<p>The main aim of this work was to identify local adaptation processes in amphibian populations, thereby improving the general understanding of genetics and mechanisms behind the evolution and maintenance of biological diversity. Phenotypic and genetic variation in life-history traits was studied within and between populations common frog (<i>Rana temporaria</i>) populations along a 1600 km transect from southern Sweden to northern Finland.</p><p>Embryonic and larval development and growth was investigated both under field and laboratory conditions. The results suggest ample genetic diversity in larval life-history traits among Fennoscandian common frog populations. Larval developmental rate along the gradient has evolved a countergradient variation pattern of genotypes and phenotypes as indicated by the positive relationship between developmental rate and latitude under laboratory conditions and the lack of such a relationship in the field. The data suggest that this pattern has evolved because of time constraints due to decreasing length of growth season with latitude. Neither field-caught adults nor laboratory raised larvae displayed a linear latitudinal size cline as expected from the so called Bergmanns rule. Rather, size increased towards the mid-latitude populations and decreased thereafter, indicating that body size is a product of direct environmental induction or a trade-off with other life-history characters. Age and size at hatching showed no consistent latitudinal pattern, indicating that the embryonic stage is not as time constrained as the larval stage.</p><p>A large part of the variation in age and size at metamorphosis among populations was due to additive genetic effects. However, small, but significant maternal effects, mostly due to variation in egg size and non-additive genetic effects also contributed to among population variation. A comparison of divergence in presumably neutral molecular genetic markers (F_ST) and quantitative characters (Q_ST) revealed that although both estimates of divergence were relatively high, estimates of Q_ST was generally higher than those of F_ST, indicating that the genetic variation observed in larval traits is primarily a result of natural selection rather than genetic drift. Hence, our results reinforce the conclusion that intraspecific genetic heterogeneity in the young northern European ecosystems may be more widespread than previously anticipated</p>

During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. Although negative effects of UV-B radiation on development of many amphibian species have been demonstrated, a number of potentially critical issues around assessment of amphibian UV-B radiation tolerance have remained unexplored. For instance, next to nothing is known about geographic variation in UV-B tolerance and about possible carry-over effects of early UV-B exposure to later life-stages. Likewise, synergistic effects with other stressors, as well as sublethal effects on growth have received little attention. The results from field and laboratory experiments show that R. temporaria and R. arvalis are relatively tolerant to even high levels of UV-B in terms of embryonic survival. However, it was found that even normal levels of UV-B can reduce early embryonic growth. In addition, the effects of early exposure to UV-B became manifested mostly or only after a considerable time-lag (i.e. at metamorphosis). Furthermore, it was found that the sublethal effects of UV-B may become manifested only in combination with other stressors, such as low pH, and this synergism may differ among different populations. No evidence for genetic differentiation in UV-B tolerance was found. These findings suggest that even a relatively tolerant species, such as R. temporaria, may be sensitive to increased levels of UV-B radiation, but that this sensitivity may be highly population, environment and trait dependent. The observed carry-over effects over life-stages emphasise the importance of the early life environment on later life fitness.

