Life Sciences Commons^™

C3 And C4 Grass Dominated Plant Communities Differ In Response To Future Larger And Less Frequent Rainfall, Zigeng Chen

Electronic Theses and Dissertations

Climate change is leading to larger and less frequent rainfall in the Northern Great Plains (NGP). We ask if this change in rainfall would influence carbon (C) and nitrogen (N) cycling in the NGP. First, we collected soils from C3 and C4 grass dominated plant communities from western South Dakota and conducted an incubation experiment to explore the effects of soil water content (SWC) and temperature on soil respiration (Rs) and N mineralization rate (ΔIN). Second, we conducted a three-year rainfallmanipulation (RaMP) experiment with two distinct rainfall regimes (frequent/small and infrequent/large events with constant total monthly precipitation) and two grasses …

Plant Responses To Drought In A Semiarid Grassland: An Isotopic Approach, Elizabeth V. Fain

Biology ETDs

Dryland ecosystems are facing unprecedented climate extremes as a result of global climate change. Water is the most limiting factor in dryland ecosystems, therefore plants in drylands have developed crucial water-use strategies for drought survival. It is important to understand plant physiological responses to water stress as drylands are projected to experience more frequent, severe droughts in the coming decades. To test how plants respond to drought in a semiarid grassland, we measured δ13C, δ15N, and C/N ratio of common C3 and C4 plants (Bouteloua gracilis, B. eriopoda, Pleuraphis jamesii, Salsola tragus, Machaeranthera pinnatifida, …

Relating Plant Community Structure To Carbon Dynamics In Semiarid Grasslands, Theodore D. Roper

Biology ETDs

Understanding how fine-scale changes in soil characteristics and plant community composition affect ecosystem functioning is key to predicting how biome shifts will affect regional and global carbon cycling. This is crucial in the dryland biomes of the US Southwest, projected to be one of the regions most affected by climate change. We examined fine-scale drivers of ecosystem function within two biomes – a Chihuahuan Desert grassland and Plains/Chihuahuan Desert ecotone – via long-term vegetation data, micrometeorological data, eddy covariance carbon flux measurements, and soil water and texture, finding that the ecotone site had over 30% higher soil water content, over …

Seasonality Of Orthohantavirus Seroprevalence In Northwest Arkansas Rodents, Amy Schexnayder

Biological Sciences Undergraduate Honors Theses

Zoonotic viruses are viruses that can be transmitted from animals to humans. Rodent species are likely to be reservoirs for zoonotic viruses, and particular rodent-borne viruses, such as orthohantaviruses, may greatly threaten human health. Orthohantaviruses are a group of rodent-borne viruses that are at risk for spillover to human populations. Many aspects of orthohantaviruses have been well-researched, yet the seasonality of orthohantaviruses has not yet been thoroughly examined, especially in the southern United States. In this study, we captured 616 rodents trapped over 5953 trap nights across 13 grassland sites in Northwest Arkansas. Rodents were trapped for two consecutive nights …

Regenerative Agriculture Effects On Invertebrate And Bird Communities And Insect-Provided Ecosystem Services, Alex Michels

Electronic Theses and Dissertations

Conventional agricultural practices can have unintended consequences on the environment and wildlife. Insects and birds are declining at rapid rates around the world, and the current conventional agricultural paradigm is a major driver through habitat loss and the intensification of production. Invertebrates in agroecosystems provide services to both farmers and the rest of society. Regenerative systems may promote the functioning of an agroecosystem by influencing invertebrate abundance, diversity, and ecosystem services and mitigate bird and insect declines through conservation practices that increase soil health, reduce disturbances, and increase biological diversity. Here I address knowledge gaps of the effects of regenerative …

Evaluating Avian Use Of Cover Crops In The Corn Belt, Megan Figura

Electronic Theses and Dissertations

The tallgrass prairie of North America has changed drastically since colonial settlement, with up to 99% of this region converted for agriculture and other land-uses. Concurrent with grassland conversion, grassland birds have experienced the most extreme, consistent, and widespread population declines of any avian guild. Agricultural lands in the U.S. Midwest were able to provide adequate habitat for several bird species until the 1950’s; however, altered and intensified management practices have degraded much of remaining suitable habitat and undermined ecosystem functions. Consequently, many grassland birds have been identified as Species of Greatest Conservation Need (SGCN) in many State Wildlife Action …

An Investigation Into Historical And Contemporary Breeding Occurrence Of The Ferruginous Hawk In Kansas, Erica Clark

Master's Theses

The Ferruginous Hawk (Buteo regalis) is the largest Buteo species occurring in grasslands, nesting along bluffs, buttes and isolated trees. In Kansas, the Ferruginous Hawk is listed as a Species of Greatest Conservation Need, Tier II. A previous study on Ferruginous Hawks nesting in Kansas during the years of 1979 to 1987, with sporadic visits from the 1990s to 2000, revealed that the most productive nesting territories were inaccessible to predators, placed on rocky ledges and the surrounding landscape was over 50% rangeland. I revisited 82 of the 111 historic nest territories in the summers of 2019 and …

