Download or read book The Influence of Landscape on Genetic Structure of a Threatened Reptile written by Michelle Francis DiLeo and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the impacts of both natural and anthropogenic landscape features on genetic diversity, population structure and connectivity has important implications for conservation of species living in fragmented environments. Here, I combine population genetic data, detailed land cover information, and computer simulations to explore how landscape shapes genetic structure across two regional populations of the threatened eastern massasauga rattlesnake (Sistrurus catenatus catenatus) in Ontario, Canada: one along the eastern shores of Georgian Bay and the other largely confined to the northern half of the Bruce Peninsula. First I used spatial Bayesian assignment to quantify the genetic population structure within each regional population. I found marked subpopulation structure within eastern Georgian Bay with differentiation of island and mainland snakes, a north-south split within the mainland coinciding with the town of Parry Sound, and evidence of further subdivision within the cluster of snakes north of Parry Sound. In contrast I found no population subdivision within the mainland of the Bruce Peninsula, but genetic distinction of mainland and island snakes. Next, I identified the landscape features that shape spatial genetic structure within regional populations. In eastern Georgian Bay I found local variation in the effect of landscape on populations. North of Parry Sound I found no effect of landscape on inter-individual genetic differentiation, but a strong pattern of isolation-by-distance. In contrast I found that both open water and roads restrict gene flow of snakes south of Parry Sound. I found no evidence of isolation-by-distance or that landscape shape genetic structure within the Bruce Peninsula. Finally I used individual-based, spatially explicit simulations to identify the lag-time associated with the detection of contemporary landscape feature effects on genetic structure of massasaugas, and explore the consequences of using spatially correlated land cover elements in landscape genetic analyses. I found that the genetic consequences of roads could be detected within 2-12 generations when population sizes were small or juvenile dispersal was low. However, I also found that roads could be spuriously identified as impediments to gene flow when spatially correlated features such as water are included in genetic models.
Download or read book Characterizing Population Genetic Structure and Inferring the Influence of Landscape Features on Gene Flow in a Temperate Snake Species written by Amanda Tonia Joan Xuereb and published by . This book was released on 2012 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Patterns of genetic diversity in natural systems are influenced by landscape heterogeneity over spatial and temporal scales. Certain natural or anthropogenic landscape features may facilitate or impede organism dispersal and subsequent gene flow. Characterizing the geographical distribution of genetic diversity and identifying the factors contributing to population genetic structure is imperative for maintaining functional connectivity between isolated populations across a fragmented landscape. In this study, I combined genetic data and high-resolution land cover information to investigate patterns of population genetic structure in the threatened eastern hog-nosed snake (Heterodon platirhinos) at its northern range limit in Ontario, Canada. First, using putatively neutral microsatellite markers, I found evidence of genetic differentiation between two geographically disjunct regional populations: in the Carolinian region of southwestern Ontario, and along the eastern shoreline of Georgian Bay. Spatial and non-spatial Bayesian clustering algorithms also detected population genetic structure within each regional population. I found evidence of weak structure within Georgian Bay, roughly corresponding to regions north and south of Parry Sound. A genetic cluster at Wasaga Beach, located at the southern terminus of Georgian Bay, was highly differentiated from other populations, despite its geographic proximity to Georgian Bay. Excess homozygosity and reduced allelic diversity in Wasaga Beach compared to other sampled populations imply a population bottleneck event. Secondly, I inferred the role of landscape features on eastern hog-nosed snake dispersal and subsequent gene flow in the Georgian Bay regional population. Using techniques derived from electrical circuit theory, I estimated pairwise resistance distances between individuals by assigning costs to landscape features that are predicted to impede hog-nosed snake movement: open water, wetland, settlement and agriculture, and roads. Landscape features did not influence genetic structure within Wasaga Beach. However, I found weak evidence for an effect of landscape features, particularly open water and roads, on gene flow in eastern Georgian Bay. This study is the first to examine potential factors driving population genetic structure of eastern hog-nosed snakes and provides an empirical foundation for future tests of demographic models and spatially explicit simulations of gene flow.