The main aim of this work was to identify local adaptation processes in amphibian populations, thereby improving the general understanding of genetics and mechanisms behind the evolution and maintenance of biological diversity. Phenotypic and genetic variation in life-history traits was studied within and between populations common frog (Rana temporaria) populations along a 1600 km transect from southern Sweden to northern Finland. Embryonic and larval development and growth was investigated both under field and laboratory conditions. The results suggest ample genetic diversity in larval life-history traits among Fennoscandian common frog populations. Larval developmental rate along the gradient has evolved a countergradient variation pattern of genotypes and phenotypes as indicated by the positive relationship between developmental rate and latitude under laboratory conditions and the lack of such a relationship in the field. The data suggest that this pattern has evolved because of time constraints due to decreasing length of growth season with latitude. Neither field-caught adults nor laboratory raised larvae displayed a linear latitudinal size cline as expected from the so called Bergmanns rule. Rather, size increased towards the mid-latitude populations and decreased thereafter, indicating that body size is a product of direct environmental induction or a trade-off with other life-history characters. Age and size at hatching showed no consistent latitudinal pattern, indicating that the embryonic stage is not as time constrained as the larval stage. A large part of the variation in age and size at metamorphosis among populations was due to additive genetic effects. However, small, but significant maternal effects, mostly due to variation in egg size and non-additive genetic effects also contributed to among population variation. A comparison of divergence in presumably neutral molecular genetic markers (FST) and quantitative characters (QST) revealed that although both estimates of divergence were relatively high, estimates of QST was generally higher than those of FST, indicating that the genetic variation observed in larval traits is primarily a result of natural selection rather than genetic drift. Hence, our results reinforce the conclusion that intraspecific genetic heterogeneity in the young northern European ecosystems may be more widespread than previously anticipated

Amphibians develop in aquatic environments where they are very susceptible to the effects of pesticides and other environmental contaminants. Glyphosate-based herbicides are widely used and have been shown to affect survival and development of tadpoles under laboratory conditions. The goal my thesis is to determine if agriculturally relevant exposure to Roundup WeatherMax®, a herbicide formulation containing the potassium salt of glyphosate and an undisclosed surfactant, influences the survival and development of wood frogs tadpoles (Lithobates sylvaticus) under both laboratory and field conditions. In the field, experimental wetlands were divided in half using an impermeable curtain so that each wetland contained a treatment and control side. Tadpoles were exposed to two pulses of this herbicide at environmentally realistic concentration (ERC, 0.21 mg acid equivalent (a.e.)/L) and predicted environmental concentrations (PEC, 2.89 mg a.e./L), after which survival, growth, development, and expression of genes involved in metamorphosis were measured. Results indicate that exposure to the PEC is extremely toxic to tadpoles under laboratory conditions but not under field conditions. Results from both experimental conditions show sublethal effects on growth and development, and demonstrate that ERC of glyphosate-based herbicides have the potential to alter hormonal responses during metamorphosis. My secondary objectives were to compare the effects of Roundup WeatherMax® to the well-studied Vision® formulation (containing the isopropylamine (IPA) salt of glyphosate and POEA), and to determine which ingredient(s) are responsible for the sublethal effects on development. Survival, growth and gene expression results indicate that Roundup WeatherMax® has greater toxicity than Vision® formulation. Contrary to my prediction, results suggest that, under realistic exposure scenarios, POEA is not the sole ingredient responsible for the observed developmental effects. However, my results demonstrate that chronic exposure to the POEA surfactant at the PEC (1.43 mg/L) is extremely toxic to wood frog tadpoles in laboratory. As part of the Long-term Experimental Wetlands Area (LEWA) project, this research contributes to overall knowledge of the impacts of glyphosate-based herbicides on aquatic communities.

Uno de los principales factores que amenazan a los anfibios es la contaminación del medio por diferentes sustancias químicas, lo que hace necesario incrementar el conocimiento que se tiene del impacto de estos compuestos sobre los anfibios.En la presente Tesis Doctoral se estudió el impacto, en diferentes condiciones experimentales, del cloruro amónio, nitrito sódico y nitrato sódico, de manera aislada o combinada, sobre la rana común, Pelophylax perezi (Seoane, 1885). Además, se intentó proporcionar una visión general de los efectos de la contaminación sobre los anfibios mediante la realización de un meta-análisis.Los resultados obtenidos permiten concluir que la contaminación afectó negativamente a la supervivencia de los anfibios y a otros parámetros subletales. Sin embargo, la contaminación puede conducir la evolución de los anfibios. Finalmente, las condiciones experimentales demostraron tener una gran importancia a la hora de establecer el impacto de un agente estresante sobre los anfibios. / Chemical pollution is one of the major factors threatening amphibians, which makes necessary to perform further studies to assess its impact on amphibians.The present PhD thesis looks at the impact, in different experimental venues, of ammonium chloride, sodium nitrite and sodium nitrate, either isolated or combined, on the Iberian water frog, Pelophylax perezi (Seoane, 1885). Moreover, an overview of pollution effects on amphibianswas provided by conducting a meta-analysis.The results obtained allowed to conclude that pollution negatively affected amphibian survival, as well as other sublethal endpoints. Neverthelesss, pollution may drive the evolution in amphibians. Finally, experimental venues were revealed to show a great relevance when assessing the impact of a stressing factor on amphibians.