Characteristics And Spatial Heterogeneity Of Prescribed Fire Behavior In North Dakota Grasslands, Megan Elizabeth Zopfi

Theses and Dissertations

Fire is a critical physical and chemical process required to sustain many grassland ecosystems. In North America, observations of grassland fire behavior in warm-season, southern grasslands are commonly used in fire behavior modeling efforts across the Great Plains. However, grasslands of the northern Great Plains contain a greater component of cool-season vegetation that may generate different fire behavior. To further our understanding of prescribed fire behavior in North Dakota grasslands, we quantified fuel, weather, and fire behavior characteristics associated with 27 prescribed fires conducted across three sites in North Dakota. We sampled 27 points on each fire arranged into a …

Several Vegetation Characteristics Affect Reproductive Success Of Grassland Birds At A Restored, Warm-Season Grassland In Central Georgia, Kayla B. Allen

Biology Theses

Grassland birds are experiencing major population declines due to habitat loss and fire suppression throughout North America. Large-scale grassland restoration efforts are ongoing, but there is little data on breeding bird productivity on restored habitats, nor on the impact of specific vegetation characteristics on reproductive output. Since 2005, agriculture fields at Panola Mountain State Park, GA have been undergoing restoration to warm-season grasslands; however, up until now there has been no monitoring of nest success or productivity. The goals of this project are to 1) quantify reproductive success and 2) determine which vegetation characteristics are associated with reproductive success. From …

Bottom-Up Herbivore-Plant Feedbacks Trump Trophic Cascades In A Wolf-Elk-Grassland System, Trevor C. Weeks

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Top-down predator-prey effects that alter the abundance, biomass, or productivity of a population community across more than one link in a food web are referred to as trophic cascades. While these effects have been extensively studied in aquatic environments, fewer studies have examined trophic cascades in terrestrial ecosystems. And fewer still terrestrial studies have tested for trophic cascades between vertebrates and grassland vegetation. Across the globe, grassland plant biomass is driven by both precipitation and non-linear positive feedbacks between grazing and plant productivity, as predicted by the Intermediate Grazing Hypothesis. Yet little is known about the role that apex carnivores …

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 …

Nesting Success Of Dickcissel (Spiza Americana) And Non-Breeding Grassland Bird Use Of Northwest Arkansas’ Remnant And Restored Tallgrass Prairies, Alyssa L. Derubeis

Graduate Theses and Dissertations

Dwindling populations of North American grassland birds are linked to habitat loss. Tallgrass prairie only covers 3% of its pre-settlement-era range. Small-scale restoration projects attempt to increase acreage for prairie avifauna, and while some breeding grassland species are present at these sites, nesting success and non-breeding use are still largely unknown. Both life history aspects are required for effective grassland bird conservation. My first objective was to access nest success of the Dickcissel (Spiza americana) at two remnant and two restored tallgrass prairies in Northwest Arkansas. From May-August 2017 and 2018, I found 114 nests that I monitored to determine …

Incorporating Multi-Spectral Imaging Into Long-Term Upland Breeding Bird Monitoring, Kyle William Schumacher

Master's Theses

Quivira National Wildlife Refuge in Kansas, United States partnered with Fort Hays State University Hays, KS in 2014 to begin a collaborative research project that aimed to develop a long-term monitoring protocol guided by the Comprehensive Conservation Plan for the refuge published in 2013. This plan identified specific wildlife taxa underrepresented in management impact assessments throughout the property. As a result of this plan, surveys were established to monitor interactions between upland breeding birds and the vegetation community. I conducted point count surveys in 2016, 2017, and 2018 for 122 observation points across four transects. I measured seventeen vegetation variables …

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 …

Improving Survey Methodology To Monitor Rare Grassland Birds In South Dakota, Kassondra Hendricks

Electronic Theses and Dissertations

Breeding Bird Survey (BBS) data for grassland bird species has shown the most rapid population decline of any other bird group. Current roadside survey techniques, however, may fall short of providing accurate numbers of rare grassland bird species such as chestnut-collared longspur (Calcarius ornatus), lark bunting (Calamospiza melanocorys), Sprague’s pipit (Anthus spragueii), and Baird’s sparrow (Ammodramus bairdii). Trends resulting from roadside data for grassland birds are oftentimes determined to be statistically insignificant because many grassland bird species occur on too few routes, occur in low numbers per route, and show high annual fluctuations in number. It is possible roadside surveys …

Swift Foxes In Southwestern South Dakota: Assessing The Current Status Of A Reintroduced Population, Sarah Ann Nevison

Electronic Theses and Dissertations

Swift foxes (Vulpes velox) were reintroduced into Badlands National Park between 2003 and 2006 after being nearly extirpated from South Dakota in the early 1900’s. Genetic analysis provided strong evidence that the reintroduction was successful, but viability analysis indicated the population may be in jeopardy with a high probability of extinction. Recently, the population has declined due to various biotic and abiotic factors (e.g., recent weather patterns, effects of plague [Yersinia pestis], and increased coyote [Canis latrans] numbers). No information on the status of swift foxes has been collected since 2009. Between 2014 and 2016, the objectives of this study …

