Life Sciences Commons^™

Bryophytes Of Goochland County, Virginia, Mikayla Quinn

Honors Theses

Bryophytes are non-vascular land plants that include mosses, liverworts, and hornworts. Although easier to overlook because of their smaller size, bryophytes are a fundamental part of the ecosystem. As such, maintaining record of their biodiversity is important. Yet, records of bryophyte species in Goochland County, VA were low compared to more thoroughly documented counties such as Prince Edward County. This study expands the documentation of bryophyte flora and presents a checklist of bryophyte species found Virginia’s Goochland County from 2020-2023. Fieldwork conducted at public and privately-owned properties throughout the county between January 2020 and March 2023 yielded 702 specimens that …

Csi Botany: Dna Barcode “Fingerprints” Identify Cryptic Urban Flora, Luis R. Vega

Theses

As short genomic markers, DNA barcodes can play a role in conservation by identifying cryptic species and hybrids when morphological approaches fall short. Here we present our application of barcodes to the identities of two wetland taxa as part of an ongoing floristic inventory of Van Cortlandt Park (VCP), Bronx, NY. Previous barcode data by Marriott et al. (2018) identified the VCP lake water lily as the exotic Nymphaea alba, rather than the native N. odorata as historically described. In addition, cattails in the park were historically identified as the native Typha latifolia and the exotic T. angustifolia …

Macrolichen Inventory Of The Horse Mountain Botanical Area, Six Rivers National Forest, California, Usa, Sarah Norvell Conway

Cal Poly Humboldt theses and projects

Macrolichen diversity and community composition was determined for an area of high botanical interest in the Coast Ranges of Northern California – the Horse Mountain Botanical Area (HMBA) in Six Rivers National Forest. The Coast Ranges have been suggested to have high epiphytic macrolichen diversity, yet detailed site-specific macrolichen surveys are lacking for the area. Here we present comprehensive data on macrolichens of the HMBA integrated with environmental metadata at the landscape level. Twenty 0.4 ha sampling plots were positioned across the varying habitats of the HMBA and macrolichens were intensively sampled from all substrata. Out of 888 total collections, …

Comparison Of Botanical Composition Methods And Change Over Time In Kentucky Pastures, Echo Elizabeth Gotsick

Theses and Dissertations--Plant and Soil Sciences

Botanical composition of pastures has been measured with numerous methods over the last century, but there have been limited direct comparisons between methods. The objective of this study was to compare botanical composition methods, to determine the most accurate and efficient method, and to access pasture composition change over time. Six farms with two pastures each were monitored across the state of Kentucky. Sampling occurred fall 2020 through fall 2022, three times a year using the following methods: step point, visual estimation, occupancy grid, and point quadrat (used as a reference method). The occupancy grid showed the highest similarity to …

Manipulating Species Diversity: Environmental Impacts In Row Crop, Livestock, And Grassland Agroecosystems, Alayna A. Jacobs

Theses and Dissertations--Plant and Soil Sciences

The diversity of living species in an agroecosystem affects both natural resources and agricultural production efficiency. The rise of managed plant monocultures has allowed agricultural yields to increase over time. However, simplifying agroecosystems affects the capacity of the system to sustainably provide clean air, water, and productive soils essential for continued food and fiber production. This dissertation manipulates species diversity in row crop and forage agroecosystems prevalent in the Eastern United States and tracks the associated environmental and agricultural production consequences.

