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 …

Livestock Producers' Perceptions Of The American Black Vulture Conflict In The Midwestern United States, Marian L. Wahl, Brooke Mcwherter, Patrick A. Zollner, Zhao Ma, Grant C. Burcham, Lee A. Humberg, Brian M. Kluever

USDA Wildlife Services: Staff Publications

Human‐wildlife interactions are present wherever both humans and wildlife are found. Interactions can be positive or negative for humans and can include impacts that range from damage to property, agriculture, health and human safety, to emotional effects. Livestock‐wildlife interactions form a major component of human‐wildlife conflicts with foci often centered on the implications of livestock predation by wildlife. While most vulture species are obligate scavengers, several species, including the American black vulture (Coragyps atratus), may attack weak or newborn livestock. Black vulture populations and distributions are expanding in the Midwestern U.S., and attacks create a novel problem for …

Bobwhite Response To Cattle Grazing In South Texas, Bradley K. Johnston, J. Alfonso Ortega-S., Leonard A. Brennan, Fidel Hernández, Humberto L. Perotto-Baldivieso

National Quail Symposium Proceedings

Range management practices to improve habitat for wildlife by reducing brush and increasing herbaceous plants, coupled with reduced stocking rates, can lead to dense stands of dominant grasses, such as four-flower trichloris (Trichloris pluriflora). This monoculture of trichloris creates dense vegetation unsuitable for northern bobwhite (Colinus virginianus; hereafter, bobwhite), reduces plant species diversity, and alters ecosystem functions. The objectives of this study are to 1) evaluate the effects of a proper cattle grazing regime to improve bobwhite habitat and 2) develop a management guide documenting how cattle grazing can be used as a tool to reduce …

Northern Bobwhite Response To Vegetation Management And Recovery In South Texas, Rachel A. Smith, Leonard A. Brennan, Humberto L. Perotto-Baldivieso, Fidel Hernández

National Quail Symposium Proceedings

The northern bobwhite (Colinus virginianus; hereafter, bobwhite) requires habitat structure and composition with grass cover for nesting, predator avoidance, and thermal refuge and forb cover for feeding on phytophagous arthropods and seeds. During the past 2 decades, many land managers with interest in promoting quail hunting opportunities have reduced or completely eliminated livestock across South Texas, USA, rangelands. Resting the land from grazing allows vegetation—especially grasses and forbs—to recover and thus provide nesting and foraging habitat for bobwhite and other birds. How bobwhite respond to postgrazing vegetation recovery is of keen interest to rangeland quail managers, but this …

Northern Bobwhite Demographics And Resource Selection Are Explained By Prescribed Fire With Grazing And Woody Cover In Southwest Missouri, Frank R. Thompson Iii, Mitch D. Weegman, Emily A. Sinnott, Alisha R. Mosloff, Kyle R. Hedges, Frank L. Loncarich, Thomas R. Thompson, Nicholas C. Burrell, Stasia Whitaker, David E. Hoover

National Quail Symposium Proceedings

Understanding the effects of landscape management on northern bobwhite (Colinus virginianus; hereafter, bobwhite) population growth requires information about seasonal- and stage-specific demographic parameters linked across the annual cycle. We review results to date from 3 years (2016–2018) of an intensive field study evaluating drivers of bobwhite population dynamics and resource selection during the breeding and non-breeding season in southwest Missouri, USA using data from adult and juvenile bobwhite fitted with radio-transmitters. Land cover of our study sites ranged from large blocks of native grasslands maintained with prescribed fire and grazing to more traditional management resulting in small patches …

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. …

Nutrient Availability Controls The Impact Of Mammalian Herbivores On Soil Carbon And Nitrogen Pools In Grasslands, Judith Sitters, E. R. Jasper Wubs, Elisabeth S. Bakker, Thomas W. Crowther, Peter B. Adler, Sumanta Bagchi, Jonathan D. Bakker, Lori Biederman, Elizabeth T. Borer, Elsa E. Cleland, Nico Eisenhauer, Jennifer Firn, Laureano Gherardi, Nicole Hagenah, Yann Hautier, Et Al.

