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The Amistad Reservoir in southern Val Verde County, Texas will impound a considerable amount of surface water in a semi-arid region in which natural surface water is scarce. Construction of the dam began in 1963 and the reservoir began to fill in the summer of 1968. This large impoundment could have a considerable ecological impact on the area. The purpose of this research was to study the ecological distribution and zoogeographic affinities of the herpetofauna and to establish an ecological baseline against which any future changes could be measured.

Desde o início a ecofisiologia tenta entender como o comportamento dos animais tampona os desafios ambientais. Anfíbios perdem água através da pele em taxas elevadas e assumem riscos quando buscam por água. Testamos se cinco espécies de anfíbios arborícolas diferem em na adoção de estratégias na busca de água e se diferenças interespecíficas na fisiologia e no comportamento se correlacionam com distribuição temporal e escolha microhabitat na atividade reprodutiva. Estratégias de busca de água foram classificadas como direta ou energética errática de acordo com a atividade de busca de água dos indivíduos em um labirinto. Foram registradas, também, a atividade reprodutiva dos machos durante um ano e sua associação com condições microambientais e de distribuição temporal relacionadas com a disponibilidade de água em um mesmo charco. Observamos grandes diferenças interespecíficas na atividade de busca de água. As espécies do gênero Hypsiboas demonstraram uma clara tendência para a estratégia direta, levando mais tempo para encontrar a fonte de água, em contraposição foram mais precisas. A estratégia das espécies do gênero Scinax foi classificada como energética errática, pois costumavam encontrar a fonte de água mais rápido por meio de uma busca ativa e errática. A espécie Hypsiboas bandeirantes, no entanto, tem um comportamento generalista, exibindo ambas as estratégias. A análise discriminante indicou que a estratégia tinha maior poder discriminativo quando associado à distribuição temporal da atividade reprodutiva (96.24% de classificação correta, 100% de confiabilidade na validação cruzada), sendo que espécies tímidas são mais dependentes da temporada de chuva. Dentro de variáveis de microhábitat, a estratégia energética errática poderia ser diferenciadas por ocupar microhabitats com maior umidade relativa. Estes resultados sugerem que, embora as espécies de estratégia direta concentrem sua atividade no pico da estação chuvosa, elas são independentes das condições do microambiente. Por outro lado, espécies energéticas erráticas se reproduzem quando a umidade relativa é muito alta, independente da temporada. A variação interespecífica na variável fisiológica de resistência da pele à perda de água (RPA) também pode ser discriminada com base na distribuição temporal (89.4% de classificação correta, 94.5% de confiabilidade na validação cruzada). Os valores mais baixos de RPA (H. albopunctatus < S. crospedospilus < S. hayii) são diretamente proporcionais à dependência a estação chuvosa e parece refletir tanto a adaptação à disponibilidade de água no ambiente quanto a herança filogenética, particularmente em espécies caracterizadas por baixo RPAE que tende a vocalizar em períodos de alta disponibilidade de água. Testes em mais espécies serão necessários para confirmar esses padrões / A longstading question in ecophysiology is how behavior buffers environmental challenges in animals. Amphibians loose water at high rates through skin and assume risks when searching for water. We tested if five species of treefrogs differ in water search strategy and whether differences in physiology and in behavior would correlate with temporal distribution and microhabitat choice for reproductive activity. We classified strategies as direct or energetic erratic according to individuals\' activity finding water in a maze. Temporal distribution and microenvironmental conditions related to water availability were recorded associated to males reproductive activity during a year in a same pond. We observed high interspecific differences in treefrogs activity in search for water. Species from genus Hypsiboas demonstrated a clear trend towards direct strategy, taking longer to find water source but being more accurate. Species from Scinax genus were energetic erratic, finding water source sooner by an erratic-active search. Hypsibos bandeirantes, however, had a generalist behavior, exhibiting both strategies. Discriminant analysis indicated that water search strategies had higher discriminative power when associated to temporal distribution of reproductive activity (96.24% correct classification, 100% cross-validated results), with higher dependence of species from direct search strategy to wet season. Within microhabitat variables, energetic erratic strategies could be differentiated by occupying microhabitats with higher humidity. These results suggest that while species with the direct strategy concentrate activity at the wet season peak regardless of microenvironment conditions, energetic erratic species opportunistically call when UR% is very high, independent of the season. Interspecific variation in the physiological variable, the skin resistance to water loss (RWL), can also be discriminated on the basis on temporal distribution (89.4% correct classification, 94.5%. cross-validated results). The lower RWL values (H. albopunctatus < S. crospedospilus < S. hayii) are directly proportional to their dependence to wet season and seems to reflect both adaptation to environmental water availability and phylogenetic inheritance, particularly with species characterized by low RWL tending to call at periods of high water availability. Tests on more species are necessary to confirm this pattern

