Plant Biology Commons^™

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

Transcriptional Regulation Of Specialized Metabolites In Arabidopsis Thaliana And Catharanthus Roseus, Craig M. Schluttenhofer

Theses and Dissertations--Plant and Soil Sciences

For millennia humans have utilized plant specialized metabolites for health benefits, fragrances, poisons, spices, and medicine. Valued metabolites are often produced in small quantities and may command high prices. Understanding when and how the plant synthesizes these compounds is important for improving their production. Phytohormone signaling cascades, such as jasmonate (JA) activate or repress transcription factors (TF) controlling expression of metabolite biosynthetic genes. TFs regulating specialized metabolite biosynthetic genes can be manipulated to engineer plants with increased metabolite production.

WRKY transcription factor are known components of both JA signaling cascades and regulation of specialized metabolism. The presence of WRKY binding …

Successional Changes In Leaf Nutrient Concentrations Of Woody And Herbaceous Species, Daniel Walter Kuchta

Masters Theses

Leaf nutrient concentrations are an example of a functional trait, a trait that can be used to understand community dynamics by observing how plants interact with their environment. I explored how leaf nutrient concentrations were affected over successional time by environmental changes. The majority of prior research on functional traits focuses on either woody or herbaceous species, but not both life forms simultaneously. To address this, I also explored the successional changes to leaf nutrient concentrations, separating the plant community into woody and herbaceous species.

Healthy, mature leaves were taken from 122 taxa of woody and herbaceous species in a …

Small Unmanned Aerial Vehicles (Micro-Uavs, Drones) In Plant Ecology, Mitchell B. Cruzan, Ben G. Weinstein, Monica R. Grasty, Brendan F. Kohrn, Elizabeth C. Hendrickson, Tina M. Arredondo, Pamela G. Thompson

Biology Faculty Publications and Presentations

Premise of the study: Low-elevation surveys with small aerial drones (micro–unmanned aerial vehicles [UAVs]) may be used for a wide variety of applications in plant ecology, including mapping vegetation over small- to medium-sized regions. We provide an overview of methods and procedures for conducting surveys and illustrate some of these applications.

Methods: Aerial images were obtained by flying a small drone along transects over the area of interest. Images were used to create a composite image (orthomosaic) and a digital surface model (DSM). Vegetation classification was conducted manually and using an automated routine. Coverage of an individual species …

Positive Interactions In Temperate And Tropical Alpine Plant Communities: The Role Of Facilitation In Species-Specific Interactions, Invasion, And Landscape-Scale Distribution, Nicole Hupp

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

School of Natural Resources: Dissertations, Theses, and Student Research

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …

Demography And Disease Of The Rare Shrub Buckleya Distichophylla (Santalaceae) In Northeastern Tennessee, William Seth Ratliff

Undergraduate Honors Theses

Piratebush (Buckleya distichophylla (Nutt.) Torr.) is a rare, hemiparasitic shrub with the only extant populations in western North Carolina, northeastern Tennessee, and southwestern Virginia. The preferred natural hosts of piratebush, Carolina and eastern hemlocks, have seen sharp declines over the last decade due to the invasive hemlock woolly adelgid. Virginia pine, another important host of piratebush, is also susceptible to disease, specifically Cronartium appalachianum, a rust fungus for which piratebush is the secondary host. This study described and analyzed current demographic parameters of three Tennessee piratebush populations. Additionally, spatial patterns of disease and demographic characters were analyzed. These …

Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore

Electronic Theses and Dissertations

Counter to what some people think, urban areas can be biodiversity hotspots. Maintaining this biodiversity can be challenging, since exotic shrubs and vines block sunlight and threaten native plant regeneration. Since 2007, the Louisville Olmsted Parks Conservancy (LOPC) has spent $2 million on invasive plant management in Cherokee Park. Before the project began, long-term transects were established by the LOPC to collect baseline presence/absence data on 11 invasive plant species. In 2014, I revisited these transects and documented presence/absence data on the entire plant community. I found that four species (garlic mustard, winter creeper, Japanese honeysuckle, and English ivy) have …

