In the southeastern United States, ephemeral wetlands in pine flatwoods provide important habitat for amphibians and aquatic invertebrates, but extensive deforestation has destroyed or isolated many wetlands and fire suppression has altered vegetation in others. My goals were to identify how wetland hydroperiods have changed through time and to examine the effects of long-term fire suppression on aquatic communities, including Reticulated Flatwoods Salamanders (Ambystoma bishopi) and Ornate Chorus Frogs (Pseudacris ornata). Chapter 1 used a modeling approach to relate wetland hydroperiods to current climate conditions and to hindcast historic conditions. Over the past 118 years, hydroperiods were often unfavorable for A. bishopi reproduction, and in recent years hydroperiods were shortened by persistent drought. Chapters 2 and 3 focused on identifying the effects of shifting from an open, grass dominated wetland to a wetland with high canopy cover and little herbaceous vegetation. In Chapter 2, I quantified amphibian and invertebrate communities in several wetlands. A. bishopi and P. ornata tended to occupy wetlands with lower canopy cover and higher herbaceous vegetation cover. Aquatic invertebrate abundance was generally higher in wetlands with lower shrub density and lower canopy cover. In Chapter 3, I examined how a reduction in herbaceous vegetation affected tadpoles when a predatory crayfish was present using two experiments. Crayfish were effective predators of both species across all vegetation treatments and often caused nonlethal tail injury. My results suggest that managers should focus on ensuring that wetland basins regularly burn, and wetlands with longer hydroperiods should be a management priority. / Master of Science

Amphibians harbor beneficial skin bacteria that can contribute to host defense against chytridiomycosis, an infectious disease caused by the lethal fungal pathogen Batrachochytrium dendrobatidis (Bd). However, while skin-associated microbial communities may alter host infection risk, the structure of these complex microbial communities can be impacted by both biotic and abiotic factors. In a series of three studies, I investigated the natural temporal and spatial variation in bacterial communities on the skin of wild and captive-born amphibians using 16S rRNA gene amplicon sequencing to characterize bacterial community diversity. First, in a study examining the skin bacterial communities of two sympatric treefrog species (Agalychnis callidryas and Dendropsophus ebraccatus) at a single pond over multiple seasons and years, I found that annual, seasonal, and even daily fluctuations in temperature and rainfall changed the skin bacterial communities on these species. Second, I further investigated the impact of seasonality and rainfall on amphibian skin bacterial communities with a study of the bacterial communities on Craugastor fitzingeri, a common terrestrial species, along a rainfall gradient, and five co-occurring amphibian species at a single site. The strong wet and dry seasonality in the tropical lowland forest impacted the bacterial communities of multiple stream-dwelling co-occurring species, but the nature of the changes differed among the frog species. For C. fitzingeri sampled along the rainfall gradient, I found there was variation in bacterial community structure among sites, although this was not correlated with the latitudinal rainfall gradient. Finally, I investigated the challenges faced by captive-reared Atelopus limosus, an endangered amphibian species, after soft-release into natural habitat with the use of mesocosms. I found that the skin bacterial communities reverted to wild-type fairly quickly, body condition decreased to come closer to wild conspecifics, and 15% of the frogs became infected with Bd during the 27 day trial in mesocosms. Overall, I found that skin bacterial communities of lowland amphibians change across time and space, that variation sometimes correlates with environmental conditions at the time and the site of sampling, and that skin bacterial communities on captive-born frogs revert to wild-frog's state soon after soft-release to natural habitat. / Doctor of Philosophy / Beneficial bacteria found on amphibian skin can provide protection against an infectious disease caused by the lethal amphibian chytrid fungus (Batrachochytrium dendrobatidis), that has been linked with the decline and extinction of amphibian species worldwide. However, while skin bacterial communities may play a key role in determining disease outcome, these complex microbial communities can be impacted by biological and environmental factors. In a series of three studies, I investigated the natural variation in skin bacterial communities on wild and captive-born amphibians through time and space using modern DNA sequencing technologies to characterize bacterial community diversity. First, in a study examining the skin bacterial communities of two treefrog species at a single pond over multiple years and seasons, I found that annual, seasonal, and even daily fluctuations in temperature and rainfall changed the skin bacterial communities on these species. Second, I further investigated the impact of seasonality and rainfall with a study sampling the skin of one common frog species along a rainfall gradient, and five amphibian species at a single site across seasons. The strong wet and dry seasonality in the tropical lowland forest impacted the bacterial communities of multiple species found near streams, but the nature of the changes differed among the different frogs. For the common species sampled along the rainfall gradient, I found there was variation in bacterial community structure among sites, although this was not correlated with the rainfall gradient. Finally, I investigated the challenges faced by captive-reared Atelopus limosus, an endangered amphibian species from Panama, after release into field enclosures in the natural habitat. I found that the skin bacterial communities reverted to wild-type fairly quickly, body mass decreased to come closer to wild frogs of the same species, and 15% of the frogs became infected with the chytrid fungus during the 27 day trial in the field enclosures. Overall, I found that skin bacterial communities of lowland amphibians change across time and space, that variation is sometimes linked with environmental conditions at the time and site of sampling, and that captive-born frogs revert to wild states soon after release to natural habitat.