Download or read book The Influence of Landscape on Genetic Divergence of the Prairie Ring necked Snake Diadophis Punctatus Arnyi in Missouri written by María Eugenia.. Degano and published by . This book was released on 2019 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Changes in land use can result in habitat fragmentation, which threatens population viability. Reptiles may be more susceptible to the effects of fragmentation because of their limited dispersal and sensitivity to environmental conditions, which will ultimately impact gene flow among remnant populations. In this study, I used the spatial distribution of Diadophis punctatus arnyi to test hypotheses of landscape effects on the genetic structure of 10 sampling sites in northern Missouri. Genetic distance (FST) among populations was based on six microsatellite markers, and I tested the observed genetic differentiation against a suite of alternative resistance surfaces representing biologically plausible hypotheses of how Ring-necked Snakes perceive the landscape. I modeled distances matrices based on putative movement barriers, Euclidean distance, roads and land cover permeability through accumulated cost of least-cost paths, and evaluated their performance using Mantel tests, two causal modelling frameworks, and the mixed-model maximum-likelihood population-effects approach. All methods performed well showing the significant effect of the Missouri River on the genetic isolation of populations on either side, followed by the effects of roads and wetlands. This study sheds light on resistance to movement by snakes based on changes in land use. The presence of roads and frequently flooded habitats were the primary potential landscape features that hinder habitat connectivity among populations."--Abstract.
Download or read book Reptile Ecology and Conservation written by C. Kenneth Dodd and published by Oxford University Press. This book was released on 2016 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: This practical handbook of reptile field ecology and conservation brings together a distinguished, international group of reptile researchers to provide a state-of-the-art review of the many new and exciting techniques used to study reptiles. The authors describe ecological sampling techniques and how they are implemented to monitor the conservation status and population trends of snakes, lizards, tuatara, turtles, and crocodilians throughout the world. Emphasis is placed on the extent of statistical inference and the biases associated with different techniques and analyses. The chapters focus on the application of field research and data analysis for achieving an understanding of reptile life history, population dynamics, movement patterns, thermal ecology, conservation status, and the relationship between reptiles and their environment. The book emphasises the need for thorough planning, and demonstrates how a multi-dimensional approach incorporates information related to morphology, genetics, molecular biology, epidemiology, statistical modelling, animal welfare, and biosecurity. Although accentuating field sampling, sections on experimental applications in laboratories and zoos, thermal ecology, genetics, landscape ecology, disease and biosecurity, and management options are included. Much of this information is scattered in the scientific literature or not readily available, and the intention is to provide an affordable, comprehensive synthesis for use by graduate students, researchers, and practising conservationists worldwide.
Download or read book The Impact of Habitat Structure on Reptile Occurrence in a Fragmented Tropical Landscape written by Alexandra Mary Evans and published by . This book was released on 2019 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Landscape and Conservation Genetics of Amphibians and Reptiles in California written by Erin Maurine Toffelmier and published by . This book was released on 2019 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examining patterns of diversity at fine and global spatial scales is an important component of to inferring underlying evolutionary mechanisms, understanding species distributional patterns, and informing conservation. Globally, amphibians and reptiles are among the fastest declining taxonomic groups, and now more than ever, it is necessary to quantify diversity and its spatial drivers in order to most effectively conserve species. In this dissertation, I examine the population, landscape, and conservation genomics of several species along a continuum of endangerment, from highly endangered and on the brink of extinction to widespread and abundant. Throughout, I use large-scale molecular data sets coupled with spatial analyses to examine spatial genetic diversity in these varied species. My goals were to contribute to our understanding of how genetic diversity is distributed across a multitude of landscapes and to provide genetic context for the conservation of these species. In Chapters 1 and 2, I examined how genetic diversity is spread across the limited ranges of two ecologically disparate species, California tiger salamanders, Ambystoma californiense, in Santa Barbara County, and the Panamint alligator lizard, Elgaria panamintina, found only in the isolated desert mountain ranges of eastern California, and found surprising parallels. In both, I found populations with exceedingly low levels of genetic diversity and genetic effective population sizes. For tiger salamanders, genetic diversity and divergence is strongly correlated with the number of suitable breeding habitats in regional neighborhoods and presence of natural vernal pools, while divergence across the range of E. panamintina is primarily mediated by geographic distance. In both cases, our findings have important implications for how management and mitigation efforts may more effectively assist the recovery and/or protection of these groups. In Chapter 3, I examined the drivers of spatial genetic structure in the widespread southern alligator lizard, Elgaria multicarinata. I found that patterns of genetic isolation are driven primarily by geographic distances, but that regional ecological niches have also diverged. Collectively, my work demonstrates the utility of integrating genetic and spatial analyses across spatial scales to help elucidate how genetic diversity is distributed across variable landscapes.
