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Articles 331 - 360 of 412

Full-Text Articles in Plant Biology

Evaluating Vascular Plant Composition And Species Richness On Horn Island, Mississippi, Using Passive And Active Remote Sensing In Conjunction With Ground Based Measurements, Kelly Lynn Lucas May 2008

Evaluating Vascular Plant Composition And Species Richness On Horn Island, Mississippi, Using Passive And Active Remote Sensing In Conjunction With Ground Based Measurements, Kelly Lynn Lucas

Dissertations

Barrier island vegetation is subjected to chronic abiotic stressors combined with periodic storm events that favor species adapted to harsh environments. These islands are the first landforms to be affected by changes in coastal subsidence and sea-level rise. Evaluating changes in vegetation is important for understanding the impact of global climate change on coastal environments.

This study assesses vegetation composition and plant species richness on Horn Island, Mississippi using ground data in conjunction with remotely sensed spectral and LIDAR data. The goals of this research are to: 1) classify and map vegetation composition on Horn Island using hyperspectral and LIDAR …


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, 2008, Margaret N. Rees Mar 2008

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, 2008, Margaret N. Rees

Fire Science

• Fence built.

• Seeds and plants obtained.

• Seeding experiment initiated at Goodsprings burn site.

• Three hundred twenty plants, comprising eight species, planted at the Goodsprings burn site on February 12, 2008.

• First of a series of Joint Fire Science update articles submitted to Mojave Applied Ecology Notes newsletter.


A Watershed Analysis Of Pattee Pond: Implications For Water Quality And Land Use Management, Problems In Environmental Science Course (Biology 493), Colby College, Colby Environmental Assessment Team, Colby College Jan 2008

A Watershed Analysis Of Pattee Pond: Implications For Water Quality And Land Use Management, Problems In Environmental Science Course (Biology 493), Colby College, Colby Environmental Assessment Team, Colby College

Colby College Watershed Study: Pattee Pond (2008, 1992)

The Colby Environmental Assessment Team (CEAT) investigated the impact of land use patterns on the water quality of Pattee Pond in Winslow, Maine, during the summer and fall of 2008. Physical, chemical, and biological characteristics of water quality were analyzed to evaluate the current health of the lake. Data collected were compared with previous studies conducted by the Maine Department of Environmental Protection (DEP) and CEAT to examine changes in water quality and land use over time. Trends in Pattee Pond water quality suggest an improvement since the 1970s. However, the lake is still experiencing algal blooms resulting from phosphorus …


Competitive Abilities Of Native Grasses And Non-Native (Bothriochloa Spp.) Grasses, Cheryl D. Schmidt, Rob Channell Ph.D., Karen R. Hickman, Keith Harmoney, William J. Stark Ph.D. Jan 2008

Competitive Abilities Of Native Grasses And Non-Native (Bothriochloa Spp.) Grasses, Cheryl D. Schmidt, Rob Channell Ph.D., Karen R. Hickman, Keith Harmoney, William J. Stark Ph.D.

Biological Sciences Faculty Publications

Old World Bluestems (OWB), introduced from Europe and Asia in the 1920s, recently have begun to raise concerns in the Great Plains. Despite suggestion in the late 1950s that OWB were weedy and negatively impacted biological diversity, they were widely introduced throughout the Great Plains for agricultural purposes. Anecdotal evidence suggests that OWB exhibit invasive characteristics that promote competitive exclusion of native species. The objective of our study was to quantify the competitive abilities of two OWB species (Caucasian bluestem; Bothriochloa bladhii (Retz.) S. T. Blake (= Bothriochloa caucasica (Trin.) C. E. Hubb.) and yellow bluestem; Bothriochloa ischaemum (L.) Keng) …


Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid Jan 2008

Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid

Biological Sciences Theses & Dissertations

The microspore wall morphogenesis and orbicule ultrastructure of Isoetes were studied using electron microscopy. Microspore wall morphogenesis in five species of Isoetes (I. appalachiana, I. engelmannii, I. hyemalis, I. piedmontana, and an undescribed species from York Co., VA, USA) was studied using scanning and transmission electron microscopy. Results show that they generally have the same developmental stages in terms of microspore wall morphogenesis. The mature microspore wall consisted of four layers: perispore, paraexospore, exospore and endospore. Paraexospore formation began during the tetrad stage. The exospore was then formed between the paraexospore and the plasma membrane. During the free spore …