Classified in the Lissamphibia, modern amphibians are the only non-amniote tetrapods living today. They consist of three morphologically distinct groups: the tailless frogs and toads (Anura), the limbless caecilians (Gymnophiona), and the tailed salamanders and newts (Urodela). With 205 species, the caecilians are highly specialized worm-like forms that live a fossorial lifestyle, with a relatively narrow distribution in the tropic rainforests of South America, Africa and Asia (Duellman and Trueb, 1994; Amphibiaweb, 2015). Salamanders, with 683 species, are widely distributed in the North America, Asia and Europe, with a few plethodontids extending to Central and South America (Duellman and Trueb, 1994; Amphibiaweb, 2015). Frogs are the most diverse amphibian groups, with 6644 species distributed over all continents except Antarctica (Duellman and Trueb, 1994; Amphibiaweb, 2015). Both frogs and salamanders develop a wide array of lifestyles, ranging from terrestrial, aquatic, fossorial to aboreal lifestyles (Duellman and Trueb, 1994). During ontogeny, amphibian larvae usually undergo a drastic post-embryonic shift into an adult form, a term known as metamorphosis. In salamanders, another developmental pathway – neoteny – also occurs, in which the larval morphology is retained in sexually mature adults (Duellman and Trueb, 1994; Rose, 2003). Because of the diverse lifestyles and developmental pathways, frogs and salamanders are often used as model systems in many fields of biology (e.g., evo-devo). Over a century, but especially in the past two decades, a wealth of frog and salamander fossils has been discovered from the Mesozoic and Cenozoic of East Asia (e.g., Noble, 1924; Young, 1936; Borsuk-Bialynicka, 1978; Gao, 1986; Dong and Wang, 1998; Gao and Shubin, 2001, 2003, 2012; Gao and Wang, 2001; Gao and Chen, 2004; Wang and Rose, 2005; Wang and Evans, 2006b; Zhang et al., 2009; Chen et al., 2016; this study). Some of these fossils represent the earliest members of many crown clades, including the earliest crown salamanders from the Middle Jurassic (~165 Ma, Gao and Shubin, 2003), the earliest salamandroid from the Late Jurassic, the earliest sirenid from the Late Jurassic (this study), and the earliest spadefoot toads from the late Paleocence (Chen et al., 2016). Other fossils also bear important anatomical, temporal and geographical information in understanding their evolution. Unfortunately, the importance of many of these fossils remains obscure in a phylogenetic context. For example, an early-middle Oligocene Mongolian spadefoot toad Macropelobates osborni (Noble, 1924) was discovered outside the current distribution of spadefoot toads, yet its phylogenetic position and its implication on spadefoot toad biogeography remain not well understood. A major reason for the poor understanding of these fossils can be attributed to a trend of dichotomy between morphological and molecular phylogenies on amphibians. Whereas morphologists and paleontologists sometimes use a relatively small morphological dataset to reconstruct relationships (e.g., Gao and Shubin, 2012; Henrici, 2013), large-scale phylogenies are almost always conducted with molecular data with only living taxa (e.g., Roelants and Bossuyt, 2005; Pyron and Wiens, 2011). Very few studies on amphibian phylogeny have combined morphological and molecular data together, and even fewer also combined fossils. Because of this, the positions of many important fossils remains unclear, and the evolutionary scenarios inferred from only living species can sometimes be inconsistent with fossil evidence. In this thesis, I adopt a total-evidence approach to understand the evolution of amphibians, especially frogs and salamanders. I will incorporate information from fossils, morphology and molecules together to reconstruct the relationships. Compared with studies with each individual datasets, this approach incorporates all available data in a single analysis, with a goal to reach robust