We reviewed the results of seven extensive and two reach-specific fish surveys conducted on the mainstem Willamette River between 1944 and 2006 to document changes in the summer distribution and species richness of non-native fishes through time and the relative abundances of these species today. The results revealed: (1) the addition of four non-native species since 1944; (2) significant summer range expansions by three recent introductions; (3) three apparent failed introductions; and (4) smallmouth bass, largemouth bass and common carp as the most abundant non-native species making up 4.2%, 1.2% and 1.1% of the total electrofishing catch in 2006. We discuss the positive effects of fishing multiple gears within varied habitats and the importance of longitudinal sampling distance on the catch species richness of large-river fish surveys. Regular standardized monitoring of large-river fish assemblages could improve the management of invasive species.

Differences in small mammal diversity and abundance between riparian and upland areas have not been consistently shown in the Pacific Northwest, and the issue is expected to be complex along the east slope of the Cascade Range with its complex biogeography and forest landscape structure. The information is important for evaluating buffer zone management and the potential impacts of fuel reduction projects. We quantified small mammal species' abundances, diversity, and indicator species in riparian and upland forest along three third-order streams. Each location had a set of four 5 x 6 pitfall kill-trapping grids with 15 m spacing and the first grid row 5 m from the water. One site had an additional set of four grids. We trapped for two weeks during late June and early July during 1997 and 1998 for a total trap effort of 13,411 trap nights. We captured 1,104 individuals of 14 species. Insectivores were 69% and rodents 31% of the captures. Sorex trowbridgii was the most abundant species (54% of all captures). Peromyscus keeni and P. maniculatus combined dominated the rodent community with 43% of rodent captures. Species richness and individuals captured generally were highest within 20–35 m of the stream. Sorex palustris, P. keeni, Microtus longicaudus, S. vagrans, and Zapus princeps showed strong affinities to the immediate riparian zone (≤5 m from the stream). No species were indicators or most abundant in the upland forest away from the riparian areas. Refuge and corridor functions for small mammals in riparian areas would be maintained by current buffer-width standards of 60–100 m.

The distribution of California red fir (Abies magnifica) and noble fir (Abies procera) in Oregon has long been debated. The objective of this study was to determine if selective parasitism of these true firs by subspecies of hemlock dwarf mistletoe (Arceuthobium tsugense) could be used to provide additional data supporting one of the geographic distributions proposed for these conifers. A total of ten mixed-conifer stands in California and Oregon infested with mountain hemlock dwarf mistletoe (Arceuthobium tsugense subsp. mertensianae) and 11 stands in Oregon infested with Pacific silver fir dwarf mistletoe (Arceuthobium tsugense subsp. amabilae) were sampled to compare host susceptibility to these parasitic plants. Populations of true firs morphologically resembling noble fir south of latitude 44° N in Oregon were immune to infection by both dwarf mistletoes. Populations of noble fir north of latitude 44° N in Oregon were principal hosts of Pacific silver fir dwarf mistletoe. The complete immunity of California red fir and trees morphologically resembling noble fir to Pacific silver fir dwarf mistletoe south of approximately latitude 44° N in Oregon supports the classification of these true fir populations as California red fir, and not noble fir. The severe parasitism of trees resembling noble fir by Pacific silver fir dwarf mistletoe north of latitude 44° N in central Oregon supports the classification of these populations as noble fir. These results provide the best example of using dwarf mistletoe-host specificity as evidence to distinguish between different interpretations of the geographic distribution of their coniferous hosts.

We examined the feasibility of using repeated sampling with binary detection of genetic markers as a means to categorize fecal pollution amongst three host sources at ten sample locations in the Colville River watershed (Washington State, U.S.A). Water samples from each site were collected eight times between June and August 2005. Total enterococci were enumerated after membrane filtration and resulting colonies were recovered for PCR testing with a panel of 16 genetic markers. The geometric mean for enterococci ranged from 38 to 945 CFU. Six of the markers were positive for all samples during the first three sample visits and four of the human markers were rarely encountered. Six markers identified four sites as impacted by human waste, four sites as impacted by cattle waste, and three sites as impacted by cervid waste. There are no gold standards by which to assess the diagnostic sensitivity and specificity of BST markers in the field, but results from our sampling scheme were consistent with proximal land-use practices and permitted relative rankings between sites in a cost-effective manner.

We studied the autecology and population status of beargrass (Xerophyllum tenax (Pursh) Nutt.) on the Olympic Peninsula of Washington State, focusing in the Olympic National Forest (ONF). Objectives were to: (1) define and describe beargrass habitat types in the ONF through an exploratory field study, and (2) determine whether beargrass populations in the ONF have declined where the species was historically present. We found three distinct beargrass habitat types in on the ONF: western low elevation, eastern low elevation, and high elevation habitats. These habitat types significantly differ in elevation, slope, topographic moisture, vegetation cover, successional stage, and litter layer thickness. We suggest environmental conditions of these habitat types may be attributed to the glacial and cultural history of the Olympic Peninsula. Beargrass cover in previously established plots on the southeastern Olympic Peninsula declined over the past 17 years, perhaps due to harvesting for the floral industry and an increase in canopy cover due to the absence of natural and anthropogenic burning. Our methods and findings may apply to other Northwestern species.

We evaluated, over nine years, the effects of thinning and burning on vegetation response in a ponderosa pine/pinegrass forest. Ponderosa pine forests in the eastern Cascade Mountains of Washington support dense, stands in which crown fires are probable, owing to post-settlement sheep grazing (increased tree seedling establishment), logging, and fire exclusion. In 1991, the Okanogan-Wenatchee National Forest began to apply long-term management techniques to mitigate post-settlement changes in ponderosa pine forests. We used a randomized complete block design with a linear regression component to analyze post-fire responses of the vegetation. Thinning and burning had little effect on the canopy layer of ponderosa pine, western larch, and Douglas-fir, but small grand fir trees, and nearly half of the saplings of all species, were killed. Shrubs in the middle forest layer were top-killed, but resprouted during the first post-fire growing season, and increased dramatically after 3 yr and 9 yr. Frequency and cover maintained or increased for species in the lower forest layer in post-fire years 1, 3, and 9. The thinning and fire treatments reduced the middle layer of small trees and shrubs in the first post-fire year, but by the third and ninth post-fire years tree seedlings, especially grand fir and ponderosa pine, and small shrubs were abundant in the understory. Thinning trees and removing excess fuels, coupled with low intensity fall prescribed burns, offers a promising management strategy for restoring the pre-settlement structure of the ponderosa pine/pinegrass community in Beehive Forest.

This note outlines the development of a multivariate linear regression model to predict peak lightning activity a year in advance. Using cloud-to-ground lightning strike data from the inception of the National Lightning Detection Network in 1985, a predictive model is proposed for the peak monthly strike total for the Pacific Northwest. Six climate indices were evaluated as potential predictors of the lightning. From these, a multivariate linear model was developed, based on the year-in-advance values of two of the indices—The El Niño-Southern Oscillation Index, and the Western North Pacific Monsoon Index. The 2007 prediction of 56,618 strikes was tested against the measured value of 38,591 strikes. The values are in agreement within the expected accuracy of the model. The model prediction represents an improvement relative to the expectation based on the past statistical history of the data and should be most useful in predicting extreme events. The model parameters have been updated to include the 2007 indices yielding a prediction of 48,418 strikes for 2008.