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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The herpetofauna of the Owen Sitole College of Agriculture, Zululand.

Hoffmann, Leonard Andrew Charles. January 1990 (has links)
A herpetofaunal study was undertaken at the 670 ha Owen Sitole College of Agriculture (OSCA) near Empangeni, Zululand, from 1986 to 1988. Collecting was carried out primarily opportunistically, throughout all seasons. A total of 28 amphibian taxa and 44 reptile taxa, comprising two chelonians, one crocodylid, 13 lizards and 28 snakes, were recorded. A further 11 amphibian and 42 reptile taxa may possibly occur. The majority of amphibians and reptiles display a tropical distribution, often with enormous ranges. Nineteen (68%) amphibian taxa have tropical or quasi-tropical (Poynton 1964) zoogeographical affinities and 33 (75%) reptile taxa have tropical wide ranging or tropical east coast littoral (Bruton and Haacke 1980) zoogeographical affinities. Only one amphibian taxon and four reptile taxa, all snakes, have Cape or temperate affinities. These taxa are marginal in the region, reaching their distributional limits in Maputaland. Niche segregation of amphibians occurs primarily according to water bodies. Vegetation per se does not appear to be important, with the majority of species occurring in a savanna environment; however, three species, Leptopelis natalensis, h. mossambicus and Arthroleptis wahlbergii, appear to be sylvicolous in habits and are restricted to riverine vegetation. The vast majority of taxa are summer breeders, whereas only one, Cacosternum nanum nanum, was recorded breeding in winter too. The syrnpatry of h. natalensis and Hyperolius semidiscus was confirmed in this study, and H. semidiscus and H. argus were shown to behave as good species with specifically distinct calls. Snakes are segregated according to size, mode of life, activity patterns and food. Certain species, such as Naja mossambica, have catholic diets whereas others, such as Duberria lutrix lutrix, Aparallactus capensis and Dasypeltis scabra, are specialists. The lizard fauna is differentiated according to diet, foraging strategies and habitat preferences, including substrate and vegetation. Amphibians are unselective feeders, consuming a variety of insects. Some, namely Xenopus laevis laevis and Pyxicephalus adspersus edulis, have catholic tastes and are even cannibalistic. Snakes and amphibians constitute the main prey items of snakes, whereas most lizards, with the exception of Varanus niloticus niloticus which is a generalist, feed exclusively on arthropods, especially insects. Schismaderma carens, Bufo gutturalis, Hemidactylus mabouia mabouia, Lygodactylus caoensis capensis, Mabuya striata striata, Lamprophis fuliginosus, Causus rhombeatus, Duberria lutrix lutrix and Naja mossambica are attracted to places of human habitation either for feeding or for shelter. Many amphibians benefit from artificial water bodies. No less than 19 taxa were recorded from the fish ponds, the majority of which bred there, possibly because the waters are more stable, permanent and relatively free of predators than natural water bodies. The Leguaan Tick Aponomma exornatum was recorded parasitizing adult Varanus niloticus niloticus, and the Snake Tick A. latum was found on N. mossambica and h. rhombeatus; A. latum, with an extensive subSaharan distribution, shows no predilection for any species of snake. Pentastomids and nematodes were found in a number of snakes (Atractaspis, Telescopus, Psammophis and Causus); the life cycle implications of these organisms are that mammals and snakes are intermediate hosts, though more ecological and experimental evidence is necessary. Python sebae natalens is and Kinixys natalensis, both Red Data Book - Reptile and Amphibian species, are particularly threatened, the first due to slaughter for traditional uses, the second due to agricultural activities and frequent fires. It is recommended that both these reptiles be afforded maximum protection in the 110 ha game park, which is regularly patrolled and which is subjected to infrequent fires. Generally, however, the herpetofauna has fared well at the hands of the local people, testimony to which is the high species diversity. / Thesis (M.Sc.)-University of Natal, 1990.
2

Padrões de riqueza, diversidade e endemismo de répteis e anfíbios na América do Sul / Patterns of richness, diversity and endemism of reptiles and amphibians in South America