and congruent results that allow further discussions on character evolution and biogeographic reconstruction. The inclusion of fossils directly into the combined analysis provides the time dimension that is independent from molecular data (Norell, 1992). The anatomical combination of fossils can represent intermediate forms that help to solve the “long branch” problems caused by highly specialized modern taxa. The morphological dataset, despite its much smaller size with molecular data, is the only link between fossils and modern taxa. The inclusion of key morphological characters in both reconstructing phylogenetic hypotheses and examining character evolution provide consistent results that allow discussion on the homology/homoplasy of a certain character without ambiguity. The molecular sequence data provides overwhelmingly large data on modern taxa for phylogenetic reconstructions compared with morphological data, which helps to reach a robust hypothesis. Although fossils contain no molecular data, the inclusion of molecular sequence data into the combined analysis does have an effect on the positions of fossil taxa. By altering the relationship “framework” of modern taxa, the character optimization of fossils and other taxa of a combined analysis also varies compared with results of morphology-only analysis, thus changing the positions of fossils. In the following five chapters, I will describe a number of fossil amphibian species, reconstruct three combined phylogenies, and use the results for discussions on character evolution and biogeography. In Chapter 1 and Chapter 2, I focus on a frog clade called spadefoot toads (Anura: Pelobatoidea). In Chapter 1, I provide descriptions on three important fossil spadefoot toads from the Cenozoic of East Asia and North America: Macropelobates osborni from the early-middle Oligocene of Mongolia, Prospea holoserisca from the latest Paleocene of Mongolia, and Scaphiopus skinneri from the middle Oligocene of the United States. In Chapter 2, I conduct a combined phylogenetic analysis of archaeobatrachian frogs, and discuss the evolution of the bony spade and the historical biogeography of spadefoot toads based on the results of the phylogeny. In Chapter 3, I describe a new fossil frog from the Early Cretaceous of Inner Mongolia, China. The unique morphology of the new fossil is distinct from previous Early Cretaceous frogs from the Jehol Biota of China. Results of the combined analysis show that the new frog represents a basal member of the Pipanura. Comparisons between the Early Cretaceous frogs from China, Spain and Brazil show a high diversity of species coupled with a high degree of endemism during the Early Cretaceous. I discuss in the phylogenetic context how early frogs gradually reach their postcranial body plan with a shortened vertebral column, loss of ribs, and specialized pelvic regions. In Chapter 4, I provide a brief review of Mesozoic fossil salamanders from northern China, and describe a new fossil from the Late Jurassic of Liaoning Province, China. I conduct a combined phylogeny of higher-level relationships of salamanders. The new fossil, despite its general-looking appearance, represents a basal member of the highly specialized eel-like neotenic family Sirenidae on the cladogram. I discuss character evolutions in the Sirenidae, and how the neotenic developmental pathway evolved in early salamanders. In Chapter 5, I conduct a combined phylogenetic analysis of the salamander suborder Cryptobranchoidea, consisting of the neotenic giant salamanders (Cryptobranchidae) and the metamorphic Asiatic salamanders (Hynobiidae). The new morphological matrix includes new characters that were previously less sampled in the hynobranchial region. The monophyly of the Hynobiidae are confirmed by the new analysis, and four unequivocal synapomorphies are found for the clade. An S-DIVA biogeographic reconstruction is conducted to disscuss the distributional patterns of the Hynobiidae.

