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Practicalities Of Re-Wilding, William C. Mcgrew

Animal Sentience

Re-wilding large-brained, intelligent mammals dependent on social learning to acquire survival skills is challenging. Each reintroduced species has different needs, but basic questions relating to essential aspects of successful release such as subsistence remain the same. Here I pose 12 ecologically and ethologically based questions that should be addressed (if not already done).

Population And Trophic Dynamics Of Striped Bass And Blueback Herring In The Connecticut River, Justin P. Davis

Doctoral Dissertations

Case studies of the ramifications of predator management for prey population dynamics can play a valuable role in developing ecosystem fisheries management. My dissertation focuses on the predator-prey interaction between Striped Bass (Morone saxatilis), an abundant predatory finfish, and an imperiled prey population of anadromous Blueback Herring (Alosa aestivalis). Annual returns of Blueback Herring to the Holyoke Dam on the Connecticut River in southern New England collapsed during the 1980-2000s, coincident with Striped Bass recovery. I studied the abundance and demography of both species in the Connecticut River during 2005-08, measured predation levels, and surveyed the …

Ecology, Phylogenetics, And Conservation Of Draba Asterophora Complex: A Rare, Alpine, Endemic From Lake Tahoe, Usa, Emily Ruth Smith Putnam

Theses and Dissertations

Rare, alpine, endemic species are particularly at risk for extinction. Alpine environments are especially vulnerable to climate change and human impacts, such as ski resort development and snowmaking. Draba asterophora Payson is a rare, alpine species that occurs only in three disjunct mountain-top regions surrounding Lake Tahoe. It is currently threatened by human impacts, such as ski resorts, as well as indirect influences of climate change and therefore in need of better understanding for conservation purposes. Draba asterophora may be able to serve as a case study for other similarly vulnerable, rare, alpine, endemic species with conservation needs. We utilized …

Warm Springs, Early Lay Dates, And Double Brooding In A North American Migratory Songbird, The Black-Throated Blue Warbler, Andrea K. Townsend, T. Scott Sillett, Nina K. Lany, Sara A. Kaiser, Nicholas L. Rodenhouse, Michael S. Webster, Richard T. Holmes

Dartmouth Scholarship

Numerous studies have correlated the advancement of lay date in birds with warming climate trends, yet the fitness effects associated with this phenological response have been examined in only a small number of species. Most of these species–primarily insectivorous cavity nesters in Europe–exhibit fitness declines associated with increasing asynchrony with prey. Here, we use 25 years of demographic data, collected from 1986 to 2010, to examine the effects of spring temperature on breeding initiation date, double brooding, and annual fecundity in a Nearctic - Neotropical migratory songbird, the black-throated blue warbler (Setophaga caerulescens). Data were collected from birds breeding at …

Detection Of Mortality In Tropical Forests Using Remote Sensing: From Treefall Gaps To Large Disturbances, Fernando Del Bon Espirito-Santo

Doctoral Dissertations

The frequency, severity, and intensity of natural disturbances in tropical forests continually re-shape forest structure. At small scale, branch or tree-falls gaps and subsequent recovery are important mechanisms for carbon cycling. At landscape scale, large disturbances (blow-downs) may also play a role on the structure and composition of tropical forests. Quantitative studies of natural disturbances across the occurrence spectrum (branch fall-gaps to blow-downs) are rare for the Amazon. Remote sensing coupled with intense field work data collection provides the means to analyze the dynamic of tropical forests at multiple scales. In this dissertation three aspects of natural disturbances were examined: …

Effects Of The Aquatic To Terrestrial Habitat Ratio On An Amphibian Predator And Its Prey, Amber Kramer

All Theses and Dissertations (ETDs)

This dissertation explores the effects of varying the composition of aquatic and terrestrial habitats in a landscape: the aquatic to terrestrial ratio) on amphibians that use both the aquatic and terrestrial habitats during their lives. In Chapter 1, I first used meta-analysis and simulations to demonstrate that as the longevity of an amphibian increases, the elasticity of the population growth rate to perturbations in the aquatic: larval) habitat decreases. In Chapter 2, I examined the abundance of larvae of a long-lived amphibian, Ambystoma maculatum, across landscapes that varied in their aquatic to terrestrial ratios and found that larvae of this …

Demographic Response Of American Ginseng (Panax Quinquefolius L.) To Climate Change, Sara Souther

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ecological response to recent climate change has been documented for a multitude of species worldwide. Climate models predict further increases in temperature, as much as 8 times the degree of warming that has already occurred. Given observations of species response to contemporary climate change and the unprecedented degree of warming expected over the next century, climate change will no doubt determine future ecosystem composition and affect global species diversity. In order to prevent loss of biodiversity, it is necessary to understand and accurately project species' response to climate, and to identify species that are vulnerable to climate change driven extinctions. …

Relative Abundance, Population Structure, And Habitat Utilization Of The Alligator Snapping Turtle (Macrochelys Temminckii) And Eastern Snapping Turtle (Chelydra Serpentina) In Southeastern Missouri, Timothy Charles Lescher

Theses

GENERAL ABSTRACT---Alligator Snapping Turtles have not been surveyed extensively in Missouri since 1993-94. Six sites that were sampled in the early nineties were re-sampled in 2009 at the same locations where previous researchers trapped. Significantly fewer significantly fewer Alligator Snapping Turtles were captured per trapnight at all six sites. The population structure of the Alligator Snapping Turtles had a significantly different distribution in 2009 compared to 1993-94. The population structure had shifted toward smaller individuals, and fewer adult males and adult females were captured in 2009 compared to 1993-94. The 1993-94 structure was normally distributed while the 2009 structure exhibited …

