Life Sciences Commons^™

The Forgotten Cousin In Freshwater Community Ecology: Tidal Freshwater Wetlands, Jack R. Mclachlan

Electronic Theses and Dissertations

Tidal freshwaters are unique in their placement in the landscape, forming where freshwater riverine flows are sufficient to overwhelm the saline water of the incoming tide, but not strong enough to suppress tidal water-height fluctuations. Tidal freshwaters and their wetlands have been overlooked by freshwater and marine researchers alike; neither discipline considers tidal freshwaters to fall under their purview. Invertebrate communities in tidal freshwaters are thought to be species depauperate; the consensus is that they support fewer taxa than nearby non-tidal freshwaters, but little is known about how these communities are structured. This study investigated how tidal hydrology, an atypical …

The Influence Of The Invasive Chinese Tallow (Triadica Sebifera) Leaf Litter On Aquatic Chemistry And Microbial Community Composition, Raymond D. Montez

Electronic Theses and Dissertations

Global climate change and anthropogenic activity have facilitated the movement and invasive potential of nonnative plants in native environments. These invasions can have negative effects on ecosystem diversity and function. The nonnative and invasive plant, Chinese Tallow (Triadica sebifera), has already invaded much of the south eastern US where it is outcompeting native tree species and changing ecosystem diversity in a variety of habitats. Leaf litter from the Chinese tallow has been shown cause changes in dissolved oxygen and pH in the aquatic environment. Turbidity is also affected when Chinese tallow litter is present in water. A series of …

Dietary Resource Utilization Patterns And Head Morphology Among Three Sympatric Watersnake Species., Micah Warren Perkins

Electronic Theses and Dissertations

The coexistence of similar species may be related to a variety of resource utilization differences. Dietary resource utilization variation may be the most important difference allowing for the coexistence of sympatric snake species. Many watersnakes (Nerodia spp.) live in sympatry and use similar aquatic habitats feeding on similar prey. While these sympatric watersnakes may have different general foraging patterns, snake diet may be affected by a variety of factors. Therefore, I initiated an investigation to understand the coexistence of sympatric plain-bellied (N. erythrogaster), diamondback (N. rhombifer) and northern (N. sipedon) watersnakes by addressing …

Understanding The Impact Of Commercial Harvest On White Suckers (Catostomus Commersonii) In Maine, Megan A. Begley

Electronic Theses and Dissertations

The State of Maine issues an unlimited number of commercial permits for the harvest of White Suckers Catostomus commersonii in Maine’s inland waters. The fishery provides a necessary source of fresh lobster Homarus americanus bait to coastal communities at a time when other bait sources are scarce. The impacts of the increasing number of permits and subsequent numbers of fishermen on the white sucker population is unknown. The Maine Department on Inland Fisheries and Wildlife (MDIFW) has closed a number of waters due to concerns that overfishing and incidental catch of other fish species may occur.

In Chapter 1, we …

Behavioral Ecology Of Landbird Migrants In A Complex And Changing Flyway System: The Gulf Of Maine, Adrienne J. Leppold

Electronic Theses and Dissertations

In and around the Gulf of Maine, over 300 species of birds have been documented during migration, and tens of millions of songbirds may pass through the region on a single autumn night. Shorelines are widely documented as major migration corridors. There is ample evidence that coastal areas concentrate migrants and many species make overwater movements to and from breeding and wintering grounds. Data collected from radar, banding, and ceilometry studies in the northeast have provided us with evidence that birds migrate along the coast and make overwater movements across the Gulf of Maine and Bay of Fundy during both …

Spruce Grouse Habitat Ecology In Maine's Commercially Managed Acadian Forest, Stephen W. Dunham

Electronic Theses and Dissertations

Spruce grouse (Falcipennis canadensis) inhabiting the mixed coniferous-deciduous forests of the northeastern United States are at the southern extent of their range. These mixed forests are known collectively as the Acadian forest and represent the transitional zone between the boreal forest to the north and the deciduous northern hardwoods forests to the south. Often assumed to be associated with mature, unharvested forest in this region, few studies have assessed habitat relationships of the species within areas dominated by commercial forest management. We investigated the influence of stand maturity, vertical and horizontal cover, and patchiness on the occupancy and …

Exploring The Threats Of Dams And Ocean Conditions: In-River Movements And Ocean Growth Of Atlantic Salmon (Salmo Salar) From Maine's Rivers, Lisa K. Izzo

