Browsing by Subject "Carex pensylvanica"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Analysis of the U.S. Department of Agriculture's regulation of genetically engineered crops and reproductive biology of Carex pensylvanica (Lam.)
    (2013-08) McGinnis, Esther Ebata
    This dissertation is divided into two parts. Chapters 1 through 3 are interdisciplinary and focus on legal and scientific perspectives regarding the regulation of genetically engineered crops. Chapters 4 and 5 evaluated the environmental factors that control flowering in Pennsylvania sedge (Carex pensylvanica Lam.). The commercial potential of genetically engineered (GE) crops has not been fully realized in the United States due to environmental litigation that dramatically affected the pace of GE crop development and deregulation. The USDA's Animal and Plant Health Inspection Service (APHIS) regulates GE crops. However, litigation initiated by nongovernmental organizations exposed APHIS's vulnerability to lawsuits under the National Environmental Policy Act. We concluded in chapters 1 and 2 that APHIS did not adequately evaluate the environmental risks of novel crops, and thus left itself open to litigation. In Chapter 3, we described how the biotechnology industry is attempting to avoid regulation of GE crops through the creation of a non-plant pest loophole.Pennsylvania sedge is an upland forest sedge with horticultural potential as a low maintenance groundcover. For large plantings, achenes are preferred, but Pennsylvania sedge typically produces few achenes in its native habitat. As a first step in improving achene production, Chapter 4 evaluated the effect of vernalization and photoperiod on floral initiation and development. We concluded that Pennsylvania sedge is an obligate short day plant that does not require vernalization for flowering. Plants flowered when exposed to daylengths of 6 to 12 hours. Flowering was completely inhibited with 14-hour photoperiods. Chapter 5 examined the environmental factors that control floral gender sequence and inflorescence culm heights. Plants were found to be determined and florally initiated in the fall in the northern United States. A post-floral induction chilling treatment (winter) was necessary to produce protogynous flowering and normal inflorescence culm elongation.
  • Thumbnail Image
    Item
    A study of herbaceous vegetation in Chequamegon - Nicolet National Forest: relationship of earthworms, white-tailed deer browsing and Carex pensylvanica Lam
    (2014-12) Ojanen, Paul Thomas
    Invasive earthworms alter multiple forest components. By accelerating litter decomposition, they alter nutrient flows, soil composition and vegetative communities. White -tailed Deer (Odocoileus virginianus) are known to alter vegetative communities by selective browsing; severity varies with population density and affects plant community population and composition. Both factors are associated with reduced vegetative community richness and dominance by graminoids. In this study, 101 randomly selected Northern Mesic Hardwood Sugar Maple sites in the Chequamegon - Nicolet National Forest were sampled for vegetation, earthworm occurrence and browsing intensity. Over three years, eighty-two percent of sites were positive for earthworms; in two non-drought years, ninety percent of sites were positive. Non-metric Multi-dimensional Scaling (NMDS) and Multiple Response Permutation Procedure (MRPP) found divergent communities; a Carex pensylvanica Lam dominated community associated with earthworm invasion and strongly linked to Lumbricus rubellus presence, and remaining Acer saccharum seedling stands associated with reduced earthworm impacts. Additionally Carex pensylvanica was strongly linked to Lumbricus rubellus presence by Indicator Species Analysis. Lumbricus rubellus invaded sites had both reduced species richness and vegetative cover. White-tailed deer (Odocoileus virginianus) browsing was found to be heavy and extensive throughout both forests, impacting Acer saccharum regeneration and further driving graminoid dominance. The results indicate earthworm invasion is geographically extensive and a principal driver of Carex pensylvanica understory dominance and reduced Acer saccharum regeneration.