Life Sciences Commons^™

Fractally Sampling Diversity-Environment Relationships To Understand Plant Assemblage Health Across Spatial Scales, Elizabeth G. Simpson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Humans influence the health of ecosystems and rely on healthy ecosystems to support their livelihoods and well-being. By looking at how the parts of ecosystems interact we can understand and improve ecosystem health. Ecosystem interactions change across spatial scales or different size patches of area. For example, individual organisms interact with each other at small spatial scales, while at large spatial scales, communities of organisms interact with weather conditions. However, many research studies do not look at how ecosystem interactions change across spatial scales. To address this gap in ecological research, I use a fractal sampling design which samples at …

Solar Grazing As A Possible Vegetation Management Solution: A Budget Analysis, Byron Louk

Agricultural Economics and Agribusiness Undergraduate Honors Theses

A growing response to climate change among agricultural producers is to integrate renewable energy production in their portfolio of enterprises. Nonetheless, land use competition for agricultural production and solar energy production exists. To alleviate some of this competition, and possibly generate income for sheep grazers, photovoltaic (PV) system operators may save on operations and maintenance by grazing forages under solar panels rather than using mechanical or chemical means of vegetation management. “Solar grazing” operations have been shown to be economically feasible for PV system operators who own the land and pay for sheep grazing as a method of vegetation management, …

Assessing Warm-Season Annual Grasses To Increase Forage Inventory, Andrea Marroquin

Masters Theses

Summers are expected to continue to increase in heat/dryness in the Northeast, causing issues pertaining to forage production during the summer to worsen. Many pastures grow cool season grasses, even during the summer. These grasses enter a dormant period and slowdown in production during the months of July and August, leading to what is referred to as “summer slump”. Some farms grow corn silage during the summer, and while corn silage is a valuable crop, its cultivation often does not support soil biology. This research addresses solutions for both summer slump foraging and more sustainable silage. Summer annuals grow more …

Effect Of Cover Crops, Grazing And Tillage Practices On Soil Microbial Community Composition, Function, And Soil Health In East Central Mississippi Soybean Production System., Namita Sinha

Theses and Dissertations

Integrating crop and livestock is being considered to improve soil health by carbon sequestration. A two-year study (2019-2021) at CPBES in Newton, MS was aimed to evaluate soil microbial diversity in the warm, humid regions, specifically southeastern USA. Amplicons targeting bacterial 16S rRNA genes and fungal ITS2 regions were sequenced. Taxonomic assignment and microbial diversity characterization were performed using QIIME2^®. Soil fungal diversity showed significant differences (alpha diversity, p = 0.031 in yr. 2020 and beta diversity, p = 0.037 in yr. 2021). Canonical Correspondence Analysis (CCA) and Mantel test showed significant influence on fungal diversity due to …

Dairy Breed, Grass-Birdsfoot Trefoil Mixture, And Pasture Nutrition Effects On Intake, Feed Efficiency, And Grazing Adaptation, Michael Greenland

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dairy cattle have lower dry matter intake (DMI) on pastures thus leading to less weight gain and milk production than feedlot cows. This study was conducted to determine whether different dairy breeds are better adapted to lower or higher quality pastures as measured in DMI and feed efficiency. The eight treatments consisted of Jersey, Holstein, Holstein-Jersey crossbreds, and 3-breed crossbreds (Montbéliarde-Swedish Red-Holstein) heifers on grass monocultures and grass-BFT mixtures. We observed greater DMI on grass-BFT mixtures. Among breeds, Holstein had the greatest DMI, then the two crossbreds, and Jersey had the least. Feed efficiency was most favorable for Jersey, less …

Soil Quality Indicators And Vegetation Responses Following Ecological Restoration Thinning Of Ponderosa Pine On Three Soil Parent Material Types Under Grazing And Non-Grazing In Northern Arizona, Christopher Macdonald

Electronic Theses and Dissertations

This research was performed in a northern Arizona ponderosa pine (Pinus ponderosa P. & C., Lawson) forest. The objectives were to a) increase understanding of long-term vegetation responses to ecological restoration treatments on three soils types, with and without grazing, b) evaluate the responses soil physical, chemical, and biological properties to restoration treatments, with and without grazing, c) determine the utility of measured soil quality indicators to informing risks to sustainable soils management in southwestern ponderosa pine forests.

