Plant Sciences Commons^™

Root Biomass And Production In Four Communities Within The Great Dismal Swamp, Susan West Powell

Biological Sciences Theses & Dissertations

A biomass difference approach was used to measure biomass and production over eleven months in four different communities within the Great Dismal Swamp. On all sites, fine roots were the moat dynamic root component. Both biomass and production were highest on the mixed hardwood site, the least flooded site, and second highest on the cedar site, the site with the longest duration of saturation. The maple-gum and cypress sites had lower amounts of biomass and rates of production. Environmental parameters that influenced production included frequency and duration of flooding, density of the stand, and soil type.

A second method, an …

An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal

Biological Sciences Theses & Dissertations

Pyxidanthera barbulata (pyxie moss), a rare and endangered subshrub, has been found in decreasing numbers in it's "pine barren" habitat. An autecological study encompassing vegetation association analysis and environmental measurements was performed in the Blackwater Ecologic Preserve, its only known location in Virginia. The preserve is being subjected to controlled burning and the effect of burning on the species was evaluated. A multivariate analysis of variance was performed to identify species associations, and simple analysis of variance was done to find trends in the environmental data. Four taxa were positively associated with P. barbulata, Gaultheria procumbens, Vaccinium tenellum, Cladonia spp., …

A Study Of Striga Chromosome Numbers With A Comparison To Those Of Some Genera In The Rhinathoideae And The Orobanchaceae, Cynthia White

Biological Sciences Theses & Dissertations

New chromosome counts are given for nine species of Striga including S. elegans (n=18), S. asiatica (n=19), S. forbesii (n=22), S. densiflora (n=26), S. aspera (n=27), S. passargei (n=28), and S. hermonthica (n=30). Previous counts reported for S. gesnerioides (n=20) and S. angustifolia (n=20) are verified. Evidence from the base number (x=10), chromosome counts, and differences in chromosome size (bimodality) suggests that the genus is an allotriploid with a descending aneuploid series. Genomic change appears to occur by different mechanisms in the Rhinanthoideae; some genera display a euploid series, others show aneuploidy, and some are very stable. Genera examined …

Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles

Dissertations, Theses, and Masters Projects

Dissolved nutrient concentrations and invertebrate grazing activity regulate epiphytic biomass. Because epiphyton may limit light and carbon at leaf surfaces and the consequent productivity of submerged macrophytes, factors which influence epiphytic biomass may indirectly affect macrophyte abundance. I measured the simultaneous effects of water column nutrients (ambient or 3x ambient concentrations of nitrogen and phosphorus) and grazing (presence or absence of epifaunal community) on epiphyton and macrophytes seasonally in eelgrass (Zostera marina L.) microcosms on lower Chesapeake Bay. Grazing was more important than nutrients in controlling accrual of total epiphytic biomass, although effects on epiphytic components varied; numbers of diatoms …

Effects Of Lake Management On Chemical, Physical, And Phycological Characteristics Of A Hypereutrophic Reservoir, Kaye J. Surratt

Masters Theses

Lake Charleston is a 1.1 billion gallon capacity side channel reservoir which was constructed in 1982 as a public drinking water supply for the City of Charleston in Coles County, Illinois. Past studies of the lake indicated an increase in eutrophication and the capacity to support large algal populations. Recent lake management practices include copper sulfate applications as an algicide and aeration to reduce flavor and odor.

In order to assess present lake status and to evaluate the effectiveness of lake management practices, two lake sites were sampled on a weekly basis from May to October, 1989. Chemical, physical, and …

The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett

Dissertations, Theses, and Masters Projects

No abstract provided.

Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney

Dissertations and Theses @ UNI

The native vegetation of Iowa was primarily tallgrass prairie and currently exists only in small isolated parcels, including some remnants occurring in roadsides. Roadside prairie remnants are important for historical, environmental, aesthetic, scientific, and economic reasons. Information about factors influencing the occurrance of roadside prairie vegetation could be useful to roadside vegetation managers in development of initial vegetation surveys and subsequent to restoration of roadside prairie vegetation.

This study was conducted to determine what factors most affected the percent coverage of prairie graminoids in roadsides; particularly soil moisture availability, drainage, soil disturbance, and availability of a prairie seed sources. Prairie …