Download or read book Reptile Ecology and Conservation written by C. Kenneth Dodd Jr. and published by Oxford University Press. This book was released on 2016-05-05 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This practical handbook of reptile field ecology and conservation brings together a distinguished, international group of reptile researchers to provide a state-of-the-art review of the many new and exciting techniques used to study reptiles. The authors describe ecological sampling techniques and how they are implemented to monitor the conservation status and population trends of snakes, lizards, tuatara, turtles, and crocodilians throughout the world. Emphasis is placed on the extent of statistical inference and the biases associated with different techniques and analyses. The chapters focus on the application of field research and data analysis for achieving an understanding of reptile life history, population dynamics, movement patterns, thermal ecology, conservation status, and the relationship between reptiles and their environment. The book emphasises the need for thorough planning, and demonstrates how a multi-dimensional approach incorporates information related to morphology, genetics, molecular biology, epidemiology, statistical modelling, animal welfare, and biosecurity. Although accentuating field sampling, sections on experimental applications in laboratories and zoos, thermal ecology, genetics, landscape ecology, disease and biosecurity, and management options are included. Much of this information is scattered in the scientific literature or not readily available, and the intention is to provide an affordable, comprehensive synthesis for use by graduate students, researchers, and practising conservationists worldwide.
Download or read book Genetics of Speciation written by David L. Jameson and published by . This book was released on 1977 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature of populations, races, subspecies, and species. Genetic basis of isolation. Origin of isolation - theoretical. Origin of isolation - experimental. The nature of the speciation process.
Download or read book Landscape Genetics Demographic Models and Conservation of the Eastern Massasauga Rattlesnake Sistrurus Catenatus written by Scott Anthony Martin and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Successful conservation actions require a detailed understanding of how individuals interact with their environment. For many threatened and endangered species, anthropogenic changes to their landscape have created barriers separating formerly connected populations. This isolation can have profound impacts on the long-term viability of these populations and ultimately the conservation status of the species. For example, as populations become more isolated, they may enter the “extinction vortex” where small populations experience high levels of inbreeding and genetic drift depressing demographic rates, driving the population into a positive feedback loop that can lead to a decline in numbers and eventual extinction. However, if barriers to movement are not complete, even infrequent dispersal between populations can counter potential vortex effects by bolstering local population sizes and introducing new genetic material. Determining if populations are connected via dispersal or if they are isolated is a difficult question with no single best approach. For the Federally threatened Eastern Massasauga Rattlesnakes, Sistrurus catenatus, their reclusive, sedentary lifestyle make many field-based methods for generating this information difficult and unreliable without unrealistic investments of time and resources. In my thesis, I used information from DNA single nucleotide polymorphisms (SNPs) from neutral genetic markers to address the following three fundamental questions regarding how S. catenatus move through their landscape in Ohio and how this information can be used to evaluate proposed activities for their conservation: (1) Do snakes in scattered habitat patches across Northeastern Ohio belong to a single connected population, a metapopulation with infrequent dispersal, or isolated populations? I used 1000s of DNA SNPs to reconstruct a pedigree across 86 individuals and showed that no individuals have moved between habitat patches separated by more than a few meters in the last three generations. This is despite known movements of over 2 km by individual snakes in other populations of this species found in more continuous habitat. From these results, I concluded that S. catenatus in NE Ohio is split into five genetically distinct populations in an area smaller than 15 km2 with no recent connectivity. (2) What landscape features drive the observed lack of connectivity? I next used the same SNP dataset with a second SNP dataset collected from 103 S. catenatus from a large population in Central Ohio to model landcover features that potentially impact resistance to movement between local habitat patches. I found that an inherent landscape feature, elevation, and contemporary landcover, specifically roads, were the main barriers to connectivity. I then used the resistance maps and pedigrees for S. catenatus populations in NE Ohio and Central Ohio to estimate the resistance values between all pairs of closely related individuals and used those to estimate dispersal kernels around each population. The kernels results reinforced our previous finding of no contemporary connectivity between S. catenatus populations in this region. (3) How would proposed management actions impact the demographic viability of S. catenatus in NE Ohio? The habitat occupied by populations of S. catenatus in NE Ohio has been targets of active management to prevent vegetation succession, and there has been increased interest in additional habitat management. Suggested management actions for individual S. catenatus populations have focused on increasing habitat sizes, increasing the frequency of woody vegetation removal, creating habitat between populations, and translocating snakes between populations. I built forward-in-time simulations of population trends under current management and five alternative management activities using resistance maps that I previously developed in Population Viability Analysis (PVA) models. I found that connectivity improvements via the formation of new habitats (and ideally new populations) between the current populations or a hybrid connectivity/translocation strategy offered the greatest improvement towards both overall population size and the number of occupied patches. These connectivity models were superior to the base scenario representing no changes to management. Overall, my research has generated novel tools and approaches based on landscape genetics and demographic modeling for conservation of endangered and threatened species in fragmented landscapes. When applied to S. catenatus population is in NE Ohio, these approaches have provided new and significant insights on contemporary population structure in S. catenatus in NE Ohio, how the landscape created the observed patterns, and how this information can be used to generate management recommendations to promote the long-term persistence of this threatened reptile.
