Download or read book Understanding the Metapopulation Structure of Frogs in the Geocrinia Rosea Complex Through Population Genetics and Population Biology written by Don Driscoll and published by . This book was released on 1996 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Status of Conservation and Decline of Amphibians written by Harold Heatwole and published by CSIRO PUBLISHING. This book was released on 2018-06-01 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphibians are among the most threatened groups of animals on earth. In part due to their highly permeable skin, amphibians are highly sensitive to environmental changes and pollution and provide an early-warning system of deteriorating environmental conditions. The more we learn about the impact of environmental changes on amphibians, the better we as humans will be able to arrest their demise, and our own. Status of Conservation and Decline of Amphibians brings together the current knowledge on the status of the unique frogs of Australia, New Zealand, and the Pacific. Although geographically proximate, each region presents unique challenges and opportunities in amphibian research and conservation. This book contributes to an understanding of the current conservation status of the amphibians of each region, aims to stimulate research into halting amphibian declines, and provides a better foundation for making conservation decisions. It is an invaluable reference for environmental and governmental agencies, researchers, policy-makers involved with biodiversity conservation, and the interested public.

Download or read book Metapopulation Dynamics Empirical and Theoretical Investigations written by Michael Gilpin and published by Academic Press. This book was released on 2012-12-02 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metapopulation Dynamics: Empirical and Theoretical Investigations covers the 1989 proceedings of a metapopulation dynamics workshop held at Lammi Biological Station, Helsinki, Finland. It is divided into 18 chapters that cover various approaches to spatially structured population and community dynamics. After briefly discussing the history of metapopulation ideas and the major conceptual links, the book covers types of studies that have been conducted on single-species and multispecies metapopulations. Then, it examines the relationships between metapopulation dynamics, the equilibrium theory of island biogeography, and the dynamics of populations living in patchy environments. It further tackles practical issues and the links between metapopulation dynamics and landscape ecology, and between metapopulation dynamics and conservation biology. Chapters 4 and 5 present structured models describing changes in the number of individuals within patches and an empirical evaluation of local extinction in metapopulation studies. The subsequent chapters discuss several aspects of metapopulation, including dispersal and connectivity, colonization, conspecific attraction, extinction and isolation, and forest fragmentation. The latter chapters describe the concept of habitat fragmentation, the diversity and competition in metapopulations, the community collapse, and the effects of metapopulation studies in predator-prey systems.

Download or read book Population and Conservation Genetic Structure of the Cascades Frog Rana Cascadae Throughout the Species Range written by Kirsten J. Monsen and published by . This book was released on 2002 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major goal of conservation biology is to elucidate the population genetic structure in threatened species and assess the relative importance of the evolutionary forces that shape that population genetic structure. I conducted three studies in the declining amphibian Rana cascadae to assess levels of population genetic differentiation and the relative importance of gene flow versus random genetic drift throughout the species' range. In the first study, 1 examined phylogeographic structure on a species-wide geographic scale with both mitochondrial and nuclear molecular markers. I found three mitochondrial groups within R. cascadae that are as divergent at the mitochondrial DNA as sister species. However, I only found two nuclear groups within R. cascadae, suggesting there are two Distinct Population Segments and three Management Units within the species' range. In the second study, I compared sequence data from mtDNA and nuclear DNA of the three R. cascadae mtl)NA groups to several closely related Pacific Northwestern ranid species. I found the surprising result that the mtDNA of R. aurora aurora is more closely related to the mtDNA of' R. cascadae than to the mtDNA of its own subspecies R. aurora drayloni. The nuclear data support the sub-specific relationship between R. aurora aurora and R. aurora draytoni. This result is most likely due to incomplete lineage sorting of ancestral mtDNA alleles. Finally, in the third study, I examined the relative importance of gene flow versus random genetic drift on a fine geographic scale using microsatellite loci. Additionally, I estimated the long-term effective population sizes and genetic neighborhood size for 11 R. cascadae populations. Rana cascadae shows extreme isolation by distance with very little gene flow occurring past a distance of 10 km. Long-term effective population sizes were unrealistically large for current effective population sizes, but the estimates oF genetic neighborhood size are consistent with those expected based on current census population size and genetic neighborhood size in other amphibians. My research suggests Rana cascadae should be managed as three separate groups corresponding to the Olympic Peninsula, the Cascades of Washington and Oregon, and Northern California. Additionally, R. cascadae exhibits extreme isolation by distance with reduced gene flow at distances greater than 10 km, suggesting metapopulation structure is weak, and populations that go extinct are unlikely to be re-colonized quickly despite the presence of nearby R. cascadae populations.