No description available.

The purpose of the present study of the herpetofauna was to obtain additional information regarding the vertebrates of Denton County, and to produce a well-preserved, cataloged collection of the amphibians and reptiles for the Museum of Zoology, North Texas State University. An understanding of the vertebrate life of the county also involves an investigation of the habitats within the county that may, in part, count for the distribution of these animals. It is well recognized that the environmental areas of the county have altered vastly during the last one hundred years. This alteration is due largely to agriculture and industry. However, there are adequate numbers of natural environments, as well as newly created ones that may contribute to the distribution of the vertebrates at the present time. Therefore, the problem not only concerned the collection of specimens, but also the identification, abundance classification, general habitat classifications, and county distribution.

Many herpetofaunal species are imperiled, and the causes of this are often a synergy of multiple factors. In wetlands specifically, two of the possible determinants of species occurrence and faunal community assemblage are fish presence and wetland permanence, which are not always correlated. Twenty wetlands were sampled in Jonathan Dickinson State Park, Florida, USA to observe how wetland herpetofaunal communities vary with fish, wetland permanence and other environmental factors. Herpetofaunal communities with and without fish were significantly different from one another and differences between herpetofaunal communities were primarily due to the contribution of four species of frogs, two generalist ranids and two specialist hylids. Wetland permanence had no observable effect on community structure. Fishless wetlands were significantly more species-rich and possessed higher numbers of individuals even for species that occurred in both fishless and fish wetlands, regardless of their permanence. These findings have implications for wetlands restoration and herpetofaunal conservation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

No description available.

A major goal of evolutionary biology and ecology is to understand why species richness varies among clades. Previous studies have suggested that variation in richness among clades might be related to variation in rates of morphological evolution among clades (e.g., body size and shape). Other studies have suggested that richness patterns might be related to variation in rates of climatic-niche evolution. However, few studies, if any, have tested the relative importance of these variables in explaining patterns of richness among clades. Here, we test their relative importance among major clades of Plethodontidae, the most species-rich family of salamanders. Earlier studies have suggested that climatic-niche evolution explains patterns of diversification among plethodontid clades, whereas rates of morphological evolution do not. A subsequent study stated that rates of morphological evolution instead explained patterns of species richness among plethodontid clades (along with "ecological limits" on richness of clades, leading to saturation of clades with species, given limited resources). However, they did not consider climatic-niche evolution. Using phylogenetic multiple regression, we show that rates of climatic-niche evolution explain most variation in richness among plethodontid clades, whereas rates of morphological evolution do not. We find little evidence that ecological limits explain patterns of richness among plethodontid clades. We also test whether rates of morphological and climatic-niche evolution are correlated, and find that they are not. Overall, our results help explain richness patterns in a major amphibian group and provide possibly the first test of the relative importance of climatic niches and morphological evolution in explaining diversity patterns.