Electronic Theses and Dissertations

Substantial declines of anadromous Atlantic Salmon Salmo salar have occurred throughout the range of the species, with many populations at the southern extent of the distribution being extirpated or endangered. While Maine is the last state in the country where adult Atlantic Salmon return to rivers each year to spawn, numbers have decreased dramatically in recent decades, with typically less than 2,000 spawners returning to all Maine's rivers combined. The complex life history of this species, which involves a juvenile freshwater phase followed by a marine phase that can last one to five years before returning to freshwater to spawn …

Effect Of Migration, Carrying Capacity, And Fecundity On The Formation Of Clinal Patterns During Range Expansions., Neha J. Angal

Electronic Theses and Dissertations

Range expansions, empirically and in simulations, lead to clinal patterns of genetic diversity. Clines are often used as spatial markers of past migrations. This study investigated the effects of migration, growth, and carrying capacities on clinal patterns during range expansions, using forward-time simulations in Nemo. Initial results show, in the absence of prior population structure, range expansions result in a loss of diversity strongly affected by migration, growth, and carrying capacity. This loss of diversity did not persist to the final generation, corresponding to 10,000 years, indicating clinal patterns are less durable than previously assumed—challenging the utility of clinal patterns …

Effects Of Invasive Shrub Honeysuckle (Lonicera Maackii) And Forest Composition On Bird Communities In Woodland Stands., Katie Rae Lynch

Electronic Theses and Dissertations

Invasive species pose a threat to aquatic and terrestrial ecosystems by decreasing biodiversity (Didham et al. 2005). Amur bush honeysuckle (Lonicera maackii) has typically reduced native plant diversity and altered animal communities by influencing animal abundance and activity (Collier and Vankat 2002). This study was intended to determine whether honeysuckle density or other characteristics of forested stands influence avian diversity, whether impacts are seasonally dependent, and whether correlations exist between attributes of forested stands and honeysuckle density. In order to test the hypotheses, thirteen forest stands within the Louisville Metropolitan Area were selected. They had similar tree composition …

Exploring The Relationship Between Behaviour And Neurochemistry In The Polyphenic Spider, Anelosimus Studiosus (Araneae: Theridiidae), Jennifer B. Price

Electronic Theses and Dissertations

The importance of social behaviour is evident in human society, but there are both costs and benefits associated with cooperation and sociality throughout the animal kingdom. At what point do the benefits outweigh the costs, and when do selective pressures favour sociality and colonization over solitude and independence? To investigate these questions, we have focused on an anomalous species of spider, Anelosimus studiosus, also known now as the northern social spider. Throughout its broad range, A. studiosus is solitary and aggressive, but recently, colonies of cooperative and social individuals have been observed at northern latitudes. This leads to two …

Assessment Of A Hatchery Based Rainbow Smelt Supplementation Effort, Andrew O'Malley

Electronic Theses and Dissertations

Rainbow Smelt (Osmerus mordax) are an important fish distributed throughout northeastern North America with both anadromous and landlocked populations. Abundance, size at age, and maximum size vary widely among populations and life histories. In order to compare anadromous and landlocked populations, we collected spawning adults in 2014 from four anadromous and three landlocked populations. Scales and otoliths from the anadromous fish were examined and compared for estimates of bias and precision in ageing. Analysis of both scales and otoliths provided age estimates that were acceptable, but estimates from scales were more precise and had less bias. Otoliths were …

Insights Into The Introduction Histories And Population Genetic Dynamics Of The Nile Monitor (Varanus Niloticus) And Argentine Black And White Tegu (Salvator Merianae) In Florida., Jared Price Wood

Electronic Theses and Dissertations

This dissertation examines the population genetic dynamics of two Florida invasives: the Nile monitor (Varanus niloticus) and Argentine black and white tegu (Salvator merianae). I also provide insights into the introduction histories of both species. This study was developed as part of a collaborative effort with the Florida Wildlife Commission to expand our knowledge of these highly detrimental, invasive lizards. All research activities involving animals and animal tissues were approved by the University of Louisville’s Institutional Animal Care and Use Committee (IACUC Proposal #: 12024). I start with a brief introduction into what makes invasive species …