Ecology Center Publications

Grasslands are subject to considerable alteration due to human activities globally, including widespread changes in populations and composition of large mammalian herbivores and elevated supply of nutrients. Grassland soils remain important reservoirs of carbon (C) and nitrogen (N). Herbivores may affect both C and N pools and these changes likely interact with increases in soil nutrient availability. Given the scale of grassland soil fluxes, such changes can have striking consequences for atmospheric C concentrations and the climate. Here, we use the Nutrient Network experiment to examine the responses of soil C and N pools to mammalian herbivore exclusion across 22 …

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 …

Use Of Uav Imagery And Nutrient Analyses For Estimation Of The Spatial And Temporal Contributions Of Cattle Dung To Nutrient Cycling In Grazed Ecosystems, Amanda Shine

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Nutrient inputs from cattle dung are crucial drivers of nutrient cycling processes in grazed ecosystems. These inputs are important both spatially and temporally and are affected by variables such as grazing strategy, water location, and the nutritional profile of forage being grazed. Past research has attempted to map dung deposition patterns in order to more accurately estimate nutrient input, but the large spatial extent of a typical pasture and the tedious nature of identifying and mapping individual dung pats has prohibited the development of a time- and cost-effective methodology. The first objective of this research was to develop and validate …

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 …

Migratory Goose Arrival Time Plays A Larger Role In Influencing Forage Quality Than Advancing Springs In An Arctic Coastal Wetland, Karen H. Beard, Ryan T. Choi, A. Joshua Leffler, Lindsay G. Carlson, Katharine C. Kelsey, Joel A. Schmutz, Jeffrey M. Welker

Ecology Center Publications

With warmer springs, herbivores migrating to Arctic breeding grounds may experience phenological mismatches between their energy demands and the availability of high quality forage. Yet, how the timing of the start of the season and herbivore arrival influences forage quality is often unknown. In coastal western Alaska, approximately one million migratory geese arrive each spring to breed, where foliar %N and C:N ratios are linked to gosling survival and population growth. We conducted a three-year experiment where we manipulated the start of the growing season using warming chambers and grazing times using captive Pacific black brant (Branta bernicla nigricans) to …

The Effects Of Native And Domestic Grazers On The Health Of Bumble Bee (Bombus Spp.) Populations In A Historical Tallgrass Prairie Ecosystem, Mckenna Conforti

Honors Program Projects

Bumble bees (Bombus spp.) play an important role in the pollination of ecologically and economically significant plants worldwide. In recent years, bumble bee populations have suffered decline throughout North America, particularly in the Midwest. Many factors likely contribute to this decline, including the use of pesticides, disease, and habitat loss. Although cattle grazing space is a common use for Midwestern grassland, a comparison had not been made between the capacity of cattle pasture to support bumble bee communities with the capacity of tallgrass prairie, a habitat thought to be optimal for requisite floral resources. Additionally, the reintroduction of bison …

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 …

Changes In Feeding Selectivity Of Freshwater Invertebrates Across A Natural Thermal Gradient, Timothy A C Gordon, Joana Neto-Cerejeira, Paula C. Furey, Eoin J. O’Gorman

Paula Furey

No abstract provided.

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 …

Green Sea Turtles (Chelonia Mydas) In Bermuda Exhibit An Ontogenetic Diet Shift Despite Overexploitation Of Resources In Their Developmental Habitat, Claire Margaret Burgett

FIU Electronic Theses and Dissertations

Green sea turtles in Bermuda are overgrazing the seagrasses on which later life stages are thought to specialize. I hypothesized that larger green turtles in Bermuda would display individual diet specializations during seagrass scarcity. Stable isotope methods were used to determine the diet composition of green sea turtles from the Bermuda Platform as a function of size class and in turtles captured in successive years. Individual turtles had a wide range of diets, however, the variation in diets was driven by differences among size class rather than within the size classes of larger turtles, indicating that green turtles undergo a …

Grazing And The Coupling Of Vascular Plant And Soil Microbial Diversity In Agricultural Landscapes Of Eastern New York, Caroline Belle Girard-Cartier

Legacy Theses & Dissertations (2009 - 2024)

ABSTRACT

Greater Bud Outgrowth Of Bromus Inermis Than Pascopyrum Smithii Under Multiple Environmental Conditions, Jacqueline P. Ott, Jack L. Butler, Yuping Rong, Lan Xu

