This thesis includes four separate studies. The first two studies assessed edge effects in a
700-year-old forest. After 20 years of exposure, epiphyte assemblages on the clearcut edge
were similar to those of the forest interior, but there were some differences in vertical
distribution patterns. Several species restricted to the...
This dissertation describes the epiphyte communities on tall shrubs in forests of
western Oregon, with a focus on potential effects of management practices on these
communities. Shrubs and other hardwoods have recently gained recognition as
hotspots of diversity for epiphytes in young conifer forests of the region. Yet little is...
Riparian forests in the Idaho Panhandle, north of Whitebird, were surveyed for rare riparian lichen species. The region was stratified into nine geographic units and by stream size. Eighty-one plots were surveyed for lichen community, stand and river characteristics. Variables important to lichen community composition included regional differences, elevation, climatic...
This dissertation describes patterns in epiphytic macrolichen community composition, diversity, and biomass across various stand types in the Blue River watershed of western Oregon. It first examines the relative importance of ecological factors such as stand age, remnant tree retention, and topography to lichen communities in the landscape. It then...
The unifying purpose of this dissertation was to describe, model, and map
relationships between epiphvtic macrolichen communities and air quality in Ibrests of
northern and central California. First, multivariate analyses were used to subdivide the
large study area into three model areas with similar climate, topography, and lichen
communities: the...
The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared following disturbance were derived from the literature. Weighted averaging of these data with a community matrix created a successional score for each sample...
Species' distributions across the landscape are perhaps the least understood yet most conspicuous features of life on earth. Ecologists have long studied species' distributions; yet, many questions remain about why species occur where they do. Such questions persist largely because species' distributions are complex systems with challenging properties like non-linearity,...
I focus on addressing knowledge gaps relating to management of cryptogams in Oregon's public lands in Pseudotsuga menziesii-Tsuga heterophylla forests on the west side of the Cascade Range and dryland steppe in the Cascade Range's rainshadow.
While a great deal of research has illustrated the importance of late-successional forests for...
Lichens play many important roles in subarctic terrestrial ecosystems by fixing nitrogen, colonizing rock and gravel, stabilizing otherwise bare soil, adding significantly to vegetation biodiversity and serving as the primary food for caribou in the winter. In these chapters, I analyzed lichen community and ecological trait structure along environmental gradients,...
Molybdenum is an essential component of biogeochemical cycling, most notably as a component of the nitrogenase enzyme used in biological nitrogen (N) fixation. While the important role of phosphorus (P) in limiting N fixation in ecosystems has been well documented, occurrence and prevalence of molybdenum (Mo) limitation is largely unknown....