Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 85-93). Also available on the World Wide Web.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2004. / Thesis documentation sheet inserted. Appendix reprints four papers and manuscripts, three co-authored with others. Includes bibliographical references. Also partially available via the World Wide Web in PDF format; online version lacks appendix.

Whitebark pine (Pinus albicaulis), a high elevation foundation species, is experiencing population declines throughout the northern part of its range. The introduced fungal pathogen, Cronartium ribicola (white pine blister rust), infects whitebark pine and kills cone-bearing branches and trees. Blister rust has spread nearly rangewide and damage and mortality are highest in the northwest US and southwest Canada. Mortality caused by mountain pine beetle (Dendroctonus ponderosae) population upsurges, and successional replacement and loss of regeneration opportunities from fire suppression, are also impacting some whitebark pine populations. Within this dissertation, I present three manuscripts that address the impact of whitebark pine's decline on species interactions and ecological processes within subalpine forests. Research was conducted in three ecosystems in the Rocky Mountains USA that are distinct in whitebark pine health conditions (rust infection and mortality) and abundance. In the first manuscript, I explore how the relationship between whitebark pine and Clark's Nutcracker (Nucifraga columbiana), its primary seed disperser, is being affected by whitebark's decline. Nutcrackers were less likely to use and disperse seeds from forests where cone production is below a threshold. In the second manuscript, I describe habitat use of whitebark pine forests by red squirrels (Tamiasciurus hudsonicus). Squirrel residency and impact of cone predation increased with decreasing whitebark pine abundance. The third manuscript focuses on the tree-level ecological process, predispersal cone survival, as a function of coarse scale whitebark pine abundance. Surviving trees in high mortality forests were found to have a lower rate and higher variability of cone survival, suggesting that the putative levels of rust-resistance in surviving trees of high mortality forests may not be passed on to future generations. At the ecosystem level, the Northern Divide had the highest levels of rust infection and tree mortality and lowest nutcracker interaction and regeneration levels; the Greater Yellowstone had the lowest infection and mortality levels and nutcrackers were present and dispersing seeds at all research sites in all years, while the Bitterroot Mountains were intermediate in these comparisons. These findings provide important components for developing a long-term strategy to conserve and restore whitebark pine ecosystems in the Rocky Mountains.

This thesis is composed of two potential professional papers written to be independent of each other. Both papers were written to explore changes in late summer discharge patterns across the Northern Rockies (NR). Water in the interior western United States is a vital resource and the demand for this resource has increased. Watersheds in the NR are mainly snowmelt dominated in that they depend on the seasonal flux of snow-melt during dry periods. During the summer months August is a critical time for aquatic ecosystems due to typical low discharge and warm air temperatures. During this period water temperatures can become elevated stressing aquatic biota. The first chapter addresses historic August discharge trends across the NR and examines the frequency of low discharge over time. Using historic discharge data from United States Geologic Surveys national water information system web interface, we analyzed data for trends of 40-59 years. Combining these records with aerial photos (<10m resolution) and water rights records we selected gaging sites based on the length and continuity of discharge records and categorized each site based on the amount of diversion and location of water storage devices. Local significance was examined using the Mann-Kendall non-parametric test and regional significance was obtained using a bootstrap procedure in combination with the Mann-Kendall test. Our analyses indicate that watersheds throughout the NR are experiencing substantial declines in stream discharge and we have found that 75% of all stations exhibit a declining slope. Bootstrap analysis indicates that the NR is experiencing a significant (á = 0.10) decline in discharge from 1951-2008. The second chapter takes a subset of the original 153 sites, deemed pristine sites, and examined the relationship of August discharge to climatic parameters for each watershed. By using stations with no identifiable diversion and minimal land use change we were able to analyze precipitation and air temperature records for correlations with discharge trends. Bootstrap methods were used to determine field significance of the region. Long term discharge analyses demonstrate that eight of the fifteen watersheds throughout the NR are experiencing significant declines in stream discharge over the last half century and all stations have a negative slope. Additionally, the region as a whole appears to have a significant decrease in discharge over the period 1951-2008. Correlations results show a weak to moderate negative relationship between air temperatures and discharge and these results coupled with increasing air temperature trends pose serious concern for aquatic ecosystems in NR.

Thesis (Ph. D.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 157-167). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 84-96). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1982. / Typescript (photocopy). Includes bibliographical references (leaves 114-116). Also available via the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1980. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.