Man-made wetlands are often created to compensate for the loss or degradation of natural wetlands, but little is known about the processes taking place in these artificial environments, especially at the community level. Throughout this thesis, we have assessed the phenomena of primary succession over different time (short-, mid- and long-term) and spatial scales (local, regional, interregional levels), applying different approaches (taxonomic and functional) and subject groups (invertebrates and amphibians). Our main findings regarding time scales show a 3-phase successional pattern in Mediterranean man-made wetlands’ communities, where at the short term (1 year) colonization processes dominate; at mid term perspectives (2 to 7 years) succession signs begin to be conspicuous, and later on (≥ 10 years) parameters such as species richness reach an asymptote. At that moment, some biological strategies dominate, and biodiversity surrogates indicate that communities are indistinct between man-made and natural wetlands. Regarding spatial effects, we corroborated that both local and regional factors affect the establishing communities. Particularly, the low hydrological stability of the Mediterranean region has enhanced biological traits favoring resilience and resistance to disturbances when comparing Mediterranean and cold temperate aquatic communities. Even within the Mediterranean region, low levels of hydrological stability have significant effects on the successional dynamics. In these cases, local communities are highly nested within regional natural ones, and so are not able to make net contributions to regional richness. We also showed the influence of the regional pool of recruiters over local communities, both in the case of invertebrates and amphibians. Especially for the latter group, man-made Mediterranean temporary ponds (MTPs) can play an important role in their conservation. / Les zones humides de nova creació són sovint concebudes per compensar la pèrdua i degradació de les naturals, però el coneixement dels processos que tenen lloc en aquests ambients artificials encara és superficial, especialment a nivell de comunitat. Al llarg d’aquesta tesi, hem analitzat el fenomen de la successió primària a diferents escales temporals (a curt, mitjà i llarg termini) i a diferents escales espacials (a nivell local, regional i interregional), mitjançant diverses aproximacions (taxonòmiques i funcionals) i subjectes (invertebrats i amfibis). Les nostres aportacions pel que fa a les escales temporals mostren un patró de successió basat en 3 fases, on a curt termini (1 any) dominen els processos de colonització; en perspectives de mitjà termini (2 a 7 anys) els signes de successió comencen a ser conspicus, i més tard (≥ 10 anys) paràmetres com la riquesa d’espècies arriben a una asímptota. En aquesta fase avançada, algunes estratègies biològiques dominen, i els índexs de biodiversitat indiquen que les comunitats poden ser indistintes entre les llacunes naturals i les de nova creació. Pel que fa als efectes espacials, hem corroborat que tant factors locals com regionals afecten les comunitats que s’hi estableixen. En particular, la baixa estabilitat hidrològica de la regió Mediterrània ha afavorit trets biològics que proveeixen resiliència i resistència enfront de pertorbacions, sobretot quan es comparen amb les comunitats pròpies del clima temperat fred. Fins i tot dins la mateixa regió Mediterrània, nivells baixos d’estabilitat hidrològica poden tenir efectes importants en la dinàmica de la successió. En aquests casos, les comunitats locals estan altament aniuades en les naturals a nivell regional, i per tant difícilment poden fer contribucions netes a la riquesa regional. També hem mostrat la influència del pool regional de colonitzadors sobre les comunitats locals, tant en el cas dels invertebrats com en el dels amfibis. Especialment per aquest darrer grup, les Basses Temporànies Mediterrànies (BTMs) de nova creació poden jugar un paper important per a la seva conservació.

