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Articles 271 - 300 of 497
Full-Text Articles in Animal Sciences
Usage And Development Of Molecular Markers For Investigation Of The Population And Ecological Genetics Of Bromus Tectorum L., Keith R. Merrill
Usage And Development Of Molecular Markers For Investigation Of The Population And Ecological Genetics Of Bromus Tectorum L., Keith R. Merrill
Theses and Dissertations
This thesis includes two studies: The first examined patterns of neutral genetic diversity within Bromus tectorum L. across the IMW region, and uses patterns of microsatellite (SSR) genotype distribution to make inferences about the respective roles of adaptively significant genetic variation, adaptive phenotypic plasticity, and facultative outcrossing in the ongoing invasion and recent range expansion of B. tectorum. It has been previously demonstrated that, due to extremely low outcrossing rates, it is possible to characterize individual genotypes of this species using four SSR loci. We sampled 20 individuals from each of 96 B. tectorum populations (classified by region and …
Apparent Competition With Bromus Tectorum Through Pyrenophora Semeniperda Reduces Establishment Of Native Grasses, Katherine Temus Merrill
Apparent Competition With Bromus Tectorum Through Pyrenophora Semeniperda Reduces Establishment Of Native Grasses, Katherine Temus Merrill
Theses and Dissertations
Contributing to the success of Bromus tectorum in the Intermountain West may be a mechanism called apparent competition, which occurs when one species increases the pressure of a consumer on a second species. This indirect interaction has been documented only a few times in invasive plant systems, and never in a fungal pathosystem. We examined the effects of the invasive annual Bromus tectorum and predation by the seed pathogen Pyrenophora semeniperda on seedling emergence and survival for two native grasses (Pseudoroegneria spicata and Elymus elymoides), by manipulating B. tectorum densities and P. semeniperda inoculum loads in randomized plots. …
Variable Palatability Of Quaking Aspen For Large Ungulate Herbivores, Patrice Alexa Nielson
Variable Palatability Of Quaking Aspen For Large Ungulate Herbivores, Patrice Alexa Nielson
Theses and Dissertations
Aspen is a key resource in the Rocky Mountain Region for wildlife forage and habitat, lumber products, scenery, and plays important roles in fire ecology and hydrological processes. There is evidence of aspen decline over much of the Intermountain West for approximately 100 years. In Dixie and Fishlake National Forests, UT, aspen distribution has decreased by nearly half. Causes of this decline are not well understood, although wildlife browsing by ungulates has been implicated as playing a major role. The objective of this research was to examine what soil or plant factors might be involved in wildlife browse choice in …
Community Response To False Hellebore (Veratrum Californicum Durand) Harvest 18 Years After Treatment, Craig Douglas Johnson
Community Response To False Hellebore (Veratrum Californicum Durand) Harvest 18 Years After Treatment, Craig Douglas Johnson
Theses and Dissertations
Discoveries revolving around false hellebore (Veratrum californicum Durand) have caused a paradigm shift in treatment from eradication to harvest and preservation. Test plots set in place 18 years ago to analyze the effectiveness of eradication treatments (tilling, herbicide, mow, and remow) give us a better idea of how false hellebore communities might respond to disturbances caused by harvest. We focused mainly on the tilling, mow, and remow treatments because of similarities to harvest techniques.We found that mow and remow treatments have little effect on the population of false hellebore in the wild. Tilling treatments were effective in reducing …
The Dirt On The Ancient Maya: Soil Chemical Investigations Of Ancient Maya Marketplaces, Daniel Aaron Bair
The Dirt On The Ancient Maya: Soil Chemical Investigations Of Ancient Maya Marketplaces, Daniel Aaron Bair
Theses and Dissertations
Various criteria or lines of evidence have been used to identify ancient Maya marketplaces, including location near trade routes, artifactual evidence of trade, open space adjacent to transportation routes, proximity to public structures, low platforms and rock alignments to denote market spaces, and regular patterns in soil and floor chemical concentrations. Seibal and Mayapán were important economic Maya polities controlling the trade routes at the apex of their civilizations. The objectives of these studies were to apply geochemical and geospatial analyses of the soils and floors from public plazas and household patios, to discover the anthropogenic chemical residues of phosphorus …