Ranavirus infection has caused severe disease and mass mortality in UK common frogs for more than twenty years resulting in serious declines in some populations. The pathogen has been studied since 1992. These studies generated two valuable resources exploited in this thesis: an archive of tissues and virus isolates and a database of reports from citizen scientists on ranavirus-consistent mortality. The previous studies yielded modest evidence suggesting that introductions from North America initiated ranavirus emergence in the UK, though little else was known about the pattern of introduction or spread. This thesis conducts a more detailed investigation, extending existing knowledge of ranavirus diversity and spread through molecular epidemiology and phylogenetics, an in vivo infection experiment, and in silico models. Non-lethal sampling protocols for ranavirus screening were assessed in a controlled setting and shown to be as effective as traditional protocols. The database of citizen science reports was utilised in spatio-temporal models of the spread of ranavirus disease, finding that ranavirus infection is spreading by transmission between ponds but that new outbreaks are also correlated with both human population density and regional temperatures. The first whole genome sequence from a UK ranavirus is presented. Analysis of the genome shows that it is an isolate of the ranavirus type species, FV3, on the basis of its near identical genome arrangement and a ‘supergene’ phylogenetic analysis. An unexpected finding was evidence for recent lateral transfer of host DNA into the FV3 genome. A candidate gene survey of European ranaviruses revealed considerable diversity that may explain the variation in virulence and host range in Spain. Two proposed new species of Ranavirus are described there - one highly virulent, the other seemingly asymptomatic – and the previously described CMTV is shown to be a likely cause of catastrophic decline across multiple hosts. A lack of monophyly among Spanish ranaviruses and the spatial pattern of incidence suggest recent introduction(s). Together, the evidence presented in this thesis underlines the key role that humans have played in the spread of this group of virulent wildlife pathogens in two European countries.

The skin is the largest organ of the body and provides many functions. Among tetrapod vertebrates, amphibian skin is semi-permeable and responsible for a greater proportion of water absorption and gas exchange. Myriad factors affect the physiological performance of amphibian skin. Morphological traits linked with amphibian skin physiology or ecology have remained difficult to discern because of a lack of quantitative comparative research and the discovery of sources of intraspecific variation that are mostly ignored in study designs. This thesis aims to address the effects of these sources of variation using a trait that is known to vary between sexes, among seasons, and among body regions and thought to be linked with physiology or ecology, skin thickness. The first source of variation addressed is sexual dimorphism. Specimens of the white-lipped treefrog, Litoria infrafrenata, that display sexual dimorphism in body size and skin thickness were used to test if body size was the main determinate of sexually dimorphic skin thickness. Size corrected values did not significantly differ between males and females, although the sample size was small. Seasonal variation in skin thickness has also been documented in some species, so the American bullfrog (Lithobates catesbeianus), the Northern leopard frog (L. pipiens), and the spring peeper (Pseudacris crucifer) from multiple months of the year were sampled to determine if skin thickness increased in the autumn or winter months. Seasonal skin thickening was only detected in L. catesbeianus, and skin from autumn and winter was significantly thicker than from earlier in the year. This pattern was also detectable in museum specimens collected 80 years ago, although the signal was damped, possibly due to preservation. Using a dataset of 10 species and published data, a general pattern was uncovered whereby the dorsal skin is the thickest region and the ventral thigh region is the thinnest. However, this pattern is not always true for every individual of every species (L. pipiens and P. crucifer) and in some species the dorsal skin is thinnest (Bokermannohyla alvarengai and Litoria infrafrenata). The same dataset found that skin thickness is significantly related to body size, as was found in the chapter on Litoria infrafrenata. Summer specimens of Lithobates catesbeianus were outliers below the interspecific regression line and winter specimens fell within the range of variation of other species, hinting that seasonal skin thickening could be renamed seasonal skin thinning in this species. Finally, a link between ecology and skin thickness was tested using the 10 species from previous analyses and data from the literature. At a phylogenetially broad scale, body size explained a greater amount of the variation in environmental parameters than skin thickness. At smaller taxonomic scales, skin thickness appears more closely linked with ecology. It is concluded that amphibians generally follow an allometric trend for skin thickness and when faced with suboptimal conditions over long periods of time, evolve integumentary structures like iridiophores to compensate for any physiological disadvantage of an ‘ideal’ skin thickness. In the interim, however, skin thickness may change, thus sacrificing e.g. mechanical support.