Natural Resource Management Faculty Publications

Tiller recruitment of perennial grasses in mixed-grass prairie primarily occurs from belowground buds. Environmental conditions, such as temperature, soil moisture and grazing can affect bud outgrowth of both invasive and native perennial grasses. Differential bud outgrowth responses of native and invasive species to climate change and grazing could alter competitive interactions that have implications for future land management. The aims of this work were to (i) compare how spring temperature altered bud outgrowth of native Pascopyrum smithii (Rydb.) Á. Löve (western wheatgrass) and introduced Bromus inermis Leyss.(smooth brome), (ii) compare how watering frequency altered bud outgrowth of these two species …

Effect Of Grazing Prairie Dog—Colonized Rangeland On Cattle Nutrition And Performance: A Progress Report, Kenneth C. Olson, Christopher Schauer, Chanda Engel, Janna J. Kincheloe, Jameson R. Brennan, Ben L. Hauptman

Natural Resource Management Faculty Publications

On the Ground

• One objective of the ongoing Renewal on Standing Rock Reservation project is to evaluate the response of grazing steers to the level of prairie dog colonization on Northern Mixed Grass Prairie.
• We fenced four pastures to create an increasing gradient of a proportion of the pasture area colonized by prairie dogs. Pastures are stocked with yearling steers during each growing season.
• Comparing steer performance, Global Positioning System (GPS) locations of grazing, diet samples, and ingestive behavior at each proportion of the prairie dog colony per pasture allows prediction of the optimal proportion of colonization, which enables selection …

Invasion During Extreme Weather: Success And Failure In A Temperate Perennial Grassland, James C. Han, Stephen L. Young

West Central Research and Extension Center, North Platte

Invasive and native plant species compete for resources in similar pools, with disturbances often favoring the invader. Yet, increased climate variability may be shifting the competitive edge back toward the natives. We conducted field studies in perennial grasslands to determine the effects of clipping and drought on resource availability (light and moisture) and subsequent establishment of Carduus nutans. We measured light penetration and soil moisture content in C. nutans monoculture, clipped and non clipped grassland with C. nutans, and bare ground control plots. We also tracked phenology of the invader and grasses. Our studies revealed that light was a limiting …

Carbon Flux Dynamics In High Altitude Peatlands In The Ecuadorian Andes, Maria Elisa Sanchez Garces

Dissertations, Master's Theses and Master's Reports

Although knowledge of peatland CH₄ and CO₂ exchange in temperate mountain ecosystems is available, information about carbon (C) exchange in peatlands of the Andean mountains is limited and these ecosystems may behave differently given the particular characteristics of the Andean tropics. These ecosystems are highly productive and under pressure by grazing. Our first objective was to measure baseline carbon dioxide (CO₂) and methane (CH₄) flux in an undisturbed peatland in Cayambe-Coca National Park. Our second objective was to quantify CO₂ and CH₄ fluxes in an intensively cattle grazed peatland near Antisana Ecological …

Phytoplankton Pigment Specific Growth And Losses Due To Microzooplankton Grazing In A Northern Gulf Of Mexico Estuary During Winter/Fall, Amanda M. Mcgehee, Donald G. Redalje

Gulf and Caribbean Research

Microzooplankton dilution grazing experiments were carried out on 6 dates, over a 3 month period at 2 locations in the Bay of St. Louis, MS (BSL) to determine phytoplankton pigment specific growth rates under natural (µ₀) and replete (µ_n) nutrient conditions and microzooplankton grazing. We hypothesized that diatoms would be the largest portion of the phytoplankton composition due to the winter/fall season and that these organisms would have the highest growth/grazing rates. We suspected that river flow from the Jourdan River would adversely affect growth and grazing rates of all phytoplankton classes. Growth rates of 5 …

Corn Residue Stocking Rate Affects Cattle Performance But Not Subsequent Grain Yield, L. A. Stalker, H. Blanco-Canqui, Jennifer A. Gigax, A. L. Mcgee, T. M. Shaver, S. J. Van Donk

West Central Research and Extension Center, North Platte

This study investigated effects of stocking rate on cattle performance, quality and quantity of corn residue, and impact of residue removal on grain yield for 5 yr at the University of Nebraska – Lincoln West Central Water Resources Field Laboratory near Brule, NE. Four removal treatments—1) no removal (control), 2) grazing at 2.5 animal unit month (AUM)/ ha, 3) grazing at 5.0 AUM/ha, and 4) baling—were applied to a center pivot–irrigated corn field (53 ha). The field was divided into eight 6.6-ha paddocks to which replicated treatments were assigned. Samples of residue were collected in October and March (before and …

