English holly (Ilex aquifolium) is an increasingly common invader of west-side Pacific Northwest forests, but little sitescale information exists about the pattern and processes of this invasion. We comprehensively surveyed English holly in an 8.4 ha area of invaded forest at St. Edward State Park (WA), a largely native forest in the Seattle metropolitan area. We measured, mapped, aged, and removed all holly ≥ 1 cm basal diameter or > 1 m from the nearest sampled holly, and used these data to characterize the invading population and the course of the invasion. Holly in our sample (n = 466 known-age plants; 55.5 stems ha^-1) ranged in age from 1 to 46 years. Trees ≥10 years old appeared to have very low mortality rates and exhibited accelerating rates of size increase and biomass accumulation with age. Native vegetation was greatly reduced under holly canopy. Our spatial and age data indicate that holly is proliferating and spreading rapidly at two scales: contiguous, primarily vegetative, expansion of tree clumps, and long distance dispersal via seed. Spread by both mechanisms appears to be accelerating, with population and canopy area both increasing approximately exponentially, having doubling times of approximately 6 and 5 years respectively. Projecting past spread patterns forward suggests that holly has the potential to soon become a prominent species both in number and canopy extent, likely at the expense of native plant diversity and forest structure. Based on these results, we offer recommendations for holly management in forested areas in the region.

Although it is well documented that the vast majority of native prairies in western Washington have disappeared, it is less clear to what extent the remaining fragments have been modified by the loss of native taxa. In this study, we focus on one group of plants—native annuals—that are notably lacking in prairies today. Based on current and historical records, we compiled a list of 190 native herbaceous plant taxa (species, subspecies, and varieties) with high or moderate fidelity to prairie and oak habitats that have been recorded in upland prairies in the South Puget Sound region. Eighty (42%) of these are annuals, a proportion that is considerably higher than what occurs in these prairies today (average 18%). In addition, most native annuals (75) are forbs. These data suggest that in the past, native annual forbs may have comprised a significantly greater proportion of the diversity in the prairies. Although it is impossible to determine how widespread these species were historically, several measures suggest significant declines have occurred. Of the 80 total native annuals observed, 39% have not been recorded in recent inventories of the floras in any prairies in the region, and another 21% are known from only one site. Data from recently burned prairies suggest that both cover and species richness of annuals may double after a single fire. To avoid further loss of native annuals, we urge the inclusion of species from this functional group in future prairie restoration in this region.

Terrestrial salmon carcass decomposition and nutrient dynamics have been reported for coastal marine ecosystems of the Pacific Northwest but are lacking for semi-arid inland ecosystems of this region. Understanding these processes is a critical step in accurately understanding the biochemical responses to natural salmon deposition and appropriately mitigating for its loss. Additionally, the movement of carcasses for nutrient enhancement poses the risk of spreading pathogens and disease. Freezing and pasteurization of the carcasses reduces this risk. However, the effect of these treatments on decomposition processes is unknown. Decomposition rate and nutrient dynamics were investigated in semi-arid central Idaho by decomposing salmon carcasses in soil-filled microcosms. Rapid thermal accumulation in this semi-arid climate resulted in completion of soft tissue decomposition (skeletonization) in 16 days. Soil dissolved organic C (DOC) and dissolved total N (DTN) increased dramatically with respective increases from pretreatment concentrations of 7 and 48 fold by the time skeletonization occurred. Isotopic analysis of fluids beneath the carcasses revealed up to a 6‰ change in fluid δ¹³C and δ¹⁵N during decomposition as well as an overall 4‰ enrichment in mean fluid δ5¹⁵N, relative to whole reference carcasses. Freezing and pasteurization of carcasses only yielded differences during the first few days of decomposition relative to the fresh carcasses. These results suggest that decomposition of carcasses in inland riparian forests proceeds very rapidly and that treated carcasses are suitable surrogates for fresh carcasses in semi-arid regions of central Idaho.