Made available in DSpace on 2014-06-11T19:30:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-21Bitstream added on 2014-06-13T19:01:03Z : No. of bitstreams: 1 campos_jrc_dr_rcla.pdf: 3693126 bytes, checksum: 956bd343abe9698615af7508045133b0 (MD5) / Até recentemente, a família Leptodactylidae era considerada polifilética, mas nenhum dos trabalhos realizados antes de 2006 resolveu essa polifilia. Nesse ano, quase que simultaneamente, duas grandes revisões foram publicadas, com base principalmente em sequenciamento gênico e sem considerar dados citogenéticos, resultando em filogenias que mudaram radicalmente a taxonomia e a sistemática de muitos grupos de anuros. Leptodactylidae foi uma das famílias que passou por grandes transformações, sendo os gêneros reduzidos de 57 para apenas quatro. Na presente Tese, foram analisados os cariótipos de nove espécies do gênero Leptodactylus e 19 representantes de famílias relacionadas à Leptodactylidae, cujos dados são apresentados em três partes. No primeiro capítulo são apresentados cariótipos com 2n=20, nos exemplares de Vitreorana eurygnatha e V. uranoscopa (Centrolenidae); 2n=22, em Adelophryne baturitensis (Eleutherodactylidae), Brachycephalus ephippium, Ischnocnema guentheri, I. manezinho e I. parva (Brachycephalidae), Leptodactylus furnarius, L. fuscus, L. latrans, L. mystaceus, L. podicipinus e L. syphax (Leptodactylidae), Odontophrynus americanus (Cycloramphidae), Physalaemus barrioi, P. cuvieri e P. moreirae (Leiuperidae); e 2n=26 para Cycloramphus boraceiensis, C. brasiliensis, C. ryakonastes, Thoropa miliaris e Zachaenus parvulus (Cycloramphidae), Flectonotus sp. e Gastrotheca microdiscus (Hemiphractidae). São também descritos o padrão de Ag-RON e bandamento C para a grande maioria das espécies. Os dados cromossômicos aqui obtidos, juntamente com os disponíveis na literatura, foram avaliados à luz das árvores filogenéticas atuais, tendo sido observada grande concordância com as alterações propostas. O segundo capítulo trata dos cariótipos de três espécies de Leptodactylus que pertenciam ao gênero Adenomera, com 2n=24 em L. cf. marmoratus, 2n=23... / Until recently, the family Leptodactylidae was considered polyphyletic, but no paper published before 2006 clarify this question. In that year two extensive revisions were published, almost simultaneously, based mainly on gene sequencing with no contribution of cytogenetic data. These studies resulted in phylogenetic trees which have radically changed the taxonomy and systematic of several groups of frogs. Leptodactylidae was one of the families that suffered great modifications, and the number of genus was reduced from 57 to only 4. In this work, the karyotypes of 9 species of Leptodactylus and representatives of 19 families related to Leptodactylidae were analyzed, and the data are presented in three parts. The first chapter describes the karyotypes with 2n=20, in species of Vitreorana eurygnatha and V. uranoscopa (Centrolenidae); 2n=22 in Adelophryne baturitensis (Eleutherodactylidae), Brachycephalus ephippium, Ischnocnema guentheri, I. manezinho and I. parva (Brachycephalidae), Leptodactylus furnarius, L. fuscus, L. latrans, L. mystaceus, L. podicipinus and L. syphax (Leptodactylidae), Odontophrynus americanus (Cycloramphidae), Physalaemus barrioi, P. cuvieri and P. moreirae (Leiuperidae); and 2n=26 in Cycloramphus boraceiensis, C. brasiliensis, C. ryakonastes, Thoropa miliaris and Zachaenus parvulus (Cycloramphidae) Flectonotus sp. and Gastrotheca microdiscus (Hemiphractidae). The C band and Ag- RON patterns are described for the majority of the species. The chromosomal data obtained here, along with those available in the literature, were analyzed in the light of the current phylogenetic trees, and are in accordance to the proposed modifications. The second chapter reports the karyotypes of three Leptodactylus species belonging to the former genus Adenomera, with 2n=24 in L. cf. marmoratus, 2n=23 in Leptodactylus sp. (aff bokermanni), and 2n=26 in L. hylaedactylus, bearing different... (Complete abstract click electronic access below)

