Satellite remote sensing is an effective tool for mapping snow covered area. However, complex terrain and heterogeneous land cover, due to vegetation and patchy snow cover, present challenges to snow cover mapping. This research compares two techniques for mapping snow covered area: binary and enhanced fractional snow cover mapping techniques....
Warming of the terrestrial biosphere due to the anthropogenic addition of carbon dioxide to the earth’s atmosphere is becoming a major focus of scientific inquiry. Predictions of the extent of this warming are hampered by uncertainty in the ability of the earth’s ecosystems to counteract this effect by sequestering carbon...
Invasion by exotic species can pose a major challenge for developing native
plant communities in wetland restoration projects. Often native plant communities
do not develop as anticipated in restored wetlands due to colonization by exotic
species that dominate the native plant community. Despite the time and expense to
restore wetlands,...
Since their discovery in 1977, hydrothermal vent communities have offered scientists
a unique glimpse into a world that is supported primarily by chemically derived
energy rather than direct energy from the sun. Furthermore, studies of hydrothermal
vent ecosystems have introduced scientists to amazing animals that have successfully
adapted to living...
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...
Increasing population and land use decisions have had a negative effect on the aquatic ecosystems in the Willamette River Basin. One result is elevated temperatures in many of the Basin’s streams, which adversely affect the fish that live in these streams. There are several regulatory mechanisms in place to improve...
This research examines the downstream fining phenomenon as it operates in coastal gravel-bed rivers of Oregon. Downstream fining is a change in bed composition toward smaller sediment sizes in the downstream direction. Changes in stream flow discharge and channel slope affect the rate of bed-load transport, thereby altering the downstream...
Hunter-gatherers depend on naturally occurring resources and, in order to survive, must overcome resource procurement challenges inherent in their environment. One challenge relates to the temporal and spatial availability of resources, which hunter-gatherers address, in part, through the strategic use of space to position themselves for optimal access to necessary...
From a landscape ecology perspective, meadows are often seen as landscapes in
transition. Succession and change in meadows may be investigated by considering the
physical and anthropogenic factors that influence the landscape through time. What is
often unknown is how changes occur and how physical and anthropogenic factors
contribute to...
Remote sensors are becoming the standard for observing and recording ecological data in the field. Such sensors can record data at fine temporal resolutions, and they can operate under extreme conditions prohibitive to human access. Unfortunately, sensor data streams exhibit many kinds of errors ranging from corrupt communications to partial...