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Results for “Northwestern Naturalist”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 37 records · Page 2Linked to original sources
USGS2019

Fall Chinook salmon (Oncorhynchus tshawytscha), sand roller (Percopsis transmontana), and smallmouth bass (Micropterus dolomieu) interactions in a Snake River reservoir: A tale of three species

We studied some of the relationships between federally listed fall Chinook Salmon, Oncorhynchus tshawytscha , endemic Sand Roller, Percopsis transmontana , and non-native Smallmouth Bass, Micropterus dolomieu , in Lower Granite Reservoir on the Snake River. Because of its recent reappearance and population increase, the Sand Rollers could be filling the role of a “native invader” in the reservoir food web. We speculated that Sand Rollers could either negatively affect fall Chinook Salmon by potentially competing with them for resources in shoreline habitats or, alternatively, benefit the salmon by providing a buffer against Smallmouth Bass predation. Nighttime beach seining showed that habitat use by fall Chinook Salmon and Sand Rollers overlapped completely in spring when both species were present along shorelines. Diet data from stomach samples also showed high overlap, but data on stable isotopes of 13 C and 15 N suggested that each species could be obtaining much of their dietary energy from different reservoir locations. Although habitat and diet overlap are evidence of competition, diel and spatial partitioning of resource use between fall Chinook Salmon and Sand Rollers may act to reduce potential competition. Analyses of Smallmouth Bass diets showed that fall Chinook Salmon and Sand Rollers comprised the majority of prey fish consumed by bass. Across years, as Smallmouth Bass increased their consumption of Sand Rollers (range 0.219 to 0.392 fish smallmouth -1 day -1 ), they decreased their consumption of fall Chinook Salmon (range 0.114 to 0.050 fish smallmouth -1 day -1 ). The greatest effect Sand Rollers may have on fall Chinook Salmon in Lower Granite Reservoir is to serve as a buffer against Smallmouth Bass predation.

Idaho, Washington↗
USGS2021

Diet composition of Fishers (Pekania pennanti) reintroduced on the Olympic Peninsula, Washington

Knowledge of diet composition can inform management strategies and efforts to recover endangered carnivore populations in vacant portions of their historic ranges. One such species, the Fisher ( Pekania pennanti ), was extirpated in Washington State prior to any formal documentation of its food habits in the coastal coniferous forests of western Washington. Fisher recovery efforts in Washington, based on translocating Fishers from extant populations, have been ongoing since 2008, beginning with the release of 90 Fishers on Washington's Olympic Peninsula from 2008 to 2010. We collected fecal samples or digestive tracts from 13 Fishers opportunistically on the Olympic Peninsula from 2009 through 2013. Subsequently, we identified the species composition of each sample's contents to determine the primary foods consumed by the reintroduced Fishers. Fisher diets were diverse and dominated by mammalian prey. Contents of feces and digestive tracts of Fishers were composed primarily of Snowshoe Hare ( Lepus americanus ) remains, followed by lesser proportions of Mountain Beavers ( Aplodontia rufa ), Northern Flying Squirrels ( Glaucomys sabrinus ), Douglas Squirrels ( Tamiasciurus douglasii ), Southern Red-backed Voles ( Myodes gapperi ), shrews ( Sorex spp.), and unidentified ungulate species. The diet of Fishers comprised species that occur across a wide range of land uses and management prescriptions, including previously logged forests and mature forests that have been set aside for retention of old-growth forest characteristics. Additional study of prey abundance and Fisher foraging behaviors related to structural habitat characteristics across a gradient of land uses would provide useful insights for enhancing the effectiveness of conservation efforts to benefit Fishers in Pacific Northwest coastal forests.