In row crop agroecosystems, increasing plant diversity with winter cover crops has been suggested as a strategy to increase …

A Flora Of Coyote Ridge And Flat, Inyo County, California, Martin Purdy

CGU Theses & Dissertations

California’s Sierra Nevada mountain range contains a disproportionate share of the state’s plant diversity and is one of the most floristically diverse regions of its size in the United States. The high Sierra Nevada, in particular, has been identified as an important center of species richness and endemism within California. Anthropogenic climate warming is expected to disproportionately affect mountain ecosystems, and models have predicted serious habitat contraction and extirpation for many alpine plant taxa. A specimen-based inventory of the vascular and non-vascular plants of Coyote Ridge and Flat was conducted to establish baseline data for one such sensitive alpine and …

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 …

Intellectual Property Rights In The Seed Industry: Barriers To Sustainable Agriculture, Elena A. Filatova

Electronic Theses and Dissertations

The dynamics of the dominant industrial agriculture system restrict the seed industry’s innovative landscape, leading to significant negative consequences including an exacerbation of environmental risks which threaten global food security. This thesis explores how exclusionary intellectual property rights (IPRs) in the context of the seed industry constrict innovation, evolutionary pathways, and opportunities for the implementation of sustainable agriculture methods. To overcome these barriers, the application of an open source framework to seed innovation, specifically through the platform of the Open Source Seed Initiative, is evaluated as a tool for enhancing innovative capacities in seed development while broadening the accessibility and …

Conifer Encroachment And Removal In A Northern California Oak Woodland: Influences On Ecosystem Physiology And Biodiversity, Gabriel S. Goff

Cal Poly Humboldt theses and projects

Oregon white oak (Quercus garryana) woodlands across their range are becoming increasingly threatened by encroaching Douglas-fir encroachment (Pseudotsuga menziesii) as a result of fire exclusion. Using water potential (Ψ), stomatal conductance (g_s), xylem water stable isotopes (dD), and three metrics of biodiversity, this study investigates the effects of conifer encroachment and removal at the ecosystem-scale. The study was set in an Oregon white oak woodland in northern California and compared three levels of encroachment before and after conifer removal. Findings indicate that heavily encroached stands have the least amount of water stress and gas …

A Taxonomic Revision Of The Genus Burmeistera (Campanulaceae) In Ecuador, Brock Mashburn

Theses

The genus Burmeistera (Campanulaceae) consists of approximately 120 species of herbaceous trailing shrubs, found mostly in cloud forests from Guatemala to Peru. Taxonomic work is difficult for the genus because of its relatively recent diversification (5–12 mya) and the morphological lability of its species. The last monograph for the genus was completed in 1943, followed periodically by country-level treatments. For Ecuador, the most recent treatment of Burmeistera was nearly 40 years ago, in Stig Jeppesen’s 1981 treatment in the Flora of Ecuador. Jeppesen’s treatment recognized 32 species and subspecies. Since then, nine new species have been described and hundreds of …

Investigations Into Aspergillus Flavus Infection Of Corn And Regulation Of Aflatoxin Production By Volatiles And Biocontrol Strains, Rebecca R. Sweany

LSU Doctoral Dissertations

Aspergillus flavus is an ascomycete fungus impacting agriculture, public and environmental health due to production of acutely-toxic, carcinogenic aflatoxins in oil seed crops, especially corn in Louisiana, and lung infections of immunocompromised patients resulting in a leading cause of AIDS patients’ deaths globally. The most effective aflatoxin mitigation strategy, biocontrol by atoxigenic A. flavus presents several concerns including: dissemination of a human pathogen, possible sexual reproduction and reliance on precise environmental conditions. Several aspects of A. flavus biology were investigated to potentially improve treatments. Studies investigated how genotypically diverse members within the A. flavus population interact with other population members …

Where Birds Chill: An Assessment Of The Habitat Preferences Of Birds Overwintering In Hudson Valley Forests, Elizabeth Claire Axley

Senior Projects Spring 2019

Many avian species overwinter in eastern North America; however, studies on bird populations are rarely undertaken during this critical survival time, and little is known as to their habitat preferences and foraging behavior. In this observational study, we performed a survey of birds overwintering in the Hudson Valley’s temperate, primarily-deciduous forests, assessing avian populations’ habitat preferences through the vegetative structural variables surrounding overwintering birds as they forage. Our results suggest that high canopy cover is critically important to predicting overwintering bird occupancy on a microhabitat scale. Moreover, overwintering birds preferentially occupy forest plots not dominated by sugar maples, in spite …

Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh

Theses and Dissertations--Plant and Soil Sciences

The relationship between biodiversity and ecosystem functioning is important in maintaining agroecosystem sustainability. Plant-microbe symbioses, such as exists between the grass tall fescue (Schedonorus arundinaceum) and the asexual fungal endophyte Epichloë coenophiala, can be utilized to enhance agroecosystem functions, such as herbivore resistance. “Novel” E. coenophiala strains that vary in the production of mammal- and insect-toxic compounds have been identified, inserted into tall fescue cultivars, and are planted in pastures globally. Novel fungal endophyte-tall fescue associations may have divergent ecosystem function effects. This study assessed effects of different fescue-endophyte symbiotic combinations on pasture ecosystem function, including aboveground …

Systematics And Biogeography Of The Cortinarius Violaceus Group And Sequestrate Evolution In Cortinarius (Agaricales), Emma Harrower

Doctoral Dissertations

Phylogenetics is a powerful tool used for illuminating the diversity of life on Earth, their evolution and their ecology. I created a multi-gene phylogenetic tree of Cortinarius section Cortinarius and uncovered five previously overlooked species, increasing the number of species in the section from seven to twelve. All members of the clade possess both cheilocystidia and pleurocystidia and possess a pigment known as (R)-39,49-dihydroxybphenylalanine. Ancestral state reconstruction estimated that the ancestral host was most likely an angiosperm, switching hosts when encountering novel host species in new lands, and only C. violaceus associating with the Pinaceae in North America. Biogeographic analysis …

Lichen Conservation In Eastern North America: Population Genomics, Climate Change, And Translocations, Jessica Allen

Dissertations, Theses, and Capstone Projects

Conservation biology is a scientific discipline that draws on methods from diverse fields to address specific conservation concerns and inform conservation actions. This field is overwhelmingly focused on charismatic animals and vascular plants, often ignoring other diverse and ecologically important groups. This trend is slowly changing in some ways; for example, increasing number of fungal species are being added to the IUCN Red-List. However, a strong taxonomic bias still exists. Here I contribute four research chapters to further the conservation of lichens, one group of frequently overlooked organisms. I address specific conservation concerns in eastern North America using modern methods. …

Political Ecology Of Medicinal Plant Use In Rural Nepal: Globalization, Environmental Degradation, And Cultural Transformation, Emily Dovydaitis

Honors Undergraduate Theses

Prior to the advent of biomedicine, rural communities in Nepal relied on phytochemically active compounds in medicinal plants as their primary source of medicine; however, ethnobotanical practices have shifted over time due to economic, environmental, and sociocultural stimuli. Findings from 2016 fieldwork conducted in Dumrikharka, Nepal and Tutung, Nepal are compared to existing literature to describe the political ecology of medicinal plants in rural Nepal.

Anthropogenic climate change threatens individual plant species and ecosystem biodiversity. Globalized markets unabated by weak conservation programs place increasing demands on medicinal plants. As indigenous plants become overharvested and more difficult to access, Nepalis incorporate …

Interactive Effects Of Cover Crops, Invertebrate Communities And Soil Health In Corn Production Systems, Claire Lacanne

Electronic Theses and Dissertations

The adoption of regenerative farming practices is gaining traction, but the costs and benefits are not often considered on a systems level. Encouraging biodiversity and soil health is the goal of many agricultural practices used in regenerative farming; regenerative systems employ practices which abide by the two main principles of increasing biodiversity and decreasing disturbance, with the goal of encouraging ecosystem functioning to minimize inputs and maximize the productivity of a farm. I examined the management of corn (Zea mays) fields across four states in the Upper Midwest region of the United States. Regenerative systems in this study …

Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho

Theses and Dissertations (Comprehensive)

