High-elevation lakes are recognized as being sensitive to changes in climate, atmospheric deposition, and other global effects. Most studies of high-elevation lakes in the North Cascades have used a landscape-scale approach to describe aquatic systems, but smaller scale research is needed to examine natural variation in these types of lakes. We conducted a watershed-scale study encompassing four close-proximity lakes near Mt. Baker (Whatcom Co., WA) in order to examine the variation in phytoplankton and water quality in these lakes. The lakes were sampled weekly during the ice-free season of 2012 to measure seasonal changes. Chlorophyll-a levels were < 2.0 µg L^-1, confirming the oligotrophic nature of these lakes. Nitrogen limitation was indicated by median DIN:TP < 3 at all sites, along with significant correlations between chlorophyll-a and nitrogen. The phytoplankton were represented by 49 genera (79 unique taxa), which was comparable to landscape-scale studies of North Cascades lakes. Ordination of phytoplankton samples separated the lakes into two groups: one group dominated by diatoms and the other dominated by Chlorophyta, Cyanobacteria, and Ochrophyta. The diatom group was associated with lower water temperatures and total nitrogen concentrations, and higher pH, dissolved oxygen, nitrate, and phosphate concentrations. Results aligned with differences in the lakes' external physical environments, including lakeshore vegetation and ice-melt timing. Our results demonstrated that close-proximity, high-elevation lakes can differ in phytoplankton and water quality, which should be taken into account when evaluating larger scale patterns across multiple watersheds and mountain ranges.

Little is known about the ecology and life history of the federally endangered Point Arena mountain beaver (Aplodontia rufa nigra). The distribution of this primitive burrowing rodent is disjunct from the balance of the species' range and occurs in a unique maritime environment of coastal grasslands and forests. Fundamental to protecting this taxon is knowledge of its breeding season and other reproductive characteristics. This information is necessary so that ground-disturbing activities near burrow systems can be scheduled to avoid the breeding season. We examined the reproductive status of 38 individuals, captured 150 times, from June 2004–July 2005 (excluding 01 February–01 May when we were prohibited from trapping). We used changes in vaginal cytology to monitor estrus and we evaluated male breeding readiness by determining whether testes were scrotal. The earliest onset of estrus occurred on 02 December and it was detected until the trapping prohibition period began on 01 February. The first males had scrotal testes somewhat earlier, in late November, and most males were still in this condition when trapping prohibition began. These data suggest an earlier onset of the breeding season than described for other subspecies. All females and a majority of males (70%) examined in December and January had evidence of reproductive condition. No evidence of pregnancy was observed during the study period, but based on allometric equations developed elsewhere, and applied to the weights of juveniles we captured, parturition was estimated to occur in early- to mid-April.

Urbanization in many coastal communities has severely reduced or eliminated salmon populations once common to these areas. The Pacific Northwest is one region where urbanization has had significant impacts on salmon. Chester Creek, which runs through the center of Anchorage, once supported a large population of coho salmon (Oncorhynchus kisutch). A significant impact on salmon access to Chester Creek occurred in the early 1970s when a weir and associated culverts were constructed at its mouth to create a recreational pond. The construction created a barrier that limited salmon passage. The purpose of this study was to evaluate the replacement of the weir and culverts in 2008 with a daylighted channel to restore natural passage of fish between the marine and freshwater environments. A major goal of restoration was to increase salmon abundance in Chester Creek. Annual monitoring of coho salmon returns from 2008 through 2013 using visual counts during the coho salmon run showed a 300% increase of coho salmon escapement from 481 in 2008 to approximately 1500 in 2009–2013. Estimated coho salmon smolt carrying capacities using several models ranged from 15 000 to 35 000 smolts. Based on these carrying capacity estimates, approximately 730 spawners should be sufficient to fully seed Chester Creek, and the observed increase in spawner escapement may therefore have little affect on smolt production. Results support the need for both extensive pre and post restoration monitoring to assess restoration.

