Master of Science - This concentration is designed for students interested in topics that intersect forestry and wildlife science as an interdisciplinary approach to attaining sustainability of both forest and wildlife resources. Additional coursework in forestry, statistics, spatial analysis, and/or the biological sciences may be suggested.
Doctorate in Philosophy - This concentration is designed for students interested in topics that intersect forestry and wildlife science as an interdisciplinary approach to attaining sustainability of both forest and wildlife resources as well as entire ecosystems. Additional coursework in forestry, statistics, spatial analysis, and/or the biological sciences may be suggested.
Current Graduate Students:
Cristina Eisenberg (PhD) Trophic Cascades Involving Wolves, Elk, and Aspen in the Crown of the Continent Ecosystem
Predation by wolves (Canis lupus) may be critical for maintaining biodiversity and sustaining aspen (Populus tremoloides) communities. Currently in decline throughout the West, aspen provides key habitat for songbirds and beaver (Castor canadensis), among other species. One of the major controversies in ecology in the past century concerns whether food has a stronger influence on herbivore population regulation than predation. Predation can drive strong lethal and non-lethal effects throughout food webs, referred to as trophic cascades. I am studying trophic cascades involving wolves, elk (Cervus elaphus), and aspen in the Crown of the Continent Ecosystem. I am investigating how an apex predator affects aspen communities by influencing abundance and behavior of large herbivore prey. This study is located in Glacier National Park, Montana and Waterton Lakes National Park, Alberta, in the Crown of the Continent Ecosystem, which spans the US/Canada border.
My research questions include: (1) Is high wolf abundance positively correlated with sustained aspen overstory recruitment? (2) Do wolf-driven trophic cascades include elk behavior effects due to predation risk? (3) Does plant and herbivore species diversity decrease as wolf abundance decreases?
This research is part of an interdisciplinary research project, The Southwest Alberta Montane Elk Study, which involves a collaboration between the University of Alberta, the University of Calgary, Oregon State University, Shell Canada, the Alberta Fish and Wildlife Division, Parks Canada, and the National Park Service. We are working with 80 radiocollared elk and several radiocollared wolf packs to evaluate elk and wolf resource selection and habitat needs.
Quantifying long-term ecological responses to predation provides a valuable reference point for understanding trophic cascades. My research can help expand ecological knowledge that is changing the way scientists, managers, and lay people view the natural world. My findings could ultimately help create more sustainable wolf populations and aspen communities.
As part of my PhD work, I am writing a book about trophic cascades in all sorts of systems, to be published by Island Press in spring 2010: Landscapes of Hope: Trophic Cascades and Biodiversity.
Previous Graduate Students:
Josh Halofsky (PhD) Trophic cascades and aspen recruitment in the Gallatin range of Southwest Montana
The proposed study will examine the relationship between wolf, elk, and aspen within the framework of trophic cascades inside and outside of the Gallatin elk winter range. The overall goal of this study is to determine if an association exists between current aspen recruitment and historic and current elk browsing activities as affected by the absence or presence of wolf predation. This study will also examine if environmental factors (climate, conifer invasion) may have had a role in aspen recruitment. Through the examination of current and historic elk browsing levels, current and historic browsing effects on aspen recruitment can be addressed. Historic browsing levels will be determined through tree ring analyses and aspen age structures. Current browsing levels will be assessed based on elk pellet counts and plant architecture methods. Current browsing will be assessed based on predation risk and viewshed using a digital elevation model.
Jeff Hollenbeck (PhD) Multi-scale bird-aspen habitat relationships in the Northern Yellowstone Ecosystem
I am conducting an investigation of the relationships between birds and aspen habitat in the northern Yellowstone Ecosystem with an emphasis on migratory bird species. The highly researched aspen of the northern ungulate range provide a rich context in which to understand how birds use and distribute themselves among aspen patches at multiple scales (patch, landscape, and regional). Specific questions include: (1) Do avian species diversity vary as a function of conifer presence in aspen habitat? (2) Do aspen patches intercept migratory birds during northward migration? and (3) How do birds respond to differences in aspen patch structure resulting from differing land management approaches in the northern Yellowstone Ecosystem?
Andrea Laliberte (PhD, June 2003) Human Influences on Historical and Current Wildlife Distributions from Lewis & Clark to Today
Although it is well known that humans are strong modifiers of their environment, there is a need for greater understanding of human-wildlife interactions, both historically as well as currently. Historical journals can help shed light on early human-wildlife interactions, and the Lewis & Clark journals contain some of the earliest and detailed written descriptions of a large part of the United States before Euro-American settlement. I used the journal entries to assess the influence of humans on wildlife distribution and abundance. Areas with denser human population, the Columbia Basin and the Pacific Coast, had lower species diversity and abundance of large mammals. The opposite was observed on the Plains. Overhunting before Euro-American contact accentuated by the introduction of the horse may have been major contributors responsible for the historic absence of some species that are present in the archaeological record. The information gained from the Lewis & Clark journals shows the considerable human influence on wildlife under relatively low human population densities. This has major implications for conservation biology and ecological restoration, since human influence is often underestimated when considering the pre-settlement condition.
