[PDF] Determining Population Demographics And Genetic Structure Of An Endangered Species The Spotted Turtle Clemmys Guttata On The Delmarva Peninsula eBook

Author : Maeghan L. Ciampa
Publisher :
Page : 116 pages
File Size : 16,39 MB
Release : 2011
Category : Clemmys guttata
ISBN :

GET BOOK

The spotted turtle (Clemmys guttata) is a small, semiaquatic species that has been listed as a species of special concern in Massachusetts. Populations of the species on Nantucket Island exist in fragmented and possibly isolated populations, although the effect of this fragmentation on current population structure is unknown. This study attempted to look at the population structure of two populations, one from the Medouie Creek Wetland Complex on Nantucket Island and a mainland population from Halifax, MA. Microsatellite loci were examined to analyze the population genetics and compare two populations. Seven microsatellite loci were analyzed in 40 spotted turtles sampled from Nantucket Island and 10 turtles from Halifax. The seven microsatellite loci were found to be highly polymorphic. A total number of 92 alleles were found across all loci, with the number of alleles per locus ranging from seven to sixteen. Using various statistical tests, the multilocus genotypes of individuals in both populations were analyzed to determine population structure. Both populations were found to be i Hardy-Weinberg and linkage equilibrium and highly significant genetic variation was found within and between the Nantucket and Halifax populations. Private alleles were found in both populations across all microsatellite loci and analysis of these alleles indicates some loss of genetic diversity in the Nantucket Island population. Overall, the results of this study were used to classify the Nantucket Island and Halifax, MA populations as genetically distinct from each other and that all individuals sampled belong to two genetic clusters that correlate to geographic population assignment. These data suggest that the two populations should be regarded as distinct management units.

Author : Amanda M. Rocker
Publisher :
Page : 88 pages
File Size : 38,32 MB
Release : 2022
Category : Clemmys guttata
ISBN :

GET BOOK

Reptiles are experiencing decreased population sizes and declines in number of populations. Despite this overall pattern, for many species, there remains insufficient data to understand population trends, let alone the specific causes of these declines. One species experiencing severe declines, but sparse assessment is the spotted turtle (Clemmys guttata), a freshwater species found in wetlands in Eastern North America and classified as endangered under the IUCN Red List. This decline likely has occurred because of potential threats such as predation, collection for the pet trade, and habitat loss. I studied the size class distributions of turtles in Maryland and Delaware populations based on frequency of juvenile and adult turtles. I found that C. guttata populations had a negatively skewed size distributions at all study sites. However, they were primarily individuals in the 90-100 mm plastron length size range, while larger, older, individuals were not typically present. Additionally, I analyzed the potential predation of C. guttata based on predator-caused injuries and assessing predator abundance via camera traps. Clemmys guttata had a greater rate of predator-caused injuries compared to other common turtle species; however, there was no correlation between injury rate and predator activity, specifically regarding raccoons (Procyon lotor). My results suggest while there was a large proportion of adults in populations of C. guttata at my sites, very old adults were absent. This was potentially caused, in part, due to predation, but the explanation for high injury rates of C. guttata is complicated and likely involves other factors such as human removal for the pet trade.

Author : Wayne G. Landis
Publisher :
Page : 18 pages
File Size : 24,29 MB
Release : 1983
Category :
ISBN :

GET BOOK

The population dynamics and structure of the spotted turtle, Clemmys guttata, were studies from 1970 until 1982. Carroll Island was the site of chemical testing from post WW II until 1971. Special consideration was given to the impact upon the populations of turtles by the chemicals released on Carroll Island. Several findings are noteworthy. The number of juveniles on the island has steadily declined over the 12 years of sampling. The current (1982) population is half of that estimated for 1972-73. The proportion of females dropped as low as 0.25 of the population. Four possible hypotheses are delivered to explain the observations. The most likely explanations are that a temperature anomaly or natural catastrophe dramatically reduced the proportion of females present. At the same time the population of turtles overshot the carrying capacity of the environment after cessation of an artificial or natural constraint.

Author : Caitlin Dailey
Publisher :
Page : 110 pages
File Size : 34,48 MB
Release : 2017
Category : Clemmys guttata
ISBN :

GET BOOK

"In order to protect threatened and endangered species, their habitat needs to be adequately documented and assessed for conservation planning. The utilization of mapping programs such as ArcGIS can help researchers in determining the most optimal sites for a particular species in a given area. This research revises a previous habitat suitability model by Correa-Berger (2007) for the spotted turtle (Clemmys guttata) in nine counties of upstate New York. Using the same initial parameters for the creation of the seed sites and habitat requirements for spotted turtles that Correa-Berger used in his 2007 analysis, the model utilized updated Land Use/Land Cover (LULC) data, added a stream connectivity parameter, and added a calcium carbonate soil parameter in order to improve the model. The initial updated model did not fit well with the historical spotted turtle sightings from the NYSDEC. A second model was created using a simplified seed site methodology, an adjusted road width parameter, and eliminated the use of the DEC classified wetlands. The revised model captured 16 out of 33 turtle sightings within what was considered optimal sites. While the second model was more successful matching the historical spotted turtle sightings compared to the first model, analysis of model misses suggest the model could potentially be improved with the use of a locally created LULC classification using remote sensing techniques, expanding the stream connectivity parameters to include stream health, and using additional soil parameters."--Abstract.

Author :
Publisher :
Page : 0 pages
File Size : 24,73 MB
Release : 2015
Category :
ISBN :

GET BOOK

Turtles (order Testudines) are an ancient but highly threatened vertebrate group. Successful preservation of biodiversity in this group (as in others) requires identification of current threats, species-level traits that modulate vulnerability to these threats, and both general and species-specific strategies for mitigating threats. In this dissertation, I address these research needs for several Wisconsin turtles, focusing on the UCN-Endangered Blanding's turtle (Emydoidea blandingii). The approaches used here encompass multiple spatial scales, combine genetic and demographic methods of characterizing population viability and spatial ecology, and utilize comparisons among species, specifically by comparing endangered Blanding's turtles with more common co-occurring painted turtles (Chrysemys picta) and snapping turtles (Chelydra serpentina). Each chapter of this dissertation is written and formatted as a manuscript for publication in a scholarly journal. Chapter 1 (published in Diversity and Distributions) investigates the population-level demographic and genetic responses of three turtle species with differing habitat preferences and life histories to roads and climate. Chapter 2 (prepared for submission to Molecular Ecology) describes the effects of past and present landscape features on population genetic structure in this same suite of turtle species. Chapter 3 (submitted to Methods in Ecology and Evolution) develops a novel method for estimating dispersal rates from genetic kinship data and uses this method to investigate the spatial ecology of nesting female Blanding's turtles. Finally, Chapter 4 (submitted to Biological Conservation) deals with the demographic response of a population of Blanding's turtles to habitat restoration. Overall, the work collected here demonstrates how differences in species' life history traits and habitat preferences can affect their vulnerability to environmental change and suggests how strategies for managing populations and genetic diversity can be tailored to these traits.