Woody Plant Communities Of Three Urban Wetlands And The Success Of An Invasive Shrub (Lonicera Maackii) Over Natural And Experimental Flooding Gradients., Meghan Rhea Langley

Electronic Theses and Dissertations

Globally, wetlands are known for providing important ecosystem services that enhance the quality of human life and regulating global biogeochemical cycles. Despite the wide recognition of their value, temperate forested wetlands are the least protected type of ecosystem world-wide, and are threatened by human activities such as logging and development. The ecology of forested wetlands remaining in urbanized areas is impacted by a multitude of anthropogenic threats, including fragmentation (which decreases the amount of interior habitat and increases edge habitat), hydrologic modification (ditching and draining of wetlands) and the incursion of invasive species (which are frequently introduced by human activities). …

Sources Of Ecologically Important Trait Variation In Mosquitofish (Gambusia Affinis And Gambusia Holbrooki), Heather Ann Arnett

Electronic Theses and Dissertations

The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (Gambusia affinis and G. holbrooki) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish …

An Examination Of Plant Community Composition In Six Carolina Bays On The Coastal Plain Of South Carolina, Katherine L. Altman-Goff

Electronic Theses and Dissertations

Historically high rates of human impact and recent Supreme Court cases, which have affected the regulation of geographically isolated wetlands in the United States, suggest that Carolina bays may be at high risk of human impacts in the future. Conservation efforts should be established based on applied ecological data and, if regulations by state and federal agencies are unable to conserve Carolina bay wetlands, it may be important to prioritize individual bays for preservation on protected lands. I examined plant community composition, diversity, richness, and rarity and soil parameters in six Carolina bays across South Carolina, using a replicated ecological …

Assessing Freshwater Mussels (Bivalvia: Unionidae) In South Dakota And Identifying Drivers Of Assemblage Variation, Kaylee L. Faltys

Electronic Theses and Dissertations

Native freshwater mussels (Family: Unionidae) are among the most threatened groups of freshwater fauna on Earth. Approximately 35 species have gone extinct since the 1900s and 72% of remaining species are considered endangered, threatened, or species of special concern. Unionid research can begin by establishing species presence and distributions via surveys. Objectives for this study were to 1) implement the first comprehensive unionid survey for South Dakota to assess distribution, composition, and decline, 2) estimate assemblage density and determine local versus broad scale habitat drivers of assemblage variation, and 3) determine areas of unionid conservation priority in South Dakota. Mussels …

Effects Of Visitors And Enrichments On Behavior Of Captive Red Wolves’ (Canis Rufus) At The Great Plains Zoo, Sioux Falls, South Dakota, Kylee S. Shotkoski

Electronic Theses and Dissertations

Red wolves (Canis rufus) are the first animals to maintain a wild population from captive, released individuals. A captive breeding program for red wolves was started before complete extirpation, and 4 breeding pairs were released in Alligator River National Wildlife Refuge (North Carolina) in 1987 and a small wild population still exists there. Currently, there are several captive breeding facilities for red wolves within the Species Survival Plan (SSP) program. The Great Plains Zoo in Sioux Falls, South Dakota participates in the SSP program. My study was initiated to create a natural history background and evaluate interaction between …

Shell Repair In Geukensia Demissa And Predation Preferences Of Callinectes Sapidus: Do Crabs Target Mussels With Weakened Shells?, Madeleine S. Gillis

Electronic Theses and Dissertations

Atlantic blue crabs, Callinectes sapidus, are voracious predators that often leave damage on the shells of unconsumed ribbed marsh mussels, Geukensia demissa. The extent of shell damage and size-dependent tradeoffs in marsh mussel growth and repair, as well as the effects of shell damage on crab predation preferences, were determined in this thesis. A preliminary experiment investigated characteristics of damaged mussels in the field. Mussels (n = 30) were collected in the fall of 2011 within two ocean-dominated inlets along the South Carolina coast and were measured for size (length, width, height), area of damage, shell thickness, mass, and strength …

Impact Of Light Pollution On Species Interactions, Kylee Grenis

Electronic Theses and Dissertations

Over half of the world's population lives in urban areas leading to night skies that are substantially degraded by artificial lights. Yet, we know little about how light pollution affects the surrounding natural communities. What we do know focuses on the impact of light pollution on individual species. Therefore, I investigated the impact of light pollution on species interactions. I determined whether light pollution is a mechanism of community change, evaluated whether there were changes in species interactions between predators and prey, and indirect and direct interactions between insect herbivores and their host plants by examining the entire life cycle …