Stream temperature is one of the most important physical parameters affecting growth and development of amphibians, especially cold-adapted stream dwelling amphibians such as tailed frogs. We characterized the annual thermal regime of streams at the northern range of the Rocky Mountain tailed frog (Ascaphus montanus) and associated it with tailed frog distribution and biomass. We monitored stream temperatures between August 2008 and August 2009 at 41 sites ranging from small headwater streams to larger valley bottom streams. At a subset of these sites (n = 27), we collected tailed frog abundance and biomass estimates. Two temperature metrics, maximum weekly average temperature (MWAT) and accumulated degree days > 5 °C (DD₅), a measure of physiological time, were related to tailed frog occurrence and abundance. Larval occurrence was found to be limited when DD₅ was ≤ 160 °C and MWAT ≤ 8 °C. No breeding streams were too warm to support tailed frogs. Frogs and tadpoles had similar realized niche centres for both MWAT (about 10.8 °C ) and DD₅ (about 355 °C ). However, frogs had greater realized niche widths than tadpoles. The temperature metrics were only weakly related to catchment-scale variables (area, mean elevation, ruggedness, aspect, site elevation), such that catchment scale variables cannot be used to make reliable predictions of thermal habitat suitability. This study provides a greater understanding of the thermal conditions required for tailed frog occurrence and may help managers predict potential range shifts resulting from climate change or land use and more effectively conserve tailed frogs into the future.

Permanent plots are essential for tracking long-term forest change and have become more important given the projected increase in widespread tree mortality and forest health issues associated with climate change, invasive pests, altered disturbance regimes, and other novel stressors. Inventory and monitoring plots can reveal otherwise undetected loss of tree biomass, initiating targeted biological investigations. Shore pine is an understudied subspecies of lodgepole pine that reaches its northern extent in southeast Alaska. U.S. Forest Service Forest Inventory Analysis data detected a significant loss of live shore pine biomass in Alaska, with greater losses among larger trees and no known cause. We installed 46 permanent plots to monitor shore pine health and survival. Mortality was higher in shore pine (13%) than most associated conifers, and 43% of pines > 40 cm diameter at breast height were dead. Western gall rust, bole wounds, and Dothistroma needle blight were the most common forms of damage to live shore pine. Western gall rust bole gall presence best predicted crown dieback. Shore pine had more bole wounds than associated trees, with wound incidence and severity of live trees increasing with tree diameter. Secondary bark beetles and stain fungi were detected on dying and dead shore pine. Prevalent biotic injury and stressful site conditions accumulate, making large, old shore pine vulnerable to secondary bark beetle attack and vectored stain fungi. This study outlines how inventory networks can detect changes in tree biomass, highlighting knowledge gaps and prompting intensive, long-term monitoring.

Understanding age distributions and dynamic rate functions is critical for effective management of Common Carp (Cyprinus carpio) populations, but requires the use of readable hard structures that produce precise age estimates. Various non-lethal hard structures for estimating age of Common Carp have been evaluated, but a comprehensive evaluation of the precision of age estimates and relative readability among widely-used hard structures is lacking. We verified age estimates obtained from asteriscus otoliths, scales, pectoral fin rays, and dorsal fin spines of 207 Common Carp from Crane Creek Reservoir and Lake Lowell in southwestern Idaho. Between-reader precision, readability, and differences in age estimates among hard structures were evaluated. Percent agreement (PA) was lower and the coefficient of variation (CV) was higher for otoliths (PA = 18.4%; CV = 17.6) and scales (PA = 29.7%; CV = 15.4) compared with pectoral fin rays (PA=51.7%; CV = 4.9) and dorsal fin spines (PA = 65.2%; CV = 3.0). Both readers displayed higher confidence in estimating age using dorsal fin spines than pectoral fin rays. In general, age estimates from scales and otoliths were lower than both pectoral fin rays and dorsal fin spines. Between-reader analysis showed high exact and within-1 year agreement, low CV, and higher confidence ratings for age estimates obtained from dorsal fin spines when compared with the other hard structures. Dorsal fin spines provide the most repeatable estimates of Common Carp age and annuli formed on dorsal fin spines were easily read. Thus, understanding Common Carp population age structure and growth can be achieved using dorsal fin spines.