There were no significant differences in soil bulk density by soil type, treatment type, or grazing treatment. No significant differences …

Evaluation Of Monthly And Seasonal Grazing Rates Of Ilyanassa Obsoleta On Benthic Microalgae In The North Inlet Estuary, Brittany Dearmitt

Theses and Dissertations

The eastern mud snail, Ilyanassa obsoleta, is found at densities of 100’s of individuals m^-2 on soft sediments in the intertidal zones of estuaries. These obligate deposit feeders consume microalgae, detritus, larvae, meiofauna, and macrofauna in the surface layers of sediments with possible trophic impacts on benthic microalgal (BMA) biomass. The goals of this study were to quantify mud snail grazing on BMA biomass, observe the variation in monthly and seasonal grazing rates, and evaluate the relationship between atmospheric temperatures and grazing rates. The sites for this experiment were two mudflats in Oyster Landing, North Inlet estuary, South …

Greater Sage-Grouse Brood Responses To Livestock Grazing In Sagebrush Rangelands, Hailey Peatross Wayment

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution and abundance of the greater sage-grouse (Centrocercus urophasianus; sage-grouse) have declined in the last 60 years. Range contractions and population declines have been attributed to loss and fragmentation of their sagebrush (Artemisia spp.) habitats. Grazing by livestock remains the predominant anthropogenic land-use across sagebrush ecosystems in North America, occurring on 87% of remaining sage-grouse habitat. Most of the peer-reviewed literature reports the potential for negative impacts of sagebrush reduction treatments, to increase livestock forage, on sage-grouse habitat. However, few studies have linked livestock grazing at the landscape level to vital rates (e.g., nest initiation rates, …

Evaluation Of Grazing Techniques As A Nutrition Source For Horses In A Pasture Environment, Brittany Perron

All Dissertations

Horses require daily access to forage in order to support their gastrointestinal tract function as well as natural grazing behaviors. Well-managed pasture provides horses with a consistent forage source and diminishes health risks such as colic, ulcers and stereotypies. However, equine grazing behaviors are more intense than other livestock and may be detrimental to plant and soil health. A grazing management technique specifically for horses is necessary to prevent both health and environmental issues. The following dissertation explores both the movement of required maintenance elements, such as feed, shelter, and water, as well as the manipulation of feeding frequency and …

Influences Of Grazing On Habitat Characteristics, Avian Community Composition And Nesting Bird Abundance Within Cheyenne Bottoms, Ks, Kirsten Granstrom-Arndt

Master's Theses

Cheyenne Bottoms is a 41,000-acre prairie-marsh ecosystem in central Kansas. Approximately 8,000 acres of mixed grassland are dedicated for the conservation of bird populations, but little is known about the status of bird communities within these areas. This study took place within grassland areas of Cheyenne Bottoms from May – July 2021. I investigated bird community composition, relative abundance of frequently observed bird species, vegetative characteristics, and similarity of sites across different grazing intensities (continuous, rotational, and non-grazed). The four most common bird species observed were dickcissel (Spiza americana), grasshopper sparrow (Ammodramus savannarum), meadowlark species ( …

Interseeding Native Warm-Season Grass Pastures, Jonathan D. Richwine

Doctoral Dissertations

Cool-season annual (CSA) grass and legume species, as well as warm-season forbs, can enhance established native warm-season grass (NWSG) pastures by extending the grazing season, reducing supplemental feed costs, suppressing weeds, increasing herbage production and overall forage quality, and increasing food and cover resources for pollinators and wildlife. Therefore, two NWSG experiments were conducted near Spring Hill, TN, 2018-2020, to assess three CSA seeding options (cereal rye monoculture, a cereal rye, ‘Purple Top’ turnip, ‘Trophy’ rape, ‘Frosty’ berseem clover, and ‘Dixie’ crimson clover polyculture, or non-planted control) and two warm-season N rates (0 or 67 kg N ha^-1) …

Corridors For Coexistence: Evaluating Spatiotemporal Impacts Of Livestock On Wildlife Community Dynamics, Edward Trout

Boise State University Theses and Dissertations

Livestock depredation by carnivores is a globally pervasive and detrimental interaction that leads to economic loss and retaliatory killings. Livestock trailed annually on US Rangelands impact wildlife communities- competing with ungulate herbivores for forage, disrupting predator-prey dynamics, and shifting community structures. In order to promote coexistence in these human-wildlife systems, a better understanding of how these processes interact is needed. However, studies on the topic fail to fully capture both the spatial and temporal signals of moving livestock herds.