A three-year study from 1998 to 2000 was performed at the Wells Hydroelectric Project on the Columbia River, Washington, to assess compliance with the Habitat Conservation Plan survival standard for project passage equal to or greater than 0.93 for salmonid smolts. For annual juvenile project survival estimates to be valid, the Habitat Conservation Plan requires the studies to measure the survival of juvenile fish migrating through the reservoir, forebay, dam and tailrace associated with a project. It also requires the study to take place during the normal smolt migration period (April—May). Valid survival estimates must also have estimated standard errors (SEs) less than or equal to 0.025. Paired release-recapture studies using PIT-tagged yearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) smolts produced successive annual survival estimates of 0.997 (SE = 0.015), 0.943 (SE = 0.016), and 0.946 (SE = 0.015) with a three-year mean of estimated survival of 0.962. A 10-year follow-up study to determine continued compliance with the survival standard produced an estimate of 0.954 (SE = 0.013) in 2010 using PIT-tagged yearling Chinook salmon smolts. The Wells Project was the first hydroproject in the Columbia-Snake River Basin to meet its survival standard for outmigrating salmonid smolts, and Public Utility District No. 1 of Douglas County was also the first to subsequently conduct and successfully meet a 10-year recertification.

Current year's growth (biomass) and nutrient levels of bluebunch wheatgrass (Pseudoroegneria spicata), a highly palatable bunchgrass in western North America, were evaluated over 20-year and 10-year periods, respectively. Three study sites representing a range of variation in conditions were located on south-facing slopes. Annual biomass ranged from 5.6 to 109.0 gm m^-2 on individual sites with means for all sites of 42.7 gm m^-2 (range 17.5–73.3 gm m^-2), with April and May precipitation best predicting the variation. Variation was highest on the site lowest in elevation and highest in biomass. A fire in August 2000 that burned all study sites suppressed biomass for the following two years, aided by lower than average precipitation. The highest elevation site had higher mean values of Cu, Mg, N, K, P, S, and Zn than the two lower sites, but the greatest range of values occurred on one of the two lower sites for Ca, Fe, K, Mg, N, P, and S. Combinations of temperature and precipitation predicted Ca, K, N, P, and Zn values, while Cu and Fe were predicted with total monthly precipitation, and Mg and S were predicted with mean monthly temperature. Values of Cu, Fe, K, N, P, S, and Zn were higher than expected for one to two years following the 2000 fire, while Ca and Mg did not show any responses to the fire. Predictions for biomass and nutrient content apply to the range of conditions, temperatures and precipitation observed over the study period. The predictions may be useful in assessing responses to changes in climate, and are helpful in explaining variation in herbivore populations relative to changes in forage quality and quantity.

In this study we evaluated the effects of region, body size, and sample size on the weight-length relationship (WLR) of small-bodied fishes that commonly occur in eelgrass meadows (Zostera marina) along the Pacific coast of Canada. Due to the location of the BC coast within Zoogeographic and oceanographic transition zones, we hypothesized that regional differences in the WLR would be observed. Surprisingly, no effect of region on the slope parameter b was detected for any of the 30 fish species examined. Further, eight species exhibited bimodality in their length-frequency histograms, but we did not detect an effect of body size on b with hierarchical mixed effects models. Moreover, the prediction that species collections with a high proportion of juveniles would be more likely to exhibit positive allometric growth (b > 3.0) is not supported by our data. We also considered the effect of sample size on estimates of the ‘true’ WLR for eight species representing different body shapes, and we found that a minimum of 100 individuals of each species could be pooled from different areas along the BC coast and used to generate precise WLRs for small-bodied fish species. Overall, the results from this study can be used to facilitate further inquiries into the functioning and production dynamics of small-bodied fish species in nursery habitats, such as eelgrass meadows.

This study characterized spatial and temporal patterns associated with riverine broadcast spawning pygmy whitefısh (Prosopium coulterii) in tributaries of Chester Morse Lake (CML), near Seattle, Washington, from 2001 to 2012. In most years, fısh spawned in a narrow linear reach of riverine habitat from 2.0 to 3.0 km upstream of CML within a two week period. Individual characteristics of spawning pygmy whitefısh were investigated through the use of mark-recapture efforts and a PIT (passive integrated transponder) tag antenna array. During the latter years of the study (2006–2011), a total of 3,012 fısh were captured and PIT tagged. Returning female pygmy whitefısh spent less time in the river (mean 2.4 days, SD 3.1) than males (mean 5.9 days, SD 2.4). In addition, 91% of all movements occurred between 1700 and 0700 during nighttime hours suggesting that spawning pygmy whitefısh are most active under the cover of darkness. Thirteen fısh returned for a fıfth spawning migration and one individual was detected six years after initial tagging, demonstrating that pygmy whitefısh spawn in multiple years and that fısh can live to at least age nine in the CML population. These data represent the fırst attempt to investigate return frequency and other reproductive characteristics of riverine spawning pygmy whitefısh throughout their range, and supports the development of practical management techniques for this and similar riverine broadcast spawning species.