Alpine aquatic environments are one of the harshest on earth and are sensitive indicators of climate change. In Washington, the most glaciated state in the contiguous United States, relatively little is known about the effect of loss of glacial water sources on macroinvertebrate communities. Our study compares the water quality conditions and composition of benthic macroinvertebrates from five rhithral (snowmelt-fed) and five kryal (glacially-fed) lake outlet streams in the North Cascade Mountains, WA. Kryal streams were characterized by lower water temperatures, higher discharge rates, higher turbidities, and less stable in-stream channels compared to rhithral sites. A total of 24 985 specimens representing 96 macroinvertebrate taxa were collected. Rhithral lake outlet streams had significantly higher densities and supported more taxa than kryal sites (9049 individuals m^-2 and 82 taxa versus 821 individuals m^-2 and 38 taxa). Chironomidae dominated macroinvertebrate populations at all sites, although densities and taxa richness were significantly lower in kryal sites. Rhithral sites contained higher densities of non-insect taxa such as Acari, Oligochaeta, Nemathelminthes, Planariidae, and crustaceans. Kryal sites were dominated by cold stenotherm or cool eurythermal taxa and supported glacial-tolerant taxa such as chironomids Diamesa and Parorthocladuis, and the mayfly Rhithrogena. Water temperature, stream discharge, and turbidity were most strongly correlated to macroinvertebrate density and taxa richness. Our results suggest that glacial presence was the dominant factor influencing in-stream environmental conditions and macroinvertebrate assemblages of alpine lake outlet streams. Continued glacial retreat due to climate change may result in an overall loss of specialists and decreased regional diversity.

Bumble bees (Hymenoptera: Apidae, Bombus) are cold-adapted insects, primarily known for their importance in providing ecosystem services to wild and cultivated flowering plants. Recent expeditions into the wilderness regions of the Olympic Mountains of Olympic National Park, USA discovered undocumented populations of two bumble bee species: Bombus sylvicola and B. vandykei. Application of species distribution models with range-wide locality records identified the Olympic Mountains to have high habitat suitability for B. sylvicola and low habitat suitability for B. vandykei. Our results suggest that Olympic National Park is a habitat island for B. sylvicola, isolated from the relatively contiguous distribution of the species in the Cascade and Sierra Nevada mountain ranges. Bumble bees are sensitive to environmental change, thus our discoveries will likely stimulate conservation-oriented investigations on these charismatic pollinators on the Olympic Peninsula and throughout the Pacific Northwest.

Western juniper (Juniperus occidentalis) “berries ” are consumed by frugivorous birds, which then defecate and disperse the seeds. However, rodents also consume western juniper seeds, and seedlings can establish from rodent scatterhoards. To explore relative roles of potential seed dispersal agents, we experimentally quantified removal rates by birds and rodents of intact western juniper berries versus seeds cleaned either manually or by passage through bird guts at two northeastern California sites (Likely and Shinn Peak). We also conducted seedling emergence experiments with berries, hand-cleaned, and bird-passed seeds placed on the soil surface or buried at a depth typical of rodent caches. Birds removed juniper berries from plots and left seeds undisturbed at Likely, but bird activity was negligible at Shinn Peak. Rodent removal of seeds versus berries was similar at Likely, but at Shinn Peak rodents removed significantly more seeds. In the seedling emergence experiment, juniper seeds or berries on the surface failed to produce seedlings. When buried, however, emergence was significantly greater for bird-passed than for hand-cleaned seeds, which both produced significantly more seedlings than intact berries. Our results indicate that: (1) birds may enhance western juniper seed germinability through gut passage, (2) most rodent species do not harvest intact berries, (3) rodents harvest seeds defecated by birds and may therefore secondarily disperse bird-passed seeds, and (4) seeds must be removed from berries and buried to establish seedlings. Sequential dispersal, or diplochory, with primary dispersal by frugivorous birds and secondary dispersal by seed-caching rodents, is ideal for satisfying these respective requirements.