Teixeira Junior, Mauro 11 August 2017 (has links)
O nosso conhecimento sobre a distribuição das espécies vem avançando desde as primeiras observações feitas séculos atrás. Recentemente uma melhoria nos métodos e na cobertura geográfica das amostragens tem melhorado significativamente nosso conhecimento sobre padrões de distribuição. O que tem permito diversos tipos de análises, revelando padrões macroecológicos com os observados aqui onde riqueza de répteis e anfíbios apresenta uma forte relação com o ambiente, sendo maiores em aras mais baixas, com temperatura e precipitação estáveis e maior estrutura no ambiente, enquanto que para endemismo e diversidade beta a relação é mais fraca. Porém este conhecimento sobre a distribuição das espécies não está homogeneamente distribuído por todas as regiões, sendo especialmente baixo na região Amazônica, que é justamente a região que abriga a maior riqueza local de espécies, estando concentrado ao longo das margens dos rios. Isto que pode indicar que os valores que temos disponíveis ainda são subestimados, e que quaisquer inferências sobre estes valores devem ser interpretados com cautela / Our knowledge on species distribution has advanced since the first observations made centuries ago. Recently the improvement on techniques and geographical coverage of samplings activities has improved significantly our knowledge on distribution patterns. This advance has allowed several analyses to be done, and macroecological patterns to emerge, such as the one observed ibn here with reptile and amphibian richness presenting a strong relationship with environmental conditions, with higher values at lower areas, with more stable precipitation and temperature, an higher environmental structure, while endemism and beta diversity have a weaker signal. However the knowledge on species distribution is not homogeneously distributed across all regions, being especially low at the Amazon, which is precisely the area that harbors the highest richness values, being concentrated at the rivers\' shores, suggesting that the values we have today may be far underestimated, and thus any inference using them should be interpreted with caution
3

A herpetological survey of the Indiana dry prairies

Morris, Larry J. 03 June 2011 (has links)
In 1934 the region now known as the Jasper-Pulaski State Fish and Game Area was the subject of a herpetological survey by Major Chapman Grant. This has been the only study directed toward the sand prairie herpetofauna. A reinvestigation of the area seemed worthwhile, and a survey was conducted from April 1, 1971, to October 30, 1971.There seems to have been less change in the amphibian population then in that of the reptiles. One notable exception is Fowler’s Toad, which Grant did not believe to occur at Jasper-Pulaski but which is now very common, while the American Toad is much rarer.The turtle population has changed noticeably. The Mud Turtle and the Spotted Turtle seem to have disappeared.There also have been several changes in the snake population. Grant did not find the Bullsnake at Jasper-Pulaski but did report the Fox Snake as being very common. Now the reverse seems true. The Smooth Green Snake has now become very rare. The Northern Water Snake is apparently now much more abundant.In 1971, a total of thirty species of amphibians and reptiles was recorded in the area: three salamanders, eight frogs and toads, eight turtles, two lizards and nine snakes.Ball State UniversityMuncie, IN 47306
4

A herpetological survey of the Transvaal.

Jacobsen, Niels Henning Gunther. January 1989 (has links)
This report discusses the taxonomy, distribution and ecology of the herpetofauna of the Transvaal based on a survey conducted over the past 10 years. Seventeen new forms, apart from four new taxa described during the course of this study, are discussed in the section on Systematics. The distribution of many species has been considerably amended. A total of 265 species and subspecies were recorded from the province. The biogeography of the herpetofauna is discussed in the light of past and present climatic events, as determined by palynological record. Factors affecting reptile and amphibian distributions are incorporated in an attempt to elucidate current distribution patterns. The conservation status of each species and subspecies is discussed and a final chapter on threats and conservation recommendations are incorporated. / Thesis (Ph.D.)-University of Natal, Durban, 1989.
5

A herpetofaunal survey of Swaziland.

