Plant Biology Commons^™

Bryoecology In The American Southwest: Patterns Of Biodiversity And Responses To Global Change, John Carroll Brinda

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation combines investigation of the large-scale responses of bryophyte species diversity and distribution with small-scale physiological adaptations to global change. These two areas of inquiry are linked because one way to predict plant species responses to global change is to examine their distribution across current ecological gradients produced by factors such as latitude and elevation. By examining these biogeographic patterns one can identify those species that have a narrow tolerance and therefore are most sensitive to change. Selected bryophytes might then be used as indicator species in long-term monitoring programs. Where historical data exist, these can be used to …

No Accession-Specific Effect Of Rhizosphere Soil Communities On The Growth And Competition Of Arabidopsis Thaliana Accessions, Anna G. Aguilera, Adán Colón-Carmona, Rick Kesseli, Jeffrey S. Dukes

Biology Faculty Publication Series

Soil communities associated with specific plant species affect individual plants' growth and competitive ability. Limited evidence suggests that unique soil communities can also differentially influence growth and competition at the ecotype level. Previous work with Arabidopsis thaliana has shown that accessions produce distinct and reproducible rhizosphere bacterial communities, with significant differences in both species composition and relative abundance. We tested the hypothesis that soil communities uniquely affect the growth and reproduction of the plant accessions with which they are associated. Specifically, we examined the growth of four accessions when exposed to their own soil communities and the communities generated by …

Is The Common Teasel (Dipsacus Sylvestris) A Carnivorous Plant Or Was Francis Darwin Wrong?, Justin Matthew Thomas

Kaleidoscope

No abstract provided.

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

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

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …

Floristic And Environmental Characteristics Of Sub-Boreal Peatlands Of Minnesota And Western Wisconsin, Kevin Douglas Clement

All Graduate Theses, Dissertations, and Other Capstone Projects

Peatland communities in the sub-boreal region of Minnesota and western Wisconsin were characterized by floristic composition, structure and environmental characteristics to determine the natural variation among peatland communities in the region and their shared associations with the boreal and temperate peatlands of North America. Floristic classification revealed five, distinct peatland community types, identified as Sphagnum Bogs, Herbaceous Fens, Forested Fens, Rich/Calcareous Fens and Phalaris anrundinacea dominated peatlands. Differences among sub-boreal peatlands largely reflected changes in the significant indicator and dominant plant species identified, which were found to exhibit high fidelities to a particular peatland community type. Floristic variations among sub-boreal …

Can Resource-Use Traits Predict Native Vs. Exotic Plant Success In Carbon Amended Soils?, Robert J. Steers, Jennifer L. Funk, Edith B. Allen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Productivity in desert ecosystems is primarily limited by water followed by nitrogen availability. In the deserts of southern California, nitrogen additions have increased invasive annual plant abundance. Similar findings from other ecosystems have led to a general acceptance that invasive plants, especially annual grasses, are nitrophilous. Consequently, reductions of soil nitrogen via carbon amendments have been conducted by many researchers in a variety of ecosystems in order to disproportionately lower invasive species abundance, but with mixed success. Recent studies suggest that resource-use traits may predict the efficacy of such resource manipulations; however, this theory remains largely untested. We report findings …

Heavy Metal Levels In Paddy Soils And Rice (Oryza Sativa (L)) From Wetlands Of Lake Victoria Basin, Tanzania, J. F. Machiwa

Tanzania Journal of Science

A survey of paddy fields in Lake Victoria Basin (LVB) wetlands was conducted at a wider scale in different locations including closer to mining and within urbanized areas in Tanzania. The objective of the study was mainly to assess the present situation with regard to levels of heavy metals in O. sativa grains harvested locally as well as to set the baseline levels of some heavy metals in paddy fields. The results showed that the levels of Cadmium, Chromium, Copper, Lead, Zinc and total Mercury in brown rice are generally within the acceptable levels for human food. However, higher concentration …

Is Orthoptera Abundance And Distribution Across A Small Grassland Area Affected By Plant Biomass, Plant Species Richness, And Plant Quality?, Caitlin Falcone

Department of Environmental Studies: Undergraduate Student Theses

The choice of a specific microhabitat represents a compromise among a number of different factors organisms use to monitor habitat suitability. Grassland vegetation structure can vary widely along environmental gradients over a relatively small area. This vegetation structure can have a large influence on habitat selection by grasshoppers (Orthoptera). However, it is not clear which vegetation characteristics are most important in determining grasshopper abundance. We found that plant biomass, plant species richness, and plant quality all have an effect on grasshopper abundance and distribution. We observe that these affects vary both within and among the two years of data collection. …

The Interaction Of Fire And Grazing In Oklahoma Artemisia Filifolia Shrubland, Stephen L. Winter

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

I. FIRE-RESILIENCY OF A NORTH AMERICAN ARTEMISIA (ASTERACEAE) SHRUB: IMPLICATIONS FOR RESTORATION OF A CRITICAL ECOSYSTEM PROCESS. Conclusions: Unlike most North American Artemisia shrub species, our research suggests that A. filifolia is highly resilient to the effects of fire. Therefore, use of prescribed fires for the restoration and maintenance of ecosystem processes and properties is appropriate in A. filifolia shrublands of the southern Great Plains in North America.

II. RESTORATION OF THE FIRE-GRAZING INTERACTION IN ARTEMISIA FILIFOLIA SHRUBLAND OF THE SOUTHERN GREAT PLAINS, NORTH AMERICA. Synthesis and applications. Vegetation structure in Artemisia filifolia shrublands of our study were readily altered …

Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and ecotypic variation of these prairie clovers is a prerequisite for developing populations suitable for rangeland revegetation in the western USA. DNA sequences of internal transcribed spacer (ITS/5.8S) and trnK/matK were used to study the phylogeny of these species. The species were distinguished …

The Endosymbiotic Relationship Of Leguminosae (Fabaceae) And Rhizobium, Sabrina Mcgee, Dolores Maceda, Maria Bustos, Maryknoll Palisoc, Rachel Dahl

Undergraduate Research Opportunities Program (UROP)

This project will look at The Endosymbiotic Relationship of Leguminosae (Fabaceae) and Rizobioum. Endoysmbiosis Theory is the concept that mitochondria and chloroplasts are the result of years of evolution initiated by the endocytosis, (the process by which cells absorb material through their cell membrane) of bacteria and algae which, instead of becoming digested, became symbiotic.The mitochondria of eukaryotes evolved from aerobic bacteria, probably rickettsias, living within their host cell and the chloroplasts from cyanobacteria, also known as blue-green algae. Endoysmbiosis is a type of symbiosis in which one organism lives inside the body of another and both function as a …

Temporal And Spatial Assessment Of Evaporation, Transpiration, And Soil Moisture Redistribution, Brian M. Bird

UNLV Theses, Dissertations, Professional Papers, and Capstones

At a native stand of creosote bush (Larrea tridentata) in North Las Vegas, a rainfall simulation study was conducted over a 12 month period from October 2005 to October 2006. Simulated rainfall occurred during the winter, spring, summer, and fall periods. Rainfall simulation systems were positioned on each of 12 plots, each containing a single creosote bush. Simulated rainfall events occurred at night with multiple short pulses designed to maximize infiltration while minimizing ponding. Yearly simulated rainfall amounts were set at 0, 15, 30 and 60 cm (replicated three times) and were approximately 0, 1.5, 3.0 and 6.0 times the …

The Loss Of Species: Mangrove Extinction Risk And Geographic Areas Of Global Concern, Beth A. Polidoro, Kent E. Carpenter, Lorna Collins, Norman C. Duke, Aaron M. Ellison, Joanna C. Ellison, Elizabeth J. Farnsworth, Edwino S. Fernando, Kandasamy Kathiresan, Nico E. Koedam, Suzanne R. Livingstone, Toyohiko Miyagi, Gregg E. Moore, Vien Ngoc Nam, Jin Eong Ong, Jurgenne H. Primavera, Serverino G. Salmo, Jonnell C. Sanciango, Sukristijono Sukardjo, Yamin Wang, Jean Wan Hong Yong

Biological Sciences Faculty Publications

Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the …

Interisland Variability Of Dune Plant Community Structure On Virginia's Barrier Islands, Justin K. Shafer

Biological Sciences Theses & Dissertations

The barrier islands of the Virginia Coast Reserve LTER site provide an opportunity to study interisland variability of dune plant communities. My research focused on the variation in biomass and diversity of communities among islands and dune positions. Grassy dunes of young, intermediate and old age were sampled on Smith, Hog, and Parramore Islands. Aboveground biomass was obtained from harvest plots, and roots were extracted from cores. Data were collected on depth to groundwater and total soil nitrogen. Variation in mean aboveground biomass was evident among the islands with the highest values on Hog Island, followed by Smith, then Parramore …

Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries

Biological Sciences Faculty Research

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now …

Carbon Dynamics In A Phragmites Australis Invaded Riparian Wetland, Steven Walters

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

Invasive plant species are widely recognized as a major threat to biodiversity and ecosystem stability. Wetland ecosystems tend to be much more susceptible to invasions because of their location on the landscape where water, nutrients, and the impacts of disturbances accumulate. Invasive plants have the ability to alter ecosystem processes and community/population dynamics. The ability of invasive plants to alter these processes can have profound economic consequences. In the United States, control of invasive wetland species alone costs approximately 155 million dollars annually. The state of Nebraska spends 2 million dollars annually controlling invasive plant species in the Platte River …

Phylogeographical Patterns Of Neobalanocarpus Heimii (Dipterocarpaceae) For The Evolutionary History And Chain Of Custody Certification., Tnah Lee Hong

Student Works (2010-2019)

Tectonic movement and climatic oscillations during the Cenozoic have had dramatic effect on the biota of the tropical rain forest. This study aims to reveal the phylogeography and evolutionary history of a Peninsular Malaysian endemic tropical timber, Neobalanocarpus heimii (Dipterocarpaceae), based on chloroplast DNA (cpDNA) variation. Fifteen haplotypes were identified from 10 intraspecific variable sites of five non-coding cpDNA regions: trnL intron, trnS-trnG spacer, trnG intron, trnK intron and psbK-trnS spacer. Two major genealogical cpDNA lineages of N. heimii were elucidated: a widespread southern and a northern region. The species is predicted to survive in multiple refugia during climatic oscillation: …

Snail Grazing Facilitates Growth Of A Bloom-Forming Alga, Michele Guidone, Carol S. Thornber, Emily Field

Biology Faculty Publications

Herbivory often has a negative effect on plants. However, there is a growing number of examples, primarily in terrestrial ecosystems, where herbivory causes an increase in plant size, growth rate, and/or reproductive output. In marine ecosystems, the positive effects of herbivores on macroalgae are not as well studied, although limited evidence exists for herbivore-induced increases in macroalgal growth rates via 2 mechanisms: nutrient addition via grazer defecation, and epiphyte removal. In this study, we examined the effects of grazing by the mud snail Ilyanassa obsoleta on Ulva lactuca, the dominant bloom-forming macroalga in many New England estuaries. We found …

Joint Fire Science Program – Lake Mead National Recreation Area Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis: Quarterly Progress Report, Time Period: July 1 — September 30, 2009, Margaret N. Rees

Fire Science

• Weighed biomass for competitive hierarchy study.
• Completed more seed granivory trials at Goodsprings.
• Monitored and maintained nursery plots.
• Submitted revised article to Journal of Arid Environments.

Effect Of Environmental Density And Buoyancy On Growth And Gravitropic Response In Maize Roots, Jessy Robbins

All-Inclusive List of Electronic Theses and Dissertations

The mechanism by which plants sense gravity is not fully understood. The statolith theory states that plants sense gravity based on the sedimentation of starch granules called statoliths. However, not all plants contain statoliths. The hydrostatic model was proposed to explain gravitropic sensing in systems which lack statoliths. This model states that the gravity sensor in a plant cell is the entire protoplast; gravitropic sensing depends on the buoyancy of the protoplast relative to the density of its external environment. The ability of maize roots to sense gravity when grown in media of differing densities is examined in these studies. …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, April 1 — June 30, 2009, Margaret N. Rees

Fire Science

• Initiated a competitive hierarchy study.
• Monitored and maintained outplanting at Goodsprings.
• Completed more seed granivory trials at Goodsprings.
• Mentored student to completion of undergraduate research project.
• Monitored and maintained nursery plots.
• Revising article submitted to Journal of Arid Environments.

Investigation Of Plant Water Use In The Great Basin, Nv, Benjamin Conrad

UNLV Theses, Dissertations, Professional Papers, and Capstones

Global climate change in addition to a growing population can have a strong impact on our natural resources. In particular, cities in the semi-arid and arid southwestern US are currently faced with the challenge of providing sustainable fresh water to a growing population. In Las Vegas, dwindling water levels in Lake Mead have forced water managers to seek water resources from Spring Valley and Snake Valley, NV, which are located 402 km north of the city. The goals of this research were to investigate the water use of shrubs located in these valleys by using a large aperture scintillometer (LAS) …

Impacts Of Plant Size, Density, Herbivory, And Disease On Native Platte Thistle (Cirsium Canescens), Deidra Jacobsen

Department of Environmental Studies: Undergraduate Student Theses

Abstract. Based on prior field observations, we hypothesized that individual and interacting effects of plant size, density, insect herbivory, and especially fungal disease, influenced seedling and juvenile plant growth in native Platte thistle populations (Cirsium canescens Nutt.). We worked at Arapaho Prairie in the Nebraska Sandhills (May - August 2007), monitoring plant growth, insect damage, and fungal infection within different density thistle patches. In the main experiment, we sprayed half of test plants in different density patches with fungicide (Fungonil© Bonide, containing chlorothalonil) and half with a water control. Fungal infection rates were very low, so we found no difference …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, January 1— March 31, 2009, Margaret N. Rees

Fire Science

• Monitored and watered native plants in nursery plots.

• Exotic grasses seeded into nursery plots.

• Nitrogen treatment applied to nursery plots.

• Granivory study trials performed each month and corresponding abstract submitted to ESA.

• Competitive hierarchy study germination trials are underway.

• Monitored seeding and outplanting experiments at Goodsprings.

• Submitted article to Mojave Applied Ecology Notes newsletter updating on JFS work.

• Mentoring UNLV undergraduate student in research project for ENV 492.

• Prepared presentation materials for two scientific meetings.

Letter From The Dean, Lalit Verma

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

No abstract provided.

Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin

Biological Sciences Theses & Dissertations

The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, October 1 — December 31, 2008, Margaret N. Rees

Fire Science

• Presented poster at Natural Areas Conference in Nashville, TN

• Initiated granivory study at Goodsprings.

• Outplanted 2376 plants for Experiment 1 at Lake Mead nursery.

• Presented poster at Wildfires and Invasive Plants in American Deserts conference in Reno, NV.

• Submitted manuscript covering our distance from road - microsite invasibility study to Journal of Arid Environments.

Ecotypic Variation In Elymus Elymoides Subspecies Brevifolius Race C In The Northern Intermountain West, Matthew C. Parsons

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Little information is available on the extent of local adaptation for many native grass species. This is the case for squirreltail (Elymus section Sitanion), despite this group's prevalence and importance in rangeland restoration efforts. I evaluated 32 populations of E. elymoides ssp. brevifolius race C, a phylogenetic subdivision of bottlebrush squirreltail (E. elymoides) centered in the northern Intermountain West, for phenotypic variables and neutral genetic markers to measure their association with geographical origin. Phenotypic traits were measured in common field and greenhouse environments, and genetic diversity was assessed using Amplified Fragment Length Polymorphism. Three factors were extracted from the phenotypic …

Seed Longevity Of Dominant Plant Species From Degraded Savanna In Semi-Arid Tanzania, Hvm Lyaruu

Tanzania Journal of Science

Artificially buried seeds were followed by periodic exhumation and germination during 21 months in Kondoa Irangi Hills, central Tanzania. Viable seeds from thirteen selected species were buried in polythene envelopes at a depth of 15 cm below woodland vegetation. Lethal germination, fungal decay and insect infestation were singled out as the most important contributors to loss of viability among seeds. Hierarchical clustering based on a seed’s mean viability, seed shape and presence or absence of dispersal appendages, produced three distinct groups: (1) non-dormant seeds (2) seeds with enforced dormancy and (3) seeds with seed coat imposed dormancy. The low decay …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, July 1 — September 30, 2008, Margaret N. Rees

Fire Science

• Cones monitored and reseeded to obtain plants for nursery study.

• Goodsprings revegetation studies monitored.

• Website developed for JFS study.

• Writing short communication for Journal of Arid Environments.

• Working on poster for NAA conference in October.