The Ecology And Evolution Of Rare, Soil Specialist Astragalus Plants In The Arid Western U.S., Joseph M. Statwick

Electronic Theses and Dissertations

Organisms that specialize in uncommon habitats are, by their very nature, inherently uncommon. Specialization has its advantages, namely reduced competition and predation, but it also incurs costs. Specialists often have small population sizes, narrow ranges, and fragmented habitat, all of which engender negative consequences on an evolutionary timescale. Herein, I examine benefits and costs of specialization in selenium-hyperaccumulating plants in the genus Astragalus (Fabaceae). These plants are disproportionately likely to be rare and of conservation concern. Thus, I optimized germination pretreatments for Astragalus species such that seed loss can be minimized during ex situ cultivation, and found that physical scarification …

The Spatial Distribution Of Terrestrial Stable Carbon Isotopes In North America, And The Impacts Of Spatial And Temporal Resolution On Static Ecological Models, Sydney M. Firmin

Electronic Theses and Dissertations

Due to the unique spatial and temporal characteristics of ecological phenomena, the extent and grain size of spatial data sets essentially filter the observations. This thesis examines the impacts of temporal and spatial resolution on the modeling of terrestrial stable carbon isotopic landscapes (isoscapes). I model the distribution of leaf stable carbon isotope composition (delta¹³C) for the continent of North America at multiple temporal and spatial resolutions. I generate each delta¹³C isoscape variation by first predicting the relative abundance of C3/C4 vegetation cover using monthly climate grids, crop distribution/type grids, and remote sensing data of plant …

Competitive Effects Of Increased Plant Species Richness And Increased Endemic Versus Native Generalist Species Dominance On The Invasive Grass Microstegium Vimineum During Oak Woodland Restoration, Sean Anthony Moyer

Electronic Theses and Dissertations

The hypothesis that species-rich assemblages are resistant to invasion by non-native species has generated considerable research and controversy. However, the relevance of such research to the conservation of biodiversity is questionable, given that local species richness often does not correlate with regional or global species richness, two metrics undoubtedly important to conservation. Furthermore, species of greater conservation interest (i.e. endemics) and widespread generalist species may compete differentially with non-native invasive species. To test whether plant species richness or species fidelity to a regionally rare habitat were more important in competitively suppressing an invasive species, I established a field competition experiment …

Evaluation Of Bison (Bison Bison) Ecology At The Olson’S Bison Conservation Ranches, Pine River Ranch, Manitoba, Canada, Joshua L. Leonard

Electronic Theses and Dissertations

Bison (Bison bison), the largest mammalian species in North America, historically numbering in the tens of millions (Roe 1970, McHugh 1972, Dary 1989, Shaw 1995), was nearly extirpated at the turn of the 19th century (Knapp et al. 1999; Gates et al. 2010). At the time, estimates of less than 1,000 bison remaining in North America are widely accepted (Hornaday 1889; Seton 1927; Gates et al. 2010). The decline of bison includes factors such as disease (Flores 1991; Isenberg 2000), sport hunting (Danz 1997; Dary 1989; Hewitt 1919; Isenberg 2000; McHugh 1972), and unofficially funded commercial hunting by the U.S. …

Community Ecology Of Soil Microbes In Southeast Usa Oak-Pine Woodlands, Ann L. Rasmussen

Electronic Theses and Dissertations

Soil microbial communities can have important effects on plant growth and plant community ecology; however, the relationships between trees and soil microbial communities are still relatively poorly understood. Here i examine several of these relationships. Chapter 1 examines how ecological restoration and environmental conditions affect the community composition and enzyme activities of Ectomycorrhizal fungi (emf). Chapter 2 considers whether host specificity in emf structures taxa occurrence on oaks and pines, and chapter 3 investigates how ash addition affects oak seedling growth and the soil bacterial community. I found that while wildfire lowered emf diversity, prescribed burning did not. Ectomycorrhizal root …

Biogeographical Patterns In The Hard-Tick Genus Amblyomma Koch 1844 (Acari: Ixodidae), Matthew H. Seabolt

