Download or read book A Multiple scale Analysis of the Effects of Landscape Structure on Populations of Yellow spotted Salamanders Ambystoma Maculatum written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Multiple scale Analysis of the Effects of Landscape Structure on Populations of Yellow spotted Salamanders Ambystoma Maculatum written by Samara T. Eaton and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I examine the effects of landscape structure on the incidence and abundance of yellow-spotted salamanders, Ambystoma maculatum, and use these population level responses as indirect measures of movement. Two surveys of breeding populations in ponds located in a heterogeneous landscape were conducted and effects of landscape structure assessed at multiple spatial scales. Landscape structure was quantified as the proportion of forest and the total length of roads surrounding ponds. Additionally, the movement capabilities of juvenile A. maculatum in different habitat types was explored. Through the first survey I show that the proportion of forest influences incidence and density at a small spatial scale (100 m). I conclude that the breeding and post-breeding migration movements are influenced by the amount of forest and identify 15% forest, within 100 m of the pond, as a threshold amount of forest below which A. maculatum cannot persist at a pond. Results from a second survey, which encompassed a greater number of ponds at broader spatial scales, concur with the previous survey for the small scale effects of the proportion of forest, however, there is a significant effect of the proportion of forest at a broad spatial scale (1000 m). This provides indication that populations are spatially structured and that the amount of forest increases the connectivity of the landscape for A. maculatum. Also, at small spatial scales the total amount of road has a negative effect on incidence and abundance. Experimentally I assess the rates of movement of juveniles in forested and field habitat. Results show that juveniles can move faster in field habitat than forest. Finally, I explore the possibilities of harmonic radar as a new technique for tracking juvenile A. maculatum.
Download or read book Regional Population Structure of Spotted Salamanders Ambystoma Maculatum in a Fragmented Landscape written by Jennifer Lyn Purrenhage and published by . This book was released on 2004 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Genetic Structure Due to Variation in Breeding Time in a Salamander Population written by Scott A. Thomas and published by . This book was released on 2013 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fine-scale genetic structure of populations is traditionally thought to be shaped primarily by geographic barriers to reproduction among local populations. However, other mechanisms of isolation have been recognized, but little has been done to determine their relative roles in shaping genetic variation in natural populations. In this study, I test whether genetic structure within and among breeding ponds of spotted salamanders (Ambystoma maculatum) is influenced by within-pond variation in breeding time. I found significant genetic structure attributable to variation in breeding time within ponds. This temporal structure was not consistent across ponds, indicating it is a local and not a regional effect. However, this temporal structure did not fully resolve strong patterns of inbreeding within ponds, indicating that reproductive barriers operating with in ponds are more effective than either spatial or phenological ones. Together, these findings reveal complex relationships between genetic structure and variation in breeding phenology that would not be uncovered by spatial or temporal analyses alone.
Download or read book Landscape Genetics of the Small mouthed Salamander Ambystoma Texanum in a Fragmented Habitat written by Elizabeth Anne Rhoads and published by . This book was released on 2011 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat loss is the leading cause of species declines and extinctions worldwide. Fragmentation of original habitat into patches often accompanies habitat loss and spatially separates breeding populations across a landscape. Habitat fragmentation poses additional challenges for species by degrading habitat quality, altering population abundance and density, and decreasing gene flow among breeding populations in separate patches. Wetland loss and deforestation in western Ohio has fragmented both breeding and terrestrial habitat for woodland amphibians, where agriculture is now the dominant landuse. This project utilized genetic markers to study the effect of habitat fragmentation on the population structure of a woodland amphibian, the small-mouthed salamander (Ambystoma texanum), in Hardin County, Ohio. This species breeds in vernal pools within forest patches, and has low vagility. It was hypothesized that salamanders were not migrating between forest patches; and that populations in different forest patches would show genetic differentiation and small populations would have decreased genetic diversity. A method was developed to screen for unisexual Ambystoma salamanders, which also reproduce in vernal pools in the study area and whose larvae are difficult to distinguish from A. texanum larvae. For the population genetic analysis, a total of 160 A. texanum from eight breeding populations in five forest patches were genotyped for eight highly polymorphic microsatellite loci. The results indicate that all sampled populations have within-population structure, with the two most isolated populations having the highest inbreeding coefficients. Estimates of historical migration rates reveal that gene flow occurred in the past among sites that today show genetic differentiation. Overall our results suggest that forest fragmentation and wetland loss have reduced the connectivity of breeding populations, which supports numerous studies that implicate landscape change as the main threat to species decline.
