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Utah State University

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ecology

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Analyzing The Von Neumann Entropy Of Contact Networks, Thomas J. Brower Aug 2020

Analyzing The Von Neumann Entropy Of Contact Networks, Thomas J. Brower

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When modeling the spread of disease, ecologists use ecological or contact networks to model how species interact with their environment and one another. The structure of these networks can vary widely depending on the study, where the nodes of a network can be defined as individuals, groups, or locations among other things. With this wide range of definition and with the difficulty of collecting samples, it is difficult to capture every factor of every population. Thus ecologists are limited to creating smaller networks that both fit their budget as well as what is reasonable within the population of interest. With …


Factors Contributing To The Conservation Of Phacelia Submutica (Boraginaceae), A Threatened Species In Western Colorado: Reproductive Biology And Seed Ecology, Alicia M. Langton May 2015

Factors Contributing To The Conservation Of Phacelia Submutica (Boraginaceae), A Threatened Species In Western Colorado: Reproductive Biology And Seed Ecology, Alicia M. Langton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Conservation and recovery plans for rare species require biological and ecological information to discern how they may be susceptible to human disturbances. Phacelia submutica is a threatened annual species in western Colorado. Human activities including energy development, recreation, and livestock grazing are occurring within the species’ range. To provide conservation practitioners with a scientific basis for management, this research aimed to elucidate elements of the species’ ecology. Chapter 2 describes the reproductive biology of P. submutica. Potential insect pollinators were not observed during two years of observations. Floral traits and development ensure self-pollination and reduce the likelihood that insects …


Statmod: A Tool For Interfacing Arcview® Gis With Statistical Software To Facilitate Predictive Ecological Modeling, Christine M. Garrard May 2002

Statmod: A Tool For Interfacing Arcview® Gis With Statistical Software To Facilitate Predictive Ecological Modeling, Christine M. Garrard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As geographical information systems and spatial data become more accessible, predictive spatial modeling in ecology is becoming more common. Unfortunately, not all ecologists possess the necessary skills to successfully combine statistical models and geographical information systems. In response to this problem, I wrote an extension for ArcView® GIS called StatMod. This extension interfaces ArcView GIS with SAS® and S-PLUS® statistical software and walks the user through creating and mapping logistic regression and classification and regression tree models.

StatMod was then used to run a series of analyses that would have been difficult without such a tool. A …


Ecological Studies Of Native Green River Fishes Below Flaming Gorge Dam, 1964-1966, Charles David Vanicek May 1967

Ecological Studies Of Native Green River Fishes Below Flaming Gorge Dam, 1964-1966, Charles David Vanicek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations to study (1) the species composition and distribution of Green River fishes between Flaming Gorge Dam and Ouray, Utah and (2) the ecology and life history of selected native species (Colorado squafish, Ptychocheilus lucius; Colorad chub, Gila robusta; bluehead sucker, Pantosteus delphinus; and humpback sucker, Xyrauchen texanus) in Dinosaur National Monument were conducted from May, 1964, to October, 1966. A total of 23,735 fish consisting of 9 indigenous and 11 exotic species, were taken in 639 collections by electrofishing gear, gill nets, seines, and fry gear. Flaming Gorge Dam has caused a major change in …


A Taxonomic And Ecological Study Of Acridinae Of Utah (Orthoptera-Locustidae), Herald C. Bennion May 1939

A Taxonomic And Ecological Study Of Acridinae Of Utah (Orthoptera-Locustidae), Herald C. Bennion

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Orthoptera, especially the family Locustidae, is one of the most important and most interesting orders of insects in the state of Utah. It includes a polyphagus group of great economic importance in the state. The topography and climate of Utah varies from forested alpine slopes to hot arid desert wastes, several life zones being represented. This great variation from desert to alpine in Utah presents a rather unique region for taxonomic and ecological studies of the Orthoptera.

The most familiar representatives of the insect order Orthoptera are the long-horned grasshoppers, locusts, crickets, katydids, and cockroaches. Orthoptera are characterized by Comstock …