Kokanee populations often require stocking to meet fishery management goals, since natural reproduction may be limited. Many kokanee stocking programs are dependent on eggs collected from a limited number of brood lakes. The anticipated loss of the primary brood source for the statewide kokanee program in Washington State prompted the evaluation of alternative egg sources. I conducted a four-year investigation of the kokanee spawning run in Harvey Creek, a tributary to Sullivan Lake, to evaluate its potential as an egg source. A weir, electrofishing, seining, and carcass surveys were used to collect and enumerate spawning kokanee from 2002 through 2005. Kokanee spawned in Harvey Creek from October through December. Escapement estimates ranged from 4,594 in 2002 to 24,611 in 2004. There were significant declines in mean total length and weight for both sexes throughout the study period. Fecundity had a significant positive relationship with length (r² = 0.38, P <0.001). The decreasing trend in mean size was suggestive of density dependent growth. The potential for density dependent effects on growth and fecundity associated with variable abundance may make management of the population for multiple uses difficult, particularly given the lack of information regarding harvest rates, food web interactions, and survival rates of various life stages.

Entire yellow starthistle, Centaurea solstitialis L. (Asteraceae), plants were harvested from three southeastern Washington sites in September 2004 for seed head dissections to assess intra-plant patterns in the spatial distribution of the introduced false peacock fly, Chaetorellia succinea (Costa), and peacock fly, Chaetorellia australis Hering (Diptera: Tephritidae). Thirty plants were partitioned into three height classes and collected at each site, spanning the longitudinal range of yellow starthistle in Washington. Seed head canopies were stratified into three vertical sections and individual heads were dissected to determine bioagent occupation. Logistic regression analysis using a binary logit model was performed on data collected from each of the three sites separately due to varying site effects. Explanatory variables included plant height, plant width, plant canopy stratum (apical, mid, basal), and presence of other bioagents within a head. ‘Other bioagents’ detected include the yellow starthistle hairy weevil, Eustenopus villosus (Boheman) (Coleoptera: Curculionidae), the yellow starthistle bud weevil, Bangasternus orientalis Capiomont (Coleoptera: Curculionidae), the yellow starthistle flower weevil, Larinus curtus Hochhut (Coleoptera: Curculionidae), and the yellow starthistle gall fly, Urophora sirunaseva (Hering) (Diptera: Tephritidae). Using Chaetorellia spp. presence as the response variable, models were significant for the western-most site in Klickitat Co. (χ²= 35.66, df = 5, P<0.0001, n = 2,783), and the eastern-most site in Asotin Co. (χ²= 17.93, df = 5, P = 0.0030, n = 939), but not for the central site in Benton Co. (χ² = 9.44, df = 5, P = 0.0929, n = 1,020). The one consistently significant site-wide predictor ofChaetorellia spp. occupation was the presence of ‘other bioagents.’ The frequent co-occurrence of Chaetorellia spp. and, in particular, E. villosus at the sampling sites suggests potentially competitive interactions between these insects.

Downed wood provides important faunal microhabitat in forests for numerous invertebrate taxa, small mammals and amphibians. Habitat suitability of downed wood as refugia is an increasing concern in managed Pacific Northwest forests, where overstory reduction may result in both reduced downed wood recruitment and increased temperatures within logs. We examined temperature profiles in western Oregon to assess differences in thermal regimes of logs and soil relative to summer air temperature extremes and their implications with respect to habitat suitability for plethodontid salamanders. Temperature profiles of small- (0.3–0.45 m) and large- (0.7–1.0 m) diameter logs, as well as ambient soil and air temperatures, were measured in a 60-year-old forest stand at two different positions (0–5 m and 35–40 m from stream edge) in three case studies: 1) along a headwater stream with a narrow riparian buffer (∼6 m) and moderate upslope thinning; 2) along a headwater stream with a wider riparian buffer (∼15 m) and moderate upslope thinning; and 3) along a headwater stream with an unthinned upslope. Streamside and upslope maximum air temperatures measured during July 2006 along all three streams were near or exceeded 30°C, the critical thermal tolerance threshold for western plethodontid salamanders. Streamside and upslope temperatures inside small logs, large logs and soils stayed below critical temperatures. Our results suggest that logs of a wide size range, as well as soils, may provide sufficient protection against thermal extremes in uncut forests and thinned stands with limited overstory.

