Environmental Sciences Commons^™

Essential Spawning Habitat For Atlantic Sturgeon In The James River, Virginia., Geoffrey Austin

Theses and Dissertations

Substrate composition plays a critical role in determining the spawning success of Atlantic sturgeon. A benthic analysis of the tidal freshwater portion of the James River, Virginia, was performed to locate and protect remaining sturgeon spawning habitat within the James River system. I modeled structural habitat, substrate distribution, and river bathymetry from Richmond, Virginia to the Appomattox River confluence. A classification model was developed to describe the dominant substrate type (mud/silt, sand, gravel, bedrock) using side scan sonar data collected from August 2011-Febuary 2012. River depth, bottom imagery, substrate density (hardness), and ground truth substrate samples were interpolated into a …

A Reexamination Of The Eastern Collared Lizard (Crotaphytus Collaris Collaris) In Arkansas, Ashley A. Grimsley

Graduate Theses and Dissertations

Loss of suitable habitat is a threat to species worldwide. Habitat destruction, including loss, change, and fragmentation of habitat, is the leading cause of species extinction. Eastern collared lizards (Crotaphytus collaris collaris) are habitat specialists on glades. Both C. c. collaris and glade habitats are rare and of special concern in the state of Arkansas. Many glade populations have already been extirpated in the Ozarks of Arkansas and Missouri. Increasing knowledge of the distribution, habitat structure, and population dynamics of C. c. collaris is important to ensure the survival of this species in Arkansas.

A literature review of …

Modeling Gopher Tortoise (Gopherus Polyphemus) Habitat In A Fire-Dependnent Ecosystem In North Florida, Christina Legleu

LSU Master's Theses

Gopher tortoise (Gopherus polyphemus) populations have declined with longleaf pine (Pinus palustris) ecosystems across their historic range. The influence of gopher tortoise burrows on co-inhabiting plants and animals necessitates an understanding of how landscape features and management practices influence gopher tortoise presence, absence, and abandonment. In this study, naïve gopher tortoise burrow encounter rates from a line transect distance sampling (LTDS) pilot study were used for two methods of modeling gopher tortoise habitat. In Chapter 1, naïve encounter rates were tested for a linear correlation to a HSI model created from three ranked geographic information system (GIS) landscape variables. Initial …

Ecology Of Rusty Blackbirds Wintering In Louisiana: Seasonal Trends, Flock Composition And Habitat Associations, Emma Elizabeth Deleon

LSU Master's Theses

With an estimated population loss of at least 5% annually and a 100-year history of decline, Rusty Blackbirds (Euphagus carolinus) are one of the fastest declining bird species in North America. Determining cause of decline is important, both for conserving the species and for identifying threats to the wooded wetland ecosystems they use on their boreal breeding-grounds and their wintering-grounds in the southeastern United States. One hypothesis is that loss of wintering ground habitat, possibly in conjunction with competition or disease, is causing Rusty Blackbird decline. To determine contribution of wintering ground conditions, it is important to understand the behaviors …