Boycott, Richard Charlton. January 1992 (has links)
The present report, based on a survey conducted over four years and on the accumulation of museum records, provides the most detailed documentation yet of the herpetofauna of Swaziland. One hundred and two new forms are recorded from the country bringing the total number of forms to 154, consisting of 44 amphibians and 110 reptiles. Up-to-date checklists of the amphibians and reptiles are presented and effectively indicate a rich and diverse herpetofauna. The biogeography of the Swaziland herpetofauna is discussed based on distribution records derived from collected specimens as well as reliable sight and audio records. Swaziland does not constitute a distinctive biogeographical unit. The present study indicates that the herpetofauna shows affinities with both the Afrotemperate and Afrotropical biomes. The traditional biogeographical classification in southern Africa, of the presence of a Cape temperate fauna and a tropical East African lowland fauna, is tested by means of a transect and is reinforced. It is also shown that Swaziland, together with Natal and southern Mozambique, forms an integral part of the tropical subtraction zone of south-east Africa. Amphibian diversity and species turnover in southern Africa are investigated by means of a transect from the east coast, through Swaziland, to the interior plateau, and a north to south transect down the eastern lowveld. The Dice-Sorenson Similarity index gives a value of 41% for the entire east-west transect and 89% for the north-south transect. The conservation status of the amphibians and reptiles of Swaziland is discussed. Conservation measures are proposed. / Thesis (M.Sc.)-University of Natal, Durban, 1992.
6

Natural history of common gartersnakes (Thamnophis sirtalis) in east-central British Columbia

McAllister, Jillian 01 August 2018 (has links)
Widely distributed species typically exhibit variation in various aspects of their ecology throughout their range. Such variation offers opportunities for fundamental studies in evolution, including local adaptation, biogeographic rules, distributional limits, and speciation. Geographic variation also limits our ability to extrapolate from one population to another, making site-specific knowledge of ecology essential for wildlife management and conservation. I studied the natural history of Common Gartersnakes (Thamnophis sirtalis) at two sites in east-central British Columbia, where active seasons are short and cool. I used opportunistic sampling of snakes to study general features of their ecology and radiotelemetry to study movements and habitat selection, including hibernating sites. In September, snakes move from summer habitats to hibernating sites and then emerge from hibernation in April or May. Adult female T. sirtalis overwintered with 0 to 16 other adults in inconspicuous underground hollows, typically in forested habitats, near water and/or coarse woody debris; this is distinct from the large-scale communal hibernation seen in other northern populations. Hibernacula were typically distant from summer habitat (mean = 1485 ± 937 m SD, n = 8, range = 148-2657 m). Under the assumption that snakes exhibit site fidelity to hibernacula in consecutive years, I estimated the cumulative distance moved over the entire active season to be 7011 ± 3756 m SD (n = 9, range = 3510-15015 m). Gravid female snakes moved at significantly lower rates, followed more tortuous paths, and inhabited areas that were more open-canopied than their nongravid counterparts (n = 13). Nongravid snakes used locations with a higher percentage of ground cover than gravid snakes. Mating occurred in early spring near the hibernacula and parturition in early to mid August in summer habitat; litter size ranged from 3 to 25 and was not significantly correlated with the size of the female. Adult snakes preyed exclusively on adult Western Toads (Anaxyrus boreas) and juvenile snakes fed on leeches and metamorphosing toads. Through the identification of migratory routes, relevant summer and winter habitat characteristics, and hibernation sites, my study contributes to the protection and conservation of northern reptiles, which are particularly vulnerable to population declines compared to southern populations due to the restrictive cold climate. / Graduate
7

Padrões de riqueza, diversidade e endemismo de répteis e anfíbios na América do Sul / Patterns of richness, diversity and endemism of reptiles and amphibians in South America