Disputats. Rheinische Friedrick-Wilhelms-Universität, 2000. / Haves kun i elektronisk udg.

Orientador: Itamar Alves Martins / Banca: Denise de Cerqueira Rossa Feres / Banca: Célio Fernando Baptista Haddad / Resumo: A Floresta Atlântica é o bioma com maior diversidade e taxa de endemismo de anfíbios anuros do mundo. Esse bioma consiste em sua maior parte de pequenos fragmentos isolados, ainda sob intensa pressão antrópica, colocando em risco a sua biodiversidade. Os anfíbios são especialmente susceptíveis à degradação ambiental devido a sua fisiologia ectotérmica, a pele permeável, a sua vulnerabilidade a diversos agentes biológicos ou químicos e por apresentarem ovos e larvas dependentes da água ou de ambiente úmidos. Tais características fazem destes animais bons modelos para o estudo de questões relacionadas à modificação de hábitats, sejam elas relativas à identificação de padrões ou inferência sobre processos associados à fragmentação ou perda do hábitat original, ou mesmo ocupação e colonização em áreas alteradas. Dentro deste contexto, este trabalho teve como objetivos principais, (1) determinar a diversidade e a estrutura de uma comunidade de anfíbios anuros e (2) investigar a possível influência do tipo de formação vegetal na composição da anurofauna terrestre, em uma região de domínio Atlântico, localizada na Serra da Mantiqueira entre os Municípios de Piquete, SP, e Marmelópolis, MG00; (22°29'37,9" a 22°31'15,7" S e 45°08'57,8" a 45°09'35,4" W; 1500 a 1640m). A partir do inventário mensal das espécies em campo durante 23 meses consecutivos para o primeiro objetivo e por 12 meses consecutivos para o segundo, utilizando-se dos métodos de procura visual e auditiva e de armadilhas de interceptação e queda, foram determinadas a abundância, a riqueza e as distribuições espaciais e temporais de anuros em diferentes áreas: mata secundária tardia, mata de araucária, plantações de Eucalyptus sp, riachos, poças permanentes e temporárias em área aberta e interior de floresta e brejos de borda de mata e de área aberta... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Atlantic Forest is the biome with the highest diversity and rate of endemism for anuran amphibians in the world. This biome currently consists mostly of isolated small forest remnants under high anthropogenic pressure, threatening its biodiversity. Amphibians are especially susceptible to environmental degradation due to their physiology, permeable skin, and their vulnerability to several biological or chemicals agents and for having eggs and larvae that depend on water or humid environments to complete their development. These features make them useful models to study the effects of hábitat change, e.g., the identification of patterns and processes associated with fragmentation or hábitat loss, or even the occupation and colonization in disturbed areas. Within this context, the main aims of this study are: (1) to determine the diversity and the structure of an anuran community and (2) to investigate the influence of vegetation type on the composition of leaf litter frogs in an Atlantic Forest area, located in the Mantiqueira mountain range between Piquete, state of São Paulo and Marmelópolis, state of Minas Gerais (22° 29' 37.9" S; 45° 08' 57.8" W and 22° 31' 15.7" S; 45° 09' 35.4" W, 1500 to 1640 m a.s.l.). I conducted 23 monthly samplings using visual and acoustical survey techniques and 12 monthly samplings using pitfall traps to estimate the abundance and richness and to determine the spatial and temporal distributions of anurans in several areas: late secondary forest, Araucaria forest, Eucalyptus woodlots, streams, permanent and temporary ponds in open and forested areas, and swamps at the forest edge and open areas. I recorded 32 species, 15 of which using pitfall traps. The species richness and abundance were different in the hábitats sampled. The forest hábitats had the highest richness (n = 16) and abundance (n = 432). Litter depth was positively correlated... (Complete abstract click electronic access below) / Mestre