Cuscuta (dodder) is a genus of roughly 200 species of obligate stem parasites with sub-cosmopolitan distribution. The fruit, generally regarded as a capsule, has a thin pericarp containing one to four seeds and opening at the base (circumscissile dehiscence; DE), or remaining closed (indehiscent; IN). IN has evolved multiple times in Cuscuta from DE, and is most common in the North American clades of subgenus Grammica. In addition, some species produce fruits that open irregularly. Characteristics pertaining to the fruits of Cuscuta are important as their seeds contribute most to their distribution and prevalence across the globe, and their reduced …

Invasive Plant Ecology In Vermont: Insights From Spatial Analysis And Interactions Of Garlic Mustard (Alliaria Petiolata) With Native Plants And Invertebrates, Chenin Kathleen Limback

Graduate College Dissertations and Theses

Causes and patterns of invasive plant species establishment and success depend broadly upon their ecology, including habitat suitability and interactions with other plants and animals. Here I examine the traits and distribution of invasive plants in Vermont, using spatial analysis, laboratory and field studies. I used GIS to investigate environmental factors correlated with presence of 19 invasive plant species in Vermont campgrounds. My results support the assumption that human dispersal of invasive plant seed and stock may be more important than natural dispersal of these plant species to new sites. I also investigate in-depth the relationships of invasive herbaceous garlic …

The Relationship Between Riparian Zone Width And Floristic Quality In Shenandoah County, Virginia, Jamie D. Smith

Masters Theses, 2010-2019

Riparian zones harbor an above average plant biodiversity. This biodiversity is threatened by invasive species and increasing human disturbance, the latter of which includes deforestation from agriculture and urban development. In this study, I examine relationship between the width of a forested riparian zone and the vegetation growing there. By using floristic quality assessment as a measure of anthropogenic disturbance, one can determine if wider riparian zones foster exclusion of non-native species while providing higher quality habitats for native plants. A randomized block design was used with three forested riparian treatments: deforested, moderately forested (woody vegetationstream), and extensively forested (woody …

A Survey Of Ballistosporic Phylloplane Yeasts In Baton Rouge, Louisiana, Sebastian Albu

LSU Master's Theses

A study documenting basidiomycete yeast biodiversity was conducted in Baton Rouge, Louisiana during 2010 and 2011. Using the spore-fall method, the leaf surfaces of seven ferns were sampled at biweekly intervals. Maximum likelihood phylogenetic analyses of the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit (LSU) of nuclear ribosomal DNA were used to identify 463 isolates representing 81 species spanning 12 orders within six classes in Basidiomycota. Nearly 30 of these isolates appear to be species new to science. Data indicate fern leaf developmental stage has an effect on the number of yeasts present. A …

Impact Of Weed Management Practices On Grapevine Growth, Yield Components, Plant And Arthropod Abundance, And Carabid Seed Predation In Paso Robles Vineyard, Paolo Sanguankeo

Master's Theses

In the Central Coast of California, USA, wine grape growers are making efforts to identify weed control practices that promote biodiversity in their vineyards while maintaining yields. A field study was conducted in Paso Robles, CA in 2006 and 2007 evaluating the effect on Zinfandel grape-vine growth and production, groundcover plant, and ground dwelling arthropod communities of five weed control practices: 1) flumioxazin, 2) simazine, 3) cultivation, 4) cover crop, and 5) untreated control.

The herbicide treatments had the lowest weed biomass followed by the cultivation, being approximately 10 and 2 times lower than the weed biomass of either the …

Growing Wild: Crested Wheatgrass And The Landscape Of Belonging, Lafe Gerald Conner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crested wheatgrass arrived in North America at the turn of the twentieth century through the foreign plant exploration missions sponsored by the United States Department of Agriculture. During the first two decades of the new century, scientists tested the grass at agricultural experiment stations. They determined it was useful for grazing and particularly valuable because it could grow in drought conditions with little or no care and would continue to produce high quality feed even after several years of heavy use. Beginning in the 1930s federally sponsored land utilization and agricultural adjustment programs sponsored the use of crested wheatgrass for …