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, 2007 To December 31, 2007, Margaret N. Rees Dec 2007

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, 2007 To December 31, 2007, Margaret N. Rees

Fire Science

The task agreement was awarded to UNLV on October 1, 2007. This report covers the period October 1, 2007 to December 31, 2007. The following activities have been conducted toward meeting or exceeding deliverables in the statement of work: hiring and project start and experimental set-up


Impact Of Small Scale Gold Mining On Soils Of The Wetland Forests In East Usambara, Tanzania, C. Kweyunga, R. B. M. Rbm Senzota Dec 2007

Impact Of Small Scale Gold Mining On Soils Of The Wetland Forests In East Usambara, Tanzania, C. Kweyunga, R. B. M. Rbm Senzota

Tanzania Journal of Science

Soil pits in disturbed and natural wetland forests of East Usambara were excavated and soil profile samples collected and analysed for physical and chemical properties. Their physical and chemical characteristics were found to be sharply different from those of the surrounding hills. Differences included lack of A Horizon, water saturation, presence of very high organic matter, very low pH and hence very poor in basic cations, and low microbial activity. Nutrient recycling, especially nitrogen and phosphorus, tended to shift from mineralization to immobilization. Effects of soil disturbance on both physical and chemical characteristics of the soils were also very vivid. …


The Jeweled Armor Of Tillandsia—Multifaceted Or Elongated Trichomes Provide Photoprotection, Simon Pierce Dec 2007

The Jeweled Armor Of Tillandsia—Multifaceted Or Elongated Trichomes Provide Photoprotection, Simon Pierce

Aliso: A Journal of Systematic and Floristic Botany

Foliar trichomes of gray-leaved Tillandsioideae (Bromeliaceae) are highly reflective, suggesting a role in protecting the leaf against direct sunlight in exposed niches. The performance of photosystem II, as denoted by the chlorophyll fluorescence characteristic Fv /Fm , was determined for seven Tillandsia species and Vriesea barclayana that were exposed to excessive light, with trichomes either present or removed. Additionally, trichome structure and interaction with light was recorded using extended depth-of-field photomicrography, and reflectance quantified using a novel photographic technique. Trichomes of mesomorphic Type IV life forms (T. cryptantha, T. cyanea) and of the intermediate life …


Towards A Comprehensive Survey Of C3 And C4 Photosynthetic Pathways In Cyperaceae, Jeremy J. Bruhl, Karen L. Wilson Dec 2007

Towards A Comprehensive Survey Of C3 And C4 Photosynthetic Pathways In Cyperaceae, Jeremy J. Bruhl, Karen L. Wilson

Aliso: A Journal of Systematic and Floristic Botany

Members of the family Cyperaceae were surveyed by original observation and from the literature to assess the distribution of C3 and C4 photosynthetic pathways in the family. All 107 genera were included in the current sample, with 91 genera assessed as consistently C3 and 11 genera as C4. The genera Abildgaardia, Cyperus, Eleocharis, Fimbristylis, and Rhynchospora are variable for this trait. Of the total number (1474) of specific (1406) and infraspecific (68) taxa sampled, 938 taxa (63%) are C3, 527 taxa (36%) are C4, and nine species …


A Geographically Constrained Molecular Phylogeny Of Panamanian Aechmea Species (Bromeliaceae, Subfamily Bromelioideae), Keri Renee Maher Jan 2007

A Geographically Constrained Molecular Phylogeny Of Panamanian Aechmea Species (Bromeliaceae, Subfamily Bromelioideae), Keri Renee Maher

Theses Digitization Project

This study lends strong support to the idea that members of Bromeliaceae have undergone a recent adaptive radiation, and therefore show that, at least in part, diversity in the tropics is due to a fast speciation rate and that the tropics can be a "cradle" for new diversification and exploitation of varying ecological niches through the diversification of ecophysiological traits within a lineage.