Multidisciplinary Assessment And Documentation Of Past And Present Human Impacts On The Neotropical Forests Of Petén, Guatemala, Christopher Stephen Balzotti
Multidisciplinary Assessment And Documentation Of Past And Present Human Impacts On The Neotropical Forests Of Petén, Guatemala, Christopher Stephen Balzotti
Theses and Dissertations
Tropical forests provide important habitat for a tremendous diversity of plant and animal species. However, limitations in measuring and monitoring the structure and function of tropical forests has caused these systems to remain poorly understood. Remote-sensing technology has provided a powerful tool for quantification of structural patterns and associating these with resource use. Satellite and aerial platforms can be used to collect remotely sensed images of tropical forests that can be applied to ecological research and management. Chapter 1 of this article highlights the resources available for tropical forest remote sensing and presents a case-study that demonstrates its application to …
Developmental Contributions To Variation In Aspen Clones And The Influence Of Pre-Fire Succession Status On Aspen Regeneration Success, Eric A. Smith
Developmental Contributions To Variation In Aspen Clones And The Influence Of Pre-Fire Succession Status On Aspen Regeneration Success, Eric A. Smith
Theses and Dissertations
This thesis includes two studies: The first examined developmental changes that take place in the physiology of aspen (Populus tremuloides Michx.) and to characterize developmental influences on patterns of phenotypic trait variation among different aged ramets within the aspen clones. We surveyed eight clones, each with 8 distinct age classes ranging from 1 to 170 yrs in age. Using regression analysis we examined the relationships between ramet age and expression of functional phenotypes. Eight of the phenotypic traits demonstrated a non-linear relationship in which large changes in phenotype occurred in the early stages of ramet development and stabilized thereafter. …
Diet Reconstruction Of Bighorn Sheep (Ovis Canadensis) Using Stable Isotopes, Joshua M. Whitaker
Diet Reconstruction Of Bighorn Sheep (Ovis Canadensis) Using Stable Isotopes, Joshua M. Whitaker
Theses and Dissertations
We determined the diet contributions of grasses, forbs and shrubs for three herds of bighorn sheep along the Wasatch Front, Utah using stable isotope techniques and determined the electivity values for different forage species for four herds. Forbs were generally the most common forage eaten across all herds while shrubs were the least used forage resource. The Provo Peak and Mount Nebo herds used grasses, forbs and shrubs at proportions similar to other bighorn sheep populations across the west, while the Antelope Island herd used forbs at higher levels than any other local herd. Additionally, the herd on Antelope Island …
An Examination Of The Dna Content, Taxonomy And Phylogeny Of Penstemon (Plantaginaceae), Shaun R. Broderick
An Examination Of The Dna Content, Taxonomy And Phylogeny Of Penstemon (Plantaginaceae), Shaun R. Broderick
Theses and Dissertations
Penstemon is the largest genus in North America with more than 270 reported species. However, little is known about the genome size of this genus and how this information may be useful in selecting species in developing hybrids for landscape use. Using flow cytometry, we estimated the genome size of approximately 40% of the genus (117 specimens from 104 different species.) Genome sizes for the putative diploids ranged from 2C = 0.94 – 1.89 pg (1C = 462 – 924 Mbp) and the putative polyploids ranged from 2.57 – 6.54 pg (1C = 1,257 – 3,156 Mbp). Chromosome counts were …
Development And Use Of Microsatellite Markers For Genetic Diversity Analysis Of Canahua (Chenopodium Pallidicaule Aellen), Amalia Vargas
Development And Use Of Microsatellite Markers For Genetic Diversity Analysis Of Canahua (Chenopodium Pallidicaule Aellen), Amalia Vargas
Theses and Dissertations
Cañahua (Chenopodium pallidicaule Aellen) is a poorly studied, annual subsistence crop of the high Andes of South America. Its nutritionally value (high in protein and mineral content) and ability to thrive in harsh climates (drought, extreme elevations, etc.) make it an important regional food crop throughout the Andean region. The objectives of this study were to develop genetic markers and to quantify genetic diversity within cañahua. A set of 43 wild and cultivated cañahua genotypes and two related species (C. quinoa and C. petiolare) were evaluated for polymorphism using 192 microsatellite markers derived from random genomic …