When An Invasive Plant Fails To Invade, Stephen L. Young

West Central Research and Extension Center, North Platte

In 2012, much of the US Midwest was gripped in one of the most severe droughts on record. While conducting experimental fieldwork at a site in Nebraska during June of that year, I noticed a single musk thistle (Carduus nutans; Figure 1) that appeared to be in the bolt or early flowering stage, which is typical for the species at that time. Here, however, two things were unusual: this plant was less than 1 meter tall (with adequate moisture and light, musk thistle typically grows to heights of 1–2.5 meters before flowering), and was only 3 months old (the bolt …

Transport Regimes And Spread Of The Common Reed, Phramites Australis, In The Saco River, Me, Usa, Michelle A. Slater

All Theses And Dissertations

Allee effects are important to species invasions because population growth may be limited by low outcrossing potential in newly founded populations leading to depressed levels of fitness. Non-native Phragmites australis (common reed) has been present in the United States for over 200 years, but has been slow to reach some areas, possibly owing to the Allee phenomenon, whereby young or isolated Phragmites patches with initially low genotypic richness are slow to recruit viable seedlings due to inbreeding, which limits the rate of patch expansion. In order to explore the importance of the Allee effect in a recently invaded system, the …

The Pioneer Of Santa Rosa Island, Andrea Martinez, Michael Perez, Kathryn Mceachern, Sarah Chaney, Ken Niessen

STAR Program Research Presentations

Santa Rosa Island which is part of the Channel Islands in California has a ranching history that goes as far back as the year 1843. While rich in history, the island is no longer “rich” in native plant populations due to the sheep, cattle and other livestock that once occupied the island. As a result of these grazers that the ranchers livelihood depended on, a great disturbance in the native plant population took place. It is up to plants such as Baccharis pilularis, commonly known as Coyote brush, to assist these endangered and threatened plants to once again flourish …

Alliaria Petiolata (M.Bieb.) Cavara & Grande [Brassicaceae], An Invasive Herb In The Southern Ozark Plateaus: A Comparison Of Species Composition And Richness, Soil Properties, And Earthworm Composition And Biomass In Invaded Versus Non-Invaded Sites, Jennifer D. Ogle

Graduate Theses and Dissertations

Invasive species are widely recognized as organisms that severely alter ecosystem processes in the habitats to which they are introduced. Alliaria petiolata is one of the most important invasive plants in forests of the northern United States. This study examined the geographic distribution of the plant in the southern Ozarks, as well as the effect that it may be having on natural processes within forests of the region by comparing plant species richness, plant cover, and soil properties in invaded and non-invaded plots. It was found that A. petiolata is not significantly altering species richness, cover, or soil properties in …

Fuels And Fires Influence Vegetation Via Above- And Belowground Pathways In A High-Diversity Plant Community, Paul R. Gagnon, Heather A. Passmore, Matthew Slocum, Jonathan A. Myers, Kyle E. Harms, William J. Platt, C.E. Timothy Paine

Biology Faculty Research

1. Fire strongly influences plant populations and communities around the world, making it an important agent of plant evolution. Fire influences vegetation through multiple pathways, both above- and belowground. Few studies have yet attempted to tie these pathways together in a mechanistic way through soil heating even though the importance of soil heating for plants in fire-prone ecosystems is increasingly recognized.
2. Here we combine an experimental approach with structural equation modelling (SEM) to simultaneously examine multiple pathways through which fire might influence herbaceous vegetation. In a high-diversity longleaf pine groundcover community in Louisiana, USA, we manipulated fine-fuel biomass and monitored the …

Elevational Gradients In Β-Diversity Reflect Variation In The Strength Of Local Community Assembly Mechanisms Across Spatial Scales, J Sebastián Tello, Jonathan A. Myers, Manuel J. Macia, Alfredo F. Fuentes, Leslie Cayola, Gabriel Arellano, M Isabel Loza, Vania Torrez, Maritza Cornejo, Tatiana B. Miranda, Peter M. Jørgensen

Biology Faculty Research

Despite long-standing interest in elevational-diversity gradients, little is known about the processes that cause changes in the compositional variation of communities (β-diversity) across elevations. Recent studies have suggested that β-diversity gradients are driven by variation in species pools, rather than by variation in the strength of local community assembly mechanisms such as dispersal limitation, environmental filtering, or local biotic interactions. However, tests of this hypothesis have been limited to very small spatial scales that limit inferences about how the relative importance of assembly mechanisms may change across spatial scales. Here, we test the hypothesis that scale-dependent community assembly mechanisms shape …

An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona

Seaver College Research And Scholarly Achievement Symposium

In recent years, the Santa Monica Mountains (SMM) have been plagued by frequent wildfires which threaten the native chaparral species. Nonsprouting chaparral species are completely killed by a fire, but their seeds germinate in response to fire cues. Facultative sprouters both resprout after a wildfire and release seeds that germinate post-fire. This project is based on data collected since 1986 at a biological preserve adjacent to the Malibu campus of Pepperdine University with an average fire return interval of 7.5 years. We present a spatial model that simulates the growth, seed dispersal and resprouting behavior of individual shrubs that compete …

Tallgrass Prairie Vegetation Response To Spring Fires And Bison Grazing, Stephen L. Winter, Brady W. Allred, Karen R. Hickman, Samuel D. Fuhlendorf

School of Natural Resources: Faculty Publications

Spring fires in tallgrass prairie can create environmental conditions conducive to plant growth in the subsequent growing season. Following fires, burned areas can also be attractive to grazing animals such as bison (Bison bison). Sustained grazing activity within recently burned areas can alter vegetation structure relative to nearby landscape patches that haven’t burned recently. In 2007, we collected data on bison grazing activity, vegetation structure, and the growth and reproduction of a perennial forb, Arnoglossum plantagineum, in Oklahoma tallgrass prairie. We compared these variables in landscape patches that had burned in the spring of 2007 to measurements …

Understory Diversity And Composition Drives Carabid Assemblages, Tierney Brosius, Michael Reisner

Biology: Faculty Scholarship & Creative Works

Fire suppression has nearly eliminated fire as a disturbance in temperate deciduous forests. Lack of fire is transforming these ecosystems through a positive feedback loop termed mesophication: cool, damp, shady conditions become continually more favorable for a few mesophytic species, while deteriorating for diverse array of heliophytic ones. Disturbances caused by urbanization fragment and degrade remnant forests. In urban settings, human management (or lack thereof) is often a dominate driver of succession. Carabid diversity, understory vegetation, patch size, patch connectivity, and permeable surface area were all examined in multiple forest plots in Rock Island and Moline. The result of this …

Physiological Variation Of Garry Oak (Quercus Garryana) Seedlings To Drought Stress, Matthew A. Merz

All Master's Theses

The purpose of this study was to determine physiological differences in drought response among Garry oak (Quercus garryana Douglas ex Hook. [Fagaceae]) seedlings that grow in distinct populations in Washington state, in order to aid in restoration efforts by informing growers of the potential differences between the acorn collection sites. Acorns from six Washington populations east of the Cascades, as well as one population from Whidbey Island, were collected and grown in containers under controlled conditions. The plants were assessed with and without moderate and severe drought stress induced by withholding water. The most extreme differences in photosynthetic characteristics …

Vegetation-Based Metrics Of Biotic Integrity For Assessing The Ecological Condition Of Wetlands Of Kentucky, Tanner Matthew Morris

Online Theses and Dissertations

Over the last two centuries, wetland acreage across the world has significantly declined due to human disturbances. It has been estimated that Kentucky has lost over 80% of its wetland area. In response to these losses occurring across the United States, the Clean Water Act was passed to halt this dramatic decline and to restore the ecological integrity of waters of the United States. To enforce the Clean Water Act, a number of ecological assessment techniques have been developed to quantify the ecological quality of the waters of the United States. Kentucky recently adopted a rapid method for assessing the …

Nutrient Competition Between Algae And Juncus Effusus In The Lake Fayetteville Artificial Spiral Wetland, Toryn Jones, Thad Scott

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

There is insufficient research focusing exclusively on how nutrient competition between algae and wetland macrophytes affects the growth of these species. This study examined the relationship between nutrient concentrations (N and P), algal concentrations, and the growth of Juncus effusus. Juncus effusus growth in the Lake Fayetteville artificial spiral wetland was monitored over a four month period during the prime growing season. Eighteen plants were taken from the wetland and replanted in 1 of 6 treatments: plant-only, algae-only, combined, plant-only +supplement, algaeonly +supplement, or combined +supplement. The algae and combined environments received an inoculation of algae, and the +supplement treatments …

The Functional Role Of Leaf Nutrients In An Old-Field Successional Community, Kirstin I. Duffin

Masters Theses

In functional ecology, traits that capture aspects of plant performance are used to understand how organisms interact with their environment. Leaf nutrients are an example of a functional trait that directly links to plant metabolic processes and therefore may describe plant assemblage dynamics. Multivariate leaf nutrient analyses may be used with other functional traits to understand ecological strategies because they are a direct measure of leaf metabolic processes and can describe nuances in plant allocation patterns. In this thesis, I explored (1) whether a suite of leaf nutrients (carbon, nitrogen, phosphorus, potassium, calcium, and magnesium) was related to plant growth …

Plant Functional Traits Of Dominant Native And Invasive Species In Mediterranean-Climate Ecosystems, Jennifer L. Funk, Rachel J. Standish, William D. Stock, Fernando Valladares

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global datasets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five Mediterranean-climate regions, which are drought-prone and increasingly threatened by human activities including the introduction of exotic species. Traits differed strongly across the five regions. In …

The Impacts Of Anthropogenic Activities On The Vegetation Communities And Structure In The Western Part Of Rungwe Forest Reserve, Tanzania, Joseph Mwakosya, Cosmas Mligo

Tanzania Journal of Science

Rungwe Forest Reserve is among the degraded southern Tanzania tropical montane forests. It was investigated the effects of illegal anthropogenic activities on the plant community structure on the western part of Rungwe mountain forest reserve. The study area was classified into three levels of disturbance (least disturbed, moderately disturbed and highly disturbed) and transect method was used to collect data. Two clusters (clusters A and B) of plant communities based on Two Way Indicator Species Analysis (TWINSPAN) were found. Cluster A included communities from the least and moderate disturbed sites and cluster B had plant communities from the highly disturbed …

Indigenous Tree Uses, Use-Values And Impact Of Human Population On Forest Size, Structure And Species Richness In Uluguru, Morogoro, Tanzania, David Sylvester Kacholi

Tanzania Journal of Science

This study assessed tree uses and use-values as well as impacts of human population on the forest size, species richness, basal area and stand density in the Uluguru forests in Morogoro Region. Interview with locals on the tree uses were done using structured questionnaires and use-value analysis techniques were used in analysing data. Trees with a diameter at breast height ≥ 10 cm measured at 1.3 m above the ground were sampled from a total of 114 plots of 20 m x 20 m (0.04 ha) from the seven forests. A total of 42 species belonging to 20 families were …

A Molecular Framework Phylogeny For Ptilotus (Amaranthaceae), Timothy A. Hammer

Biological Sciences Theses & Dissertations

Ptilotus (Amaranthaceae) is an Australian genus with over 100 species, most of which occur in arid Western Australia. Ptilotus has been a taxonomically difficult genus; despite rigorous morphological studies into the genus over many years, previous workers have found it difficult to delimit infrageneric groups due to inconsistent morphological variation. With the goal to establish a phylogenetic framework for the genus, 100 taxa were sampled, including 87 Ptilotus spp., and the ITS nrDNA and matK cpDNA were sequenced. The phylogeny was reconstructed using Bayesian, maximum likelihood and maximum parsimony analyses on separate and concatenated datasets. Morphological characters were assessed and …

The Trehalose Pathway In Maize: Conservation And Gene Regulation In Response To The Diurnal Cycle And Extended Darkness, Clémence Henry, Samuel W. Bledsoe, Allison Siekman, Alec Kollman, Brian M. Waters, Regina Feil, Mark Stitt, L. Mark Lagrimini

Department of Agronomy and Horticulture: Faculty Publications

Energy resources in plants are managed in continuously changing environments, such as changes occurring during the day/night cycle. Shading is an environmental disruption that decreases photosynthesis, compromises energy status, and impacts on crop productivity. The trehalose pathway plays a central but not well-defined role in maintaining energy balance. Here, we characterized the maize trehalose pathway genes and deciphered the impacts of the diurnal cycle and disruption of the day/night cycle on trehalose pathway gene expression and sugar metabolism. The maize genome encodes 14 trehalose-6-phosphate synthase (TPS) genes, 11 trehalose-6-phosphate phosphatase (TPP) genes, and one trehalase gene. Transcript abundance of most …

Water Use And Water Tolerance In The Riparian Species American Sycamore (Plantanus Occidentalis L.) And How Its Physiology Compares To The Coexisting Black Willow (Salix Nigra Marshall), Eric Duncan

Dissertations, Theses and Capstone Projects (Full IR Collection)

This study set out to compare aspects of water use and tolerance to inundation and drought of two riparian tree species, Platanus occidentalis L. and Salix nigra Marshall. The main goal of the study was to better understand the two species and assess the suitability of P. occidentalis for use in riparian restoration. To accomplish this, potted individuals were subjected to treatments of drought, inundation, or control, under greenhouse conditions, and separately, in order to estimate water use in trees, season-long diurnal measurements of sap flux (using Granier type thermal dissipation probes) were determined in situ for trees growing in …

Habitat Assessment Of Two Narrowly Endemic Plant Species, Ozark Spiderwort (Tradescantia Ozarkana) E. S. Anderson And Woods. And Newton's Larkspur (Delphinium Newtonianum) D. M. Moore, Autumn Lynn Coffey Olsen

Graduate Theses and Dissertations

The threat of biodiversity loss is upon us with the onset of climate change and our ever-demanding needs of the Earth's resources for a rapidly growing human population. Species highly vulnerable to loss are those limited in abundance and distribution, or those with reduced genetic diversity. Efforts to actively conserve a sensitive species require effectual data on the probable causes of their vulnerability. Two species of concern, Delphinium newtonianum and Tradescantia ozarkana, are globally rare endemic vascular plant species found only in the Interior Highlands of North America. In an attempt to understand the causes for their endemism, habitat …

From The Inside Out, And Through., Dominique Ovalle

The Transdisciplinary STEAM+ Journal

These photographs describe “Science” born of consumerism, hijacked by me, economically disenfranchised, or rather—temporarily embarrassed, artist. I was putzing around Malibu—my old college stomping ground, looking for free food; maybe a sample of some gourmet $5 chocolate, and all I got were these photographs.

2matrix: A Utility For Indel Coding And Phylogenetic Matrix Concatenation, Nelson R. Salinas, Damon P. Little

Publications and Research

Premise of the study: Phylogenetic analysis of DNA and amino acid sequences requires the creation of files formatted specifically for each analysis package. Programs currently available cannot simultaneously code inferred insertion/deletion (indel) events in sequence alignments and concatenate data sets.

Methods and Results: A novel Perl script, 2matrix, was created to concatenate matrices of non-molecular characters and/or aligned sequences and to code indels. 2matrix outputs a variety of formats compatible with popular phylogenetic programs.

Conclusions: 2matrix efficiently codes indels and concatenates matrices of sequences and non-molecular data. It is available for free download under a GPL (General Public License) open …