Thesis (Ph.D.) in Wildlife Ecology--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 100-117).

Orientador: Jorge Jim / Banca: Denise de Cerqueira Rossa Feres / Banca: Elieth Spirandelli Cruz / Resumo: Os objetivos deste trabalho foram analisar o status de conservação de Odontophrynus moratoi na região de Botucatu, mapear as áreas de ocorrência, incluindo os registros históricos, realizar um estudo ecológico das populações remanescentes e identificar as possíveis ameaças a estas populações. Odontophrynus moratoi tinha registro de ocorrência restrito ao Distrito de Rubião Jr., Botucatu, onde era registrada somente em duas localidades, desde sua descoberta em 1976, até 2003. Recentemente foi encontrada na região de Itirapina e de Brotas. Durante o estudo a espécie foi registrada em duas novas localidades, uma na região de Brotas e uma em Bauru. A espécie demonstrou ser altamente especialista na ocupação do habitat, por ter sido registrada somente em dois ambientes dentre os 129 amostrados, os quais compõem as 26 localidades estudadas e considerando que os mesmos são áreas de nascente de cerrado próximas de mata. A espécie não foi registrada em sua localidade-tipo, nem em sua segunda área de ocorrência na região de Botucatu e nem em outras nove localidades amostradas no município de Botucatu durante o estudo, demonstrando um possível desaparecimento da espécie da área onde foi primeiramente descoberta. As possíveis causas deste desaparecimento são alterações antrópicas que ocorreram em suas áreas de ocorrência, modificando os microambientes reprodutivos e de desenvolvimento larval da espécie. É de suma importância a preservação das localidades de ocorrência de O. moratoi e da área de entorno das mesmas / Abstract: The objectives of this work were to analyse the conservation status of Odontophrynus moratoi in Botucatu region, map the occurrence areas, including the historical registers, to carry out an ecological study of the leftover populations and to identify the possible threats to these populations. Odontophrynus moratoi had limited occurrence to Rubião Jr. District, Botucatu, where it was registered only in two localities, from his discovery in 1976 up to 2003. Recently it was found in Itirapina and Brotas region. During the study the species was registered in two new localities, one in Brotas region and one in Bauru. The species demonstrated to be highly an occupation specialist of this habitat, because the species was being registered only in two environments among the 129 sampled, which compose 26 studied localities and considering that same are areas of source of Cerrado near forest. The species was not registered in his locality-type, not even in his second area of occurrence in Botucatu region and not even in another nine localities sampled in Botucatu local municipality during the study, demonstrating a possible disappearance of the species of the area where it was firstly uncovered. The possible causes of this disappearance are anthropics alterations that occurred in his place areas, modifying the reproductive microenvironments and larval development of the species. It is of abridgement importance the preservation of the occurrence localities of O. moratoi and the area that involve the same / Mestre

The Appalachian Mountains are the source of the greatest diversity of salamanders in the world and the preservation and protection of this unique regional diversity are of important consideration. Salamanders can be subject to numerous diseases like ranaviruses and chytrid fungi, but an important factor to consider is other stressors that may affect salamander’s ability to recover from outbreaks. Human activity, be it habitat disruption or providing some vector for disease spread between populations and species, may have large impacts upon salamander population health. Identifying sites where salamanders and human activity are frequently overlapping in the territory could provide sites for future comparisons between more isolated populations and allow a better understanding of how humans may affect salamander populations. To identify sites where human activity may be common, a newt that is a quick colonizer of ephemeral pools, the Eastern Newt (Notophthalmus viridescens) was selected to observe. These sites were qualified upon their likeliness to support Notophthalmus viridescens individuals and other amphibian life cycles. Details such as forested canopy, ephemeral pools or stationary water ponds, leaf litter, and other amphibian activity were qualified by their presence or lack thereof. These sites were surveyed during fall thru winter, and the distance between these sites and closest human activity centers were measured in meters using Google Maps. Such activity centers could be classified as residences, public buildings, roads, trails, fences, or land disturbed by human activity like a construction site. Some sites will be purposely further away from human activity as for some comparison to more isolated sites. These sites should show that Notophthalmus viridescens can be found near human activity centers and therefore may be subject to be much influence from them.

