I conducted a field study using gray wolf and mountain lion urine to investigate white-tailed deer and mesopredator behavioral responses to novel predator cues in a natural setting and to see if any changes in wildlife activity correspond to changes in the local biodiversity of a wetland environment. I created...
Many of Earth’s terrestrial large carnivore species are threatened with extinction. As a result, some of the ecological effects associated with these species may be lost. With the goal of furthering large carnivore conservation research, I conduct three global scale analyses involving these species. First, I explore prey depletion as...
Reintroduction of wolves to Yellowstone National Park (YNP) in 1995-96 provided a rare opportunity to observe the response of an ecosystem to the return of a top predator, including possible reversal of decades of decline of aspen, cottonwood, and tall willows suppressed by intensive herbivory on elk winter ranges. To...
This study describes the composition of forest landscapes surrounding
northern spotted owl (Strix occidentalis caurina) nests in the central Cascade
Mountains of Oregon. I compared forest composition around 126 owl nests in 70 pair
territories with forest composition around 119 points drawn randomly from all
terrestrial cover-types, and around 104...
Quaking aspen (Populus tremuloides) is an important tree species in the western United States and there has been much concern about its persistence. In this thesis, I report on aspen in a portion of its range that has not been previously evaluated: the eastern and western slopes of the Central...
There has been an increased interest in the
quantification of pattern in ecological systems over the past
years. This interest is motivated by the desire to construct
valid models which extend across many scales. Spatial methods
must quantify pattern, discriminate types of pattern, and
relate hierarchical phenomena across scales. Wavelet...
Gray Wolves (Canis lupus) were once found throughout North America including Oregon. Wolves were extirpated from Oregon due to heavy hunting pressure in the late 19th and early 20th centuries and have been absent for over 50 years. Successful reintroduction efforts in Idaho and the greater Yellowstone area have caused...
This study examined the differences, at various scales, between northern spotted owl (Strix occidentalis caurina) nest sites and non-nest sites, i.e., sites where no nests were found during surveys, in the Coast Ranges of Oregon. I compared land cover around 41 owl nest sites (ONS) and 41 non-nest sites (NNS)...
I used satellite remote sensing to examine the key factors controlling the natural revegetation of Mount St. Helens since its eruption in 1980. The study required three stages: determining the amount of vegetation present; characterizing vegetation change; and analyzing the influence of factors affecting vegetation change. To determine the amount...
Using historical maps and tools provided by GJS, the spatial patterns of
pre-logging forest conditions were quantified for three landscapes in western
Oregon. The spatial coincidence between forest patches and topographic
features was determined for slope gradient, aspect, elevation, and distance
from streams. Pre-logging and current forest compositions were compared....