Download or read book Population Biology and Reproductive Ecology of Geocrinia Alba and G Vitellina Two Threatened Frogs from Southwestern Australia written by Simon D. S. Conroy and published by . This book was released on 2001 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canadian Journal of Zoology written by and published by . This book was released on 2000 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Reproductive Biology of Amphibians written by D. Taylor and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Population Genetics of Ranid Frogs written by Ivan Clayton Phillipsen and published by . This book was released on 2011 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary change caused by genetic drift can be quantified through the use of the effective population size (N[subscript e]) parameter. The effective size of a population is the number of breeding individuals in a conceptual, ideal population that would evolve by genetic drift at the same rate as the real population being studied. How a population responds to mutation, selection, and gene flow depends on N[subscript e], rather than the actual census population size (N). In most natural populations, N[subscript e] is considerably smaller than N. For these reasons, N[subscript e] is a fundamental parameter in basic population genetics theory as well as in applied conservation genetics. The degree of neutral genetic similarity between populations is highly dependent upon gene flow. When gene flow between a pair of populations is low, the populations are likely to become genetically differentiated. Conversely, when gene flow between populations is high, the populations will tend to be more genetically similar. Amphibians are good model organisms for studying genetic drift and gene flow because they tend to exhibit strong population structure at small spatial scales. This is a consequence of their generally small population sizes, natal philopatry, limited dispersal capabilities, and restricted habitat requirements. They are expected to have easily-detectable signatures of spatial genetic structure and genetic drift. Amphibians can be used as models to further our understanding of evolutionary processes and that understanding can be applied to the conservation of amphibians. Equipped with knowledge of what naturally influences genetic drift and gene flow in amphibians, we can apply the principles of population genetics to mitigate the genetic consequences of amphibian declines. In Chapters 2 and 3, I used molecular genetic data from frog populations to investigate N[subscript e] and the related parameter N[subscript b] (the effective number of breeders). Chapter 2 is a study of a single population of the Oregon spotted frog (Rana pretiosa). My aim was to determine where in the life cycle of this species the greatest reduction in N[subscript b] occurs. I used genetic data from microsatellites to estimate N[subscript b] at two different life stages, eggs and metamorphs, and found that estimates of N[subscript b] were similar at both stages. This result suggests that inflated variance in family size due to egg mass mortality is not a primary cause of N[subscript e] reductions relative to N in this species. Chapter 3 is a comparison of N[subscript e] estimates within and among four species of frogs in the family Ranidae: R. pretiosa, R. luteiventris, R. cascadae, and Lithobates pipiens. I obtained N[subscript e] estimates for 90 populations across the four species, using microsatellite data and several different estimators. The first three species and the western populations of L. pipiens have very small effective sizes (

Download or read book Zonal Hybridization in Frogs of the Geocrinia Laevis Complex Anura Myobatrachidae written by Michael Peter Scroggie and published by . This book was released on 2001 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Colonizing Northern Landscapes written by Andrée-Michelle D'Aoust-Messier and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The genetic structuring of populations can be influenced by present processes and past events. One of the largest historical events to affect the distribution and genetic characteristics of present-day North American biota is the Pleistocene glaciation. Thus, the study of post-glacial colonization patterns of species in northern landscapes can relay important ecological information, as species had to expand their range extensively following the retreat of the glaciers and are often at the terminal end of their expansion. These species consequently exhibit the genetic fingerprints of sequential founder events, in turn decreasing the genetic variation available for adaptation. Using amphibians to investigate post-glacial range expansion is advantageous, as they have limited dispersal abilities revealing fine-scale patterns and they are thought to be one of the first vertebrates to colonize post-glacial habitat. Therefore, to model the phylogeography of a primary colonizer and the population structure of anurans in northern landscapes, population genetics analyses of wood frogs (Lithobates sylvaticus) were performed in the James Bay area. Wood frogs were sampled from 17 localities around James Bay and genetic analyses were conducted with seven microsatellite loci and mitochondrial DNA sequences of the ND2/tRNATRP genes. Results show that the post-glacial recolonization of the James Bay area by wood frogs originated from the putative refugium in western Wisconsin, an area known as the Driftless Area. Two routes were taken by founders to colonize the James Bay area: one north-west of Lake Superior, colonizing western Ontario, and one through the Upper Peninsula of Michigan, colonizing southern and eastern Ontario and western Québec. Interestingly, the meeting of the two lineages south-west of James Bay led to the establishment of a zone of higher genetic variation than expected under the founder effect hypothesis. Additionally, population structure analyses revealed the segregation of three genetic populations east, north-west, and south-west of the bay, the latter showing the highest genetic variation and likely representing a zone of secondary contact. This study shows that past events such as post-glacial range expansions can explain present patterns of genetic variation and population structure, and that studies in northern landscapes may be very useful in understanding genetic patterns throughout the range of a species.