Electronic Theses and Dissertations

Amblyomma Koch is a genus of hard-ticks with approximately 130 species. Its geographical range is typical for organisms with a Gondwanan origin. A majority of these species are endemic to the Neo- and Afrotropical regions, with the remaining taxa dispersed throughout Southeast Asia, Australia and the Pacific islands. Based on this distribution, we hypothesize that the genus dispersal patterns will mirror the fragmentation and continental drift of the Gondwanan supercontinent. Maximum parsimony, maximum likelihood, Bayesian inference and node-dating analyses of nuclear 18S rDNA gene sequences reveal a more recent origin and radiation patterns within the genus and suggest that Amblyomma …

Developing Management Guidelines That Balance Cattle And Timber Production With Ecological Interests In The Black Hills Of South Dakota, Kurt M. Chowanski

Electronic Theses and Dissertations

Forested lands contribute to the United States (US) economy by providing livestock and timber production. Livestock grazing of forested lands has been widespread throughout the western US since the settlement era, and currently occurs on 51.4 million hectares (ha) representing 16% of all US grazing land and 22% of all US forested land (Nickerson et al. 2011). While livestock grazing and timber harvest are occurring on a substantial amount of forested land, relationships between management practices, tree stocking, timber production, forage production, livestock grazing, wildlife, aesthetics, and ecological integrity are not well documented. Whether considering timber or cattle, finding a …

Impacts Of Wetland Characteristics On Duck Use In The Prairie Pothole Region (Ppr) 1987-2013, Fred Thomas Oslund

Electronic Theses and Dissertations

Since 1987 the Waterfowl Breeding Populations and Production Estimates, also called the Four Square Mile Survey, has been conducted annually in the U.S. Prairie Pothole Region. The survey was designed to assess the influence of the Small Wetlands Acquisition Program on contributions to continental waterfowl populations (Cowardin et al. 1995). Each year cooperators visit sample wetlands during two survey periods, collecting data on observed waterfowl and pond conditions. Along with ground counts, aerial photography of sample areas is collected annually, capturing habitat conditions. My objective was to assess the influence of local and landscape factors on duck pair densities. Local …

Effect Of Oil And Natural Gas Development On Survival And Health Of White-Tailed Deer In The Western Dakotas, Katherine L. Moratz

Electronic Theses and Dissertations

Oil and gas development in North Dakota has resulted in the need for information regarding how increased activity has affected white-tailed deer (Odocoileus virginianus) populations. We evaluated white-tailed deer ecology in response to energy development and hypothesized that oil and gas development would negatively affect adult and neonate white-tailed deer due to increased vehicle traffic and human-related effects. We captured and radio-collared adult female and neonate white-tailed deer across three study areas: Dunn County, North Dakota, an area influenced by energy development, and Grant County, North Dakota, and Perkins County, South Dakota, areas not impacted by energy development at this …

Assemblage Structure, Production, And Food Web Dynamics Of Macroinvertebrates In Tropical Island Headwater Streams, Keysa G. Rosas-Rodriguez

Electronic Theses and Dissertations

Variation in long-term temperature and precipitation patterns will likely influence the decomposition and export of benthic organic matter and influence aquatic macroinvertebrate consumer communities. Tropical systems are relatively understudied; therefore basal information is urgently needed. As part of an ongoing long-term study, we monitored macroinvertebrates in two shrimp-dominated and fishless headwater streams within the Luquillo Experimental Forest in Puerto Rico from 2009-2010. We combined growth rates with yearly biomass data to calculate secondary production and examined gut contents to develop quantitative food webs. Macroinvertebrate assemblages were dominated by a few insect taxa, with similar biotic composition across streams and habitats, …

Genetic And Temporal Variation In Resource Exchange Between An Ectomycorrhizal Fungus, Rhizopogon Occidentalis, And Seedlings Of Pinus Radiata, Mariah Meachum

Electronic Theses and Dissertations

Various economic theories have been adapted to explain the evolutionary persistence of resource exchange mutualisms such as mycorrhizae. The ratio of resources exchanged is an important variable comto all these models. Measuring resource exchange ratios is the first step in testing the hypotheses predicted by these models and will provide insight into resource dynamics of mutualisms. We examined how the carbon, nitrogen and phosphorus resource exchange dynamics between Pinus radiata and an ectomycorrhizal fungus, Rhizopogon occidentalis, varied between native populations of Pinus radiata and over the first 64 weeks of the mycorrhizal mutualism. Using a mycocosm approach, the C:N and …