Selenium (Se) is a contaminant of potential concern in aquatic systems due to its efficient incorporation into food webs, potential for bioaccumulation at higher trophic levels, and role as a developmental toxicant in oviparous vertebrates. While the presence of embryonic/larval deformities due to in ovo Se exposure is considered the most sensitive toxicological endpoint, elevated levels of dietary Se have also been associated with alterations to bioenergetic and hormonal status of adult female fishes, which consequently could lead to diminished fitness and impaired reproduction. Adverse reproductive effects in fishes have been the primary focus of Se research thus far, while studies focusing on Se toxicity in amphibians in any regard are severely lacking. The US EPA has recently proposed a new set of criteria for the protection of freshwater aquatic life with regards to acceptable Se tissue threshold levels; however, these values were generated based on effects observed in fishes with negligible existent data on amphibians to assist in this process. Thus, the overall goal of this thesis research was to characterize the reproductive and developmental effects of elevated dietary Se exposure in Xenopus laevis, in order to provide a foundation for amphibian related Se research that may assist in establishing effective regulatory guidelines that protect this highly vulnerable and ecologically valuable taxon. The research presented in this thesis was performed as one large generational bioassay with the analysis of experimental variables divided into three sections in order to evaluate the effects of elevated in ovo Se exposure via maternal transfer on early and late stages of larval development in addition to the overall fitness of adult X. laevis females after a dietary exposure. Adult X. laevis females were fed a diet augmented with L-selenomethionine (SeMet) for 68 days after which they were bred with untreated males. The resultant embryos were incubated up to 5 days post fertilization (dpf) to determine fertilization success, hatchability, mortality and frequency/severity of malformations. Subsamples of 5 dpf tadpoles were selected and raised to completion of metamorphosis for evaluation of mortality, growth and maturation rate. In addition, tissue and blood samples as well as morphometric indices were collected from X. laevis females, upon completion of the exposure period and subsequent breeding, to ascertain Se tissue distribution, triglyceride and glycogen levels, cortisol concentrations and the overall health status of SeMet-treated females. Within the data gathered throughout this research, a foundation of knowledge characterizing Se toxicity in amphibians was established along with the development of an early life stage toxicity threshold for the frequency of teratogenic abnormalities in X. laevis. The bioenergetic and stress status in addition to the overall body condition of adult females after a 68 day dietary exposure showed no significant differences among treatment groups. The concentrations of Se measured in the ovary, egg, liver and muscle samples increased with female dietary Se levels with strong positive relationships between egg Se concentrations and the other three tissues being illustrated. Elevated in ovo Se exposure had no biologically significant effect on fertilization success, hatchability or mortality within the first 5 dpf; however, the frequency and severity of morphological abnormalities was significantly greater in tadpoles from the highest dose group, with eye lens abnormalities most prominently observed. Late stage larval survival and growth was unaffected by in ovo Se exposure; however, the distribution of developmental stages observed at the set time point when 50% of tadpoles completed metamorphosis showed a larger portion of tadpoles at earlier stages of development in the highest dose group despite no overall change in time to metamorphosis. The results of this thesis research in its entirety suggest that amphibians, as represented by X. laevis, are potentially more tolerant to elevated in ovo and dietary Se exposures than other oviparous vertebrates studied to date; however, without sufficient data for comparison it is unknown whether X. laevis is a tolerant, average or sensitive species among amphibians.

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines around the world, including the southwestern United States. I studied patterns of Bd infection in Hyla arenicolor, Rana catesbeiana, and R. yavapaiensis in the Rincon Mountains and Tucson Basin in Arizona. Bd prevalence and infection intensity were location dependent in all species and R. yavapaiensis may be a reservoir of Bd for H. arenicolor, where they co-occurred. Treatment of a backyard population of R. yavapaiensis with itraconazole did not reduce winter frog mortality due to Bd. The lethal Bd infection threshold of this population was between 59,847 and 4,237,330 zoospores. Zoospore loads from swabs of freshly dead frogs did not differ significantly from those taken from those same frogs following freezing and thawing. Thus, important information regarding infection intensity and probable cause of death can be gathered from frogs collected by others and frozen until convenient to process.

No description available.

<p>There have been many cases reported of amphibian populations declining. These are often due to anthropogenic factors such as habitat destruction and pollution. However, some eclines have not had an obvious cause and many of these have been investigated and found to be due to pathogenic disease. Batrachochytrium dendrobatidis is a recently described pathogen of frogs. The population declines that have been associated with chytridiomycosis have occurred in relatively undisturbed areas such as national parks. The declines tend to occur at higher altitudes or in colder climates. This is thought to be because of the frog immune system being slower at lower temperatures. This project gives an overview of chytrid infection in the Western Cape and at a small number of sites in the Northern Cape and Eastern Cape.</p>

No description available.

Size fluctuations in amphibian populations at single breeding sites are related to variations in recruitment from the larval stage. However, overall patterns of abundance should be related to the pattern of recruitment success at the many sites where breeding occurs over a landscape. Recruitment patterns for six amphibian species, Ambystoma laterale, A. maculatum, Bufo americanus, Hyla versicolor, Pseudacris crucifer and Rana sylvatica, were investigated at multiple sites within the 10 km 2 Mont St. Hilaire nature reserve during 2001 and 2002. Amphibians bred at eighteen sites but recruitment occurred at only 8 and 11 sites in each year, respectively. Hydroperiod and predation were the most important determinants of recruitment. Four species suffered multiple recruitment failures both years. However, when sites were considered collectively, recruitment was successful for all species because of asynchronous recruitment patterns across heterogeneous sites. Amphibian population dynamics may be stochastic at any single site but recruitment success at multiple sites is a plausible predictor of abundance and trends in regional population persistence.

<p>There have been many cases reported of amphibian populations declining. These are often due to anthropogenic factors such as habitat destruction and pollution. However, some eclines have not had an obvious cause and many of these have been investigated and found to be due to pathogenic disease. Batrachochytrium dendrobatidis is a recently described pathogen of frogs. The population declines that have been associated with chytridiomycosis have occurred in relatively undisturbed areas such as national parks. The declines tend to occur at higher altitudes or in colder climates. This is thought to be because of the frog immune system being slower at lower temperatures. This project gives an overview of chytrid infection in the Western Cape and at a small number of sites in the Northern Cape and Eastern Cape.</p>