In this study I investigated the effects of sheep grazing on a wildlife community in the Big Wood River Valley, Idaho. …

Establishing Regenerative Pasture Systems Using Management Intensive Grazing In The Ozarks, Shelbi M. Mundy

MSU Graduate Theses

Soil carbon and soil health are important topics relating to how climate change is impacting agriculture, and how agriculture can in turn impact climate change. The agriculture industry, particularly beef production, has a large opportunity to use conservation agriculture techniques, such as rotational grazing, to offset some of the industry’s impact on carbon emissions, erosion, water pollution, and other environmental issues. This study is the beginning of a long-term project exploring regenerative pasture systems in the Ozarks. The project takes place in a rotational grazing system with 12 paddocks. The objectives of this study are to characterize soil types by …

Understanding The Interaction Between Habitat Use Of Feral Horses And The Abundance Of Greater Sage-Grouse In The Great Basin, Mikiah R. Carver

Theses and Dissertations

Environmental impacts of feral horses (Equus caballus) are a subject of conservation concern and controversial national policy. In North America, feral horses are considered an invasive species where they impact rangelands of the arid and semi-arid western United States. The greater sage-grouse (Centrocercus urophasianus) is a native sagebrush obligate bird species that relies on sagebrush habitats to sustain viable population levels. Recent literature suggests that feral horse presence can have a notable effect on the fitness of native and sagebrush obligate species throughout the arid and semi-arid western United States. The purpose of this thesis was to assess the potential …

Establishing Agroforestry Silvopasture Systems In The Missouri Ozark Region, Kara Lynn Powelson

MSU Graduate Theses

The Missouri Ozarks is located in the south-central part of Missouri, ranging from the very southwest corner of the state and east to St. Louis. This region is enriched with large dense populations of oak and hickory tree species, while also being occupied with prime forage pastures for livestock grazing. Missouri is ranked second in the nation for farming operations and hay production, while also third in the nation for beef cow number of head (MDA 2021). The objective of this study is to observe the establishment of two separate silvopasture systems: a planted walnut plantation and a converted silvopasture. …

The Effects Of Different Organic Pastures On Dairy Heifer Growth And Development, Jacob A. Hadfield

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Raising dairy heifers in a certified organic setting can be difficult for producers. Conventionally, heifers are raised in a confined setting, and fed a total mixed ration (TMR) that is balanced daily to contain all the needed nutrients for developing heifers. Organic producers can use a TMR in their operations, but due to high organic feed costs, many choose to raise their heifers in pasture-based systems. While pasture-based systems may lower costs, heifers on pasture commonly have lower rates of gain, which can be financially burdensome to producers. Grass-legume pastures may help improve rates of gain in heifers on pasture-based …

Partitioning Variation In Vegetation And Landscape Functionality In Arid Land Piosphere, Eahsan Shahriary

Open Access Theses & Dissertations

A piosphere is an interaction between vegetation community, watering point, and grazing livestock/wildlife. In this Dissertation, I begin by reviewing the concept of the piosphere, and the progress, knowledge gaps and common statistical approaches and errors in piosphere research. Landscape functionality, plant community distribution and their influencing factors on a piosphere in Iran are then investigated.

