Livestock exclusion is a widespread restoration technique in the Pacific Northwest to protect and improve riparian and stream habitats. To assess stream restoration outcomes from excluding livestock, the Washington State Salmon Recovery Funding Board and the Oregon Watershed Enhancement Board evaluated 12 livestock exclusion projects from 2004 to 2017 using a before-after control-impact design. Paired treatment and control reaches were monitored once before restoration implementation (year 0) and several years after implementation (years 1, 3, 5, and 10) to assess bank erosion, bank canopy cover, riparian vegetation structure, pool tail fine sediment, and exclosure fencing function. Livestock exclusion significantly reduced bank erosion and bare ground. Bank erosion in treatment reaches decreased from 44% pre-project to 11% by year 10. In treatment reaches, bare ground was over 1.5 times lower in year 10 than pre-project. Most treatment reaches had intact fencing at the conclusion of the ten-year monitoring period, but there were instances where fencing did not fully function as intended, allowing livestock to access riparian areas inside the exclosure. Several metrics did not respond over time, which may be the result of several factors, including limitations of the sampling protocols, evidence of livestock grazing in treatment reaches, lack of site stratification, control reaches that were not well matched with treatment reaches, and short-duration of pre-project data collection. Despite these limitations, we still detected significant decreases in bank erosion and bare ground within treatment reaches. Future livestock exclusion monitoring should consider focus on ensuring fence maintenance, improved monitoring oversight, and the use of more quantitative monitoring protocols.

Retention and development of fruits containing inviable seeds has been considered anomalous, because such seeds cannot contribute to plant fitness. Although trees in the genus Juniperus are conifers and thus not true fruiting plants, junipers package seeds within fruit-like female cones commonly referred to as “berries,” and juniper seeds often exhibit high levels of inviability. We tested the prediction that inviable seeds in western juniper (J. occidentalis) reduce levels of pre-dispersal seed predation by arthropods. From 2009 to 2014 we assessed production of berries and seeds in two northeast California populations of western juniper and documented presence of four arthropods (three seed predators, one fruit predator) as well as condition of seeds. The number of inviable seeds per juniper berry was directly associated with numbers of the pulp-feeding frugivore in berries collected both in fall and spring, suggesting that trees may abort seeds within berries experiencing heavy frugivore damage. Consistent with the hypothesis that inviable seeds can reduce seed predation, numbers of a granivorous mite were inversely related to numbers of inviable seeds in fall berry collections. However, the pattern switched to a direct relationship between mites and inviable seeds in spring-collected berries, perhaps due to the timing of mite infestation during berry development. Inviable seeds occurred most frequently during a year of mast production of juniper berries, and the lowest levels of seed damage by a granivorous chalcid wasp occurred during the mast year. The following year saw the greatest levels of seed damage by granivorous moths and mites, possible hold-over effects from large populations built during the mast year. The production of inviable seeds, together with satiating granivores through masting, may represent complementary mechanisms for reducing pre-dispersal seed predation.

Nonpoint-source nutrients contribute to eutrophication of surface waters. While effects of particular management actions are difficult to identify at the watershed scale, assessing nutrient fluxes over time can illuminate the net impact of trends in land use and management. We investigated nutrient fluxes in upper Kamm Creek in northwest Washington State to determine if historical changes in land management, responding to economic and regulatory shifts, had impacted nutrient export. We compared current (October 2015 to September 2018) nitrogen and phosphorus fluxes in Kamm Creek to data from a previous study (1993 to 1998). We found significantly higher current fluxes of nitrate, and significantly lower current fluxes of orthophosphate (P) and total phosphorus (TP), compared to the historical sampling period. The increased annual nitrate flux resulted from slightly higher average discharge and significantly higher nitrate concentrations throughout the year. In contrast, current P and TP concentrations were significantly lower throughout the year than previously. The Nooksack River, which receives water from the study stream, showed similar patterns for P and TP, but not nitrate. Kamm Creek had reduced phosphorus fluxes and increased nitrate fluxes between the 1993 to1998 and 2015 to 2018 time periods. The watershed experienced several concurrent land-use changes, including reductions in hay and corn acreage, increases in berry crop acreage, legislation to reduce manure application, and altered use of nitrate-enriched groundwater. We cannot currently distinguish among these. Further understanding relationships between specific management changes and nutrient fluxes will help to maintain local agricultural productivity and improve water quality.

In this study, I documented the results of 11 years of passive restoration of a small mountain stream in northeastern Oregon. Removal of the main stressors on the system, grazing and agricultural practices, resulted in a strong recovery of the riparian vegetation over the middle two-thirds of the reach. Cover of trees and shrubs tripled, tree density increased sevenfold, and stream shading fourfold over the period 2007 through 2018. Average maximum daily stream temperature declined by 2.1 to 2.8 °C, and average maximum diurnal temperature range narrowed by 3.7 to 4.6 °C. Recolonizing American beavers (Castor canadensis) played an essential role in improving the condition of the streambed over 18% of the reach. Their dams and ponds initiated the process of streambed aggradation and transformed the single-thread, incised channel into a multi-thread configuration within beaver complexes. Vegetation expansion was much stronger in impounded than in un-impounded parts of the stream. Passive restoration was not effective in two sections, together comprising one-third of the reach. In the upper part of the stream, recovery stalled because of continued (unauthorized) trespass grazing during late summer and fall. The channelized lower section of the stream was too severely modified for measurable recovery to occur. I concluded that 11 years of passive restoration improved the functionality of the stream from 24% to 32%, and within beaver complexes, up to 57% of its pre-disturbance condition.

