Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 25 of 25

Full-Text Articles in Life Sciences

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe Dec 2015

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe

Electronic Theses and Dissertations

Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while …


Biogeography And Conservation Of Tidal Marsh Bird Communities Across A Changing Landscape, Maureen D. Correll Dec 2015

Biogeography And Conservation Of Tidal Marsh Bird Communities Across A Changing Landscape, Maureen D. Correll

Electronic Theses and Dissertations

Given the current mass extinction crisis and continued fragmentation of resources worldwide, the outlook is dire for global biodiversity. Rising global temperature, sea levels, and storm frequency all create environmental conditions that can drive change in species abundance and distribution across a landscape. Those species reliant upon a single type of habitat and resource for survival, termed “specialists”, are particularly vulnerable to change due to their inability to utilize a variety of resources well. As a result, specialism is now considered one of the dominant factors determining extinction of species. In this dissertation I explore the effects of disturbance on …


Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore Dec 2015

Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore

Electronic Theses and Dissertations

Counter to what some people think, urban areas can be biodiversity hotspots. Maintaining this biodiversity can be challenging, since exotic shrubs and vines block sunlight and threaten native plant regeneration. Since 2007, the Louisville Olmsted Parks Conservancy (LOPC) has spent $2 million on invasive plant management in Cherokee Park. Before the project began, long-term transects were established by the LOPC to collect baseline presence/absence data on 11 invasive plant species. In 2014, I revisited these transects and documented presence/absence data on the entire plant community. I found that four species (garlic mustard, winter creeper, Japanese honeysuckle, and English ivy) have …


Impact Of Urban Factors And Invasive Species On White-Footed Mouse (Peromyscus Leucopus) Habitat Use And Foraging Behavior In An Urban Forest Park., William Persons Dec 2015

Impact Of Urban Factors And Invasive Species On White-Footed Mouse (Peromyscus Leucopus) Habitat Use And Foraging Behavior In An Urban Forest Park., William Persons

Electronic Theses and Dissertations

White-footed mice (Peromyscus leucopus) select for areas of greater canopy cover at the macro scale, and for areas with more CWD at the micro-scale. White-footed mice potentially avoid habitats with higher invasive species richness. White-footed mice preferentially foraged under the honeysuckle canopy in response to changes in temperature and humidity. This study suggests that the interaction between P. leucopus and ground layer invasive species is complex, and that the effect of moonlight may be diminished in this urban park. Urban ecosystems demonstrate high levels of anthropogenic land-use change, modification of abiotic inputs, and altered disturbance regimes. These changes result …


Dietary Carotenoids And The Complex Role Of Redness In The Behavior Of The Firemouth Cichlid Thorichthys Meeki., Sarah Anne Fauque Dec 2015

Dietary Carotenoids And The Complex Role Of Redness In The Behavior Of The Firemouth Cichlid Thorichthys Meeki., Sarah Anne Fauque

Electronic Theses and Dissertations

This dissertation takes a comprehensive approach to the role of dietary carotenoids on redness and the subsequent behaviors in the firemouth cichlid, Thorichthys meeki. I start with a brief introduction into signaling, the importance of carotenoids, and mate choice. The dissertation is then divided into three data chapters which are designed to stand as independent manuscripts. Chapter II documents how altering the availability of dietary carotenoids affects redness in the integument of male and female T. meeki. I tracked how redness changed in color and distribution in individuals over the course of 12 weeks. I confirm that a dichotomy …


Reproductive Ecology Of Black Bears In Maine: Maternal Effect, Philopatry, And Primiparity, Alyssa A. Vitale Aug 2015

Reproductive Ecology Of Black Bears In Maine: Maternal Effect, Philopatry, And Primiparity, Alyssa A. Vitale

Electronic Theses and Dissertations

The American black bear (Ursus americanus) relies upon dens in order to successfully reproduce and protect their offspring. Black bears utilize a variety of den types, each providing a different degree of protection. Black bears also exhibit an extended maternal care period in which offspring stay with their mother for 18 months. Maine’s black bear population is one of the largest in the U.S. (>30,000 bears) and since 1975, the Maine Department of Inland Fisheries and Wildlife has conducted research and monitoring to manage the population. This unique dataset allowed for examination of several generations of multiple …


Intra- And Interspecific Variation In Demographic Rates And Niche Across The Range Of A Species, The Saltmarsh Sparrow (Ammodramus Caudacutus), Katharine J. Ruskin Aug 2015

Intra- And Interspecific Variation In Demographic Rates And Niche Across The Range Of A Species, The Saltmarsh Sparrow (Ammodramus Caudacutus), Katharine J. Ruskin

Electronic Theses and Dissertations

In this project, we examined various hypotheses that address one of the fundamental questions in ecology and evolution: what determines the range of a species? We used demographic data for saltmarsh sparrows (Ammodramus caudacutus) collected over the majority of the global breeding range. Saltmarsh sparrows are considered threatened by climate change, specifically sea level rise, which is predicted to result in loss of the tidal marsh habitat where saltmarsh sparrows live across their entire life cycle. For my dissertation, I investigated the reproductive biology of saltmarsh sparrows both to provide vital information for wildlife managers and to explore …


Social Network Analysis Of Partner Preference In Lemon Sharks, Negaprion Brevirostris, During The Introduction Of Unfamiliars To Familiar Groups, Bryan Keller May 2015

Social Network Analysis Of Partner Preference In Lemon Sharks, Negaprion Brevirostris, During The Introduction Of Unfamiliars To Familiar Groups, Bryan Keller

Electronic Theses and Dissertations

In order to understand what drives group formations and to predict spatial occurrences, investigations on individual preferences within the groups have proved to be very useful. Groups of sharks have been observed for centuries; however, there is a dearth of quantitative analyses on the mechanisms that drive their formation. In this study, we use controlled, semi-captive behavioural experiments to assess the potential role of familiarity in group formation and on social behaviour in a large marine vertebrate. Juvenile lemon sharks, Negaprion brevirostris, (n =23) in Bimini, Bahamas were captured, measured and tagged with external colour codes for individual identification and …


Seasonal Influences On Habitat Use By Snowshoe Hares: Implications For Canada Lynx In Northern Maine, Sheryn J. Olson May 2015

Seasonal Influences On Habitat Use By Snowshoe Hares: Implications For Canada Lynx In Northern Maine, Sheryn J. Olson

Electronic Theses and Dissertations

Snowshoe hares (Lepus americanus) respond to seasonal changes in vegetation in the northern and western portions of their range. During winter, hares use dense conifer stands that may provide thermal and predatory refugia, then during summer move to areas with more herbaceous food and cover. These movements influence hare demographics, with greater survival rates corresponding to seasonal use of dense, primarily coniferous stands. Different harvesting practices in commercial forests produce vegetative communities that may support differing hare densities among forest stand- types between seasons, but seasonal use of habitat had not been documented in northern Maine on a large spatial …


A Systematic Review Of The Soricimorph Eulipotyphla (Soricidae: Mammalia) From The Gray Fossil Site (Hemphillian), Tennessee, Joshua Doby May 2015

A Systematic Review Of The Soricimorph Eulipotyphla (Soricidae: Mammalia) From The Gray Fossil Site (Hemphillian), Tennessee, Joshua Doby

Electronic Theses and Dissertations

Due in part to the incompleteness of the Cenozoic fossil record in the eastern U.S., the evolution and immigration of shrews (Soricidae) is not well understood. A rich soricid fauna from the Gray Fossil Site (GFS), Washington County, TN, has enabled many new inferences to be made. There are 7 new species in 6 genera: Paenelimnoecus, “Blarinella”, Petenyia, Tregosorex, Crusafontina, and Gen et sp. nov. GFS species of the genera Paenelimnoecus, “Blarinella”, and Petenyia are the first occurrence of each genus in the New World. Tregosorex, Crusafontina, and the N.A. taxon Limnoecus all have their latest documented occurrence at the …


Impact Of Development On Freshwater Turtle Populations Of Coastal South Carolina: An Examination Of Land Use And Road Density, Andre Dominguez Jan 2015

Impact Of Development On Freshwater Turtle Populations Of Coastal South Carolina: An Examination Of Land Use And Road Density, Andre Dominguez

Electronic Theses and Dissertations

Previous studies (Haxon 2000; Steen and Gibbs 2004; Marchand and Litvaitis 2004; Aresco 2005) have demonstrated that urbanization and development have disproportionally adverse affects on female turtles. In order to test this paradigm I caught 301 turtles (primarily Trachemys scripta scripta) in ten ponds (5 impacted and 5 unimpacted) across coastal South Carolina. Not only do coastal South Carolina turtles not follow the same male biased pattern of many other studies, there was an overall female bias (154:95). Turtle metrics were between the types of sites existed as well, indicating larger/older population of turtles in unimpacted sites. Water quality parameters …


Tide-Dependent Predation Patterns Of Piscivorous Fishes In Shallow Estuarine Creeks, Matthew Ross Helms Jan 2015

Tide-Dependent Predation Patterns Of Piscivorous Fishes In Shallow Estuarine Creeks, Matthew Ross Helms

Electronic Theses and Dissertations

The distribution and foraging behavior of predatory salt marsh fishes is shaped by the movements of prey, many of whom seek shelter in shallow and tributary creeks. I hypothesized that the distribution of piscivorous fishes in marsh creek channels would differ with proximity to the mouths of intertidal creeks and with tidal stage. Custom-built trotlines baited with live minnows were deployed during four discrete tidal stages at two microhabitats in main creek channels: (1) adjacent to intertidal creek mouths, and (2) along straight banks in North Inlet estuary, South Carolina. Catch-per-unit-effort of predatory fishes was significantly higher (Wilcoxon signed-rank tests, …


Phytoremediation Of Metal Contamination Using Salix (Willows), Gordon J. Kersten Jan 2015

Phytoremediation Of Metal Contamination Using Salix (Willows), Gordon J. Kersten

Electronic Theses and Dissertations

Abandoned hardrock mines and the resulting Acid Mine Drainage (AMD) are a source of vast, environmental degradation that are toxic threats to plants, animals, and humans. Cadmium (Cd) and lead (Pb) are metal contaminants often found in AMD. In my mine outwash water samples, cadmium and lead concentrations were 19 and 160 times greater than concentrations in control waterways, and 300 and 40 times greater than EPA Aquatic Life Use water quality standards, respectively. I tested the phytoremediation characteristics of three montane willows native to the Rocky Mountains: Salix drummondiana, S. monticola, and S. planifolia. I tested …


Is Colorado Buddhism Green? A Study Of The Interaction Of Buddhist Practice With Environmental Concerns, Mengye Liu Jan 2015

Is Colorado Buddhism Green? A Study Of The Interaction Of Buddhist Practice With Environmental Concerns, Mengye Liu

Electronic Theses and Dissertations

The human community is paying more attention to our growing environmental crisis. Religious beliefs are often proposed as effective ways to address environmental ethics. It is often supposed that Buddhism is a "green" religion because of its intimate associations with nature. My research focuses on whether or not Buddhism in Colorado influences Buddhist practitioners' environmental awareness by identifying and evaluating Buddhist ecological attitudes and values. My research questions include: (1) what aspects of Buddhist practice refer to the elements of natural environment, (2) do Buddhist practitioners profess different attitudes and behaviors than non-Buddhist practitioners, and (3) If so, how does …


The Role Of Cognition In Sexual Signals And Mate Choice Decisions, Ross Minter Jan 2015

The Role Of Cognition In Sexual Signals And Mate Choice Decisions, Ross Minter

Electronic Theses and Dissertations

Cognitive ability varies dramatically among individuals, yet the manner in which this variation affects reproduction has rarely been investigated. Here, we asked 1) whether male sexual signals reflect cognitive ability and whether females prefer males with superior cognitive abilities, and 2) whether female cognition affects male and female mating decisions? We addressed these questions in a mutual mate choice system, threespine sticklebacks (Gasterosteus aculeatus). We tested cognitive performance by presenting the males and females with a novel task (a barrier to food) to evaluate problem-solving abilities and learning. We found that males that problem solve have elaborate sexual …


A Socio-Economic Assessment Of Marine Turtle Eco-Tourism, Kendra Cope Jan 2015

A Socio-Economic Assessment Of Marine Turtle Eco-Tourism, Kendra Cope

Electronic Theses and Dissertations

Marine turtles have historically contributed to economic activity through consumptive harvest for food, tools, and decorative objects. Only recently have they begun to benefit humans economically through non-consumptive roles, primarily as a focal point of educational eco-tourism. In recent years, the annual number of turtle walks conducted around the Archie Carr National Wildlife Refuge (ACNWR) has risen. This expansion contributed to a statistically significant increase in attendance from 2,162 in 2001 to 3,047 participants in 2014. I examined the regional economic impacts of marine turtle eco-tourism around the ACNWR using social surveys and an economic impact analysis tool. IMPLAN, an …


An Economic Analysis Of High-Intensity, Short-Duration Grazing Systems In South Dakota And Nebraska, Bronc Mcmurtry Jan 2015

An Economic Analysis Of High-Intensity, Short-Duration Grazing Systems In South Dakota And Nebraska, Bronc Mcmurtry

Electronic Theses and Dissertations

Four different grazing systems: two rotational, a continuous, and a high-intensity, short-duration (mob) system, replicated twice, were evaluated from an economic perspective. Mob grazing is defined as a system having very high stocking rates for a small amount of time. Livestock are forced to eat or trample the vegetation. Stocking rates and average daily gains (ADG) were collected from the UNL Barta Brothers ranch near Rose, Nebraska. The study started in 2011 and lasted until 2014. Using the performance data and other cost data relevant to South Dakota and Nebraska, budgets were set up for each system and extrapolated to …


Oviposition Site Selection By Mosquitoes: Predator-Released Kairomones And Responses To Different Taxa, Lauren Larea Eveland Jan 2015

Oviposition Site Selection By Mosquitoes: Predator-Released Kairomones And Responses To Different Taxa, Lauren Larea Eveland

Electronic Theses and Dissertations

Oviposition site selection is a critical reproductive behavior for egg-laying organisms that offer little to no parental care. Determining the mechanisms females use to assess sites is critical to understanding life history traits, community structure, and species interactions. Mosquitoes are excellent model organisms for studying oviposition site selection for numerous reasons: 1) a poor decision can lead to zero reproductive success, 2) females actively assess and choose among habitat patches when locating an oviposition site, 3) larvae remain in the habitat where they hatch until they metamorphose, and 4) they lay conspicuous egg rafts that allow direct assessment of oviposition. …


The Influence Of Current Year Fire On Leaf Litter Decomposition Rates And Microbial Enzyme Activity In Forests Undergoing Ecological Restoration, Megan E. Overlander Jan 2015

The Influence Of Current Year Fire On Leaf Litter Decomposition Rates And Microbial Enzyme Activity In Forests Undergoing Ecological Restoration, Megan E. Overlander

Electronic Theses and Dissertations

As a result of fire suppression, open oak woodlands, once characteristic of the interior of the southern USA, are being lost to mesophication. This process leads to changes in the plant community and has the potential to change rates of decomposition and nutrient cycling through changes in environmental conditions or leaf litter composition. Restoration projects to reduce the effects of mesophication include thinning the canopy to remove mesophytic species and prescribed burn regimens to return the plant community to a fire tolerant and dependent one. However it is unclear what effects restoration (or mesophication) has on the decomposition of leaf …


Population Ecology Of Rocky Mountain Elk In The Black Hills, South Dakota And Wyoming, Benjamin D. Simpson Jan 2015

Population Ecology Of Rocky Mountain Elk In The Black Hills, South Dakota And Wyoming, Benjamin D. Simpson

Electronic Theses and Dissertations

We conducted a 2-year (2012–2013) study of survival and cause–specific mortality using individually marked adult cow and neonate elk (Cervus elaphus) occupying the southwestern region of the Black Hills. We used known-fate analysis in Program MARK for survival analysis of adult cows and calves. We estimated survival and cause-specific mortality of 49 adult female elk over the 2 years of the study. Annual adult cow survival was 0.85 (95% CI = 0.72–0.87). We documented 12 mortalities with harvest (58.3%) and predation (16.6%) accounting for the majority of known mortalities. We captured and fit 71 neonates < 10 days of age with expandable Very High Frequency (VHF) radiocollars during summer 2012 (n = 37) and 2013 (n = 34). Annual (12 month) survival of elk calves was 0.75 (95% CI = 0.61–0.84) while summer (20 weeks; 15 May–25 September) survival was 0.79 (95% CI = 0.68–0.88). Predation accounted for 87.5% of mortalities; remaining mortalities were from starvation (6.3%) and unknown (6. 3%) causes. We used Global Positioning System (GPS) collars to collect 167,707 locations to determine home range, movement ecology, and macroscale resource selection of 48 adult cow elk. We documented elk using a variety of migration strategies (obligate migrator, resident, conditional migrator, disperser); the majority of the population (58%) was migratory. Spring migration distance travelled ranged from 2.45 km – 74.44 km (n = 42); fall migration distances ranged from 6.41km – 153.95 km (n = 46). We used 99% Brownian Bridge Movement Models to create seasonal and overall home ranges of adult cow elk. Mean overall home range size for conditional migrators was 249.28 km2 (SE = 28.60, n = 7, range = 233.75), for obligate migrant elk it was 227.18 km2 (SE = 13.94, n = 29, range = 346.83), and for resident elk it was 175.65 km2 (SE = 22.75, n = 11, range = 216.04). We used discrete choice models to determine resource selection at the macro-habitat scale of collared adult elk using ArcMap 10.1 data. Adult cow elk selected for open grassland/herbaceous areas and early successional forest areas close to forested edges at higher elevations. Our study showed that elk populations have the ability to thrive within an ecosystem with healthy predator populations.


Drought Resistance And Resilience Of Non-Native Vs. Native Grasses In The Northern Tallgrass Prairie, Wyatt Kirwan Jan 2015

Drought Resistance And Resilience Of Non-Native Vs. Native Grasses In The Northern Tallgrass Prairie, Wyatt Kirwan

Electronic Theses and Dissertations

Drought can have major impacts on rangeland productivity and remains highly unpredictable. Like many other rangelands in the US, the Tallgrass Prairie of eastern South Dakota contains native prairie where the plant composition includes mostly native species as well as pasture that has been converted to or invaded by cool-season introduced species. So how are these two plant communities impacted by drought? The specific objective of this study was to compare drought resistance and drought resilience of native prairie to introduced cool-season pasture (Smooth brome - Bromus inermis and Kentucky bluegrass - Poa pratensis). Our Hypothesis was that native prairie …


Soil Bacterial Structure And Function Associated With The Invasive Grass Microsteguim Vimineum And Two Native Grasses, Jennifer Kay Bell Jan 2015

Soil Bacterial Structure And Function Associated With The Invasive Grass Microsteguim Vimineum And Two Native Grasses, Jennifer Kay Bell

Electronic Theses and Dissertations

Soil microorganisms play vital roles in biogeochemical cycles and are necessary for maintaining soil health. An invasive plant that alters the structure and function of the soil microbial assemblage could gain an advantage over native plants, enhancing its ability to invade new habitats, alter ecosystem function, and hinder efforts to reestablish native populations. Assays of enzyme activity and next generation sequencing of bacterial 16S rRNA genes were used to assess the soil microbial function and community structure associated with the invasive grass, Microstegium vimineum and two co-occurring native grasses (Dichanthelium boscii and Chasmanthium laxum). Significantly lower enzyme activity was found …


Helping To Resolve Taxonomic Conflicts Within The Genus Amblyomma (Acari:Ixodidae) From A Molecular Perspective, Paula Lado Jan 2015

Helping To Resolve Taxonomic Conflicts Within The Genus Amblyomma (Acari:Ixodidae) From A Molecular Perspective, Paula Lado

Electronic Theses and Dissertations

This work sought to reassess the taxonomic status of Amblyomma parvum Aragao, 1908 and of the A. maculatum group of ticks Camicas, 1998. By using different molecular markers, 12SrDNA, 16SrDNA, DL, COI, COII (mitochondrial) and ITS2 (nuclear), I analyzed the systematic relationships between these taxa and their closest relatives. Phylogenetic analyses by maximum parsimony, maximum likelihood, and Bayesian analysis were performed in order to determine relationships among species and populations, and to determine the evolutionary history of these ixodids. The data obtained supported the hypothesis of cryptic speciation occurring within A. parvum, with the northern populations of Central America being …


Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims Jan 2015

Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims

Electronic Theses and Dissertations

Nonstructural carbohydrates (NSC) can supply substrate during periods when current photosynthate is unavailable or inadequate to meet metabolic demands. I hypothesized that natural selection has favored higher nonstructural carbohydrate concentrations ([NSC]) in species that have an evolutionary history of frequent disturbance and tested this using three southern pine species that have evolved under a continuum of disturbance frequencies (evolutionary history of fire ~ longleaf > slash > loblolly). Stem and root samples were collected from 12 similar-sized individual trees of each species during time periods that reflect the annual minimum and maximum [NSC]. A modified colorimetric method was performed on the samples …


Predators And Anti-Predator Behavior Of Wilson's Plover (Charadrius Wilsonia) On Cumberland Island, Georgia, Mary K. Strickland Jan 2015

Predators And Anti-Predator Behavior Of Wilson's Plover (Charadrius Wilsonia) On Cumberland Island, Georgia, Mary K. Strickland

Electronic Theses and Dissertations

Predation, the major cause of nest failure in birds, is an important factor when considering management and conservation plans. The predator assemblage in an ecosystem changes each year and can cause profound differences in bird nest survival rates. Shorebirds such as Wilson’s Plovers (Charadrius wilsonia) are ideal study species because they are declining and predator control is often a recommended component of management plans. Therefore the objectives of my research were to determine the predator assemblage of the southern end of the beach on Cumberland Island National Seashore, Georgia, and to determine how three variables affected the display …