A total 862 piosphere publications of multiple types from 68 countries and 10 different languages during the period of 1915 â?? 2018 were reviewed. Australia was the most productive country followed by South Africa, the USA, Botswana and Argentina. Ivan Thrash is the most …

Variation In Herbivore Effects On Grassland Primary Production: A Test Of Three Models, Jacob Penner

Theses - ALL

Grazing animals influence a wide range of plant and soil processes in the world’s grasslands. Ecologists have long understood that grazing can stimulate aboveground net primary production (ANPP), although this phenomenon has not been broadly generalizable across grasslands and grazing regimes. The mechanisms underlying grazer stimulation of ANPP are therefore of interest to a wide variety of stakeholders from ecologists to land managers. Three data-supported hypotheses offer differing explanations for the ways in which grazing interacts with resource availability to drive ANPP: the compensatory continuum hypothesis (CCH) implicates background resource availability, the limiting resource model (LRM) considers the direct effects …

Herbage Characteristics Affecting Intake By Dairy Heifers Grazing Grass-Monoculture And Grass-Birdsfoot Trefoil Pastures, Marcus F. Rose

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pasture-based dairies have become more prevalent in recent years due to a higher proportion of organic milk demand and production. Organic certification requires that animals must graze at least 120 days in each growing season. However, dry matter intake is often limited when dairy animals receive most of their herbage from pasture, resulting in lower animal performance and milk production. The purpose of this study was to analyze the complimentary effect of high energy grasses with birdsfoot trefoil (BFT) tannins to improve intake of dairy heifers. Jersey heifers were rotationally grazed for 105 days in 2017 and 2018 on eight …

Macronutrient Content Of Winter Annual Cereal Grains With Phosphorus Fertilization, Taylor Anne Young

MSU Graduate Theses

Missouri ranks third in the United States in cow-calf production, and much of the land these cattle graze has acidic soil that is low in plant available phosphorus (P). Proper soil fertility is important to ensure that these forages meet the nutritional requirements of cattle. Tall fescue (Festuca arundinaceum (Schreb.)), has been shown to respond to increased soil P levels with increased growth and leaf concentrations of P, calcium (Ca), magnesium (Mg), and potassium (K). It is unknown if winter annual cereals will respond similarly. The objective of this study is to examine cereal rye (Secale cereal L.), winter wheat …

Outplanted Acropora Cervicornis Enhances The Fish Assemblages Of Southeast Florida, Ellen Dignon Goldenberg

HCNSO Student Theses and Dissertations

Acropora cervicornis, commonly known as the staghorn coral has historically been a major contributor to reef structural complexity, providing habitat for many functionally important fish species throughout Florida and the Caribbean. Unfortunately, due to disease, bleaching, and local anthropogenic stressors, A. cervicornis populations have suffered drastic declines that have negatively impacted associated reef fish populations. In order to promote recovery, A. cervicornis fragments can be cultivated in nurseries and outplanted back onto reefs. This practice can effectively increase A. cervicornis abundance, but the long-term effects on local fish assemblages, and specifically functionally important grazing fishes, has not been assessed. …

Impacts Of Cattle Grazing As A Tool To Control Phragmites Australis In Wetlands On Nitrogen, Phosphorus, And Carbon, Brittany L. Duncan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phragmites australis is a plant that is causing problems in wetlands by outcompeting native plants that provide food and shelter for millions of migratory birds. Currently, managers try to control Phragmites australis by spraying herbicide, burning, and mowing, but these methods are costly, time consuming, and have low levels of success. Adding grazing as a tool to control Phragmites australis provides a cheap and low labor alternative. However, there are many concerns regarding if grazing will cause nutrient loading in our wetlands that will decrease water quality and alter beneficial functions of wetlands.

To better understand the effects of grazing …

Cryptic Herbivorous Invertebrates Restructure The Composition Of Degraded Coral Reef Communities In The Florida Keys, Florida, Usa, Angelo Jason Spadaro

Biological Sciences Theses & Dissertations

Coral reefs have been on a trajectory of decline for nearly a century due to a variety of factors that have contributed to the shift in these communities away from dominance by reef-building corals, with commensurate changes on community composition and function. Florida’s reefs are a compelling example of a degraded system that has undergone a phase shift, and thus offered an excellent model system for my study of the effects of grazing by cryptic herbivores on community composition and their potential restoration value. I had four major objectives: (1) determine the suitability of Maguimithrax spinosissimus for manipulating grazing intensity …

Analysis Of The Soil Health Of Pastures Over-Seeded With Winter Annuals, Kathleen M. Bridges