Download or read book Conservation Genetics in the Neotropics written by Pedro M. Galetti Jr. and published by Springer Nature. This book was released on 2023-08-29 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores how genetics and the new technologies in genomics have been used for conservation of plants and animals in the Neotropics. It shows the new perspective for conservation genetics beyond the use of theoretical and methods in genetics at species level and presents how genetics and genomics can be used for assessing communities. Conservation genetics and genomics are presented as a helpful field of study for resolving taxonomic uncertainties and hidden biodiversity, understanding populations and extinction risk, genetic management, wildlife forensic genetics, assessing biology and molecular ecology, assessing communities, conservation genomics and the use of conservation biology and genetics in science learning, highlighting case studies in the Neotropics. Applications of conservation genetics for management or policy, decision making, planning, and implementation of conservation practice in the Neotropics are addressed across chapters. This book will interest to researchers and students in conservation genetics and biology conservation interested in the Neotropics. Stakeholders and decision makers in conservation biology may also find this book useful.
Download or read book Landscape Genetics of Habitat Alteration Across Multiple Spatial and Temporal Scales in the Anuran Genus Ascaphus written by Stephen Frank Spear and published by . This book was released on 2009 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Urban Herpetology written by Joseph C. Mitchell and published by Society for the Study of Amphibians & Reptiles. This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Action Plan for Australian Lizards and Snakes 2017 written by Nicola Mitchell and published by CSIRO PUBLISHING. This book was released on 2019-12-01 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lizards and snakes (squamate reptiles) are the most diverse vertebrate group in Australia, with approximately 1000 described species, representing about 10% of the global squamate diversity. Squamates are a vital part of the Australian ecosystem, but their conservation has been hindered by a lack of knowledge of their diversity, distribution, biology and key threats. The Action Plan for Australian Lizards and Snakes 2017 provides the first comprehensive assessment of the conservation status of Australian squamates in 25 years. Conservation assessments are provided for 986 species of Australian lizards and snakes (including sea snakes). Over the past 25 years there has been a substantial increase in the number of species and families recognised within Australia. There has also been an increase in the range and magnitude of threatening processes with the potential to impact squamates. This has resulted in an increase in the proportion of the Australian squamate fauna that is considered Threatened. Notably over this period, the first known extinction (post-European settlement) of an Australian reptile species occurred – an indication of the increasingly urgent need for better knowledge and management of this fauna. Six key recommendations are presented to improve the conservation management and plight of Australian squamates. This Action Plan represents an essential resource for research scientists, conservation biologists, conservation managers, environmental consultants, policy makers from Commonwealth and State/Territory governments, and the herpetological community.
Download or read book The Natterjack Toad written by Trevor John Clark Beebee and published by Oxford University Press, USA. This book was released on 1983 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Austral Ark written by Adam Stow and published by Cambridge University Press. This book was released on 2015 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed, research-informed synthesis of the current issues facing the Australasian biota and the challenges involved in their conservation.
Download or read book The Status and Distribution of Reptiles and Amphibians of the Mediterranean Basin written by Neil Cox and published by IUCN. This book was released on 2006 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mediterranean-rim countries hold around 400 million people and 135 million of them live on the coast. A steady migration towards coastal areas, specifically in the south and east of the Mediterranean, is causing pressure on the coastal environment and, more importantly, on its biodiversity. In this second Mediterranean regional assessment, all the reptile and amphibian species existing within the region of study have been evaluated for their global conservation status. This assessment aims to assist in regional planning and to help identify internationally important sites for biodiversity. Like the first in the series, it also hopes to encourage development of a network of regional experts to enable future assessments and the continued updating of the baseline dataset.
Download or read book Amphibian and Reptile Road Ecology written by Cheryl S. Brehme and published by Frontiers Media SA. This book was released on 2024-05-21 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Roads may threaten the persistence of wildlife populations by acting as barriers to movement and/or sources of increased mortality across the landscape. Amphibians and reptiles have been identified as being particularly susceptible to negative road impacts. Many species migrate annually among habitats to support basic life history requirements such as breeding, development, foraging, and overwintering. For these species, individuals may need to successfully cross roads multiple times each year for the population to persist. Many are slow-moving and freeze in the presence of danger, making it almost impossible for them to avoid oncoming vehicles. Although there are a plethora of road mortality location and count data, the effects of road mortality on the long-term viability of amphibian and reptile populations and metapopulations are mostly unknown due to a lack of information on their abundance, vital rates, behavior, and spatial and temporal dynamics.