Diversity And Abundance Of The Dark Kangaroo Mouse, Microdipodops Megacephalus, In Communities Of Nocturnal Granivorous Rodents In Western North America, Ashley Sagers Haug
Diversity And Abundance Of The Dark Kangaroo Mouse, Microdipodops Megacephalus, In Communities Of Nocturnal Granivorous Rodents In Western North America, Ashley Sagers Haug
Theses and Dissertations
The dark kangaroo mouse, Microdipodops megacephalus, is a sensitive species in the Great Basin Desert. This thesis explores the structure of desert rodent communities of the Great Basin to better understand M. megacephalus' place in the community and the conditions that promote large and stable populations. To determine community structure, I used nestedness analysis to evaluate 99 communities of nocturnal granivorous rodents. I found that the community structure was non-random, indicating the existence of assembly rules and ecological constraints. I also found that M. megacephalus was the second most vulnerable species in the community. To explore the correlation …
Diet Reconstruction Of Wild Rio-Grande Turkey Of Central Utah Using Stable Isotope Analysis, Benjamin D. Stearns
Diet Reconstruction Of Wild Rio-Grande Turkey Of Central Utah Using Stable Isotope Analysis, Benjamin D. Stearns
Theses and Dissertations
The wild turkey is endemic to North America and has played a role in human cultures past and present. However, with the turkey's elusive behavior some aspects of its ecology are challenging to understand. Diet is one of these difficult aspects to study. The purpose of this study was to determine the diet selection of wild turkeys in central Utah using non invasive stable isotope technology. We hypothesize that turkey diet is highly specific, that consumption of specific plant species correlates with the needs of the individual turkey, and that stable isotope analysis will reveal patterns in annual dietary intake. …
Historic Fire Regimes On Eastern Great Basin (Usa) Mountains Reconstructed From Tree Rings, Stanley G. Kitchen
Historic Fire Regimes On Eastern Great Basin (Usa) Mountains Reconstructed From Tree Rings, Stanley G. Kitchen
Theses and Dissertations
Management of natural landscapes requires knowledge of key disturbance processes and their effects. Fire and forest histories provide valuable insight into how fire and vegetation varied and interacted in the past. I constructed multi-century fire chronologies for 10 sites on six mountain ranges representative of the eastern Great Basin (USA), a region in which historic fire information was lacking. I also constructed tree recruitment chronologies for two sites. I use these chronologies to address three research foci. First, using fire-scar data from four heterogeneous sites, I assert that mean fire interval (MFI) values calculated from composite chronologies provide suitable estimates …
Part I: Evaluation Of Student Assessment Of Learning Gains (Salg)In Two Different Biology 100 Classes Part 2: What Biology Concepts Are Important In General Education?: Analysis Of Seventeen Core Concepts, Jessica Marie Rosenvall Howelle
Part I: Evaluation Of Student Assessment Of Learning Gains (Salg)In Two Different Biology 100 Classes Part 2: What Biology Concepts Are Important In General Education?: Analysis Of Seventeen Core Concepts, Jessica Marie Rosenvall Howelle
Theses and Dissertations
The purpose of this two-part study is to examine how to improve introductory level non-majors biology courses to improve student attitude and learning gains in the sciences. The first part of this study examines the collective effect of three different pedagogies (service learning, concept mapping and guest lectures) on student attitude and learning gains in a freshman, non-majors biology course. Two classes, one with the three pedagogies, and one without, were compared. Data were collected from two classes in Fall 2008 (one treatment and one control) and two similar classes replicated in Fall 2009. Learning and attitude gains were measured …
Influence Of Soil Water Repellency On Post-Fire Revegetation Success And Management Techniques To Improve Establishment Of Desired Species, Matthew D. Madsen
Influence Of Soil Water Repellency On Post-Fire Revegetation Success And Management Techniques To Improve Establishment Of Desired Species, Matthew D. Madsen
Theses and Dissertations
The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that:
• Post-fire patterns …
Ecophysiological Mechanisms Underlying Aspen To Conifer Succession, William J. Calder
Ecophysiological Mechanisms Underlying Aspen To Conifer Succession, William J. Calder
Theses and Dissertations