American martens use resting habitat between periods of activity to provide both thermal refugia and protection from predators. Maintenance or restoration of key elements of marten resting habitat, such as resting structures, requires that managers recognize their characteristics to protect them, or manage for their creation. We measured resting habitat at 4 scales : (1) the resting location—where the marten actually rested; (2) the resting structure—the habitat element that contained the resting location; (3) the resting site—characteristics in the immediate vicinity of each resting structure; and (4) the resting stand—the forest stand containing the resting structure. During the summer and fall of 2001 and 2002 we identified resting structures used by 12 radio-collared martens (7 Male, 5 Female) and 1 uncollared marten. The animals were the members of the only remnant population of martens within the historical range of the Humboldt marten (M. a. humboldtensis). The study area included portions of the Six Rivers National Forest, Smith River National Recreation Area, and adjacent Green Diamond Resource Company lands in coastal northwestern California. We located martens resting on 55 occasions in the following types of structures: snags (37%), logs (23%), live-trees (17%), slash-piles (10%), rock-piles (8%), and shrub clumps (6%). The location in the structure where the marten actually rested was determined on 92% of occasions and included chambers (33%), cavities (33%), broken tops (22%), branch platforms (6%), ground sites (6%), and basal hollows (2%). Woody structures were large, with mean dbh of 93.9 cm for live-trees , 94.9 cm for snags, and 88.2 cm maximum-diameter for logs. The mean age of 24 of the woody resting structures was 339 years (range 131–666 years). Our results are consistent with results from other studies on resting structure use and highlight the importance of large live and dead woody structures for American martens in coastal forests of northwestern California.

Western red-backed voles are endemic to western Oregon and northern California and represent a large proportion of the rodent community in mature Douglas-fir forests. Despite their dominance in these forests, little is known about their selection of home ranges. We radiotracked 23 western red-backed voles in 3 mature, coniferous forest stands in the southern Oregon Cascades during 1994 and 1995 and estimated home range size, movements, and habitat associations. Males had larger home ranges than females and males moved farther each evening than females. Females were most active during 2 periods: shortly after dusk and before dawn. Males were active all night. Core areas for home ranges of females were characterized by deep organic soil layers and large volumes of decayed logs. Results underscore the importance of organic matter and coarse woody debris on the forest floor for maintaining populations of western-red-backed voles.

A widespread and intense spruce beetle outbreak during the 1990s has killed most of the mature white spruce (Picea glauca) trees across many watersheds in south-central Alaska. To investigate the potential habitat impacts in a salmon stream, we characterized the current abundance and species composition of large woody debris (LWD), examined the linkages between LWD and salmonid habitat, and estimated changes in LWD abundance and associated pool habitat over time. LWD abundance was relatively low (97 pieces/km overall) and varied widely according to riparian vegetation typology, ranging from 15 pieces/km at sites with non-forested riparian zones to 170 pieces/km at sites adjacent to cottonwood forest. LWD provided significant fish cover in pools, especially in cottonwood forest stream reaches. LWD-formed pools were relatively rare (15% of total), but LWD abundance explained much of the variation in pool frequency (r² = 0.86 in spruce forest reaches) and in the proportion of pool habitats (r² = 0.85 in cottonwood forest reaches). We project the spruce beetle outbreak to result in a substantial net increase in LWD abundance over a 50-year span, peaking with 243% and 179% increases in LWD abundance for spruce forest and cottonwood forest stream reaches, respectively, in the year 2025. Concurrent with the peak in LWD abundance, our estimates show pool frequency in spruce forest reaches to reach 207% of current levels and the proportion of pools in cottonwood forest reaches to reach 167% of current levels, changes that correspond with substantially increased potential habitat for juvenile salmonids.

The inland temperate rainforest (ITR) in east-central British Columbia is marked by superlative examples of old-growth cedar-hemlock forest. How long has this old-growth forest structure been a major component of this landscape? What is the biological and conservation significance of the history of this forest type? Here we present paleoecological evidence from a study in the Robson Valley of the Upper Fraser River. Sediment cores from Gerry Lake and Redmountain Lake show that western hemlock and western redcedar increased in abundance only within the last 2000 years. Thus, the old-growth forests of the northern ITR may have been present for only a few generations of trees. It is even possible, based on our preliminary evidence, that the oldest western redcedar in these stands may be the first colonizing individuals at these sites. Further paleoecological studies, including a combination of stand-age structure and pollen analysis from small lakes and forest hollows, are needed in order to understand the historical significance of these stands. A recent establishment of the ITR has implications for understanding the assembly of the modern diverse biota of the region as well as how the biota will respond to future climate change.