To better understand the effects of debris flows on salmonid populations, we studied juvenile steelhead/rainbow trout (Oncorhynchus mykiss) populations in six streams in the Klamath Mountains of northern California: three affected by debris flows on 01 January 1997 and three that experienced elevated streamflows but no debris flows. We surveyed habitat and fish in study reaches on all six streams in September for three years following the disturbance. Pool depths, substrate size and substrate embededdness varied among streams but with no clear patterns to distinguish debris-flow from no-debris-flow streams. However, the debris-flow streams had significantly less canopy cover and significantly more woody debris. Debris-flow streams did not differ from no-debris-flow streams in biomass and numeric densities of both young-of-year and age 1 and older (age 1 ) O. mykiss. In debris-flow streams in the first year following the debris flows (1997), we observed low numbers of age 1 O. mykiss and variable year-class strength of young-of-year fish. In 1997, the young-of-year cohort in one debris-flow stream exhibited exceptional growth. In all three debris-flow streams, age 1 biomass increased each year through 1999 when total O. mykiss biomass in the debris-flow streams exceeded that in the no-debris-flow streams. Surprisingly, we collected larval coastal giant salamander (Dicamptodon tenebrosus) in all streams in all years. We suspect the recovery of juvenile O. mykiss following the debris flows may have been hastened by increased productivity stimulated by clearing of dense, alder-dominated riparian corridors while salamanders likely recolonized from nearby unaffected tributaries.

Introduced American Bullfrogs (Lithobates catesbeianus) have been present in Grand Teton National Park since approximately the 1950s, but little is known about their distribution and potential impacts. In this study, we surveyed the current bullfrog distribution and spatial overlap with sympatric native amphibians in the park, and characterized post-metamorphic bullfrog diets from July–September 2015. Despite surveys in multiple large rivers and floodplain habitats, we only documented bullfrogs in a geothermal pond and 5 km of stream channel immediately downstream of this pond. In these waters, bullfrogs overlapped with native amphibians at the downstream end of their distribution, and we did not document native amphibians in bullfrog stomach contents. Larger bullfrogs (SVL ≥ 96 mm) primarily consumed native rodents (especially meadow voles, Microtus pennsylvanicus), while smaller bullfrogs frequently consumed native invertebrates and less frequently consumed non-native invertebrates and fish. Taken together, these data indicate that the distribution and implications of the bullfrog invasion in Grand Teton National Park are currently localized to a small area, so these bullfrogs should therefore be vulnerable to eradication.

Upper Klamath Lake (UKL) in southern Oregon has experienced declines in water quality due to excessive nutrient loading. This has led to annual cyanobacterial blooms, primarily of Aphanizomenon flos-aquae (AFA). Benthic invertebrates are important food resources for benthic feeding fishes; however, they can increase autochthonous nutrient cycling in lakes and as a result might be contributing to poor water quality in UKL. This study determined the density and taxonomic richness of benthic invertebrate assemblages in three geographic regions (north, central, and south) and three habitats (littoral, open-water and trench) across UKL. Sediment composition and water quality were also characterized at each of the 21 benthic invertebrate collection sites. Three sampling trips were made from May–July 2013. Mean lake-wide invertebrate density was 12 617 ± 7506 individuals m^-2 (n = 63, based on 189 Ekman grabs) with oligochaetes, chironomids, and leeches representing 97% of all individuals. Mean invertebrate richness per sample was 16 ± 4 (n = 63). Two and three-way repeated measures ANOVAs identified differences in invertebrate densities and richness among regions, habitats, and sampling periods. There were no differences in total density among sampling periods. Total density was higher in littoral compared to open-water habitats, and in the northern region, proximal to all riverine inputs to the lake, compared to the central or southern regions. Although variances were heterogeneous, the number of taxa appeared to differ between habitats and regions.

Native eelgrass (Zostera marina) is an important contributor to ecosystem services that supplies cover for juvenile fish, supports a variety of invertebrate prey resources for fish and waterbirds, provides substrate for herring roe consumed by numerous fish and birds, helps stabilize sediment, and sequesters organic carbon. Seagrasses are in decline globally, and monitoring changes in their growth and extent is increasingly valuable to determine impacts from large-scale estuarine restoration and inform blue carbon mapping initiatives. Thus, we examined the efficacy of two remote sensing mapping methods with high-resolution (0.5 m pixel size) color near infrared imagery with ground validation to assess change following major tidal marsh restoration. Automated classification of false color aerial imagery and digitized polygons documented a slight decline in eelgrass area directly after restoration followed by an increase two years later. Classification of sparse and low to medium density eelgrass was confounded in areas with algal cover, however large dense patches of eelgrass were well delineated. Automated classification of aerial imagery from unsupervised and supervised methods provided reasonable accuracies of 73% and hand-digitizing polygons from the same imagery yielded similar results. Visual clues for hand digitizing from the high-resolution imagery provided as reliable a map of dense eelgrass extent as automated image classification. We found that automated classification had no advantages over manual digitization particularly because of the limitations of detecting eelgrass with only three bands of imagery and near infrared.