This thesis includes three studies. The first study examined how reductions in light availability and changes in soil chemistry that occur as conifers establish in aspen stands, differentially affects the regeneration success of aspen and conifers. We found that aspen were more sensitive to changes in light and soil then subalpine fir. For aspen, reduced light and conifer influenced soils significantly reduced height, biomass, photosynthesis and the production of secondary defense compounds. Subalpine fir seedlings were significantly reduced in photosynthesis, biomass and R:S under lower light conditions but showed no differences in physiology or growth when grown on the contrasting …
Genetic Dissection Of Triterpenoid Saponin Production In Chenopodium Quinoa Using Microarray Analysis, Derrick James Reynolds
Genetic Dissection Of Triterpenoid Saponin Production In Chenopodium Quinoa Using Microarray Analysis, Derrick James Reynolds
Theses and Dissertations
Quinoa (Chenopodium quinoa Willd.) is an important food crop for subsistence farmers in the Altiplano (high plains) of Peru, Bolivia, and Argentina. Saponins are part of a diverse family of secondary metabolites that are found in high concentrations in the pericarp of many varieties of quinoa. Due to their bitter taste and anti-nutritive properties, saponins must be removed before the quinoa grain is consumed. There are ‘sweet’ varieties of quinoa that have significantly reduced levels of saponin. Previous research suggests saponin production is controlled by a single locus. The major objective of this research was to elucidate the genetic …
Predictive Modeling Of Sulfur Flower Buckwheat (Erigonum Umbellatum Torrey) Using Non-Parametric Multiplicative Regression Analysis, David B. Davis
Predictive Modeling Of Sulfur Flower Buckwheat (Erigonum Umbellatum Torrey) Using Non-Parametric Multiplicative Regression Analysis, David B. Davis
Theses and Dissertations
Impacts of humans on ecosystems in western United States have necessitated ecological restoration, which includes the development of native seed that can be used for revegetation efforts. Development of such seed sources are costly and time consuming. This study describes the use of non-parametric multiplicative regression analysis (NPMR) to develop a predictive model for occurrence of sulfur-flower buckwheat (Eriogonum umbellatum Torrey) population seed collection. This perennial forb species is of interest for seed source development in the western United States. Presence and absence data for E. umbellatum was taken from the Utah Division of Wildlife Resources Big Game Range …
Identification And Manipulation Of Resistance To Tomato Spotted Wilt Virus Derived From Solanum Peruvianum, Luis F. Gordillo Jr.
Identification And Manipulation Of Resistance To Tomato Spotted Wilt Virus Derived From Solanum Peruvianum, Luis F. Gordillo Jr.
Theses and Dissertations
The domesticated tomato Solanum lycopersicum (L.), formerly known as Lycopersicon esculentum is a genetically well-studied crop species with high-density linkage and molecular maps based on crosses done between cultivated tomato and its distant related wild species. Wild tomato species harbor a wealth of resistance to many pathogens that have been introgressed into domesticated tomato for genetic control of diseases and pests and for improvement of many agronomic traits. The wild tomato S. peruvianum (L.) is the source of the Sw-5 gene, characterized and mapped to chromosome 9 of the tomato genome and introgressed into elite tomato germplasm, providing resistance to …
Stable Carbon Isotope Evidence Of Ancient Maya Agriculture At Tikal, Guatemala, Richard Lee Burnett
Stable Carbon Isotope Evidence Of Ancient Maya Agriculture At Tikal, Guatemala, Richard Lee Burnett
Theses and Dissertations
Stable carbon isotope analyses of the humin fraction of the soil organic matter were conducted on more than 160 soil profiles from Tikal, Guatemala. The profiles were collected from near areas associated with the earthworks of Tikal; an ancient ditch and parapet construction hypothesized to have formed ancient boundaries of the polity. In addition to the isotope analyses, the physical and chemical characteristics of the horizons were determined. Maize, a C4 plant, formed an integral part of the ancient Maya diet and is the only known C4 plant cultivated by the Maya. Prior to and subsequent to the ancient Maya …
Physiological Assessment Of Chenopodium Quinoa To Salt Stress, Arturo Jason Morales
Physiological Assessment Of Chenopodium Quinoa To Salt Stress, Arturo Jason Morales
Theses and Dissertations
