We utilized summer salmonid electrofishing surveys and mitochondrial DNA analysis to study the margined sculpin (Cottus marginatus), a stream fish endemic to eastern Washington and Oregon. Our examination of margined sculpin in the Walla Walla River sub-basin yielded the first estimates of density, physical habitat characteristics and genetic diversify. Surveys of salmonids at 33 fish-bearing sites in the Walla Walla and Touchet rivers yielded 0.23 margined sculpin min-¹, possibly representing 18.9% of all fishes. The final model from a stepwise multiple regression of potential independent physical habitat variables included only boulder density and stream temperature, which were both significantly correlated with increasing catch per unit effort (r² = 0.41 and 0.20, respectively). A fish community examination via non-metric multidimensional scaling revealed consistent positive associations among catch per unit effort of margined sculpin, speckled dace (Rhinichthys osculus) and steelhead trout (Onchorhynchus mykiss). Mitochondrial DNA sequences from 20 specimens showed low genetic diversity (π < 0.01, h = 0.84) and no significant population structure (Φ_ST = 0.08) at cytochrome b, but significant diversity among 26 specimens for the non-coding control region (π = 0.02, h = 0.99, _ΦST = 0.15). Our results indicate that a single genetic lineage of margined sculpin within the Walla Walla River sub-basin was able to colonize a wide variety of microhabitats, yet inter- and possibly intraspecific interactions have allowed the accumulation of substantial genetic endemism.

Restoration treatments in ponderosa pine forests may not promote understory recovery where residual understory plant abundance or propagule availability is insufficient for natural re-establishment. The value of the seed bank for understory recovery in Pacific Northwest ponderosa pine forests is not fully understood, therefore, we designed this study to evaluate the potential of the seed bank as a source of desired herbaceous understory species recruitment. Seed bank samples were collected from 14 ponderosa pine stands, seven with a perennial bunchgrass dominated understory (intact) and seven with little or no understory (depauperate). Seedling emergence methods were used to estimate the germinable seed bank; seedling density and diversity comparisons were made using non-parametric Wilcoxon rank-sum tests; and seedling species composition compared using multiple response permutation procedures. Comparisons were also made between seed bank and understory vegetation species composition. No statistical differences were observed in seedling density or diversity, but the intact group appeared higher in both. Seedling species composition differed between the two groups and in both groups several species present in the seed bank were also present in the corresponding understory vegetation. However, species that germinated from the seed bank of the depauperate understory group did not include any of the predominant species in the standing vegetation of the intact group indicating that a suitable propagule source for understory recovery is not available in dense ponderosa pine forests with severely degraded understories. Direct seeding of desired understory vegetation should be considered in ponderosa pine restoration activities.

Supplementation is a widespread response to the declining runs of anadromous salmonids in the Pacific Northwest. A common type of supplementation is the intentional release of adult hatchery fish to spawn naturally (outplanting) but this method has seldom been evaluated. Our objective was to quantify the juvenile steelhead (Oncorhynchus mykiss) produc tion from the adult outplants during a 14 year period in two streams. Although densities of juvenile steelhead were highly variable, outplanting status (supplemented versus not supplemented) explained a significant proportion of the variance for the age-1 densities but not for the age-2 densities. We used a simulation model to predict smolt production and adult returns given the observed juvenile age-1 densities from each adult cohort we outplanted. In general, predicted smolt production was greater during the mid 1990s and lower after 1999, despite the fact that more females were stocked into the study streams after 1999. Given the SAR rates measured during the study period and plausible over-winter survival rates in the study streams, we predicted that the observed juvenile production would produce few adults and would not result in a self-sustaining population. This conclusion was corroborated by adult return data. VVe found no evidence that adult outplanting increased wild population levels, i.e., there was no demographic boost in adult spawners. Further, the differences between lire two study streams showed that supplementation programs should carefully assess each target stream.

Groundwater scientists use fluorescein dyes to trace ground water resources that supply springs which may contain threatened or endangered mollusk species. To estimate risks of a commonly used groundwater tracer to the threatened Bliss Rapids snail Taylorcocha serpenticola we tested the toxicity of sodium fluorescein solutions to a surrogate species, the ashy pebblesnail Fluminicola fuscus. Trials were conducted in static 24-h exposures to several levels of treatment as well as controls with no sodium fluorescein at temperatures similar to those in the habitat of concern. We estimated 377 mg L^-1 as the median lethal concentration for the ashy pebblesnails. Using these data, we concluded that risks to mollusks from the proposed groundwater testing were likely low.

Introgressive hybridization with introduced rainbow trout (RBT) (Oncorhynchus mykiss) has led to the loss of native cutthroat trout species (O. clarkii) throughout their range, creating conservation concerns. Monitoring temporal hybridization trends provides resource managers with a tool for determining population status and information for establishing conservation goals for native cutthroat trout. In this study, we re-sampled six locations in 2010 within the Stehekin River watershed, North Cascades National Park, which were originally sampled between 1999 and 2003. We used genetic markers to monitor changes in hybridization levels between sampling periods in the native westslope cutthroat trout (WCT) (O. c. lewisi) stemming from past RBT introductions. Additionally, two new locations from the lower Stehekin drainage were added to the baseline data. We found that the frequency of WCT, RBT, and their hybrids was not significantly different between monitoring periods, but that RBT allele frequencies decreased in two locations and increased in one location. We also found a consistent, substantial reduction in the frequency of RBT alleles over the monitoring period in the Stehekin River upstream of Bridge Creek (SR3) compared to the Stehekin River downstream of Bridge Creek (SR1 -2) and within lower Bridge Creek (BR1) although these three locations are confined to a small geographic area (approximately 5 km). Ecological and/or evolutionary processes likely restrict the dispersal of RBT alleles in the Stehekin River upstream of Bridge Creek.

Four North American bumble bee species in the subgenus Bombus sensu stricto, including Bombus occidentalis (Hymenoptera: Apidae), are experiencing dramatic declines in population abundance, geographic range and genetic diversity. The prevailing hypothesis concerning their decline is the transmission of the intracellular fungal pathogen. Nosema bombi (Microsporida), and other pathogen species from commercially reared bumble bees to wild populations. While N. bombi incidence has been investigated in the contiguous U.S.A. and Canada, virtually nothing is known about the status of Alaskan bumble bees. This study presents the distribution and relative abundance of B. occidentalis and B. moderatus, two co-occurring species in the subgenus Bombus sensu stricto, in Alaska and the prevalence of N. bombi detected in these species. Bombus occidentalis and B. moderatus accounted for 28% and 4% of the 942 bumble bees surveyed, respectively. Bombus occidentalis was the most abundant species collected in the survey and prevalence of N. bombi infections (44% infected) was also highest in this species. The proportion of infected B. moderatus did not differ significantly from other co-occurring bumble bees. Despite the presence of N. bombi infections, both Bombus s. str. species were commonly detected in Alaska with our survey method. Alaskan bumble bee populations may thus provide important insights on the role of pathogens, particularly N. bombi, in bumble bee decline in the contiguous U.S.A.