Vegetation Structure And Heavy Metal Uptake By Plants In The Mining-Impacted And Non Mining-Impacted Sites Of Southern Lake Victoria Wetlands, G. Y. S. Mtui, C. Mligo, M. K. D. Mutakyahwa, J. R. Ikingura Dec 2006

Vegetation Structure And Heavy Metal Uptake By Plants In The Mining-Impacted And Non Mining-Impacted Sites Of Southern Lake Victoria Wetlands, G. Y. S. Mtui, C. Mligo, M. K. D. Mutakyahwa, J. R. Ikingura

Tanzania Journal of Science

This study assessed the plant species composition and the heavy metal uptake by plants in the mining-impacted and non mining-impacted areas of the southern Lake Victoria basin. The vegetation of the wetlands was stratified into riverine forest, riverine thickets, swampy grassland, open woodland and floodplain grassland. Plant diversity at Nyamtukuza ranged between 2.34 to 2.70; at Geita was 2.29 to 2.57 and Mwakitolyo was between 1.08 to 1.70, which was significantly lower than the other two sites; whereas variation in plant species richness was not significant. TWINSPAN classification resulted into four clusters of the vegetation communities. Cluster A, a shrubby …


Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2006, Margaret N. Rees Dec 2006

Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2006, Margaret N. Rees

Vegetation Monitoring

Executive Summary

  • Two new Weed Sentry research assistants were hired.
  • Weed Sentry staff surveyed for exotic species on 89 miles of roads on NPS and BLM land and treated more than 21,000 exotic plants in incipient populations.
  • A grid-based rare plant monitoring method was tested this quarter.
  • A manuscript detailing vegetation succession on a water pipeline at Lake Mead NRA was submitted for review to the journal Crossosoma.
  • New integrative projects undertaken this quarter included establishing a competition study between a native grass and the exotic Sahara mustard, salvaging plants for research purposes from private sites with permission from landowners, …


Spring Ephemeral Plant Diversity As It Relates To Gap Dynamics In Vigo County, Indiana, Jodi K. Farrell Sparks Dec 2006

Spring Ephemeral Plant Diversity As It Relates To Gap Dynamics In Vigo County, Indiana, Jodi K. Farrell Sparks

All-Inclusive List of Electronic Theses and Dissertations

During the course of 25 years, plant specimens from several local locations have been collected and deposited into the Indiana State University (ISU) Herbarium by plant taxonomy students. The locations of some of these plots were reestablished in the spring of 2004. In each plot, all woody and spring herbaceous plants were collected from 26 February 2004 to 12 May 2004. These specimens were identified and compared to previous collections to examine species change in the context of gap dynamics. I compiled a species list for each plot and each preserve. Objectives for this thesis were to document plant diversity …


Lake Mead National Recreation Area Vegetation Monitoring And Management: Final Close-Out Report, Time Period: October 1, 2005 To September 30, 2006, Margaret N. Rees Sep 2006

Lake Mead National Recreation Area Vegetation Monitoring And Management: Final Close-Out Report, Time Period: October 1, 2005 To September 30, 2006, Margaret N. Rees

Vegetation Monitoring

The National Park Service (NPS) at Lake Mead National Recreation Area (LAME) entered into a cooperative agreement with the University of Nevada, Las Vegas (UNLV) to accomplish vegetation monitoring and management activities. This report summarizes activities that took place by UNLV under this task agreement between October 1, 2005, and September 30, 2006. The activities included:

  • Weed Sentry mapping and treating incipient populations of exotic invasive plants throughout Clark County, including along shorelines of Lakes Mead and Mohave;
  • Monitoring of targeted rare native plant species;
  • Sahara mustard research; and
  • Providing technical assistance upon request to the NPS vegetation manager.

In …


Effects Of Smoke And Fire-Related Cues On Panstemon Barbatus Seeds, Scott R. Abella Apr 2006

Effects Of Smoke And Fire-Related Cues On Panstemon Barbatus Seeds, Scott R. Abella

Public Policy and Leadership Faculty Research

Previous research has found that exposure to fire-related cues enhances germination of some plant species, and such species may exist in frequent-fire southwestern United States Pinus ponderosa forests. I performed four greenhouse experiments with Penstemon barbatus, a perennial forb common in P. ponderosa forests, testing seed responses to liquid and air smoke, charred P. ponderosa wood and leachate, heat and emergence substrates. Liquid smoke increased P. barbatus emergence to as high as 63%, 44% greater than controls, and enhanced emergence in all 4 experiments. Air smoke produced by burning P. ponderosa litter for 15 min appeared to increase emergence similar …