Mauro Teixeira Junior 11 August 2017 (has links)
O nosso conhecimento sobre a distribuição das espécies vem avançando desde as primeiras observações feitas séculos atrás. Recentemente uma melhoria nos métodos e na cobertura geográfica das amostragens tem melhorado significativamente nosso conhecimento sobre padrões de distribuição. O que tem permito diversos tipos de análises, revelando padrões macroecológicos com os observados aqui onde riqueza de répteis e anfíbios apresenta uma forte relação com o ambiente, sendo maiores em aras mais baixas, com temperatura e precipitação estáveis e maior estrutura no ambiente, enquanto que para endemismo e diversidade beta a relação é mais fraca. Porém este conhecimento sobre a distribuição das espécies não está homogeneamente distribuído por todas as regiões, sendo especialmente baixo na região Amazônica, que é justamente a região que abriga a maior riqueza local de espécies, estando concentrado ao longo das margens dos rios. Isto que pode indicar que os valores que temos disponíveis ainda são subestimados, e que quaisquer inferências sobre estes valores devem ser interpretados com cautela / Our knowledge on species distribution has advanced since the first observations made centuries ago. Recently the improvement on techniques and geographical coverage of samplings activities has improved significantly our knowledge on distribution patterns. This advance has allowed several analyses to be done, and macroecological patterns to emerge, such as the one observed ibn here with reptile and amphibian richness presenting a strong relationship with environmental conditions, with higher values at lower areas, with more stable precipitation and temperature, an higher environmental structure, while endemism and beta diversity have a weaker signal. However the knowledge on species distribution is not homogeneously distributed across all regions, being especially low at the Amazon, which is precisely the area that harbors the highest richness values, being concentrated at the rivers\' shores, suggesting that the values we have today may be far underestimated, and thus any inference using them should be interpreted with caution
8

Toolkit to manage key habitat for amphibians in Ontario forests / Toolkit for amphibian habitat monitoring in Ontario

Luymes, Nicholas January 2021 (has links)
Forest-dwelling amphibians contribute to diverse ecosystem services in Ontario but are threatened by habitat degradation and fragmentation. My thesis investigated key amphibian habitats in Ontario forests with the goal of providing resource managers with tools and techniques to protect and restore amphibian populations. I primarily focussed on amphibians that breed in temporary forested wetlands known as vernal pools, as these wetlands are overlooked in provincial legislature and particularly sensitive to changes in land-use and climate. First, I investigated the distribution and community structure of vernal pools in forests of eastern Georgian Bay, Lake Huron. I developed an accurate remote sensing technique to map vernal pool habitat using readily available spatial data and found that undocumented vernal pools accounted for over half of the wetlands in the region. I documented the importance of the length of pool inundation (hydroperiod) and canopy openness in determining the composition of vernal pool amphibian assemblages. In particular, pools with short hydroperiods and closed canopies tended to support only early breeders and canopy generalists. Next, I used two case studies to demonstrate the usefulness of existing amphibian occurrence datasets, specifically for the improvement of habitat mapping and monitoring. For the first case study, I created habitat suitability models using known locations of the endangered Jefferson salamander (Ambystoma jeffersonianum). Models yielded good discriminatory ability between presence and pseudo-absence data and confirmed the importance of deciduous/mixed forests as key habitats. Habitat suitability maps revealed potential undocumented habitat in the Greenbelt region of Ontario. For the second case study, I developed optimizations of time and effort for a salamander monitoring program. I verified the need for at least ten years’ worth of monitoring data for reliable trend detection and demonstrated that the precision and accuracy of occupancy estimates are dependent on the allocation of effort across monitoring sites and repetitions. / Thesis / Doctor of Philosophy (PhD) / Amphibian declines represent one of the hallmarks of the current biodiversity crisis. While there are many factors responsible for amphibian declines, the most significant threats are habitat loss and degradation. This Ph.D. thesis describes amphibian habitat use in Ontario forests and provides resource managers with tools and techniques to protect habitat. Using satellite imagery, I developed a strategy to map small amphibian breeding wetlands (vernal pools) in forests of eastern Georgian Bay. I also identified the importance of pool drying times and forest canopy cover to the amphibians that breed in these wetlands. In the fragmented forest patches of southern Ontario, I mapped suitable habitat for the endangered Jefferson salamander and identified the importance of large deciduous/mixed forests. Lastly, I assessed the effectiveness of a long-term salamander monitoring program in southern Ontario and demonstrated the use of techniques to optimize the allocation of effort and maximize the accuracy of monitoring results.
9