Download or read book Persistence of the Larval Environment on Post metamorphic Performance and Population Dynamics in Amphibians written by Julie Charbonnier and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organisms with complex life cycles may experience diverse stressors during their development. Stressors experienced in early life stages may influence the quantity and quality of individuals in later life stages. However, it is unclear if these effects persist later in life and how they may influence population dynamics. This dissertation uses two amphibian species, the Western spadefoot toad (Pelobates cultripes) and the spotted salamander (Ambystoma maculatum) to explore how biotic and abiotic factors experienced in aquatic and terrestrial environments influence phenotype and survival. We use a combination of field mesoscosm studies, laboratory studies and modeling to explore how early life history stressors persist in diverse environmental contexts. In Chapter 1, pond drying and larval density negatively influence multiple aspects of phenotype in the Western spadefoot toad. In Chapter 2, reduced body size due to larval stressors persisted in the first year of life in spotted salamanders in both high and low terrestrial resource environments. Additionally, there was no relationship between size at metamorphosis and post-metamorphic terrestrial survival. In Chapter 3, low terrestrial moisture levels reduced post-metamorphic growth rates by reducing food intake in juvenile spotted salamanders from both high and low larval density treatments. In Chapter 4, we scale up the effects of reduced body size in the Western spadefoot toad to explore how reduced body size due to pond drying may influence population densities using a stage specific matrix model. Reduced body size, by delaying maturity, may reduce adult densities in the Western spadefoot toad. This dissertation suggests that life stages are highly interconnected, as stressors experienced early in life stage may persist through their effects on phenotype in the absence of compensatory mechanisms. Variation in later life stages may also influence phenotype, but may not completely erase effects of early environments. Stressors experienced early in life may also translate to population level consequences, especially when organisms experience multiple stressors across life stages.
Download or read book The Effects of Parasites Metals and Environmental Conditions on Spotted Salamander Ambystoma Maculatum Populations Breeding in Northern Arkansas written by Heather M. DeMali and published by . This book was released on 2014 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Terrestrial Habitat Use by Radio implanted Spotted Salamanders Ambystoma Maculatum written by Ashley Lynn Nussbaum and published by . This book was released on 2005 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptation to Acidification in Spotted Salamanders Ambystoma Maculatum written by Nicholas Gervais and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Declines in amphibian populations have been noted since the late 1980's with many of the causes linked to habitat contamination and destruction by natural and anthropogenic sources. Amphibians with bi-phasic life histories have been thought to be particularly vulnerable to negative environmental conditions but there is much evidence of their resilience and capacity to survive in degraded or contaminated environments. Larval amphibians in small permanent or ephemeral ponds may be particularly vulnerable to altered environmental conditions and may face the greatest pressure to adapt. In Chapter 1, I briefly review the evidence of amphibian declines and how populations may adapt to and overcome assorted negative environmental factors. In Chapter 2, I investigated the phenomenon of adaptation in a particular circumstance. I collected Spotted Salamander (Ambystoma maculatum) egg masses from a population breeding in a naturally acidic pond called Bat Lake, as well as four other populations living in lakes closer to pH neutral. To determine if the salamanders were adapted to their particular breeding lakes, I used common garden experiments in the lab where I raised larvae from each of the lakes in the waters from all the other lakes, as well as their own and compared the survival rates, size at metamorphosis and time to metamorphosis. Bat Lake larvae grew larger and survived longer in their acidic native breeding pond water than in the waters of other lakes suggesting they are adapted to their native pond waters. The larvae from the other lake populations showed similar results and fared better in their native waters than in the Bat Lake water. Based on these results, in Chapter 3, I tested if pH, specifically, was causal. I raised larvae from the five populations in waters of different pH (4.0, 5.5, 7.0), reasoning that if the Bat Lake population was more adapted to the high acidity compared to the other populations, the larvae from Bat Lake should demonstrate higher fitness correlates at lower pH than larvae of other populations. In this experiment, the Bat Lake larvae survived longer and grew larger in the highly acidic water than did larvae from the other populations. My results are consistent with natural selection for tolerance of low pH conditions tolerance among Bat Lake Spotted Salamander larvae and indicate that the salamanders from Bat Lake potentially exhibit signs of local adaption to the highly acidic conditions in which they live. This study was unable, however to prove whether this adaptation was due to evolutionary change, phenotypic plasticity, maternal effects or some other unknown factor. " --
Download or read book Influence of Landscape Arrangement and Wetland Condition on Breeding Dynamics of Ambystoma Maculatum spotted Salamander in Maine USA written by Amanda Frances Shearin and published by . This book was released on 2012 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Use of Microsatellites to Determine the Effective Population Size of a Local Population of Spotted Salamanders Ambystoma Maculatum written by Caroline G. Letourneau and published by . This book was released on 2011 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spotted salamander (Ambystoma maculatum) is an aggregate breeding amphibian that is dependent upon vernal pools for its reproductive life cycle. However, as wetland habitats become increasingly fragmented as the result of human activity, populations of A. maculatum may become progressively isolated from one another. Such isolation can impact the genetic variation of a population and thus pose challenges to its long term survival. This study used nine microsatellite loci to determine the levels of heterozygosity and the effective population size (Ne) of a population of spotted salamanders (Ambystoma maculatum) located at Wheaton College in Norton, Massachusetts. The mean observed heterozygosity was calculated as 0.59, which is similar to estimates of other A. maculatum populations, and Ne was estimated between 42 and 60 individuals. These values suggest that the Wheaton College vernal pool population of A. maculatum is genetically stable in the short term.