Orientador: Eduardo Alves de Almeida / Resumo: O Estado de São Paulo é responsável pela produção da metade da cana-de-açúcar no Brasil, e segue crescendo, sendo esse cultivo um dos principais responsáveis pelo desmatamento no interior do estado. A atual expansão da cana-de-açúcar está ocorrendo principalmente sob áreas de cultivos anuais e pastagens de pecuária extensiva. Embora possa parecer positivo, essa conversão de pastagens supõe um grande impacto sobre as poças de água construídas como bebedouros para o gado, as quais abrangem altas proporções de biodiversidade a sua vez. Nesse cenário, os anfíbios são especialmente vulneráveis, uma vez que a grande maioria das espécies de anuros, registrados no interior do estado, se reproduz nestas poças que estão sendo transformadas ou mesmo desaparecendo. Além disso, o cultivo intensivo de cana-de-açúcar exige o uso de agrotóxicos que devido as fortes precipitações sazonais provocam escoamento superficial a estes leitos aquáticos e sua subsequente contaminação por misturas complexas de pesticidas. Nesta dissertação de doutorado são apresentados os resultados de um estudo sobre os impactos ecológicos e ecotoxicológicos em girinos de diferentes espécies de anuros que habitam poças temporárias anexas aos cultivos de cana-de-açúcar. O estudo foi realizado na área agrícola circundante da cidade de São José do Rio Preto, uma das principais áreas de produção de cana-de-açúcar no noroeste paulista. A vegetação nativa dessa região tem sido continuamente desmatada desde o século XIX, e n... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: São Paulo state cultivates half of the sugarcane in Brazil, being this culture among the main responsible for deforestation in the inland of the state. Current expansion of sugarcane is taking place mostly over annual croplands and extensive cattle ranching pastures. Although it may seem positive, this pasture conversion supposes a major impact on cattle ponds which support high proportions of biodiversity. In this scenario, amphibian populations are especially vulnerable since the vast majority of the anurans registered in the inland of the state breed in cattle ponds which are been transformed or even disappearing. In addition, intensive sugarcane culture demands the usage of pesticides which can enter ponds when heavy precipitation events cause surface run-off. Consequently, complex mixtures of pesticides occur in ponds near to cultures. In this doctoral dissertation are presented the results of a study of the ecological and ecotoxicological impacts on tadpoles of anurans species inhabiting temporary breeding ponds annex to sugarcane cultures. The study was conducted in the surrounding sugarcane-dominated agricultural area of the city of São José do Rio Preto, which stands out as an appropriate place for the research purpose, since it is part of São José do Rio Preto macro region, in the northwestern of São Paulo state, one of the major sugarcane production areas in Brazil, its native vegetation has been intensely deforested since the 19th century, in the last decades has ... (Complete abstract click electronic access below) / Doutor

Range change is a common species response to global change. Comparing historical species distribution data with recent biological surveys has the potential to quantify changes to species geographic ranges. However, the broad-scale sampling strategies typically employed to acquire primary species distribution data are prone to errors of omission. The aim of this study was to evaluate the South African Frog Atlas Project (SAFAP) as a means for detecting changes in amphibian species distributions and to relate observed range changes to extrinsic environmental factors and intrinsic species characteristics. The SAFAP provided historical (1905 – 1995) and recent (1996 – 2003) species distributions of the amphibians of South Africa. Geographic sampling bias in the dataset was assessed by relating collection density and species richness to hypothesised sources of bias. Several methods for managing differing sampling intensity were tested on hypothetical ranges. The best methods were applied to the South African species to investigate range dynamics. Changes to the size of species ranges and shifts in mean range centre were assessed. An Ecological Niche Factor Analysis provided comparative measures of climate and habitat niche breadth for each species. SAFAP sampling was concentrated around cities, roads and protected areas, resulting in relatively overestimated species richness and range sizes near to these features. Large parts of the arid northwestern regions were under-sampled. An increase in sampling intensity over time resulted in the false detection of range expansions. The most reliable method to correct for increased sampling was a mathematical correction factor, according to which, 60.2% of South African frog species have undergone range contractions. Upslope shifts of 47.6 m were found for South African species and species of the Bushveld region shifted towards an area of Savanna Biome resilience. While several of the observed changes to species ranges were consistent with global change predictions, southern hemisphere amphibians may show a differing response to global change to that which is commonly predicted. Small range size, habitat specialisation and climate specialisation were significant predictors of range contractions for all species. Contracting habitat specialists were concentrated within two areas of endemism that also had high levels of land transformation. The use of methods that correct for sampling variation has allowed the SAFAP to be valuable in investigating species range change.