Species ranges are dynamic and change greatly over time. In order to identify large-scale patterns in range contractions and/or expansions, I compared historic and current geographical ranges of 43 North American carnivores and ungulates. Seventeen of the species had undergone range contractions over >20% of their historic range. In areas of higher human influence, species were more likely to contract and less likely to persist. Species richness declined considerably since historic times, and the temperate grasslands and temperate broadleaf/mixed forest biomes lost the highest average number of species, while the boreal forest and tundra showed fewer numbers of species lost. The study of species range changes contributed new quantitative information about human influences on range contractions in North America. The results can be used to improve our knowledge of historical reference conditions, for the creation of wildlife reserves, and for wildlife re-introductions.
Eric J. Larsen (PhD, July 2001) Aspen Age Structure and Stand Conditions
on Elk Winter Range in the Northern Yellowstone Ecosystem
Aerial photographs and field sampling were used to compare aspen (Populus tremuloides) age structure and stand conditions on elk winter range in the northern Yellowstone ecosystem. The elk winter ranges studied were the northern range in Yellowstone National Park (YNP) and the Gallatin National Forest, and the Sunlight/Crandall elk winter range in the Shoshone National Forest. I found significant differences when comparing aspen stands inside and outside of YNP borders. The aspen stands in the Gallatin and Sunlight/Crandall areas had a greater incidence of tall aspen suckers and stems in the 1-4, 5-9, and 10-19 cm diameter at breast height (DBH) classes. Aspen stems within YNP had a significantly higher percentage of stems with high levels of bark damage (>66% of bark surface damaged on the lowest 3 m of stem) than aspen stems in the Gallatin or Sunlight/Crandall.
An aspen age structure was developed using 598 increment cores. The aspen age structure in YNP was significantly different than the age structures of the Gallatin and Sunlight/Crandall elk winter ranges. The Gallatin and Sunlight/Crandall areas did not have significant differences in their age structures. The greatest differences between YNP and the National Forest areas was in the younger age classes, measured as aspen stems originating between 1920-1989.
Aspen stands have successfully recruited new stems into their overstories in all habitat types from 1880-1989 on the Sunlight/Crandall elk winter range and the Gallatin’s portion of the northern range. Within YNP, aspen stands successfully recruited new overstory stems between 1860-1929 in all habitat types. Since 1930, YNP aspen have successfully recruited overstory stems only in scree habitat type stands and other areas protected from browsing. I discussed several potential ecological factors impacting aspen overstory recruitment and conclude that changes in ungulate browsing patterns best explains the spatial and temporal patterns observed
Tad Larsen (MS, July 2004)
Modeling Gray Wolf Habitat in Oregon Using a Geographic Information System
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 wolf populations in the Rocky Mountain region to rise dramatically, giving way to wolf dispersal into Oregon. This research used logistic regression and a Geographic Information System (GIS) to model and assess potential wolf habitat in Oregon. Models based on previous research were analyzed to find the best approximating wolf habitat model. These a priori models were formulated under the hypotheses that wolf habitat (1) will include relatively high densities of prey, (2) will be limited by human influence, (3) will include favorable landscape characteristics (e.g. forest cover, public ownership), and (4) may be influenced by some combination of these factors. The final model was tested and validated with wolf pack data from the Rocky Mountain region. The results show that a habitat model including variables of forest cover and public land can successfully predict wolf habitat in the study area. These results may assist natural resource managers in developing and implementing of a wolf management plan in Oregon.
Amie
Shovlain (MS) Oregon Spotted Frog Habitat Use and the Effects of Grazing
Limited information on grazing impacts on amphibians in the US northwest is available. I am studying the effects of livestock grazing on amphibian behaviour by assessing Oregon spotted frog (Rana pretiosa) microhabitat preference in grazed and ungrazed treatments on Jack Creek, Fremont-Winema National Forest, Oregon. The Oregon spotted frog was an ideal species to address this issue due to its rarity and potential vulnerability to disturbance. Secondary objectives of this study are to identify frog overwintering sites and migration routes, to provide a more complete understanding seasonal habit use.
Support for the Leopold site is provided by: Dept. of Forest Resources, OSU,
280 Peavy Hall, Corvallis, OR 97331.
phone: 541-737-4951 | fax: 541-737-3049
Copyright 2003, Oregon State University | Disclaimer.