Life Sciences Commons^™

Predator-Prey Relationships And Spatial Ecology Of Jaguars In The Southern Pantanal, Brazil: Implications For Conservation And Management, Sandra Maria Cintra Cavalcanti

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Pantanal wetland of Brazil is an important area for the conservation of jaguars (Panthera onca) and a stronghold for the species. Although our knowledge of jaguar ecology has increased since the first field studies in the mid 1980’s, a detailed study of this cryptic species remains challenging. In the following chapters, we investigated the ecology of jaguars in the southern Pantanal of Brazil. In Chapter II, we examined the foraging ecology of jaguars, documenting predation rates, patterns, and species killed. We found individual jaguars differed in the selection of their prey. There were differences in the proportion …

Ecotypic Variation In Elymus Elymoides Subspecies Brevifolius Race C In The Northern Intermountain West, Matthew C. Parsons

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Little information is available on the extent of local adaptation for many native grass species. This is the case for squirreltail (Elymus section Sitanion), despite this group's prevalence and importance in rangeland restoration efforts. I evaluated 32 populations of E. elymoides ssp. brevifolius race C, a phylogenetic subdivision of bottlebrush squirreltail (E. elymoides) centered in the northern Intermountain West, for phenotypic variables and neutral genetic markers to measure their association with geographical origin. Phenotypic traits were measured in common field and greenhouse environments, and genetic diversity was assessed using Amplified Fragment Length Polymorphism. Three factors were extracted from the phenotypic …

Decadal-Scale Changes On Coral Reefs In Quintana Roo, Mexico, Thaddeus Allen Nicholls

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In 1988 data on coral reef community composition were collected from two areas, Akumal and Chemuyil, Quintana Roo, Mexico, ranging from 5-35m depth. These areas were revisited in 2005 and data were collected by the same methods and at the same depths as in 1988. Data from 1988 and 2005 were compared to determine if the coral reefs had undergone significant changes, and what specific changes had occurred. Chi-square analysis determined that community composition data collected in 1988 are significantly different from data collected in 2005 at all sites and depths within the categories of corals, gorgonians, sponges, and macroalgae. …

Reproductive Tactics Of Aphidophagous Lady Beetles: Comparison Of A Native Species And An Invasive Species That Is Displacing It, Yukie Kajita

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Coccinella septempunctata L. (Coleoptera: Coccinellidae) has been introduced to North America in recent decades, raising concerns of adverse impacts on native lady beetles, including the congeneric C. transversoguttata richardsoni (Brown). The central focus of my dissertation is to understand the importance of reproduction, in particular, in promoting invasion of C. septempunctata and its replacement of native lady beetles in alfalfa fields of western North America.

Studies were conducted to compare reproductive tactics of the invasive C. septempunctata and the native C. transversoguttata, by addressing: 1) maximum rate of reproduction of overwintered lady beetles, 2) population dynamics of the invasive …

Livestock Mortality At Beef Farms With Chronic Wolf (Canis Lupus) Depredation In The Western Great Lakes Region (Wglr), Arion Vandergon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Gray wolf (Canis lupus) depredation on beef calves has been studied extensively in recent years. As wolf populations increase throughout the United States there is a corresponding increase in wolf/livestock interactions. Most research concentrates on summaries of reported depredations and surveys of producers affected by depredations. The objective of this study was to present data on the fate of beef calves on 3 farms in Minnesota and Wisconsin over a 2-year period. Predator presence/absence was studied as an indicator of potential depredations. Also, data are presented comparing 2 techniques that may aid researchers and livestock producers with monitoring …

Growth And Water Relations Of Native Wheatgrass Populations, Brian P. Bell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Screening populations for development into released plant materials can be done inexpensively and in a timely manner. A common approach has been to quantify the amount of shoot dry mass produced as a surrogate for competitiveness. Besides dry mass production , other morphological characteristics have been employed , but physiological parameters have received less emphasis. Dry mass production may be an important characteristic, but identifying the traits responsible can be just as imperative . Populations with greater drought tolerance may be less impacted by competition for water from weeds, which could lead to greater establishment of desirable grasses on disturbed …

An Investigation Of The Early Life-History Of Brown Trout (Salmo Trutta) And Potential Influences On Invasion Success In The Logan River, Utah, Jeremiah Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Due to the significant threats posed by nonnative fish species worldwide, it is important to understand how life-history strategies of individual species interact with environmental conditions to explain the success or failure of nonnative fish invasions. Brown trout are prolific invaders, but often exhibit upstream distributional limits in Intermountain West streams, potentially due to a maladaptive reproductive life-history strategy influenced by hydrologic conditions in high-elevation areas. We used redd counts, egg survival experiments, and temperature modeling to investigate the reproductive life-history strategy of brown trout and its potential for success along an elevational stream gradient. We documented brown trout spawning …

Granivores And Restoration: Implications Of Invasion And Considerations Of Context-Dependent Seed Removal, Steven M. Ostoja

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Granivores are important components of sagebrush communities in western North America. These same regions are being altered by the invasion of the exotic annual Bromus tectorum (cheatgrass) that alters physical and biological dynamics in ways that appear to promote its persistence. This research directly relates to the restoration of B. tectorum-dominated systems in two inter-related ways. First, because these landscapes have large quantities of seeds applied during restoration, it is important to determine the major granivore communities in intact sagebrush communities and in nearby cheatgrass-dominated communities. Second, it is important to develop an understanding of patterns of seed harvest …

Conservation Implications Of Winter-Feeding Policies For Mule Deer In Utah, Chris C. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Policies regulating wildlife winter-feeding programs may have long-term impacts on conservation and future management of both target and non-target species. In 2000, the Utah Wildlife Board, upon reviewing input from a series of public regional meetings, adopted a Utah Big Game Winter-Feeding Policy. The Utah Division of Wildlife Resources used this policy to regulate winter-feeding programs for mule deer in northern Utah, 2001-2005. I monitored the program effects on mule deer biology, activity and migration, and winter browse utilization and productivity.

While feed rations generally compensated for protein and energy deficiencies, they may overlook mineral deficiencies. To determine if mule …