An Integrated Evaluation Of The Conservation Reserve Enhancement Program In South Dakota, Jarrett D. Pfrimmer

Electronic Theses and Dissertations

Grassland restoration efforts in North America typically share the goal of improving ecological conditions for wildlife; however, it is unclear in many cases if goals are met. The South Dakota Conservation Reserve Enhancement Program (CREP) was initiated to alleviate agriculturally-related environmental degradation by converting 40,469 hectares of eligible cropland and marginal pastureland to perennial vegetation. The program aims to provide habitat for obligate grassland breeding songbirds, while producing an additional 285,000 pheasants and 60,000 ducks annually. As part of a collaborative comprehensive evaluation effort, my research assessed the response of grassland-dependent breeding birds to CREP implementation at varying spatial scales …

Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …

Occupancy Modeling Of Herpetofauna And Grassland Nesting Birds At Quivira National Wildlife Refuge, Kasandra A. Brown

Master's Theses

Only about 11% of native grasslands remain in the United States (North America Bird Conservation Initiative, 2011). Grasslands are a considerable source of biodiversity and play a crucial role in nutrient cycling (Suttie et al. 2005; Holechek et al. 2011). Stewards, such as the US Fish and Wildlife Service, are essential to grassland conservation, especially in Kansas, where less than one percent of land is under federal stewardship or public trust (Holechek et al. 2011). Quivira National Wildlife Refuge, an 8,900 hectare refuge located in Stafford County, has traditionally been managed as a stopover for migratory birds, but is now …

Habitat Associations Of Grassland Birds Along A Gradient Of Eastern Red Cedar Succession In Central Kansas, Scott W. Schmidt

Master's Theses

Grassland birds have declined more rapidly than any other avian taxa in North America. While woody encroachment is often cited as a threat, some grassland-dependent species requiring habitat with scattered trees or shrubs also are declining at statistically significant rates. To better understand the ecological costs and benefits of woody vegetation from a brush management perspective, I studied bird-habitat associations along a canopy cover gradient of eastern red cedar (Juniperus virginiana). Habitat associations were tested by the comparing the relative abundance of breeding birds between 3 habitat treatment levels (0% eastern red cedar canopy cover [open grassland], < 5% eastern red cedar canopy cover [light encroachment], and > 5-25% eastern red …

Nest Survival Of Grassland Breeding Birds In A Southern Mixed-Grass Prairie Wetland, Clinton Helms

Master's Theses

As a group, grassland birds have been declining significantly since European settlement of the prairie. The subsequent plowing of the prairie by settlers was compounded by fire suppression, resulting in a patchwork of cultivated fields with intermittent tracts of overgrown grassland. Over an interval of ~200 years, these practices lead to an estimated decline of 96 % of native tallgrass prairie habitat. Due to the imperiled status of grassland birds, an emphasis has been placed on managing for this particular group throughout the southern mixed-grass prairie region. I investigated the effects of adaptive three-pasture rotational grazing treatments (3ROT) versus traditional …

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 …

Agricultural Conservation Buffers For Breeding Grassland Birds In Eastern Mississippi, Heidi Lynn Adams

Theses and Dissertations

Periodic disturbance in CP33 habitat buffers is required to maintain early-successional plant communities for grassland birds. However, effects of disturbance on habitat suitability and nesting success of grassland birds are unknown. Furthermore, the grassland bird community and reproductive performance in CP33 habitat buffers may be influenced by the landscape context (e.g., edge habitat, surrounding land cover). My objectives for this study were to determine how periodic disturbance and the agricultural landscape mosaic influence the breeding grassland bird community in buffers, and how these same factors influence grassland bird nesting success and density in buffers. Data collected during line-transect surveys conducted …

Establishment And Aesthetic Value Of Native Grass, Legume, And Forb Species For Grassland Restoration In The Northern Intermountain West, Bridget M. Atkin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Interest in the restoration of landscapes native to the Intermountain West is growing as the value of these arid ecosystems is increasingly recognized. Many landscapes within the Intermountain region have been impacted by grazing, development, recreation, and other human-caused disturbances. The complex relationships within the native plant communities of these arid landscapes need to be well-understood biologically, while considering their aesthetic contribution, if restoration efforts are to succeed. Although the use of ecologically appropriate native species is increasing in popularity, there is discontinuity between aesthetics and meaningful ecological contributions. A series of studies was designed to aid in the restoration …

A Spatio-Temporal Analysis Of Landscape Change Within The Eastern Terai, India: Linking Grassland And Forest Loss To Change In River Course And Land Use, Tanushree Biswas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Land degradation is one of the most important drivers of landscape change around the globe. This dissertation examines land use-land cover change within a mosaic landscape in Eastern Terai, India, and shows evidence of anthropogenic factors contributing to landscape change. Land use and land cover change were examined within the Alipurduar Subdivision, a representative of the Eastern Terai landscape and the Jaldapara Wildlife Sanctuary, a protected area nested within Alipurduar through the use of multi-temporal satellite data over the past 28 years (1978 – 2006).

This study establishes the potential of remote sensing technology to identify the drivers of landscape …