Digital Commons Network^™

Establishing Weed Prevention Areas And Evaluating Their Impact, Stephanie Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The spread of invasive weeds continues to be a serious economic and environmental threat. Weed prevention has the potential to stop weeds before they become well established in an area conserving time, energy, and resources. Unfortunately, weed prevention is often overlooked. Weed Prevention Areas (WPAs) are a relatively new tool developed to help improve the application of weed prevention. They are cooperatively managed areas that focus on implementing prevention and early detection strategies at a community level. The purpose of this research was to establish baseline data that will be used to evaluate the overall effectiveness of the WPA concept, …

An Ecological, Genetic, And Reproductive Study Of Big Bluestem (Andropogon Gerardii) Populations In The Carolinas, Robert Tompkins

All Dissertations

ABSTRACT
AN ECOLOGICAL, GENETIC, AND REPRODUCTIVE STUDY OF BIG BLUESTEM (ANDROPOGON GERARDII) POPULATIONS IN THE CAROLINAS
Andropogon gerardii (Big Bluestem) is a dominant grass of the North American tallgrass prairie and is also found in remnant populations in the eastern U.S., including North and South Carolina. This research included a systematic study of the ecology, genetics, and reproductive potential within and among A. gerardii populations in the Carolinas. Floristic composition and edaphic (soil) features were characterized for eight A. gerardii populations across various physiographic regions of North and South Carolina. A total of 362 quadrats (1 m x 1 m) …

Characterization Of Three-Dimensional Spatial Aggregation And Association Patterns Of Brown Rot Symptoms Within Intensively Mapped Sour Cherry Trees, Sydney E. Everhart, Ashley Askew, Lynne Seymour, Imre J. Holb, Harald Scherm

Department of Plant Pathology: Faculty Publications

Characterization of spatial patterns of plant disease can provide insights into important epidemiological processes such as sources of inoculum, mechanisms of dissemination, and reproductive strategies of the pathogen population. While two-dimensional patterns of disease (among plants within fields) have been studied extensively, there is limited information on three-dimensional patterns within individual plant canopies. Reported here are the detailed mapping of different symptom types of brown rot (caused by Monilinia laxa) in individual sour cherry tree (Prunus cerasus) canopies, and the application of spatial statistics to the resulting data points to de-termine patterns of symptom aggregation and association. …

Uncertainty In Modelling Of Faecal Coliform Overland Transport Associated With Manure Application In Maryland, A. K. Guber, Y. A. Pachepsky, A. M. Yakirevich, D. R. Shelton, A. M. Sadeghi, D. C. Goodrich, C. L. Unkrich

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Concerns for microbial safety of surface water facilitate development of predictive models that estimate concentrations and total numbers of pathogen and indicator organisms leaving manure-fertilized fields in overland flow during runoff events. Spatial variability of bacterial concentrations in applied manure introduces high uncertainty in the model predictions. The objective of this work was to evaluate the uncertainty in model predictions of the manure-borne bacteria overland transport caused by limited information on the spatial distribution of bacteria in surface-applied manure. Experiments were carried out at the ARS Beltsville experimental watershed site (OPE3) in Maryland. Dairy bovine manure was applied at a …

A Comparative Assessment Of Fruit Formation In Some Orchid Species From The Southern Caucasus Region, Houshang Nosrati, Roghieh Hajiboland, Ahmad Razban-Haghighi, Maryam Nikniazi

Turkish Journal of Botany

The distribution and population size of 5 orchid species (Cephalanthera longifolia, Orchis simia, Platanthera bifolia, Dactylorhiza romana, and Ophrys scolopax) were studied in the southern Caucasus based on the individual numbers in a given area. The fruit set was recorded for the latter 3 species and compared in natural and control groups (pollinators prevented) for D. romana and O. scolopax. We compared the obtained fruit set values with those reported from other regions. The distributions of the 5 species were completely fragmented and the population sizes were extremely small. This is the first report of O. scolopax from the region, …

Carrying Capacity For Species Richness As A Context For Conservation: A Case Study Of North American Breeding Birds, Andrew J. Hansen, Linda Bowers Phillips, Curtis H. Flather, Jim Robinson-Cox

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Aim To demonstrate that the concept of carrying capacity for species richness (S_K) is highly relevant to the conservation of biodiversity, and to estimate the spatial pattern of S_K for native landbirds as a basis for conservation planning.

Location North America.

Methods We evaluated the leading hypotheses on biophysical factors affecting species richness for Breeding Bird Survey routes from areas with little influence of human activities.We then derived a best model based on information theory, and used this model to extrapolate SK across North America based on the biophysical predictor variables. The predictor variables included the …

The Landscape Similarity Toolbox: New Tools For Optimizing The Location Of Control Sites In Experimental Studies, Thomas E. Dilts, Jian Yang, Peter J. Weisberg

Articles

Large‐scale manipulative experiments are critically important for linking ecological theory with land management at a relevant spatial scale. Statistically powerful inferential approaches such as the before‐after‐control‐impact design involve pairing a small number of treatment sites with control sites of analogous ecological structure and landscape context. Pairing treatment and control sites that are as analogous as possible is an important step to ensuring that differences are due to a treatment effect. The Landscape Similarity Toolbox provides tools for optimizing the location of potential control sites based upon the spatial characteristics of the treatment site.

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 …

Evaluating Native Wheatgrasses For Restoration Of Sagebrush Steppes, Jayanti Ray Mukherjee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pseudoroegneria spicata and Elymus wawawaiensis are two native perennial bunchgrasses of North America's Intermountain West. Frequent drought, past overgrazing practices, subsequent weed invasions, and increased wildfire frequency have combined to severely degrade natural landscapes in the region, leading to a decline in the abundance of native vegetation. Being formerly widespread throughout the region, P. spicata is a favorite for restoration purposes in the Intermountain West. Elymus wawawaiensis, which occupies a more restricted distribution in the Intermountain West, is often used as a restoration surrogate for P. spicata. However, since most restoration sites are outside the native range of …

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 …

Combining Local- And Large-Scale Models To Predict The Distributions Of Invasive Plant Species, Chad C. Jones, Steven A. Acker, Charles B. Halpern

Botany Faculty Publications

Habitat-distribution models are increasingly used to predict the potential distributions of invasive species and to inform monitoring. However, these models assume that species are in equilibrium with the environment, which is clearly not true for most invasive species. Although this assumption is frequently acknowledged, solutions have not been adequately addressed. There are several potential methods for improving habitat-distribution models. Models that require only presence data may be more effective for invasive species, but this assumption has rarely been tested. In addition, combining modeling types to form ‘ensemble’ models may improve the accuracy of predictions. However, even with these improvements, models …

Liana Host Preference And Implications For Deciduous Forest Regeneration, Laura M. Ladwig, Scott J. Meiners

Faculty Research & Creative Activity

Lianas have the potential to shape forest communities and alter forest regeneration. However, impacts of lianas on forest regeneration, particularly in temperate forests, are largely unstudied. To understand potential liana impacts on the community we need to first know the location and intensity of liana burdens on host trees. We examined liana-tree host references within a series of young regenerating deciduous forests in the Piedmont region of New Jersey, USA. Established trees ($ 5 cm dbh) and the lianas associated with each tree were surveyed in 2008. The five most abundant liana species were Celastrus orbiculatus, Lonicera japonica, Parthenocissus quinquefolia, …

Post-­Fire Alterations In Mechanical Strength Of Leaves In Heteromeles Arbutifolia, Andrew Hair, Madeline Dilascia, Nick Novella, Taylor Wurdeman

Featured Research

Wildfires in the Santa Monica mountains in Southern California burn down a decent percentage of the local vegetation. However, some plants like Heteromeles Arbutifolia, are considered to be resprouters because they return a mere two years after being burnt down. It is hypothesized that the artificially browsed resprout leaves will have a lower tensile strength than both the young and adult leaves because they use a lower amount of carbohydrates per unit-leaf-area. Data showed that although there was a slight different between the young leaves and the adult leaves of the Heteromeles, there was no statistically significant difference between the …

Combining A Dispersal Model With Network Theory To Assess Habitat Connectivity, Todd R. Lookingbill, Robert H. Gardner, Joseph R. Ferrari, Cherry E. Keller

Geography and the Environment Faculty Publications

Assessing the potential for threatened species to persist and spread within fragmented landscapes requires the identification of core areas that can sustain resident populations and dispersal corridors that can link these core areas with isolated patches of remnant habitat. We developed a set of GIS tools, simulation methods, and network analysis procedures to assess potential landscape connectivity for the Delmarva fox squirrel (DFS; Sciurus niger cinereus), an endangered species inhabiting forested areas on the Delmarva Peninsula, USA. Information on the DFS’s life history and dispersal characteristics, together with data on the composition and configuration of land cover on the peninsula, …

Phylogenetic Relationships Of Some Turkish Crocus (Iridaceae) Taxa Based On Morphological And Anatomical Characters, Fati̇h Coşkun, Selami̇ Selvi̇, Fati̇h Satil

Turkish Journal of Botany

In this study, relationships among the 15 taxa of the genus Crocus L. distributed in Turkey were analysed using 29 morphological and 4 anatomical characters. Analysis of the data set utilising maximum parsimony criterion with Branch-and-Bound search algorithm yielded 32 most parsimonious trees. Bootstrap analysis with the majority rule consensus algorithm generated a consensus tree supporting some branches. Our data mostly did not agree with the previous sectional and serial treatments. The most interesting result was the condition of Crocus pallasii, which was previously included in the section Crocus. C. pallasii showed a sister group relationship with C. cancellatus from …

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 …

Yield Potential And Resource-Use Efficiency Of Maize Systems In The Western U. S. Corn Belt, Patricio Grassini

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

Maize demand for food, livestock feed, and biofuel is expected to increase substantially. The Western U.S. Corn Belt accounts for 23% of U.S. maize production, and irrigated maize accounts for 43 and 58% of maize land area and total production, respectively, in this region. The most sensitive parameters (yield potential [YP], water-limited yield potential [YP-W], yield gap between actual yield and YP, and resource-use efficiency) governing performance of maize systems in the region are lacking. A simulation model was used to quantify YP under irrigated and rainfed conditions based on weather data, soil properties, and crop management at 18 locations. …

Effects Of Moist Chilling, Gibberellic Acid, And Scarification On Seed Dormancy In The Rare Endemic Pedicularis Olympica (Scrophulariaceae), Serap Kirmizi, Gürcan Güleryüz, Hülya Arslan, Fatma Selcen Sakar

Turkish Journal of Botany

We investigated the germination requirements of a rare endemic plant species, Pedicularis olympica Boiss. (Scrophulariaceae), which grows in wet habitats on Uludağ Mountain, Turkey. We studied the effects of scarification, moist chilling (+4 °C) for 15 days, different doses of gibberellic acid (GA_{3}; 100, 150, and 250 ppm) and combined hormone and moist chilling treatments under dark (20 °C) and photoperiod (20/10 °C; 12/12 h, respectively) conditions. GA_{3} was able to break dormancy. The highest germination rate was found in the seeds treated with 250 ppm GA_{3}; 64% of these seeds germinated when treated with moist chilling and incubated in …

Biofuels: Cultivating Energy, Not Invasive Species, Invasive Species Advisory Committee

National Invasive Species Council

Biofuels: Cultivating Energy, not Invasive Species, approved by ISAC on August 11, 2009

ISSUE

To provide alternatives to petroleum-based energy, the United States government has mandated a greater proportion of plant-based biofuels be integrated into its energy portfolio. However, certain plant species being proposed for biofuel production in the United States are invasive species or are likely to escape cultivation and become invasive. United States Executive Order (EO) 131121 defines invasive species as “alien [non-native] species whose introduction does or is likely to cause economic or environmental harm or harm to human health” and states: “Each Federal agency whose actions …

Estimating Water Application Efficiency For Drip Irrigation Emitter Patterns On Banana, Alisson Jadavi Pereira Da Silva, Eugênio Ferreira Coelho, Jarbas Honorio De Miranda, Stephen Ray Workman

Biosystems and Agricultural Engineering Faculty Publications

The objective of this work was to evaluate root and water distribution in irrigated banana (Musa sp.), in order to determine the water application efficiency for different drip irrigation emitter patterns. Three drip emitter patterns were studied: two 4-L h^-1 emitters per plant (T1), four 4-L h^-1 emitters per plant (T2), and five 4-L h^-1 emitters per plant (T3). The emitters were placed in a lateral line. In the treatment T3, the emitters formed a continuous strip. The cultivated area used was planted with banana cultivar BRS Tropical, with a 3-m spacing between rows and a …

Spatiotemporal Dynamics Of Immature Culicines (Subfamily Culicinae) And Their Larval Habitats In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Joseph M. Mwangangi, Benjamin G. Jacob, Josephat I. Shililu, Charles M. Mbogo, John I. Githure, Robert J. Novak

All Peer-Reviewed Publications

An ecological study was conducted at three study sites in Mwea Rice Scheme, Kenya to identify the diverse aquatic habitats in which culicine mosquitoes thrived and to explore the best strategies for mosquito control in the area. During the 11-month study period, ten habitat categories and 11 culicine species mainly dominated by Culex quinquefasciatus (72.0%) and Culex annulioris (17.9%) were identified from pupae and late instars larval samples. Two of the 11 culicine species, Ficalbia (Mimomyia) plumosa and Uranotaenia spp., have not been reported previously in the study area. Rurumi had more habitat types than either of the other study …

Advances In Serpentine Geoecology: A Retrospective, N Rajakaruna, R S. Boyd

Faculty Publications, Biological Sciences

No abstract provided.

Phylogeny, Adaptive Radiation, And Historical Biogeography In Bromeliaceae: Insights From An Eight-Locus Plastid Phylogeny, Thomas J. Givnish, Michael H. J. Barfuss, Benjamin Van Ee, Ricarda Riina, Katharina Schulte, Ralf Horres, Philip A. Gonsiska, Rachel S. Jabaily, Darren M. Crayn, J. Andrew Smith

Biological Sciences Faculty Publications

Premise: Bromeliaceae form a large, ecologically diverse family of angiosperms native to the New World. We use a bromeliad phylogeny based on eight plastid regions to analyze relationships within the family, test a new, eight-subfamily classification, infer the chronology of bromeliad evolution and invasion of different regions, and provide the basis for future analyses of trait evolution and rates of diversification.

Methods: We employed maximum-parsimony, maximum-likelihood, and Bayesian approaches to analyze 9341 aligned bases for four outgroups and 90 bromeliad species representing 46 of 58 described genera. We calibrate the resulting phylogeny against time using penalized likelihood applied …

Evolution And Systematic Significance Of Reproductive Structures In The Genus Cuscuta (Dodders, Convolvulaceae): Pollen And Gynoecium, Mark Welsh

Theses and Dissertations (Comprehensive)

The genus Cuscuta (dodders, Convolvulaceae) is one of the most significant lineages of parasitic plants from economic, conservation, and anthropogenic perspectives. Members of the genus are twining stem parasites with no roots, lacking almost completely chlorophyll or its function, and gather required nutrition from their host via specialized haustorial connections. While there are almost 200 described species, problems with species identification exist because many diagnostic characters are restricted to their tiny flowers. Probably contributing to this identification difficulty is the fact that the group has not received taxonomic attention for over 75 years; even knowledge of its basic reproductive biology …

Response Of Adult Mosquitoes To Light-Emitting Diodes Placed In Resting Boxes And In The Field, Michael T. Bentley, Phillip E. Kaufman, Daniel L. Kline, Jerome A. Hogsette

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The response of adult mosquitoes to 4 light-emitting diode (LED) wavelengths was evaluated using diode-equipped sticky cards (DESCs) and diode-equipped resting boxes at 2 sites in north central Florida. Wavelengths evaluated were blue (470 nm), green (502 nm), red (660 nm), and infrared (IR) (860 nm). When trapping with DESCs, 15 mosquito species from 7 genera (Aedes, Anopheles, Coquillettidia, Culex, Mansonia, Psorophora, and Uranotaenia) were captured. Overall, approximately 43.8% of all mosquitoes were trapped on DESCs fitted with green LEDs. Significantly more females of Aedes infirmatus, Aedes vexans, and Culex nigripalpus were captured on DESCs fitted with blue …

Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Year-End Progress Report, October 1, 2007 To September 30, 2008, Margaret N. Rees

Vegetation Monitoring

Executive Summary

• The Weed Sentry program surveyed over 335 miles and 2,610 acres of transportation corridors on federal land in Clark County for incipient populations of exotic plants.
• 18 manuscripts attained in-press or published status and one manuscript was submitted for review this year. Among published manuscripts, are one documenting Sahara mustard germination patterns (Western North American Naturalist), one assessing exotic species distributions in Clark County (Environmental Monitoring and Assessment), and another is a synthesis of burro effects on Mojave Desert vegetation (Environmental Management), and one assessing vegetation in grassy remnants of the Las Vegas Valley (Desert Plants)
• Staff delivered …

The Prairie Naturalist. Volume 40, No. 3/4 September/December 2008, The Great Plains Natural Science Society

The Prairie Naturalist

WINTERKILL AND BIOMASS OF THE PAINTED TURTLE IN A SOUTH DAKOTA WETLAND. S. G. Platt, Z. Fast Horse, W. Cross, S. Mannel, and T. R. Rainwater

NON-BLACKBIRD AVIAN OCCURRENCE AND ABUNDANCE IN NORTH DAKOTA SUNFLOWER FIELDS. O. A. Schaaf, G. M. Linz, C. Ooetkott, M. W. Lutman, and W. J. Bleier

USING LOCAL KNOWLEDGE AND REMOTE SENSING TO MAP KNOWN AND POTENTIAL PRAIRIE-CHICKEN DISTRIBUTION IN KANSAS. M. E. Houts, R. O. Rodgers, R. D. Applegate, and W. H. Busby

A CASE STUDY OF A SUCCESSFUL LAKE REHABILITATION PROJECT IN SOUTH-CENTRAL NEBRASKA. P. J. Spirk, B. A. Newcomb, and K. O. …

Non-Blackbird Avian Occurrence And Abundance In North Dakota Sunflower Fields, Dionn A. Schaaf, George M. Linz, Curt Doetkott, Mark W. Lutman, William J. Bleier

The Prairie Naturalist

Sunflower fields are well-documented as foraging habitat for fallmigrating blackbirds (Family Icteridae). There is, however, a paucity of information on the use of sunflower fields by non-blackbirds. We assessed non-blackbird use of 12 ripening sunflower fields in the Prairie Pothole Region of central North Dakota. From mid-August to mid-October 2000, we counted 4,129 individual birds, consisting of 22 families and 61 species, in the sample fields and within 5 m of the field edges. We saw the largest number of birds from 18 September to 27 September. The Family Emberizidae (sparrows) accounted for 26% of the species and 20% of …

Winterkill And Biomass Of The Painted Turtle In A South Dakota Wetland, Steven G. Platt, Zannita Fast Horse, Warren Cross, Sylvio Mannel, Thomas R. Rainwater

The Prairie Naturalist

Winterkill occurs when drought conditions expose hibernating turtles to desiccation and lethaly cold temperatures. Winterkill is thought to represent a major source of mortality in northern populations of the painted turtle (Chrysemys picta), but few field observations are available. We herein reported on catastrophic winterkill among western painted turtle (C. pieta bellii) at Limestone Butte Lake (LBL) in western South Dakota during the winter of 2003-2004. Additionally, we used the carcasses of winterkilled turtles (n = 86) to estimate the standing crop biomass of the painted turtle at LBL (0.6 kg/ha). This was the only estimate …

New And Current Microbiological Tools For Ecosystem Ecologists: Towards A Goal Of Linking Structure And Function, Rebecca E. Drenovsky, Kevin P. Ferris, Katharine M. Batten, Krassimira Hristova

Biology

Interest in the relationships between soil microbial communities and ecosystem functions is growing with increasing recognition of the key roles microorganisms play in a variety of ecosystems. With a wealth of microbial methods now available, selecting the most appropriate method can be daunting, especially to those new to the field of microbial ecology. In this review, we highlight those methods currently used and most applicable to ecological studies, including assays to study various aspects of the carbon and nitrogen cycles (e.g., pool dilution, acetylene reduction, enzyme analyses, among others), methods to assess microbial community composition (e.g., phospholipid fatty acid analysis …