Washington↗
USGS2022

Rural turtles: Estimating the occupancy of Northwestern Pond Turtles and non-native red-eared sliders in agricultural habitats in California's Sacramento Valley and Sacramento-San Joaquin River Delta

The Northwestern Pond Turtle ( Actinemys marmorata ; WPT) was once widespread throughout the Sacramento Valley and the Sacramento-San Joaquin River Delta. Much of its historical range has been converted into agricultural land, reducing and altering aquatic habitat and surrounding uplands. Red-eared Sliders ( Trachemys scripta elegans ; RES) have been introduced throughout much of the existing WPT range, particularly near urban centers, potentially competing with WPT for resources. Previous surveys for turtles in central California have primarily focused on rivers, lakes, and protected wetlands. Little is known about where WPT and RES occur in the vast expanses of agricultural land across the Sacramento Valley and Sacramento-San Joaquin River Delta. Using aquatic hoop nets, we surveyed 142 locations (102 irrigation canal sites, 39 wetlands, 1 tidally influenced slough) across 8 counties during the summers of 2018 and 2019. Both species were detected in agricultural habitats. Using occupancy modeling, we estimated that WPT occur at 44 (95% CRI = 38–53) of our trapping sites and RES occur at 51 (41–66) sampled sites. Co-occurrence of these 2 species was rare; the species were found together at only 6 sites. RES were primarily found in restored wetlands near major roads and the Sacramento metropolitan area, whereas WPT were more commonly found farther from urban areas in wider canals. Our work provides a picture of how WPT and RES occupy this modified agroecosystem that can inform future conservation efforts.

California↗
USGS2023

Fishes of Harney Basin revisited: An assessment of the distribution of native and nonnative fishes over a half century

The Harney Basin is Oregon's largest internally draining basin and contains a unique native fish assemblage. The first and only comprehensive study of the origin and distribution of Harney Basin fishes occurred in 1971. Here, we update this study and identify potential threats to the basin's native fishes a half century later. Our assessment documents that all species of native fishes are still present, and with some exceptions distributed as originally reported. The distinctive fish assemblages in each of the 3 major subbasins within the Harney Basin (Silvies River, Silver Creek, and Donner und Blitzen River) support the hypothesis that terminal lakes in the Harney Basin (Malheur, Mud, and Harney Lakes) act as dispersal barriers, at least for native species. More than half of the fish species in the basin at present are introduced, primarily inhabiting low-elevation sites. We suggest that native non-salmonid species cohabiting these sites face the most immediate threats from climate change, water demands, and impacts from introduced fishes. Overall, our results show that native fish are still relatively widespread across the Harney Basin, but also face increasing threats despite the basin having experienced less development than many other areas in the Pacific Northwest. Improved understanding of the unique fishes of the Harney Basin, along with more detailed assessments of likely future trajectories of environmental risks are proactive measures that could improve conservation outcomes.

Oregon↗
USGS2026

Status and trend of white-cheeked geese wintering in coastal Nestucca Valley, Oregon

The status and trend of wintering goose populations along the coast of the Pacific Northwest is relatively unstudied. We estimated the status and trends of 6 subspecies of white-cheeked geese wintering in Nestucca Valley, Oregon, USA. Surveys conducted from 2007 to 2019 revealed significant variability in weekly counts among subspecies and years. Dusky ( Branta canadensis occidentalis ) and Cackling ( B . hutchinsii minima ) Geese typically arrived by mid-October and stayed until mid-April, while Aleutian Geese showed lower autumn numbers but doubled in spring. Trends indicated a significant delay in Dusky Geese arrival in recent years, with departure dates remaining constant. Total goose use-days averaged 903,899, with notable declines over the period for Aleutian ( B. h. leucopareia ), Taverner's ( B. h. taverneri )/Lesser ( B. c. parvipes ), and Western ( B. c. moffitti ) Geese. Supporting approximately 6000 geese daily, these results underscore the importance of Nestucca Bay National Wildlife Refuge and adjacent lands for wintering geese. These findings also highlight Nestucca Valley's role as a critical late-winter staging ground, particularly for Aleutian Geese, and emphasize that continued monitoring and adaptive management are essential to sustain these populations.

Oregon↗
USGS1999

Discovery of a new Kittlitz's murrelet nest: Clues to habitat selection and nest-site fidelity

On 13 June 1993, a new Kittlitz's murrelet ( Brachyramphus brevirostris ) nest was discovered near Red Mountain on the Kenai Peninsula, Alaska. The nest was on a 22° slope at about 900 m elevation with a northeast aspect, and contained a 60.2 × 40.6 mm egg that weighed 49.0 g. Downy feathers and weathered fecal material found at the nest indicated re-use from a previous year, suggesting possible nest site fidelity. The nest was located in an area scoured by winds and free of snow during early spring, suggesting that this may be an important mesoscale factor influencing selection of nesting habitat. Proximity to suitable foraging habitat, particularly sheltered bays and glacial river outflows, may affect breeding habitat choice over larger spatial scales.