Because of their abundance and intermediate trophic level positions, benthic invertebrates can affect trophic dynamics in aquatic ecosystems by routing and regulating energy through aquatic food webs. Significant reductions in nutrient loading and primary production downstream from dams can profoundly affect benthic insect assemblages. The Kootenai River, a large 7th order river in Idaho, Montana, and British Columbia, experienced such changes following construction of Libby Dam in 1972. A nutrient addition program was initiated in 2005 to mitigate the resulting cultural oligotrophication. The goal of this study was to evaluate long-term responses to nutrient addition among benthic insects at the assemblage and species levels, using replicated data collected from 2003 to 2016, and classified into pre-, early post-, and late post-nutrient addition periods. Response metrics included total abundance and biomass measures across all species, as well as aggregated species of major insect orders, five functional feeding groups, and species richness. We also included abundance responses from a substantial number of individual Chironomidae, and non-Chironomidae insect species. Effects of nutrient addition were assessed using before-after-control-impact and before-and-after analyses. Spearman's Rank correlation coefficients were used to express the degree of association between biotic and abiotic factors. Nutrient addition consistently contributed to increased individual and total insect abundance each year for over a decade without inducing substantive changes in community composition or species dominance. Overall, benthic insects responded positively to nutrient addition and did so in a similar fashion in the early and late nutrient addition periods.

Eighty-three samples of moss and/or lichen were collected during a horse-packing trip into the southern half of Montana's Bob Marshall Wilderness Area in 2012. Tardigrades representing five families, ten genera, and eleven species were recovered from the samples. Two are new to Montana, and one is new to science. Raising the Montana tardigrade biodiversity to 23. The new species Platicrista brunsoni nov. sp. is distinguished by having a tubercated dorsal/lateral cuticle, a unique buccal tube to pharyngeal tube ratio, a serrated base on the claws of the fourth legs, a cuticular bar at the base of the inner claws on legs II and III, prominent stylet supports, and two thin macroplacoids, the first half the length of the second in the elongated pharynx. In addition, specimens of the monospecific genus Multipseudechiniscus were recovered.

The invasive virile crayfish Faxonius virilis (Hagen 1870) has recently been documented in the upper Snake River drainage of Idaho, but its distribution is poorly known. Our objective was to determine the presence and distribution of F. virilis in the Henrys Fork drainage of the Snake River. Sampling was conducted during summer and autumn 2018 at 30 sites located in Henrys Fork River drainage, including the major tributaries Teton River, North Fork Teton River, South Fork Teton River, and Moody Creek. We used baited minnow traps and kick nets to determine presence of F. virilis. Absence was only reported if we unsuccessfully captured F. virilis using kick nets because this technique is more effective. Faxonius virilis was detected in all five streams. We did not detect F. virilis at sites at the upstream extent of sampling. This pattern suggests that F. virilis are invading the drainage in an upstream direction. Presence of species of conservation concern (e.g., Yellowstone cutthroat trout [Oncorhynchus clarkii bouvieri Jordan and Gilbert 1883], bluehead sucker [Catostomus discobolus Cope 1871], and western pearlshell [Margaritifera falcata Gould 1850]) warrant additional research to determine the effect of F. virilis on these species.

Quantifying forest understory biomass is important for understanding ecological processes, but there are few methods for non-destructive measurement of understory biomass in southeast Alaska. We developed cover-to-biomass equations for common understory species in young-growth Sitka spruce (Picea sitchensis)–western hemlock (Tsuga heterophylla) forests. A sampling method of visually estimating cover and destructively measuring biomass was used at 35 stands aged 10 to 67 years on Prince of Wales Island in southeast Alaska from 2007 to 2018. Linear cover to biomass regressions were fitted for 42 species and other genera. In addition to total biomass, regressions were fitted by part (leaves, twigs, wood) for all woody species. Regressions were also fitted for graminoid, fern, forb, shrub, tree, and conifer functional classes. We demonstrate the utility of these regressions by applying them to the Tongass-wide young-growth studies, a rich dataset with understory cover measurements from treated and un-treated stands in four young-growth age classes. Understory biomass was greater in 0- to 5-year-old even-aged stands than stands greater than 15 years old. Treated stands (thinned, etc.) had a greater understory biomass, annual growth, and carbon than untreated stands older than 15 years. Additionally, biomass composition became less woody with increasing stand age in treated stands. These regressions provide an approach to estimate understory biomass, which can be used for evaluation of forest functions, including understory dynamics, wildlife habitats, and total stand carbon.