Desde o início a ecofisiologia tenta entender como o comportamento dos animais tampona os desafios ambientais. Anfíbios perdem água através da pele em taxas elevadas e assumem riscos quando buscam por água. Testamos se cinco espécies de anfíbios arborícolas diferem em na adoção de estratégias na busca de água e se diferenças interespecíficas na fisiologia e no comportamento se correlacionam com distribuição temporal e escolha microhabitat na atividade reprodutiva. Estratégias de busca de água foram classificadas como direta ou energética errática de acordo com a atividade de busca de água dos indivíduos em um labirinto. Foram registradas, também, a atividade reprodutiva dos machos durante um ano e sua associação com condições microambientais e de distribuição temporal relacionadas com a disponibilidade de água em um mesmo charco. Observamos grandes diferenças interespecíficas na atividade de busca de água. As espécies do gênero Hypsiboas demonstraram uma clara tendência para a estratégia direta, levando mais tempo para encontrar a fonte de água, em contraposição foram mais precisas. A estratégia das espécies do gênero Scinax foi classificada como energética errática, pois costumavam encontrar a fonte de água mais rápido por meio de uma busca ativa e errática. A espécie Hypsiboas bandeirantes, no entanto, tem um comportamento generalista, exibindo ambas as estratégias. A análise discriminante indicou que a estratégia tinha maior poder discriminativo quando associado à distribuição temporal da atividade reprodutiva (96.24% de classificação correta, 100% de confiabilidade na validação cruzada), sendo que espécies tímidas são mais dependentes da temporada de chuva. Dentro de variáveis de microhábitat, a estratégia energética errática poderia ser diferenciadas por ocupar microhabitats com maior umidade relativa. Estes resultados sugerem que, embora as espécies de estratégia direta concentrem sua atividade no pico da estação chuvosa, elas são independentes das condições do microambiente. Por outro lado, espécies energéticas erráticas se reproduzem quando a umidade relativa é muito alta, independente da temporada. A variação interespecífica na variável fisiológica de resistência da pele à perda de água (RPA) também pode ser discriminada com base na distribuição temporal (89.4% de classificação correta, 94.5% de confiabilidade na validação cruzada). Os valores mais baixos de RPA (H. albopunctatus < S. crospedospilus < S. hayii) são diretamente proporcionais à dependência a estação chuvosa e parece refletir tanto a adaptação à disponibilidade de água no ambiente quanto a herança filogenética, particularmente em espécies caracterizadas por baixo RPAE que tende a vocalizar em períodos de alta disponibilidade de água. Testes em mais espécies serão necessários para confirmar esses padrões / A longstading question in ecophysiology is how behavior buffers environmental challenges in animals. Amphibians loose water at high rates through skin and assume risks when searching for water. We tested if five species of treefrogs differ in water search strategy and whether differences in physiology and in behavior would correlate with temporal distribution and microhabitat choice for reproductive activity. We classified strategies as direct or energetic erratic according to individuals\' activity finding water in a maze. Temporal distribution and microenvironmental conditions related to water availability were recorded associated to males reproductive activity during a year in a same pond. We observed high interspecific differences in treefrogs activity in search for water. Species from genus Hypsiboas demonstrated a clear trend towards direct strategy, taking longer to find water source but being more accurate. Species from Scinax genus were energetic erratic, finding water source sooner by an erratic-active search. Hypsibos bandeirantes, however, had a generalist behavior, exhibiting both strategies. Discriminant analysis indicated that water search strategies had higher discriminative power when associated to temporal distribution of reproductive activity (96.24% correct classification, 