The physiological responses to salt stress were measured in Chenopodium quinoa. In a greenhouse experiment, salt water was applied to the quinoa varieties, Chipaya and KU-2, and to the model halophyte Thellungiella halophila to assess their relative responses to salt stress. Height and weight data from a seven-week time course demonstrated that both cultivars exhibited greater tolerance to salt than T. halophila. In a growth chamber experiment, three quinoa cultivars, Chipaya, Ollague, and CICA 17 were hydroponically grown and physiological responses were measured with four salt treatments. Tissues collected from the growth chamber treatments were used to obtain …
The Grass Seed Pathogen Pyrenophora Semeniperda As A Biocontrol Agent For Annual Brome Grasses, Thomas E. Stewart
The Grass Seed Pathogen Pyrenophora Semeniperda As A Biocontrol Agent For Annual Brome Grasses, Thomas E. Stewart
Theses and Dissertations
Bromus tectorum and other annual brome grasses have invaded many ecosystems of the western United States, and because of an annual-grass influenced alteration of the natural fire cycle on arid western range lands near monocultures are created and conditions in which the native vegetation cannot compete are established. Each year thousands of hectares become near monocultures of annual brome grasses. Pyrenophora semeniperda, a generalist seed pathogen of annual grasses, shows major potential as a possible mycoherbicide that could help in reducing the monocultures created by annual grasses. The purpose of this research was to identify the requirements for isolating …
Diversity Of Insects From The Vespidae Family In Three Ecological Niches (Forest, Forest Border, And Agricultural Area) In Six Communities In The Coroico And Coripata Municipalities, Department Of La Paz, Edwin Zapata Mayta
Theses and Dissertations
The Vespidae family (order Hymenoptera) is comprised of 4500 species of wasps in 268 genera and 7 subfamilies. These wasps prey upon a wide range of insects, including Lepidopteran caterpillars. Because of their low prey specificity, the use of Vespid wasps in biological control programs is limited. However, in their natural habitat, they play a role in controlling populations of some pest species. This study was conducted in six different communities in the department of La Paz within the municipalities of Coroico and Coripata. Three ecological niches were selected in each community: 1) the forest, 2) the edge of the …
Evaluation Of The Effects Of Saka Or Suncho (Viguera Pascensis) In The Feeding Of Guinea Pigs (Cavia Aparea Porcellus) In The Community Of Sococoni, Muñecas Province, La Paz, Boris Rodriguez Peñaranda
Evaluation Of The Effects Of Saka Or Suncho (Viguera Pascensis) In The Feeding Of Guinea Pigs (Cavia Aparea Porcellus) In The Community Of Sococoni, Muñecas Province, La Paz, Boris Rodriguez Peñaranda
Theses and Dissertations
The following work was conducted in the community of Socononi, La Paz, in which we analyzed the effects of three different portions of saka or suncho (viguera pascensis) during the growth, and fattening stages in guinea pigs (cavia aparea porcellus). We used 32 mestizo guinea pigs (improved Peruvian creole breed) weaned 21 days after birth. Four treatments were administrated to the 32 animals (16 males and 16 females), the treatments were the following: (R0) or witness, consisting of corn alone, (R2) consisting of 30% of saka, (R3) consisting of 50% of saka, and (R4) consisting of 70% saka. The variables …
Concentration Of Metabolites And Behavior Of Live Weight In Llamas (Lama Glama) Fed With Natural Grass And Barley During Gestation, Postpartum, And New Born Phases In Turco, Department Of Oruro, Eduardo Ticona Benique
Concentration Of Metabolites And Behavior Of Live Weight In Llamas (Lama Glama) Fed With Natural Grass And Barley During Gestation, Postpartum, And New Born Phases In Turco, Department Of Oruro, Eduardo Ticona Benique
Theses and Dissertations
The llama, a potential socioeconomic resource in the Bolivian highlands, faces serious nutritional deficiencies during the gestational and postpartum stages that negatively affect production. This study was conducted at the Tika Huta Experimental Center in the Llachu community of the Oruro prefecture. Our objectives were to determine metabolite concentration in blood plasma as well as live weight performance of pregnant and postpartum female llamas. Adult and juvenile llamas were fed diets of either plain natural grass or natural grass combined with 0.4 kg of barley hay. In addition, we determined metabolite concentrations in blood plasma and live weight performance of …
Zoometric Measures In Llamas (Lama Glama) Of Rural Families In The T'Olar And Pajonal Natural Grazing Fields Of The Municipality Santiago De Machaca - Department Of La Paz, Eloy Tuco Cano
Theses and Dissertations