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A Mata Atlântica brasileira concentra uma das maiores diversidades biológicas da Terra com cerca de 7% das espécies animais e vegetais do planeta. Esse bioma abriga atualmente mais de 50% das espécies de anuros do Brasil (c.a. 500 espécies), mas sofre intensa perda e fragmentação de habitat. Um dos principais fragmentos da Mata Atlântica, a Reserva Ecológica de Guapiaçu (REGUA) abriga vasta anurofauna, com cerca de 71 espécies já descritas. Acredita-se, porém, que muitas ainda precisam ser identificadas e estudadas. A identificação de espécies baseada em caracteres moleculares vem se mostrando uma alternativa para dar suporte à identificação morfológica, e dentro deste contexto os genes de DNA mitocondrial, como o 16S, são utilizados para a realização de barcode. O objetivo deste estudo foi testar a metodologia de identificação molecular de espécies (DNA barcode) na comunidade de anfíbios anuros da REGUA utilizando o gene mitocondrial 16S. Para isso, foram coletados tecidos de 99 indivíduos, entre adultos e girinos de 23 espécies, agrupados em seis famílias distintas. Desses 99 indivíduos, 88 foram amplificados corretamente para o gene em referência e foram realizadas, com sucesso, a determinação de espécies de 84 anuros (95,45%) da REGUA. As espécies de Scinax albicans, Scinax flavoguttatus e Hylodes charadranaetes, cujas identificações haviam sido determinadas com base em critérios morfológicos, agruparam em clados de mesmo gênero, porém de espécies diferentes quando analisadas pelas metodologias neighbor-joining e maximum-likelihood. Além de altos valores de distância intraespecífica (2,18%, 3,49% e 3,77%, respectivamente) e distâncias interespecíficas nulas (0%) temos a indicação de possíveis equívocos em determinações de espécies feitas exclusivamente por critérios morfológicos. Nesse caso, as discordâncias morfológica e molecular são exclusivamente de girinos, demonstrando a dificuldade na identificação morfológica e a escassez de chaves de identificação dessas espécies em estágio larval. Os resultados mostram que o gene mitocondrial 16S teve seu uso na identificação de anuros da REGUA confirmada e apontam que, em casos de estudos com indivíduos em estágios larvais, como em girinos, a metodologia de barcode, quando complementada a identificação morfológica, suporta a correta identificação das espécies de anfíbios anuros. / The Brazilian Atlantic Forest focuses one of the greatest biological diversity of the Earth with about 7% of the planet's animal and plant species. This biome is currently home to more than 50% of anurans species from Brazil (c.a. 500 species), but it suffers severe loss and fragmentation of habitat. One of the main fragments of the Atlantic Forest, the Reserva Ecológica de Guapiaçu (REGUA) houses a wide anuran fauna, with about 71 species had already described. It is believed, however, that lots of them still need to be identified and studied. The identification of these species based on molecular characters has proven to be an alternative to support a morphological identification, and in this context the mitochondrial DNA genes, such as 16S are used to perform barcode. The goal of this study was to test the methodology for molecular identification (DNA barcode) in anurans of REGUA community using 16S mitochondrial gene. For this, tissues of 99 individuals, including adults and tadpoles of 23 species, grouped into six different families were collected. Of these 99 individuals, 88 were amplified correctly to the reference gene and were successful determination of 84 species of anurans (95.45%) of the REGUA. Scinax albicans, Scinax flavoguttatus and Hylodes charadranaetes species whose identifications had been determined based on morphological criteria, grouped into clades of the same gender, but different species when analyzed by methodologies neighbor-joining and maximum-likelihood. In addition to high intraspecific distances (2,18%, 3,49% and 3,77% respectively) and interspecific distances to nil (0%), we have an indication of possible mistakes of species determinations made by a morphological criterion. In this case, the morphological and molecular disagreements are exclusively on tadpoles, demonstrating the difficulty of morphological identification and the shortage of identification of these species larval stage. The results show that the 16S mitochondrial gene had its use in identifying the anurans REGUA confirmed and indicate that the case studies with individuals in larval stages, as in tadpoles , the methodology of the barcode when complemented morphological identification, supports the correct identification of species of anurans amphibians .