Influence Of Nutrient Availability, Stand Age, And Canopy Structure On Isoprene Flux In A Eucalyptus Saligna Experimental Forest, Jennifer L. Funk, Christian P. Giardina, Alexander Knohl, Manuel T. Lerdau Jan 2006

Influence Of Nutrient Availability, Stand Age, And Canopy Structure On Isoprene Flux In A Eucalyptus Saligna Experimental Forest, Jennifer L. Funk, Christian P. Giardina, Alexander Knohl, Manuel T. Lerdau

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Eucalyptus plantations occupy approximately 10 million ha of land in the tropics and, increasingly, afforestation and reforestation projects are relying on this genus to provide rapid occupation of degraded sites, large quantities of high-quality wood products, and high rates of carbon sequestration. Members of the genus Eucalyptus are also very high emitters of isoprene, the dominant volatile organic compound emitted by trees in tropical ecosystems, which significantly influences the oxidative capacity of the atmosphere. While fertilization growth response of these trees has been intensively studied, little is known about how fertilization and tree age alter isoprene production from plantations of …


Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2005, Margaret N. Rees Dec 2005

Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2005, Margaret N. Rees

Vegetation Monitoring

Executive Summary

  • Required reports on sticky buckwheat (Eriogonum viscidulum) and threecorner milkvetch (Astragalus geyeri var. triquetrus) to be submitted through appropriate protocols by December 30, 2005
  • Summary report on several other rare plants to be submitted through appropriate protocols by December 30, 2005
  • Invasive perennial pepperweed (also called tall whitetop; Lepidium latifolium) documented and treated by Weed Sentry within Black Canyon, Lake Mojave


Ecological Costs And Benefits Of Defenses In Nectar, Lynn S. Adler, Rebecca E. Irwin Nov 2005

Ecological Costs And Benefits Of Defenses In Nectar, Lynn S. Adler, Rebecca E. Irwin

Dartmouth Scholarship

The nectar of many plant species contains defensive compounds that have been hypothesized to benefit plants through a variety of mechanisms. However, the relationship between nectar defenses and plant fitness has not been established for any species. We experimentally manipulated gelsemine, the principal alkaloid of Carolina jessamine (Gelsemium sempervirens), in nectar to determine its effect on pollinator visitation, nectar robber visitation, and male and female plant reproduction. We found that nectar robbers and most pollinators probed fewer flowers and spent less time per flower on plants with high compared to low nectar alkaloids. High alkaloids decreased the donation of fluorescent …


Reproductive Ecology Of Two Common Woody Species, Juniperus Sabina And Artemisia Santolinifolia, In Mountain Steppes Of Southern Mongolia, Katrin Ronnenberg Jan 2005

Reproductive Ecology Of Two Common Woody Species, Juniperus Sabina And Artemisia Santolinifolia, In Mountain Steppes Of Southern Mongolia, Katrin Ronnenberg

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The present study describes the reproductive ecology of the prostrate shrub Juniperus sabina and the dwarf shrub Artemisia santolinifolia in dry mountain steppes of southern Mongolia. Whereas stands of the juniper are located at the drought limit of the genus’ distributional range, the genus Artemisia is typical of central Asian drylands. Both species produce large numbers of reproductive organs. For Juniperus sabina, however, only 2.5% of the morphologically intact seeds were found to be viable. Correspondingly, neither seedlings nor saplings were found in the field, and recruitment by reseeding happens at most rarely under the present climatic conditions.

Instead, …


2005 Virginia Wildflower Of The Year: Bloodroot, Sanguinaria Canadensis, W. John Hayden Jan 2005

2005 Virginia Wildflower Of The Year: Bloodroot, Sanguinaria Canadensis, W. John Hayden

Biology Faculty Publications

Bloodroot is an herbaceous perennial that grows from a persistent, branched underground stem or rhizome. Early each spring, while the forest canopy is still bare, each well-developed rhizome tip produces one leaf and one flower stalk. The leaf is kidney-shaped in its overall outline, but it is also divided into a pattern of rounded lobes and sinuses, rendering a complex overall shape. At flowering time, bloodroot leaves form a loose vertically-oriented collar around the flower stalk with the bluish-green lower leaf surface forming the outside of the collar; as the season progresses, the leaves open flat and expand to their …


Concentrations Of Metals In River Sediment And Wetland Vegetations In Mining, Lake Victoria Basin, Tanzania, Jf Machiwa Dec 2003