Llamas have provided, and continue to provide, fiber, meat, skins, fertilizer and transport for the Andean people. In addition, they are part of the traditional and religious culture of the Aymara and the Quechua. Both are currently unaware of the productive qualities of llamas, especially those related to meat production, which is the principle product responsible for generating greater income for farmers. For this reason, 554 llamas were evaluated from a total of 3,693 in 2005. The llamas came from T’olar and Pajonal grasslands in the Santiago de Machaca region of La Paz, Bolivia and represented males and females from …
Hair, Feces And Breath Isotope Fractionation In Alpacas (Llama Pacos), Llamas (Llama Glama) And Guanacos (Llama Guanacoe) From Bolivia And Chile, Lino Constancio Lopez Lopez
Hair, Feces And Breath Isotope Fractionation In Alpacas (Llama Pacos), Llamas (Llama Glama) And Guanacos (Llama Guanacoe) From Bolivia And Chile, Lino Constancio Lopez Lopez
Theses and Dissertations
This study was conducted to determinate carbon and nitrogen isotope fractionation in Bolivian and Chilean alpaca, llama and guanaco, hair, breath, plasma and feces. We also wanted to determine forage selection for these camelids using stable isotope technology. From the data, niche feeding and diet selection habits will determinate based on fecal composition. Bolivian sites were located near the high snow Altiplano Mountains at Tomarapi, Sajama, and at the Technical University Oruro's research center at Condoriri, Bolivia. Chilean samples were collected at INIA's (Instituto Nacional de Investigacion Agropecuaria) Kampenaike Research Station, Punta Arenas, Chile. Bolivian alpacas and llamas were 3 …
Physical Mapping Of Ribosomal Genes In New World Members Of The Genus Chenopodium Using Fluorescence In Situ Hybridization, Maria C. Sederberg
Physical Mapping Of Ribosomal Genes In New World Members Of The Genus Chenopodium Using Fluorescence In Situ Hybridization, Maria C. Sederberg
Theses and Dissertations
The genus Chenopodium contains many economically important species in the New World, but is relatively understudied and poorly understood, especially in terms of evolutionary relationships. A better understanding of the structure of this genus could significantly help in breeding efforts on its cultivated members, notably the tetraploid C. quinoa and also certain varieties of C. berlandieri, also tetraploid. Of special concern is determining which diploid weed species are the most likely ancestors for C. quinoa, C. berlandieri, and the other tetraploid members of subsection Cellulata. The phylogeny can be understood in part by examining the ribosomal RNA loci and observing …
Domain Duplication, Darwinian Selection, And The Origin Of The Globulin Seed Storage Proteins, Nathaniel S. Cannon
Domain Duplication, Darwinian Selection, And The Origin Of The Globulin Seed Storage Proteins, Nathaniel S. Cannon
Theses and Dissertations
The seed storage globulins found among virtually all spermatophytes comprise a multi-gene family of proteins with ancient evolutionary origins. The two main groups of storage globulins include the legumins (11S) and vicilins (7S), both of which play a main role in protein deposition and storage in the seed endosperm. Composed of two cupin domains (bicupin), these proteins have been recently noted not only for their close structural relationships among the two subfamilies (7S and 11S) but also for their similarity to other proteins such as germin-like proteins (GLP's), bacterial oxalate decarboxylases, and other cupin containing proteins. Previous studies have investigated …
Arthropod And Plant Communities As Indicators Of Land Rehabilitation Effectiveness In A Semi-Arid Shrub-Steppe, Eric T. Gardner
Arthropod And Plant Communities As Indicators Of Land Rehabilitation Effectiveness In A Semi-Arid Shrub-Steppe, Eric T. Gardner
Theses and Dissertations
We describe a case study evaluating the ecological impact of Bromus tectorum L. (cheatgrass) invasion following fire disturbance and the effectiveness of revegetation in improving ecological integrity in a degraded semi-arid shrub steppe system. The effectiveness of rehabilitation efforts was assessed from measurements of arthropod richness, vegetation and arthropod community composition, and ground cover characteristics in three habitats: undisturbed, burned and weed-infested (B. tectorum), and burned and rehabilitated with native and non-native vegetation. Arthropods were collected in each habitat using pitfall traps. Differences in arthropod richness were compared using rarefaction curves. Non-metric multidimensional scaling, and non-parametric multivariate statistical procedures including …