A Panax-Centric View Of Invasive Species And A Case Study On The Effects Of Garlic Mustard (Alliaria Petiolata), Kerry Lynn Wixted

Graduate Theses, Dissertations, and Problem Reports (ETD)

American ginseng (Panax quinquefolius L.) is a long-lived, valuable herb found throughout the eastern United States. Habitat degradation, harvest pressures, overbrowsing by deer and reduced genetic diversity are believed to be the primary causes of decline for this rare species; however the widespread threat of invasive species has yet to be investigated. Therefore, my research focused on examining the level of exposure of individuals and populations of ginseng to invasive plant species as well as partitioning the effects of a particular invasive, garlic mustard (Alliaria petiolata ), into those owing to competition and allelopathy. For my first study, I used …

An Ecological Study Of Panax Quinquefolius In Central Appalachia: Seedling Growth, Harvest Impacts And Geographic Variation In Demography, Martha E. Van Der Voort

Graduate Theses, Dissertations, and Problem Reports (ETD)

American ginseng (Panax quinquefolius L.) is a long-lived, slow-maturing understory perennial herb found in eastern North American forests. The economic value of P. quinquefolius on the world market has remained strong for nearly 300 years. It has high economic and social value in the central Appalachians as well. Persistent harvest of ginseng combined with habitat loss has reduced populations in the wild, threatening the future of the species and its continued harvest. American ginseng was placed on the CITES Appendix II list in 1973 due to population declines. These concerns led to a series of studies investigating the population dynamics …

Gopher Tortoise Habitat Use And Spatial Distribution In A Southeastern Florida Population, E. H. King

Electronic Theses and Dissertations 2000 - 2009

Gopher tortoise ecology is poorly understood in the rapidly developing, urbanized southeastern end of its range. This study reports on a population at Florida Atlantic University in Boca Raton, Florida. Burrow surveys were conducted from May to July 2003 and May to August 2004. Burrows were marked and mapped as was vegetative cover. Burrow locations were tested against vegetative cover height and soil types. Burrow locations did not differ among soil types. The densest concentrations of burrows were located in areas of low, patchy vegetative cover. This is consistent with known gopher tortoise habitat preferences elsewhere in their range. Gopher …

Effects Of Herbivory By White -Tailed Deer (Odocoileus Virginianus Zimm.) On The Population Ecology And Conservation Biology Of American Ginseng (Panax Quinquefolius L.), Mary Ann Furedi

Graduate Theses, Dissertations, and Problem Reports (ETD)

American ginseng (Panax quinquefolius L.) is a long-lived understory herb considered rare within its range. Harvesting pressures and habitat degradation/destruction are thought to be the primary causes of population decline although others factors such as browsing by white-tailed deer (Odocoileus virginianus Zimm.) have not yet been explored. To understand the effects of deer browsing on natural ginseng populations, my research focused on four specific objectives. First, I investigated how plant characteristics and microsite conditions influence the susceptibility to being browsed. I found that apparency plays a role in influencing browse selection, such that large, reproductive plants in visible and accessible …

Censusing And Modeling The Dynamics Of A Population Of Eastern Hemlock (Tsuga Canadensis L.) Using Remote Sensing, W. Robert Lamar

Graduate Theses, Dissertations, and Problem Reports (ETD)

A population of eastern hemlock (Tsuga canadensis L.) was censused from the ground using traditional field methods and from the air using large scale, high-resolution, aerial imagery in the early spring of 1997, 1998 and 1999. A manual crown survey map of the population, prepared from aerial imagery, was compared to a traditional field census. Over 60% of the individuals measured on the ground were not detected in the aerial census. Tree size, crown density and crown position all played roles in determining a crown's visibility from the air. Nearly all large, upper canopy hemlocks were visible in the aerial …

Habitat And Demography Of Understory Trees In Mixed Species Hardwood Forests In Northern Florida, United States Of America., Charles Kwit

LSU Historical Dissertations and Theses

Temperate mixed-species hardwood forests of northern Florida, USA, contain a high diversity of understory tree species, some of which have been hypothesized to require disturbance (e.g., hurricanes and/or treefall gaps). Taxus floridana is a rare understory conifer endemic to midslopes of ravines of the Apalachicola River Bluffs, and is found primarily on north-facing slopes. Vegetation sampling in the southern portion of T. floridana's range revealed the presence of an upslope oak-hickory community of suggested recent origin, and higher densities of American beech (Fagus grandifolia ), southern magnolia (Magnolia grandiflora), and evergreen understory trees on north-facing midslopes with T. floridana than …

Life History And Reproductive Biology Of The Estuarine Nudibranch Tenellia Adspersa (Nordmann, 1845), Charles Morgan Chester

Doctoral Dissertations

Tenellia adspersa is a small (5-7 mm) estuarine nudibranch. Tenellia lives in a highly variable environment and feeds on many gymnoblastic and calyptoblastic hydroids. I undertook a field study at four sites in the Great Bay Estuary (Durham, New Hampshire) to assess the amount of variability in abiotic and biotic factors. Environmental parameters (temperature and salinity) and the availability of hydroid prey (Cordyolophora lacustris and Obelia spp.) varied within the generation time of Tenellia and could affect its life history.

Laboratory studies compared the growth rate of the hydroid, Cordylophora to the growth rate and predation rate of Tenellia. The …