Made available in DSpace on 2014-06-11T19:22:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-29Bitstream added on 2014-06-13T19:08:31Z : No. of bitstreams: 1 provete_db_me_sjrp.pdf: 1175451 bytes, checksum: 67537c8f0f07b7c8a68bfe408c754c71 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Girinos são um importante componente de ecossistemas de água doce e, ao longo dos últimos trinta anos, vêm sendo utilizados como modelos para testar hipóteses em ecologia de comunidades. O conjunto de informações disponível atualmente sugere que a presença de predadores influencia a abundância e o uso de hábitat por girinos e, conseqüentemente, a estrutura da comunidade. O objetivo deste estudo foi determinar o uso de recursos e investigar a influência de predadores na distribuição espacial de espécies e na estrutura de comunidades de girinos. As principais questões deste estudo foram: 1) qual o papel dos fatores abióticos na estruturação de comunidades de girinos?; 2) qual o grau de sobreposição de nicho entre as espécies nos três principais eixos de recursos: tempo (ocorrência sazonal), alimento e espaço (hábitat)?; 3) os girinos apresentam um padrão de distribuição não-aleatório em relação aos predadores? As amostragens tiveram freqüência mensal com coletas simultâneas de girinos e insetos predadores. Na caracterização dos corpos d’água foram utilizados dez descritores ambientais. Para determinar as guildas de espécies com relação ao uso de hábitat e ocorrência mensal foi implementada, respectivamente, uma análise de agrupamento e de ordenação por escalonamentro multidimensional não métrico. Para investigar a associação entre a abundância de girinos e os gradientes ambientais foi usada uma análise de correspondência canônica. A partilha de recursos entre girinos foi analisada utilizando-se uma análise de sobreposição de nicho em conjunto com um modelo nulo, considerando como eixos de recursos a ocorrência mensal, ocorrência nas poças e os itens alimentares. A análise da co-ocorrência pareada de girinos e predadores foi efetuada utilizando-se... / Tadpoles are an important component of freshwater ecossystems and in the last thirty years has been used as model organisms to test hypothesis in community ecology. The data currently available suggest that the presence of predators influences the abundance and habitat use by tadpoles and, consequently the community structure. The aims of this study were to establish how tadpoles divide resources and to investigate the influence of predators on species distribution and on community structure of tadpoles. The main questions were: 1) What is the role of abiotic factors in the community structure?; 2) What is the extent of niche overlap among species, considering the three main resource axes: time (seasonal occurrence), diet items and space (macrohabitat)?; 3) Tadpoles exhibit a non-random distribution pattern in relation to predaceous insects? We conducted monthly samplings to collect tadpoles and predaceous insects. We also used 10 environmental descriptors to characterize the water bodies. To recognize species guilds in relation to habitat use and monthly occurrence, we employed respectively a cluster analysis and a n-MDS, respectively. To investigate the association between species abundance and environmental gradients we used a canonical correspondence analysis. The resource partitioning among tadpoles was analyzed using a null model, considering as recource axes monthly occurrence, pond occupancy and diet items. The pair-wise co-occurrence analysis between tadpoles and predaceous insects was carried out using a null model. Our main findings demonstrate that forest canopy cover and pond hydroperiod were the main factors influencing species abundance along water bodies sampled. There was a species sorting along these two environmental gradients, with species restricted to both ends of these continuums. There was a high overlap in seasonal occurence... (Complete abstract click electronic access below)