Concentrations Of Metals In River Sediment And Wetland Vegetations In Mining, Lake Victoria Basin, Tanzania, Jf Machiwa

Tanzania Journal of Science

Levels of metals were determined in river sediment, rice and sugarcane juice from Lake Victoria basin where small-scale gold processing activities are carried out to assess levels of contamination. Concentrations of metals in river sediments were generally high in areas that were closest to gold ore processing sites. For instance, mercury was highest (36.3 ±12.8 mg/g dw) in river sediments of Tigiti River in Mugumu District. Other heavy metals (Cd, Pb, Zn and Cu) had highest concentrations (2.20±0.71, 208±19.3, 412±20.1 and 132.7±11.9mg/g dw, respectively) in sediment samples from Kagota. The concentration of arsenic was highest (985.0±67.2 mg/g dw) in Mugusu …


Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore Sep 2003

Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore

Publications (WR)

The Las Vegas Wash (Wash) is the primary drainage for the metropolitan Las Vegas Valley, eventually finding its way into the Colorado River watershed system. Pursuant to the recommendations of the Water Quality Citizens Advisory Committee, the Las Vegas Wash Coordination Committee (LVWCC) was formed in 1998 to develop a comprehensive plan for the long-term stabilization and management of the Wash. Consisting of representatives from 28 government agencies, businesses, environmental groups and citizens, the LVWCC formulated the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP) and designated the Southern Nevada Water Authority (SNWA) as the lead agency for the implementation …


A Watershed Analysis Of Threemile Pond: Implications For Water Quality And Land Use Management, Colby Environmental Assessment Team, Colby College, Problems In Environmental Science Course (Biology 493), Colby College Jan 2003

A Watershed Analysis Of Threemile Pond: Implications For Water Quality And Land Use Management, Colby Environmental Assessment Team, Colby College, Problems In Environmental Science Course (Biology 493), Colby College

Colby College Watershed Study: Threemile Pond (2003)

The 2003 Colby Environmental Assessment Team chose to study the Threemile Pond watershed. The Threemile Pond watershed is located in Vassalboro, China., Windsor, and Augusta, Maine. Threemile Pond is a popular site for recreation and is home to a wide range of flora and fauna. Like all other lakes in Maine, it is a young lake. However, intensive human activity in the watershed contributes a substantial amount of nutrients and the lake has algal blooms annually in the summer months. The purpose of this study was to assess the impact of land use and development on the water quality of …


Effect Of Cement Production On Vegetation In A Part Of Southwestern Nigeria, A. T. Salami, A. I. Farounbi, J. I. Muoghalu Dec 2002

Effect Of Cement Production On Vegetation In A Part Of Southwestern Nigeria, A. T. Salami, A. I. Farounbi, J. I. Muoghalu

Tanzania Journal of Science

The impact of cement dust emissions from the factory of West African Portland Cement at Ewekoro in Southwestern Nigeria on the surrounding vegetation was investigated. Sample plots of 20 m x 20 m were established at 1 km intervals from the factory site up to a distance of 10 km intervals from the factory site up to a distance of 10 km in the four cardinal directions. Leaves of common species were randomly selected for chlorophyll content analysis, leaf abundance and leaf area measurement. Woody as well as herbaceous species encountered within the established plots were enumerated, while soil samples …


Fine Root Vitality And Its Application In A Minirhizotron Study Of A Co2 Enrichment In A Florida Scrub Oak Ecosystem, Brandon Todd Herbert Jul 2002

Fine Root Vitality And Its Application In A Minirhizotron Study Of A Co2 Enrichment In A Florida Scrub Oak Ecosystem, Brandon Todd Herbert

Biological Sciences Theses & Dissertations

Minirhizotron images are assigned color codes to approximate the age of individual roots in situ. Triphenyl-tetrazolium chloride (TTC) has been used to measure the vitality of plant tissue by detecting dehydrogenase activity. TTC was used to assess the vitality of root tissue by color in a scrub oak ecosystem at Kennedy Space Center in central Florida. Roots were excavated, sorted into four color classes and stained with TTC. The product of the reduction of TTC by dehydrogenase enzyme, formazan, was extracted and its absorbance recorded using a spectrophotometer. A significant difference (p2 enrichment being conducted on a scrub oak …