LSU Doctoral Dissertations

Utilizing winter annuals in livestock pastures reduces feed costs of hay, and provides additional vegetative cover that is beneficial to the soil. However, how this practice affects the soil microbial communities has not been well studied. Two sites were included in this study. Both were commercial cattle grazing operations that over-seeded a mixture of grasses, legumes, and brassicas into pastures dominated by bahiagrass (Paspalum notatum). Soil health was assessed using a suite of physical, chemical, and biological properties. Soil physical assessments included bulk density and aggregate stability. Soil chemical assessments included macronutrients, pH, soil organic matter (SOM), total …

Foraging Ecology Of Parrotfishes In The Greater Caribbean: Impacts Of Specialization And Dietary Preferences On Marine Benthic Communities, Madelyn V. Roycroft

Master's Theses

Coral reefs are one of the world’s most diverse yet heavily impacted marine ecosystems. As a result of many direct and indirect stressors, coral reefs have experienced major degradation over the last several decades. Declines in coral reefs in the Caribbean have been particularly acute and generally associated with the loss of key herbivores and an increase in algae. Herbivorous fishes such as parrotfishes can positively impact coral reefs by removing algae that compete with corals for light and space. However, many parrotfishes are also important coral predators. Predation on corals, known as corallivory, can adversely affect coral growth, reproduction …

Evaluating In Situ Grazing Patterns Of Lytechinus Variegatus And Their Effects On Seagrass Beds Of Thalassia Testudinum, Adrianna Parson

Master of Science in Integrative Biology Theses

The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m². Changes in temperature and sediment size in the bay indicate …

Avian Community Responses To Bison Grazing In North American Intermountain Grasslands, Danielle A. Fagre

Graduate Student Theses, Dissertations, & Professional Papers

Grassland and shrubland songbird species are a guild of conservation concern in North America. Many of these species have experienced severe population declines, due to habitat loss and land use change. This makes the conservation and management of remaining habitat of crucial importance for this guild. Grazing by large herbivores is an ecosystem process in grassland systems, and in North America, one of the major historic grazers was the Plains bison (Bison bison). Bison are considered ecosystem engineers, because they modify habitat to be more or less suitable for other species, such as grassland and shrubland songbirds. Bison …

Quantifying The Short-Term Impacts Of Cover Crops And Grazing On Soil Health Under An Integrated Crop-Livestock System In South Dakota, Vishal Seth

Electronic Theses and Dissertations

Cover crops and grazing under Integrated Crop-Livestock System (ICLS) can impact the rhizosphere nutrient cycling and may have potential to increase the long-term sustainability and economic profitability of agricultural production system. In South Dakota, crop production practices and livestock husbandry are both common which provide the opportunity for ICLS to be successful in this region. However, little is known about the impacts of the cover crops and grazing under ICLS on soil properties in this region. The present study was conducted at South Dakota State University Research Farm (44°20'34.8"N, 96°48'14.8"W), Brookings, SD, to quantify the impacts of cover crops and …

Coping With Drought In Beef Cattle Production: Innovation Through Optimal Warm-Season Forage Systems, Katelynn Elizabeth Zechiel

Masters Theses

Drought conditions have had detrimental effects on beef cattle production in the southeastern states where forages are the primary source of feed for livestock. Many southeastern states lie within the fescue-belt, where tall fescue is the predominant livestock forage. Tall fescue is a cool-season (CS) grass that thrives in the cooler temperatures of spring and fall, becoming semi-dormant during peak summer temperatures and again in winter. Conversely, warm-season (WS) forage species increase in production during the summer months and exhibit drought tolerant qualities, making them a viable summer forage option to complement tall fescue for beef cattle producers. The primary …

Effects Of Phosphorus Availability On Growth And Leaf Nutrient Concentrations In Wheat, Oat, And Cereal Rye, Jerri Lynn Dodson

MSU Graduate Theses

Adequate soil phosphorus (P) is critical for the growth and nutrient content of forages for grazing animals. On low fertility soils, tall fescue responds to P fertilization with increased yields and improved leaf nutrient contents of P, magnesium (Mg), calcium (Ca), and potassium (K) in winter months. My objective was to examine the effect of P availability on growth and leaf nutrients in annual cereal grains commonly grown for winter forage. Soft red winter wheat (Triticum aestivum), oat (Avena sativa), and cereal rye (Secale cereale) were grown hydroponically in greenhouse conditions in complete nutrient solutions with varying P concentrations of …