Distribution of Populations and Suitable Habitat for Spotted Turtles (Clemmys guttata) and Blanding’s Turtles (Emydoidea blandingii) in Indiana

Jessica Hinson (5931170) 04 January 2019 (has links)
The spotted turtle (<i>Clemmys guttata</i>) and Blanding’s turtle (<i>Emydoidea blandingii</i>) are two state-endangered species in Indiana whose populations are in decline. Historically, both species were found across the northern portion of Indiana in various wetland habitats. There are multiple causes of population decline for both species, including habitat fragmentation, habitat loss and degradation, urban development and encroachment, poaching, and road mortality. Despite efforts to record these species across the state, there has been no intensive population assessments. Based on this need, I conducted both visual encounter surveys across the state and used Maximum Entropy (MaxEnt) modeling to facilitate understanding the current distribution of both species in Indiana. Twenty-three locations were visited and surveyed in Indiana, with trapping being conducted at an additional four locations where populations were known to be larger. Surveys aided in delineation of six populations of Blanding’s turtles and five populations of spotted turtles. A total of 69 Blanding’s turtles and 70 spotted turtles were observed between surveying and trapping. Delineated populations were mainly found in the northern third of Indiana. This data and other occurrences were used to predict suitable habitat across Indiana. The Blanding’s turtle models were sufficiently resolved to predict potential localities or potential sites for focused management or repatriation. Spotted turtle model performance reflected the need for more samples, but also the likelihood of fewer numbers due to declining habitat availability. Both Blanding’s turtle and spotted turtle models argue for the need of more intense survey efforts based on historical occurrences, as well as restoration efforts across the state. Most models for both species were observed to have a trend towards suitable habitat in the northern third of the state, correlating with the results of the survey efforts. The results of this project indicate that Blanding’s turtle and spotted turtle populations are still in decline likely due to limited habitat availability.
10

Fossils, phylogeny, and anatomical regions : insights exemplified through turtles

Burroughs, Robert Wayne 15 November 2013 (has links)
There are more than 300 species of extant turtles, the majority of which belong to the Testudinoidea. Here I describe a new box turtle from the Eocene-Oligocene boundary of west Texas. This specimen impacts the phylogeny of Testudinoid turtles by pulling the divergence of extant Testudinoid turtles back in time approximately 25 million years. This results in a need to refocus on paleontological research of Testudinoid turtles into the late Paleogene and early Neogene to identify fossil localities and specimens that can help further elucidate the evolution of the group. New work on the fossil record of turtles also requires a re-evaluation of methods used for identifying and evaluating the evolutionary history of turtles as a group. An implicit assumption over the last 150 years of turtle paleontology was that both turtle shells and turtle heads reveal congruent and complimentary evolutionary relationships. This assumption was never adequately tested. I utilized a series of methods to evaluate the congruency of phylogenetic hypotheses using disparate anatomical regions. Using a dataset of extant Emydid turtles, I evaluated whether turtle shells and turtle heads provided congruent and complimentary phylogenetic hypotheses. My methods employed parsimony-based reconstruction, maximum-likelihood-based reconstruction, and Bayesian-based reconstruction, including Bayesian-partition analyses. My conclusions are that heads and shells do not provide fully congruent topologies, and that in many cases there is a loss of phylogenetic resolution when only turtle sklls are used to generate phylogenies. The implication is that a focus on a robust and complete dataset of anatomical features will provide the best basis for further investigation of fossils. My work also provides a framework for dataset exploration by providing a method to identify the most robust phylogenetic signal found within a dataset. This framework will allow non-turtle paleontologists and systematists the ability to further investigate their own datasets and develop robust hypotheses of evolutionary relationships across the diversity of the tree of Life. / text

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