Elevated CO2 and warming may alter terrestrial ecosystems by promoting invasive plants with strong community and ecosystem impacts. Invasive plant responses to elevated CO2 and warming are difficult to predict, however, because of the many mechanisms involved, including modification of phenology, physiology, and cycling of nitrogen and water. Understanding the relative and interactive importanc...

Managers reduce piñon (Pinus spp.) and juniper (Juniperus spp.) trees that are encroaching on sagebrush (Artemisia spp.) communities to lower fuel loads and increase cover of desirable understory species. All plant species in these communities depend on soil water held at . 1.5 MPa matric potential in the upper 0.3 m of soil for nutrient diffusion to roots and major growth in spring (resource g...

Cheatgrass (Bromus tectorum) is an invasive weed in western North America found primarily growing at elevations less than 2200 m. We asked whether cheatgrass is capable of becoming adapted to a marginal habitat, by investigating a population at a high elevation invasion edge. We used a combination of methods, including reciprocal field transplants, controlled environment studies and molecular a...

Cheatgrass (Bromus tectorum) is of growing concern among farmers, ranchers, and researchers in the intermountain west due to its ability to alter rangeland vegetation communities and their associated fire regimes. Quickbird multi-spectral imagery (spatial resolution 2.4 mpp) was used to detect and model cheatgrass presence in southeastern Idaho. Training sites were created using 2003 field data...

The Plasmodium falciparum genome is equipped with several subtelomeric gene families that are implicated in parasite virulence and immune evasion. Members of these families are uniformly positioned within heterochromatic domains and are thus subject to variegated expression. The best-studied example is that of the var family encoding the major parasite virulence factor P. falciparum erythrocyte...

Sequestration and antigenic variation are essential for Plasmodium falciparum survival in vivo contributing to severe pathologic findings and, also, chronic infection. Both are conferred by P. falciparum erythrocyte membrane proteins encoded by ~60 var genes. To study the dynamics of var gene expression, we conducted a 4-month longitudinal study of semi-immune children from Papua New Guinea. By...

Although cheatgrass (Bromus tectorum) has been widely distributed across western rangelands for >70 years, the full ecologic and economic impacts of this non-native invasive plant have not yet occurred. Unfortunately, several independent lines of evidence indicate that the rate at which acreage becomes infested with cheatgrass is increasing rapidly. Furthermore, the invasion and spread of a num...

Changes in the species composition of biotic communities may alter patterns of natural selection occurring within them. Native perennial grass species in the Intermountain West are experiencing a shift in the composition of interspecific competitors from primarily perennial species to an exotic, annual grass. Thus traits that confer an advantage to perennial grasses in the presence of novel ann...

Title of Thesis: DYNAMIC STUDY OF HEAVY METAL FATES IN BIORETENTION SYSTEMS Xueli Sun, Master of Science, 2004 Thesis directed by: Professor Allen P. Davis Department of Civil and Environmental Engineering Bioretention is a best management practice (BMP). In this research, pot prototypes filled with bioretention media were built to simulate the conditions of natural growth of three grasses: Pan...