Assessing Changes In Avian Communities, Jessie D. Golding

Graduate Student Theses, Dissertations, & Professional Papers

Grazing is a potentially powerful tool to address wildlife declines associated with land use conversion in the western United States. Grazing systems can be manipulated to achieve desired vegetation outcomes, preserve native habitat and economically benefit multiple stakeholders. As a result, systems designed to benefit native ecosystems are being widely implemented. However, the benefits of these grazing systems on many wildlife communities remain relatively unexplored. Songbirds provide an ideal study system to test these benefits because they continue to use native habitat that is currently grazed. Given limited time and resources, conservation practitioners often monitor a single focal species or …

Response Of Grassland Songbirds To Grazing System Type And Range Condition, Stephen K. Davis, Brenda C. Dale, Tom Harrison, David C. Duncan

The Prairie Naturalist

Much of the remaining prairie in Canada is grazed by cattle and most grassland birds of conservation concern occupy such habitat. Identifying vegetation features related to grassland bird habitat selection that can be easily understood and measured by professional range managers and livestock producers on private lands is an important step towards conserving and restoring remaining grasslands. We conducted grassland bird surveys on 28 native mixed-grass prairie pastures in southern Saskatchewan to determine whether grazing system type (season-long vs. rotational) influenced avian abundance. Grazing system had no influence on abundance of grassland passerines. Conservation agencies that promote particular grazing systems …

The Ecological Effects Of Cattle Grazing On Reptiles And Small Mammals In A San Joaquin Valley Grassland, Michael William Tom

Master's Theses

Livestock grazing is a common and extensive land use practice in the United States occurring in a wide range of habitat types. As such, livestock grazing has the potential to alter ecosystem structure, function and community composition. The primary component (Chapter 1) of this thesis examined the effects of cattle grazing in a San Joaquin Valley grassland on two target taxa: reptiles and small mammals. The study took place on the Chimineas Unit of the Carrizo Ecological Reserve, San Luis Obispo County, California during Fall 2009 and Spring 2010. These taxa were sampled on matched pairs of two grazed and …

Sarpa Salpa Herbivory On Shallow Reaches Of Posidonia Oceanica Beds, Latina Steele, Kelly M. Darnell, Just Cebrián, Jose Luis Sanchez-Lizaso

Biology Faculty Publications

Sarpa salpa herbivory on shallow reaches of Posidonia oceanica beds.— Here, we examined the temporal and small–scale spatial variability of grazing by the herbivorous fish Sarpa salpa on shallow beds of the temperate seagrass Posidonia oceanica. Herbivory intensity expressed as the percent of leaf area taken by fish bites was higher in September 2006 than in February 2007, and at 0.5 m than at 1.5 m during both sampling times. All S. salpa feeding at the shallow locations studied were juveniles, with bite sizes ranging from 0.03 to 0.62 cm2. Juveniles feeding at 1.5 m were larger in February 2007 …

Drought-Induced Woody Plant Mortality In An Encroached Semi-Arid Savanna Depends On Topoedaphic Factors And Land Management, Dirac L. Twidwell Jr, Carissa L. Wonkka, Charles A. Taylor, Chris B. Zou, Jeremiah J. Twidwell, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

Questions: How do recent patterns of drought-induced woody plant mortality in Texas semi-arid savanna compare to the extended drought of the 1950s? Does the relative composition of the woody plant community shift ubiquitously across the landscape following woody plant mortality and dieback or are shifts dependent on differences among species, soils, land use and plant demography?

Location: Texas Agrilife Research Station, Sonora, Texas, USA (30.1° N 100.3° W).

Methods: Following an exceptional drought from 1951 to 1957, a study was conducted to quantify rates of mortality for various woody plant species. In 2011, we repeated this study within three long-term …

Conserving The Land Of The Giants: Critical Threats To Asian Elephant Habitat In Sri Lankan Protected Areas, Christie Sampson

All Theses

Grasslands habitats are hypothesized to be a critical resource for the endangered Asian elephant (Elephas maximus) throughout its range. However, this hypothesis has not been rigorously tested. My study examined elephant habitat selection in Sri Lanka to determine the importance of grassland versus other local habitats, and how livestock abundance, fire, and the invasive plant Lantana camara affect the relative abundance of elephants within habitats. My research was conducted in two protected areas in Sri Lanka, Udawalawe National Park (UNP) and Hurulu Forest Reserve (HR). I used distance-sampling on a total of 50.8 km of dung line-transects in the four …