, landscape and historical perspectives. I initially tested the accuracy and reliability of a proposed diagnostic screening test for BD in four larval species that occur on the site. The screening test proposed by Fellers et al. (2001) and Vredenburg and Summers (2001) consisted of examining larval amphibian mouthparts for abnormalities and or defects, based on their hypothesis that mouthpart defects are clinical signs of BD infection. Sensitivity and specificity of the diagnostic screening test were 76% and 58%, respectively, indicating that the proposed screening test was not a reliable diagnostic test for BD infection for the four species I examined. I conducted controlled laboratory experiments to examine the consequences of BD infection in the two threatened California species that occur on my study site: Rana draytonii and Ambystoma californiense. Both species were susceptible to infection, but all infected animals survived the 18-month study. Infected A. californiense sloughed skin at three times the rate of uninfected salamanders, a pattern that may have long-term energetic costs potentially leading to population-level consequences of sublethal infection by BD. I conducted a retrospective survey of the California Academy of Sciences' (San Francisco, California, USA) amphibian collection, testing for BD in four amphibian species collected from central California between 1897 and 2005 to assess whether the pathogen is novel versus endemic. The earliest detection of BD was in two Rana catesbeiana collected in 1961, and the data support the hypothesis that BD was a novel pathogen introduced into central California prior to 1961 that spread geographically and taxonomically from at least one point of introduction and is now endemic throughout most of central California. I analyzed how environmental factors, amphibian community composition, land use practices, and landscape structure affect the dynamics of the pathogen's distribution on my study site in central California. The distribution of BD in ponds within the landscape varied markedly between years and increases were associated with precipitation, mean minimum and maximum temperatures, and presence of particular species. Pseudacris regilla infection patterns were highly indicative of overall patterns of pond BD status. Fourteen ponds were identified as BD hotpots (BD-positive three of four years). Occurrences of the pathogen within the landscape were spatially autocorrelated and ponds in close proximity to BD hotspots were more likely to test positive. Local land use, (presence/absence of grazing or recreational activity and developed lands), apparently did not influence BD status of a pond. My studies show that BD was likely a novel pathogen introduced into California ca. 1961 that has since become established as an endemic pathogen throughout most of central California. The listed amphibian species that occur in central California can be infected with BD but appear to be resistant to manifesting amphibian chytridiomycosis, and the data from the studies herein could support one of two hypotheses: that natural selection acting over the past 48 years has selected for those individuals that were resistant to the disease; or that the species on my site have always been resistant to BD. The research I conducted further supports the hypothesis that BD is locally vectored by native amphibians (e.g. P. regilla) moving between ponds and that local ecological constraints likely limit vectoring of BD by non-native species. These findings contribute substantially to elucidating and understanding the responses of amphibian populations to disease/pathogen introduction and lay groundwork for future investigations into the host-pathogen-environment relationship as it relates to declining amphibian populations.