Spring creeks are highly prone to degradation from anthropogenic (e.g., grazing-related) sediment, yet little is known to guide sediment reduction through restoration. This long-term study explored associations of basic channel form with riffle substrates and trout spawning site quality, along with nine macroinvertebrate taxa groups and two biotic indices in four actively restored (reconstructed with > 10 years rest from livestock grazing) and four unrestored (damaged by land use, including riparian livestock grazing) spring creeks in western Montana. Despite no change in channel slope, riffles in restored streams had lower width-to-depth ratios (10.2 ± 1.8 versus 19.2 ± 4.6), higher velocities (0.71 ± 0.18 versus 0.39 ± 0.09 m/s), lower percentage of sediment < 6.3 mm (25.9 ± 6.6 versus 41.4 ± 6.2) and higher quality spawning sites than unrestored streams. These results suggest stream restoration can improve spawning substrate by facilitating sediment transport via reduced width-to-depth ratio. When all streams were considered, the richness of sediment-tolerant macroinvertebrates were inversely correlated with riffle substrate size; whereas, clinger (sediment-intolerant) richness correlated positively with riffle substrate size. Of the two biotic indices, the Montana Mountains and Foothills Biotic Index showed no correlation to the nine taxa groups. Whereas, a significant correlation of the Fine Sediment Biotic Index with sediment < 6.35 mm suggests it may be a better indicator of spring creek habitat integrity and restoration effectiveness.

We addressed three questions relevant to patterns of mountain goat abundance in Washington's North Cascades: 1) What are forages used by mountain goats during summer? 2) Is canopy cover of mountain goat forage species predicted by geological substrates? and 3) Are indices of nutritional quality and digestibility of two mountain goat forage species predicted by geological characteristics? These questions were motivated by observations that historical abundance of mountain goats in Washington, accounting for habitats generally documented as suitable for them, was greater over some geological substrates than others. Mountain goats ate primarily sedges, secondarily rushes, and made surprisingly little use of grasses. Mountain goats ate a wide variety of forbs, with none showing overwhelming use. Despite their abundance in many landscapes near mountain goat escape terrain, Vaccinium spp. were rarely consumed, and other shrubs in Ericaceae were avoided entirely. Geological substrate explained only a small proportion of variability in mountain goat forage availability. Categorized by geological origin, sedges had higher canopy cover when over sedimentary and shale substrates than when over plutonic substrates. Categorized by geochemistry, sedges had higher canopy cover when over sedimentary rocks than over potassium-feldspar substrates. Sodium-rich substrates generally supported less vegetation than other substrates across all forage categories. Neither nutrients nor digestibility of the two focal species were predicted by geological type. Our study suggests that geological substrates in the North Cascades vary slightly in their production of forage plants valued by mountain goats, but do not affect the nutritional quality of two key forage plants.

Fishery enhancement projects can provide unanticipated research opportunities to reveal fundamental aspects of the biology of species being produced. Although Pacific salmon are well known for their abilities to migrate home to freshwaters for spawning, homing to marine release sites is not widely known or understood. For more than three decades, juvenile Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) have been released into and subsequently homed back as adults to a nondescript semi-natural saltwater lagoon in Homer, Alaska, supporting a popular sport fishery. Through a case study of the fishery enhancement project at the “Homer Spit Fishing Hole”, also known as the Nick Dudiak Fishing Lagoon (NDFL), we illustrate a rare example of homing to marine release sites by Pacific salmon. Our goals are to briefly review the history of the NDFL sport fishery and provide evidence of homing through patterns of release, angler harvest, and coded-wire tag recoveries. We discuss the potential for olfactory imprinting to marine-derived environmental cues in conjunction with geomagnetic imprinting and navigation that may be underpinning the ability for adult salmon to home to this marine release site. Although the proximate factors that allow homing to the NDFL remain unclear, we suggest that this peculiar fishery represents a serendipitous opportunity to explore patterns of migration, imprinting, and homing by Pacific salmon.