100% cross-validated results), with higher dependence of species from direct search strategy to wet season. Within microhabitat variables, energetic erratic strategies could be differentiated by occupying microhabitats with higher humidity. These results suggest that while species with the direct strategy concentrate activity at the wet season peak regardless of microenvironment conditions, energetic erratic species opportunistically call when UR% is very high, independent of the season. Interspecific variation in the physiological variable, the skin resistance to water loss (RWL), can also be discriminated on the basis on temporal distribution (89.4% correct classification, 94.5%. cross-validated results). The lower RWL values (H. albopunctatus < S. crospedospilus < S. hayii) are directly proportional to their dependence to wet season and seems to reflect both adaptation to environmental water availability and phylogenetic inheritance, particularly with species characterized by low RWL tending to call at periods of high water availability. Tests on more species are necessary to confirm this pattern

Bibliography: v. 1, leaves 277-300 / 2 v. : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1987

Currently there are three companies producing bitumen from the Athabasca Oil Sands Region located near Fort McMurray, Alberta, Canada. Extraction of bitumen produces solid (sand) and liquid (water with suspended fine particles) tailings material, called oil sands process affected-materials (OSPM). These waste materials are stored on site due to a zero discharge policy and must be reclaimed when operations end. The OSPM is known to contain naphthenic acids (NAs) and polycyclic aromatic hydrocarbons (PAHs) and has high pH and salinity. A possible method of reclamation is the wet landscape approach, which involves using OSPM to form wetlands that would mimic natural wetland ecological functioning. This study investigated the effects of wetlands formed with OSPM on wood frog larvae (<i>Rana sylvatica</i>), using endpoints including survival, growth, time to metamorphosis, hormonal status, and detoxification enzyme induction [ethoxyresorufin-o-dealkylase (EROD) activity].<p> <i>In-situ</i> caging studies were completed in 2006 and 2007. Four wetlands were studied in 2006 and 14 wetlands were studied in 2007. The 2006 season saw a host of problems that were resolved for the 2007 season. In 2006, tadpole survival did not differ among reference wetlands and old OSPM-affected wetlands but there was 100% mortality of tadpoles in the young OSPM-affected sites that contain the highest concentration of toxic components. Results were similar in 2007, with tadpoles raised in young OSPM-affected wetlands having 41.5%, 62.6%, and 54.7% higher tadpole mortality than old OSPM-affected, young reference, and old reference wetlands, respectively. In 2007, tadpoles from young OSPM-affected sites had delayed metamorphosis (12 days longer than tadpoles from old reference wetlands and 18 days longer than tadpoles in old OSPM-affected wetlands). The thyroid hormone ratios of tadpoles in young OSPM-affected wetlands were between 25% and 42% lower than tadpoles in all other wetlands groups. The EROD activity of tadpoles in young OSPM-affected wetlands was an average 223% higher than those in old OSPM-affected wetlands, showing us that tadpoles were responding to higher levels of contaminants in young OSPM-affected wetlands. Size differences were only noted in 2007, most likely not as a result of exposure to OSPM, but due to differences in population density. The results of this study lead us to believe that toxicity due to OSPM decreases as wetlands get older and OSPM-affected wetlands could support native amphibian populations if they are allowed to mature. Since we considered wetlands to be old if they were seven years or older and the fact that old-OSPM wetlands showed effects on tadpoles similar to those of reference wetlands and showed much less toxicity than young OSPM-affected wetlands, we believe wetlands that are at least seven years old would sustain amphibian life.