Download or read book Predator and Environmental Effects on the Polymorphic Egg Masses of Spotted Salamanders Ambystoma Maculatum written by Simon Leslie King and published by . This book was released on 2016 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Acid Precipitation on Embryonic Mortality of Spotted Salamanders Ambystoma Maculatum and Jefferson Salamanders Ambystoma Jeffersonianum in the Connecticut Valley of Massachusetts written by Robert Peter Cook and published by . This book was released on 1978 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Individual Population and Landscape scale Effects of Timber Harvest on the Red legged Salamander Plethodon Shermani written by Grant McClintock Connette and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat loss and alteration are widely recognized as major threats to global biodiversity and the vulnerability of animal species to these disturbance processes can depend on the behavioral responses of individuals to modified landscapes. In response to a changing environment, individuals may either attempt to adapt to changing conditions or disperse to new habitat. At the local scale, the emigration of individuals or changes in activity patterns could lead to reduced counts of animals in ecological studies. At broader spatial scales, organismal movement may enable population rescue or reestablishment after disturbance and maintain demographic connectivity among populations. These complex mechanisms underlying the perceived abundance and distribution of species often requires a careful deconstructing of demographic trends and sampling variation in ecological data. Lungless salamanders (Family Plethodontidae) are extremely abundant in many forest and headwater stream ecosystems of eastern North America. These salamanders breathe across their moist skin surface, making them sensitive to fluctuations in temperature and moisture conditions. Thus, changes in habitat characteristics are known to have a considerable effect on populations of these salamanders. However, studies identifying the behavioral or demographic causes of declines as well as patterns of long-term recovery are critically needed. My dissertation research combined behavioral, population and landscape-scale studies to identify the effects of timber harvest on a lungless woodland salamander (Plethodon shermani). The primary objectives of my research were to 1) to describe the short-and long-term effects of timber harvest on salamander abundance and 2) to determine the behavioral or demographic processes dictating the abundance and distribution of salamanders at both local and landscape scales. To characterize baseline population dynamics of the salamander, P. shermani, I conducted a 5-year capture-mark-recapture study which revealed substantial annual variation in survival, recruitment, and population size under natural conditions. Initial results suggest that differences in recruitment and over-winter survival might be responsible for the lower abundances of terrestrial salamanders in logged areas at the end of this study. In an experimental translocation of salamanders into a timber cut and nearby forest habitat, I found that salamanders respond to differences in habitat quality by altering their movement behavior. This type of behavioral shift might help mitigate the risk of sustaining activity in recently logged forest. In an additional study, I tracked salamanders using a PIT-tag telemetry system in order to identify mortality, rather than emigration or reduced activity, as the likely cause for perceived declines in salamanders immediately following timber harvest. Finally, in a series of landscape-scale surveys, I found that salamander abundance was positively correlated with forest age (i.e., years since harvest), that full population recovery can require greater than 100 years, and that populations of species with greater movement ability may recover faster due to immigration of individuals from surrounding forest. Collectively, these studies identify key behavioral and demographic processes responsible for observed changes in salamander populations and suggest specific strategies for conservation and management.
Download or read book Landscape level Population Structure and Local Variability in Marbled Salamanders Ambystoma Opacum of Western Massachusetts written by Lloyd R. Gamble and published by . This book was released on 2004 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Landscape Effects on Genetic Structure in Tiger Salamander Ambystoma Tigrinum Melanostictum Populations Across the Northern Range of Yellowstone National Park written by Stephen Spear and published by . This book was released on 2004 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Body Size on the Intraspecific Interactions and Behavior Among Larval Spotted Salamanders Ambystoma Maculatum written by David Gordon Chiller and published by . This book was released on 1993 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
