In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, whole components of the ecosystem, like lichenized fungi, remain mostly unknown. Crustose lichens in these forests are so abundant, that they are responsible for the characteristic appearance of a “white bark forest” during the dry season....
Cyanolichens, lichens with a cyanobacterial photobiont, benefit our ecosystems by the fixation of atmospheric nitrogen into a usable form for other organisms. They are highly sensitive to air pollution and require liquid water for photosynthesis. Many cyanolichen species frequently occur on the ground in the Pacific Northwest, however, most macrolichen...
Climate and terrestrial vegetation have had mutual feedbacks for nearly five hundred million years, yet both are now departing from recent historical norms, with uncertain implications for forest ecosystems. This dissertation outlines the current and potential future climate responses of lichen and bryophyte communities in the United States as part...
Functional traits of vascular plants have been an important component of ecological studies for a number of years; however, in more recent times vascular plant ecologists have begun to formalize a set of key traits and universal system of trait measurement. Many recent studies hypothesize global generality of trait patterns,...
This dissertation describes patterns in epiphytic macrolichen community composition along a nitrogen deposition gradient in the Yosemite region of the Sierra Nevada in California. This region is part of the largest federal air quality Class 1 designated air-shed in the western United States, covering the entire crest of the Sierra...
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,...
A severe wildfire burned 454 hectares of a second-growth Douglas-fir forest
in 1977 on a north-facing slope in Pattee Canyon, near Missoula, Montana. The
slope was aerially seeded with a grass mixture, from which Dactylis glomerata
established best. Community structure, conifer regeneration, and the impact of the
seeded grass on...
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...
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...