Download or read book Population Genetics and Metapopulation Structuring of the Wood Frog Rana Sylvatica in the Kenai National Wildlife Refuge Alaska written by Margaret K. Perdue and published by . This book was released on 2009 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Frogs written by Henry Lambert and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the authors present current research in the study of frogs. Frog's neuromuscular junction (NMJ) is a classic and favourite object which have played a leading role in developing understanding of the basic mechanisms of synaptic transmission and secretion of neuromediator. The genetic diversity, neural development and ecological implications of frogs are examined throughout the book. Some of the topics the authors discuss in this compilation include poison storage and maturation in serous cutaneous glands of anurans; a mini review of the suppression of anuran metamorphosis by synthetic chemical compounds; mechanisms of suprathreshold excitation of a frog tectal neuron column by discharge of a single moving edge or darkness detector and their relation to a frog escape reactions; behavioral, ecological, and evolutionary aspects of diversity in frog colour patterns; physiological features of blood's system of frogs rana ridibuda pall; and presynaptic voltage-dependent calcium channels at the frog neurmuscular junction.

Download or read book Conservation Genetics of the Growling Grass Frog Litoria Raniformis in Urbanising Landscapes written by Claire Catherine Keely and published by . This book was released on 2016 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proportion of the world's human population living in cities and towns (urban areas) grew rapidly over the 20th century. Indeed, the global urban population grew by an order of magnitude during this period, from 220 million to 2.8 billion. By 2030, the global urban population is expected to swell to almost 5 billion. Urbanisation is a key threatening process for amphibians, with the global amphibian assessment listing greater than one-third of the world's known amphibian species as currently threatened by urbanisation. As is the case for biodiversity more generally, habitat loss and fragmentation represent pervasive impacts of urbanisation for amphibians. The International Union for Conservation of Nature (IUCN) recognises genetic diversity as one of three forms of biodiversity requiring conservation. However, surprisingly few studies have focused on the genetic consequences of urbanisation for amphibians. With the global rate of urbanisation set to steadily increase, and its recognition as a key threatening process to amphibians, the application of genetic techniques will be an important component of conservation planning for these animals. This thesis investigates the conservation genetics of the Growling Grass Frog, Litoria raniformis, around Melbourne, Australia. This species has declined significantly since the late 1970s, largely due to habitat loss and fragmentation, drought and disease. Remnant populations around Melbourne occur in four main regions, three of which are marked for urban growth, causing further loss, degradation and fragmentation of habitat for L. raniformis. The aim of this thesis was to assess the genetic structure and diversity of remnant populations of L. raniformis across Melbourne. There were four main objectives: 1. Assess four different genetic sampling techniques for amphibians, using a multi-criteria decision framework and L. raniformis as a case study. 2. Document the genetic structure and diversity of L. raniformis across Melbourne's urban fringe, using mitochondrial DNA (mtDNA) and microsatellites. 3. Investigate the population genetic structure of L. raniformis in the northern region of urbanising Melbourne and develop a model of the landscape determinants of gene flow for the species. 4. Undertake a Bayesian metapopulation viability analysis for L. raniformis, incorporating estimates of gene flow to define population connectivity. The thesis concludes by outlining directions for further research on the conservation genetics of the Growling Grass Frog and its management.