The Pollinator Fauna Of Two Spring Wildflowers Of Midwestern Deciduous Forest, Erigenja Bulbosa And Claytonia Virginica, Robert P. Jean May 2002

The Pollinator Fauna Of Two Spring Wildflowers Of Midwestern Deciduous Forest, Erigenja Bulbosa And Claytonia Virginica, Robert P. Jean

All-Inclusive List of Electronic Theses and Dissertations

Eastern deciduous forests have spectacular spring floral display and a diverse array of insect pollinators. From March to May, some 20-25 species of understory herbs flower in west-central Indiana. I focused on the earliest species to bloom, Erigenia bulbosa (Apiaceae), and the most abundant, Claytonia virginica (Portulacaceae), which flowers immediately after Erigenia. l characterized insect visitor assemblages in terms of species richness and relative abundance, and measured visitation rates. For Erigenia (Chapter 1), I asked whether early flowering was necessarily associated with pollinator scarcity. I examined six sites in 2000 and resampled three of these in 2001. Erigenia attracted 10 …


Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith Jan 2002

Arbuscular Mycorrhizae Of Mojave Desert Plants, J. H. Titus, P. J. Titus, R. S. Nowak, S. D. Smith

Life Sciences Faculty Research

Roots of 15 Mojave Desert plant species were assessed for arbuscular mycorrhizal (AM) colonization in spring and autumn 1999. Another 19 species were assessed in autumn only. Perennial species were AM colonized, whereas annual species contained very low levels of AM hyphae or were nonmycorrhizal. The nonnative tree Tamarix ramosissima was also nonmycorrhizal. Levels of hyphae changed over the season in 2 species, arbuscle levels increased in 1 species, and vesicles decreased in 7 species. Mycorrhizal inoculum potential (MIP) was assessed in the soils associated with spring-collected plants. All soils were found to contain MIP. MIP values were not correlated …


Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker Jan 2002

Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker

Diana Pilson Publications

Herbivore damage is generally detrimental to plant fitness, and the evolutionary response of plant populations to damage can involve either increased resistance or increased tolerance. While characters that contribute to resistance, such as secondary chemicals and trichomes, are relatively well understood, characters that contribute to a plant’s ability to tolerate damage have received much less attention. Using Helianthus annuus (wild sunflower) and simulated damage of Haplorhynchites aeneus (head-clipping weevil) as a model system, we examined morphological characters and developmental processes that contribute to compensatory ability. We performed a factorial experiment that included three levels of damage (none, the first two, …


Clone Size Of Andropogon Gerardii Vitman (Big Bluestem) At Konza Prairie, Kansas, Kathleen H. Keeler, Charles F. Williams, Linda S. Vescio Jan 2002

Clone Size Of Andropogon Gerardii Vitman (Big Bluestem) At Konza Prairie, Kansas, Kathleen H. Keeler, Charles F. Williams, Linda S. Vescio

School of Biological Sciences: Faculty Publications

Clone size of plants of Andropogon gerardii from Konza Prairie Biological Station, Manhattan, Kansas was estimated from spatial patterns of genetic variation, using proteins detected by starch gel electrophoresis and DNA content (ploidy) measured by flow cytometry. Unique multi-locus protein banding patterns and differences in ploidy were used to exclude plants as members of the same clone. Individual clones averaged about 2 m in diameter and areas of prairie of 100 m2 were calculated to contain an average of 31.8 genetic individuals.


Avian And Mammalian Use Of Three Small Urban Wetlands Invaded By A Pest Species, Reed Canarygrass (Phalaris Arundinacea L.), Laurie Dizney Jul 2001

Avian And Mammalian Use Of Three Small Urban Wetlands Invaded By A Pest Species, Reed Canarygrass (Phalaris Arundinacea L.), Laurie Dizney

Dissertations and Theses

Small urban wetlands are being destroyed and degraded at an alarming rate. One result of degradation is invasion by pest species, such as reed canarygrass (Phalaris arundinacea L. ). Reed canarygrass forms virtual monocultures in a wide range of wetland types. Wetlands normally have high plant species richness and abundance, which is widely believed to lead to faunal diversity. The purpose of the present study was to determine to what extent birds and mammals use a wetland dominated by reed canarygrass. The research was conducted at Tualatin Hills Nature Park in Beaverton, Washington County, Oregon. I examined three sites …