Digital Commons Network^™

Influence Of Tillage On Common Ragweed (Ambrosia Artemisiifolia) Emergence Pattern In Nebraska, Ethann R. Barnes, Rodrigo Werle, Lowell Sandell, John L. Lindquist, Stevan Z. Knezevic, Peter H. Sikkema, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Spring tillage is a component of an integrated weed management strategy for control of early emerging glyphosate-resistant weeds such as common ragweed; however, the effect of tillage on common ragweed emergence pattern is unknown. The objectives of this study were to evaluate whether spring tillage during emergence would influence the emergence pattern or stimulate additional emergence of common ragweed and to characterize common ragweed emergence in southeast Nebraska. A field experiment was conducted for three years (2014 to 2016) in Gage County, Nebraska in a field naturally infested with glyphosate-resistant common ragweed. Treatments consisted of a no-tillage control and three …

Phytophagous Insect Oviposition Shifts In Response To Probability Of Flower Abortion Owing To The Presence Of Basal Fruits, Shivani Jadeja, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Phytophagous insects use a wide range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant’s resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late-opening distal flowers are more likely to be aborted in the presence of already-initiated basal fruits because they are strong resource sinks. If flowers are aborted, all eggs of the phytophagous insect, Tegeticula yuccasella, within the flower die. We used the phytophagous insect T. yuccasella that lays …

Native And Agricultural Forests At Risk To A Changing Climate In The Northern Plains, Linda A. Joyce, Gary Bentrup, Antony S. Cheng, Peter Kolb, Michele Schoeneberger, Justin Derner

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

Native and agricultural forests in the Northern Plains provide ecosystem services that benefit human society—diversified agricultural systems, forest-based products, and rural vitality. The impacts of recent trends in temperature and disturbances are impairing the delivery of these services. Climate change projections identify future stressors of greater impact, placing at risk crops, soils, livestock, biodiversity, and agricultural and forest-based livelihoods. While these native and agricultural forests are also a viable option for providing mitigation and adaptation services to the Northern Plains, they themselves must be managed in terms of climate change risks. Because agricultural forests are planted systems, the primary approaches …

An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll

Theses and Dissertations (Comprehensive)

Giant Mine is an inactive gold mine located nine kilometers north of Yellowknife, Northwest Territories. Giant Mine has been the source of arsenic trioxide for the Baker Creek watershed since it opened over 60 years ago. Although arsenic levels in the creek are above the limits considered to be biologically relevant, there is no concrete evidence that plants and mycorrhizae have actually been affected. This study provides an initial assessment of the impacts mining activity at Giant Mine has had on plants and mycorrhizae in the Baker Creek watershed. Nine sites were sampled around Giant Mine: five sites downstream from …

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 …

Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.

Theses and Dissertations (Comprehensive)

The Arctic has warmed by at least 3^°C over the past 50 years and this rapid warming is expected to continue. Climate warming is driving the proliferation of shrubs across the tundra biome with implications for energy balance, climate, hydrology, nutrient cycling, and biodiversity. Changes in tundra plant water use attributable to shrub expansion are predicted to increase evapotranspirative water loss which may amplify local warming and reduce run-off. However, little is known about the extent to which shrubs will enhance evapotranspirative water loss in these systems. Direct measures of shrub water use are needed to accurately predict …

Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton

Theses and Dissertations

Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response …

Increasing Renewable Oil Content And Utility, William Richard Serson

Theses and Dissertations--Plant and Soil Sciences

Since the dawn of agriculture man has been genetically modifying crop plants to increase yield, quality and utility. In addition to selective breeding and hybridization we can utilize mutant populations and biotechnology to have greater control over crop plant modification than ever before. Increasing the production of plant oils such as soybean oil as a renewable resource for food and fuel is valuable. Successful breeding for higher oil levels in soybean, however, usually results in reduced protein, a second valuable seed component. We show that by manipulating a highly active acyl-CoA: diacylglycerol acyltransferase (DGAT) the hydrocarbon flux to oil in …

Evaluating Soil Physical And Chemical Properties Following Addition Of Non-Composted Spent Coffee And Tea For Athletic Fields, Shuang Zhou

Theses and Dissertations--Plant and Soil Sciences

Physical and chemical properties of non-composted spent coffee (CF) and tea (T) suggest they may have applications as soil amendments for improving poor soils. Studies were conducted to determine 1) the effect of amendments on grass growth and soil properties, 2) the effect of incorporation versus surface application of amendments on soil properties, and 3) the effect of amendment application frequency on grass growth and soil properties. In the first study, amendments were mixed with sand and planted to bermudagrass. Treatments included CF, T, and peat moss (PM) mixed with sand, and 100% sand as a control. In the second …

Taxonomic Revision Of Dendrobium Sw. Section Stachyobium Lindl. (Orchidaceae) In Thailand, Phataravee Prommanut

Chulalongkorn University Theses and Dissertations (Chula ETD)

Taxonomic revision of Dendrobium Sw. section Stachyobium Lindl. in Thailand has been conducted from 2015-2018 based on natural habitats observation in Thailand as well as various herbaria visits, i.e. BCU, BK, BKF, BM, C, CMUB, E, K, KKU and QBG. Key to species, taxonomic descriptions, ecological data, illustrations and geographical distribution of all taxa are provided. Twenty four taxa with including 21 species and 3 varieties were recognized. Among these, two species namely Dendrobium chiangdaoense and D. obchantiae are new to Thailand and two species viz. Dendrobium sp.2 and Dendrobium sp.3 are being proposed as new species. Besides, Dendrobium sp.1 …

Are Weevils Picky Eaters? Community Structure And Host Specificity Of Neotropical Saproxylic Beetles (Coleoptera: Curculionidae), Jhunior A. Morillo

Dissertations and Theses

Abstract Primary saproxylic beetles play a major role in forest nutrient cycling and making deadwood accessible to other decomposers. Understanding beetle host preferences and patterns of community assembly is critical for their conservation, and for predicting which species might become invasive. This project aims to investigate the ecological and host specificity, as well as the community composition of curculionids in a mosaic of old-growth (OG) and secondary forest on the Osa Peninsula, Costa Rica. The subfamily Scolytinae was expected to be the most species-rich and abundant. Ambrosia beetles were expected to have more generalist species than other curculionids. Old growth …

A New Bryophyte Community And Three New Records For The Epiphytic Bryophyte Vegetation Of Turkey, Mevlüt Alataş, Güray Uyar

Turkish Journal of Botany

Based on 38 relevés, the Lewinskyetum affinis ass. nov. (Ulotion crispae alliance) was described and characterized as a new epiphytic association from the Abant Mountains (Northwest Turkey). To the best of our knowledge, this is the first report about three epiphytic bryophyte associations, namely Dicranetum taurici, Pterigynandretum filiformis, and Orthotricho straminei-Pterigynandretum filiformis, in Turkey. In addition, multivariate analysis techniques such as two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DECORANA) were used to examine epiphytic bryophyte communities for cluster analysis and ordination analysis, respectively.

A New Species Of Micromeria (Lamiaceae) From Köyceğiz (Muğla, Southwest Of Turkey), Hayri̇ Duman, Tuncay Di̇rmenci̇

Turkish Journal of Botany

A new species, Micromeria aybalae H.Duman & Dirmenci (Lamiaceae), Micromeria Benth. sect. Micromeria, is described from Muğla Province in southwestern Turkey. A description, taxonomic note, distribution map, habitat, and nrDNA ITS and cpDNA trnL-F based phylogeny are presented. The differences between the new species and its allies, Micromeria cremnophila Boiss. & Heldr. s.l. and M. hispida Benth., are discussed, and an identification key is provided for the Turkish Micromeria.

Syntaxonomical Analysis Of The Riparian Vegetation Of The Porsuk River (Eskişehir-Kütahya/Turkey), Ebru Özdeni̇z, Lati̇f Kurt, Erwin Bergmeier

Turkish Journal of Botany

This study is about the classification and syntaxonomic allocation of the riparian vegetation of the Porsuk River (Eskişehir-Kütahya, western part of Central Anatolia). The Porsuk is part of the Sakarya River basin and is the longest tributary of the Sakarya River. The data were collected using the phytosociological method of Braun-Blanquet and analyzed using TWINSPAN classification and NMDS ordination. Ten syntaxa were identified, all of which are more or less widespread in the nemoral and meridional zone. The woody alluvial vegetation of the study area comprises the associations Salicetum albae, Populetum albae, and Elymo-Rubetum caesii. The riparian reed bed vegetation …

Frost: Frequently Asked Questions, Department Of Primary Industries And Regional Development, Western Australia

Grain and other field crops published reports

Frequently asked questions regarding frost from the National Frost Initiative.

Modeling The Spread Of Sudden Oak Death Across A Heterogeneous Landscape In Redwood National Park Using A Spatially-Explicit Epidemiological Model, Laura A. Morgan

Cal Poly Humboldt theses and projects

The pathogen Phytophthora ramorum, the causal agent of Sudden Oak Death (SOD), is responsible for the deaths of millions of oak (Quercus spp.) and tanoak (Notholithocarpus densiflorus) trees in California and Oregon (USA). A recent infection in Redwood National Park (RNP) in California (USA) provided an opportunity to adapt an existing SOD model to assess the efficacy of current and proposed management strategies. A common method of SOD treatment includes killing both infected and uninfected hosts in the area of infection, as well as the area surrounding the infection to create buffers to account for undetected …

Ecology Of Savanna Ecosystems In Indonesia, Sutomo

Theses: Doctorates and Masters

Tropical savannas in South East Asia are important yet understudied ecosystems. In fact, the description of savanna is limited in the Indonesian Archipelago, a region which, based on climate alone, would be expected to have mostly forest. In this thesis, I compared and contrasted the vegetation characteristics of four savannas in the wetter part of the Indonesian archipelago (Java – Bali – Lombok) to understand how fire and grazing influence their dynamics, and searched for evidence of savanna origins, maintenance, invasion by exotic/woody species and possible ecosystem transitions. Vegetation surveys, remote sensing techniques and statistical models were used to spatially …

Twenty-First Century Climate Change And Submerged Aquatic Vegetation In A Temperate Estuary: The Case Of Chesapeake Bay, Thomas M. Arnold, Richard C. Zimmerman, Katharina A.M. Engelhardt, J. Court Stevenson

OES Faculty Publications

Introduction: The Chesapeake Bay was once renowned for expansive meadows of submerged aquatic vegetation (SAV). However, only 10% of the original meadows survive. Future restoration effortswill be complicated by accelerating climate change, including physiological stressors such as a predicted mean temperature increase of 2-6°C and a 50-160% increase in CO2 concentrations.

Outcomes: As the Chesapeake Bay begins to exhibit characteristics of a subtropical estuary, summer heat waves will become more frequent and severe. Warming alone would eventually eliminate eelgrass (Zostera marina) from the region. It will favor native heat-tolerant species such as widgeon grass (Ruppia maritima) while facilitating colonization by …

Regime Shifts And Panarchies In Regional Scale Social-Ecological Water Systems, Lance Gunderson, Barbara A. Cosens, Brian C. Chaffin, Craig A. (Tony) Arnold, Alexander K. Fremier, Ahjond S. Garmestani, Robin Kundis Craig, Hannah Gosnell, Hannah E. Birge, Craig R. Allen, Melinda H. Benson, Ryan R. Morrison, Mark C. Stone, Joseph A. Hamm, Kristine Nemec, Edella Schlager, Dagmar Llewellyn

Tallgrass Prairie Publications and Reports

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate …

Opuntioid Cacti Management Guide: Best Practice Information For Austrocylindropuntia, Cylindropuntia And Opuntia Species In Australia, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

Key points:

• Australia does not have any native cacti.
• Opuntioid cacti impact on Australia environmentally, agriculturally and aesthetically, as well as posing a risk to animal welfare and human safety.
• Invasive cacti are drought resistant and hardy, surviving in low rainfall environments.
• All species spread vegetatively through the rooting of cladodes (stem segments), fruits or flowers. Some species also spread by seed.
• Opuntioid cacti vary significantly in their form and habit, ranging from low-growing shrubs under 50 cm to erect trees up to approximately 6 m tall.
• Australian rangelands are especially vulnerable to cacti invasion.
• The cost of control often …

Root Community, Tallgrass Prairie Center

Open Educational Resources

Pairs of students play a battleship-style game to show how roots explore the soil to obtain resources.

Routes For Infiltration, Tallgrass Prairie Center

Open Educational Resources

Students become a carbon atom and experience the movements of carbon through the environment, including its time sequestered in prairie roots.

Effects Of Fertilizer And Shade Management On Nitrogen Mineralization, Nitrifying Microbial Abundance And Nitrogen-Fixing Capacity Of Erythrina Poeppigiana In Coffee (Coffea Arabica) Agroforestry Systems In Costa Rica, Stuart E. Barker Iii

College of Graduate Studies: Theses & Dissertations

Worldwide chemical fertilizer use has increased by four times during the last 50 years. Conventional agricultural systems have a high nitrifying nature, resulting in a loss of nearly 70% of overall nitrogen (N) fertilizer inputs, an estimated economic loss of $81 billion. Over application of fertilizer is rampant in tropical developing nations in Central America, where coffee is major crop. Agroforestry offers ecologically sustainable land management strategies that promote the provision of ecosystem services such as, protection of biodiversity, climate change mitigation, and water and soil regulation. When legume trees are incorporated as the shade tree in coffee production, direct …

Impact Of Push-Pull Technology On The Nutritional Status Of Farmers' Children In Western Kenya, Nicholas O. Ogot, J. O. Pittchar, C. A.O. Midega, Z. R. Khan

All Peer-Reviewed Publications

This study examined the impact of push-pull technology (PPT) on the nutritional status of children aged 1-12 years. Non-push-pull (NPPT) farmers were used as a control group to establish a comparative model for this study. It determined household production, consumption, and surpluses, comparing the PPT adopters to the nonadopters; found out the incomes and food expenditures from farm products; found out the household dietary diversity scores; and finally found the nutritional status of the two household groups. A six faceted household-level metrics was employed. A sample of 216 households that registered 326 children was derived. This study was conducted in …

Disturbance Is An Important Driver Of Clonal Richness In Tropical Seagrasses, Kathryn M. Mcmahon, Richard D. Evans, Kor Jent Van Dijk, Udhi E. Hernawan, Gary A. Kendrick, Paul S. Lavery, Ryan J. Lowe, Marji L. Puotinen, Michelle Waycott

Research outputs 2014 to 2021

Clonality is common in many aquatic plant species, including seagrasses, where populations are maintained through a combination of asexual and sexual reproduction. One common measure used to describe the clonal structure of populations is clonal richness. Clonal richness is strongly dependent on the biological characteristics of the species, and how these interact with the environment but can also reflect evolutionary scale processes especially at the edge of species ranges. However, little is known about the spatial patterns and drivers of clonal richness in tropical seagrasses. This study assessed the spatial patterns of clonal richness in meadows of three tropical seagrass …

Vegetable And Fruit Intake And Fracture-Related Hospitalisations: A Prospective Study Of Older Women, Lauren C. Blekkenhorst, Jonathan M. Hodgson, Joshua R. Lewis, Amanda Devine, Richard J. Woodman, Wai H. Lim, Germaine Wong, Kun Zhu, Catherine P. Bondonno, Natalie C. Ward, Richard L. Prince

Research outputs 2014 to 2021

The importance of vegetable and fruit intakes for the prevention of fracture in older women is not well understood. Few studies have explored vegetable and fruit intakes separately, or the associations of specific types of vegetables and fruits with fracture hospitalisations. The objective of this study was to examine the associations of vegetable and fruit intakes, separately, and specific types of vegetables and fruits with fracture-related hospitalisations in a prospective cohort of women aged ≥70 years. Vegetable and fruit intakes were assessed at baseline (1998) in 1468 women using a food frequency questionnaire. The incidence of fracture-related hospitalisations over 14.5 …

Vascular Plants Of Preston Peak, Siskiyou County, James P. Smith Jr

Botanical Studies

No abstract provided.

Vascular Plants Of The Scott Mountain Campground Area Trinity And Siskiyou Counties, California, James P. Smith Jr, John O. Sawyer Jr.

Botanical Studies

No abstract provided.

Oklahoma Vascular Plants - A Numerical Conspectus, James P. Smith Jr

Botanical Studies

No abstract provided.

Effects Of In-Situ Leaf-Level Canopy Warming In A Northern Hardwood Forest, Kelsey Carter

Dissertations, Master's Theses and Master's Reports

Rising mean annual temperatures due to climate change have intensified the need to understand the effects of warming on plant physiological processes. Forest photosynthesis is the most important pathways of terrestrial carbon sequestration, yet continued warming could reduce this important carbon sink. Photosynthesis is highly sensitive to temperature and begins to decline after an optimum temperature (T_opt) is reached, leading to reduced carbon uptake. To date, logistical difficulties have limited our ability to test photosynthetic responses to sustained warming in mature forest canopies. In order to understand how elevated temperatures will affect forest ecosystems, we need to be …