Download or read book Population Genetics of a Sentinel Stream breeding Frog Rana Boylii written by Ryan A. Peek and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rana boylii is an imperiled frog species native to CA and OR, and it is currently designated as a species of special concern in the state of CA. It has been petitioned as candidate for federal (USFWS) and state (CDFW) listing. As a lotic breeding amphibian, R. boylii is tied closely to local flow regimes in the watersheds it inhabits and is therefore particularly sensitive to alterations to the natural flow regime. Effective conservation management of this species should consider and prioritize maintenance of genetic diversity as part of any listing decision because it is closely related to the evolutionary capacity for adaptation to environmental change. Conservation of genetic diversity in this species will require several components, including refining potential conservation units (i.e., distinct population segments) and quantifying of genetic diversity and genetic diversity trajectories across the species range. To assess these components, fine-scale and landscape-scale analyses were conducted using genomic data from over 600 samples from 89 localities across the range of the species. Six genomically-distinct groups were identified, as well as population subdivisions at local watershed scales. One major impact on R. boylii populations has been river regulation. River regulation has been implicated as a cause of fundamental changes to downstream aquatic ecosystems. Regulation changes the natural flow regime which may restrict population connectivity and decrease genetic diversity in some species. Since population connectivity and the maintenance of genetic diversity are fundamental drivers of long-term persistence, understanding the extent that river regulation impacts these critical attributes of genetic health is an important goal. However, the extent to which R. boylii populations in regulated rivers have maintained connectivity and genetic diversity is unknown. The impacts of river regulation on R. boylii were investigated with genomic data to explore the potential for long-term persistence of R. boylii under continued regulation. R. boylii in regulated rivers showed striking patterns of isolation and trajectories of genetic diversity loss relative to unregulated rivers. For example, river regulation explained the greatest amount of variance in population genetic differentiation compared with other covariates including geographic distance. Importantly, patterns of connectivity and genetic diversity loss were observed regardless of regulation level but were most prominent in locations with the greatest regulation intensity. Using the same genomic data, fine-scale analyses of R. boylii and R. sierrae in a single region of the Sierra Nevada of California was conducted to evaluate the potential for hybridization between species. Hybridization between species may combine parental genotypes in ways that yield reproductively sterile or isolated lineages, and hybridization events may be short-lived and difficult to detect. Limited hybridization between the species was detected in the Feather basin, though it appears these are terminal events based on PCA, admixture, and tests of heterozygosity using species diagnostic SNPs. Finally, rangewide quantification and comparison of genomic variation across populations indicates the southern coast, southern Sierra Nevada, Northern Sierra Nevada, and Feather basin in California should have high prioritization in conservation efforts due to low genomic diversity and trajectories of diversity loss. More broadly, these results demonstrate both the critical need for regional conservation in a sentinel river species, and the utility and power of genetic methods for assessing and monitoring sensitive species across many scales.

Download or read book Frogs written by James L. Murray and published by Nova Science Publishers. This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the authors gather and present topical research from across the globe in the study of the biology, ecology and uses of frogs. Topics discussed include using frog red blood cells for exploring the ion transport pathways across cellular plasma membranes and their regulation; the significance of retinal glial cells for glutamatergic neural transmission in frog retina; a review of the intraspecific patterns and differences in life-history traits of frog populations living at different altitudes; the peripheral nervous system in the frog as a tool to examine the regulation of the transmission of neuronal information; ecological traits in the Omei treefrog in western China; taxonomic patterns of tadpole behavioural responses to alarm cues and frogs and toads used as bioindicator organisms in pollution studies.

Download or read book Population Status and Population Genetics of Northern Leopard Frogs in Arizona written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-03-04 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing isolation of populations by habitat fragmentation threatens the persistence of many species, both from stochastic loss of small isolated populations, and from inbreeding effects in populations that have become genetically isolated. In the southwestern United States, amphibian habitat is naturally patchy in occurrence because of the prevailing aridity of the region. Streams, rivers, and other wetlands are important both as habitat and as corridors that connect populations. However, populations of some species have become more fragmented and isolated by habitat degradation and loss. Northern leopard frogs (Rana pipiens) have experienced serious declines in the Southwest.

Download or read book Metapopulation Biology of Rana Lessonae Camerano on the Northern Periphery of Its Range written by Per Sjögren and published by . This book was released on 1988 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: