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Full-Text Articles in Physical Sciences and Mathematics

Forest Disturbance And Occupancy Patterns Of Carnivores: Results Of A Large-Scale Field Study In Maine, Usa, Bryn E. Evans Dec 2021

Forest Disturbance And Occupancy Patterns Of Carnivores: Results Of A Large-Scale Field Study In Maine, Usa, Bryn E. Evans

Electronic Theses and Dissertations

Understanding trends in the abundance and distribution of carnivores is important at global, regional and local scales due to their ecological role, their aesthetic and economic value, and the numerous threats to their populations. Carnivores in Maine range from the American black bear (Ursus americanus), to numerous native mesocarnivore species, such as American marten (Martes americana), fisher (Pekania pennanti), coyote (Canis latrans), red fox (Vulpes vulpes), bobcat (Lynx rufus), Canada lynx (Lynx canadensis) and to two small weasel species (Mustela erminea and Neogale frenata). …


Population Genetic Analyses Of Arctic Char (Salvelinus Alpinus) Life History Types In Nettilling Lake & Amadjuak River Ecosystem: A Test Of Reproductive Isolation, Chen Liu Oct 2021

Population Genetic Analyses Of Arctic Char (Salvelinus Alpinus) Life History Types In Nettilling Lake & Amadjuak River Ecosystem: A Test Of Reproductive Isolation, Chen Liu

Electronic Theses and Dissertations

A great number of studies have identified strong genetic differences between sympatric anadromous and resident populations of Salmonidae. However, Arctic char (Salvelinus alpinus) migratory phenotypes in the Nettilling Lake and Amadjuak River ecosystem in Nunavut, Canada have not been genetically characterized, and it remains unclear if distinct genotypes and phenotypes associated with migratory life history differences are maintained through reproductive isolation, and they have been assumed to be sympatric populations, or co-occurring populations. Co-occurring Arctic char (n=225) were sampled from eleven sites along the Amadjuak River in 2014 and 2015. Twelve microsatellite loci were used to quantify genetic variation among …


Physiological State Determinants Of Maternal Cortisol Signaling And Its Impact On Offspring Quality And Fitness, Sydney Currier Oct 2021

Physiological State Determinants Of Maternal Cortisol Signaling And Its Impact On Offspring Quality And Fitness, Sydney Currier

Electronic Theses and Dissertations

Assessing the intergenerational effects of maternal stress is important for predicting how offspring will respond to changing environments. The overall aim of my thesis was to quantify the effects of maternal state on maternally derived egg cortisol and determine whether this variation in egg cortisol impacts Chinook salmon offspring performance and fitness in a sex-specific way. I quantified within-female changes in maternal energetics and reproductive metrics that I linked to egg quality and ultimately embryo survival. I found egg cortisol increases with increasing maternal plasma cortisol, and increases further as plasma cortisol levels rise with each day that eggs are …


To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand Aug 2021

To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand

Electronic Theses and Dissertations

Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …


Effects Of Harvest Regulations And Post-Release Hooking Mortality On Walleye Populations In South Dakota, Cade Lyon Jan 2021

Effects Of Harvest Regulations And Post-Release Hooking Mortality On Walleye Populations In South Dakota, Cade Lyon

Electronic Theses and Dissertations

Harvest regulations are commonly implemented to manipulate fisheries stocks. By regulating the size and number of fish that are harvested by anglers, managers are able to meet the goals and needs of regions. However, these management actions come with the potential for negative consequences. Overexploitation due to less restrictive harvest regulations can cause collapses in fisheries populations. In addition, indirect consequences such as hooking mortality brought on by length-based regulations can also be detrimental to populations. In this study, I investigated the effects of various harvest regulations on Walleye populations in three western South Dakota irrigation reservoirs: Angostura, Belle Fourche, …


Effects Of Predator Management And Parasitism On Over-Water Nesting Diving Duck Production In Southwestern Manitoba, Trenton E. Rohrer Jan 2021

Effects Of Predator Management And Parasitism On Over-Water Nesting Diving Duck Production In Southwestern Manitoba, Trenton E. Rohrer

Electronic Theses and Dissertations

Nest survival of upland nesting waterfowl (e.g., mallard [Anas platyrhynchos], blue-winged teal [Anas discors]) has been studied extensively in the Prairie Pothole Region (PPR) of North America. Conversely, over-water nesting diving ducks’ nest survival is poorly understood, likely because over-water nests are more challenging to find, may be less concentrated, and searching for these nests is physically demanding. Nest depredation is considered a leading cause of duck nest failure and is considered a limiting factor on upland nesting waterfowl production in the PPR. Similar factors limiting upland nesting duck production may limit over-water nesting duck productivity, but studies of this …