Alaska↗
USGS1997

Survey and assessment of amphibian populations in Rocky Mountain National Park

We conducted surveys in Rocky Mountain National Park, Colorado for amphibians in 1987-1994. Four species, Ambystoma tigrinum, Bufo boreas, Pseudacris maculata, and Rana sylvatica , were recorded. Pseudacris maculata was the most widely distributed and abundant species in the Park. Two populations of E maculata were estimated to contain 161 and 136 breeding males in 1988. There was no evidence of a decline of A. tigrinum or R. sylvatica , but these species were found at relatively few locations. We did not detect Rana pipiens , which had been known previously from 3 locations in the Park. We found 7 breeding populations of B. boreas , which has declined recently elsewhere in the southern Rocky Mountains, but all but 2 of these populations were small and may not reproduce annually. At least one of these small populations is thought to have been extirpated. Estimated numbers of males in the 2 large populations, which are 6.4 km apart in the same drainage, were stable or increasing slightly from 1992 to 1995, averaging 189 and 239 individuals. Current and known locations of amphibians did not differ in elevation, size, lake type, presence of shallow water or emergent vegetation on the north shore, or presence of trout. Water chemistry at amphibian breeding sites was variable, but pH decreased significantly with increasing elevation. Causes of declines of B. boreas and R. pipiens are not known. Populations of B. boreas in the North Fork of the Big Thompson River are critically important to the conservation of this species in the Rocky Mountains.

Colorado↗
USGS2000

A comparison in Colorado of three methods to monitor breeding amphibians

We surveyed amphibians at 4 montane and 2 plains lentic sites in northern Colorado using 3 techniques: standardized call surveys, automated recording devices (frog-loggers), and intensive surveys including capture-recapture techniques. Amphibians were observed at 5 sites. Species richness varied from 0 to 4 species at each site. Richness scores, the sums of species richness among sites, were similar among methods: 8 for call surveys, 10 for frog-loggers, and 11 for intensive surveys (9 if the non-vocal salamander Ambystoma tigrinum is excluded). The frog-logger at 1 site recorded Spea bombifrons which was not active during the times when call and intensive surveys were conducted. Relative abundance scores from call surveys failed to reflect a relatively large population of Bufo woodhousii at 1 site and only weakly differentiated among different-sized populations of Pseudacris maculata at 3 other sites. For extensive applications, call surveys have the lowest costs and fewest requirements for highly trained personnel. However, for a variety of reasons, call surveys cannot be used with equal effectiveness in all parts of North America.

Northwestern Naturalist↗
USGS1989

Leopard frog and wood frog reproduction in Colorado and Wyoming

Between 1978 and 1988, we recorded reproductive information from populations of ranid frogs in Colorado and Wyoming. Egg masses from five plains and montane populations of northern leopard frogs ( Rana pipiens ) contained 645-6272 eggs (x̄ = 3045, N = 68 egg masses). In two montane populations of wood frogs ( Rana sylvatica ) numbers of eggs per egg mass varied from 711-1248 (x̄ = 876, N = 15) and probably were equal to total clutch size. Mean hatching success was 90% in egg masses from one R. sylvatica population and ranged from 70% to 99% in R. pipiens egg masses. Rana pipiens egg masses from one location were assigned to three overlapping size distributions, which we believe reflects the underlying age structure of female frogs.

Colorado;Wyoming↗
USGS1995

Black bear damage to lodgepole pine in central Oregon

Black bear damage to 108 lodgepole pine trees was found in mixed conifer habitat in central Oregon. No trees of three other conifer species were injured. Eighty-nine percent of the damage occurred in the same year. Nearly 20% of the freshly damaged trees had bark removed from more than 75% of the circumference and, judging from the fate of trees damaged in prior years, probably succumbed.

Northwestern Naturalist↗
USGS1999

DDE, PCBs, cadmium, lead, and mercury concentrations in rhinoceros auklets from Washington

In July 1981, 5 adult rhinoceros auklets (Cerorhinca monocerata) were captured on the ground near nesting areas on each of Protection and Destruction Islands, Washington. The birds were euthanized, and their livers and kidneys removed and analyzed. Levels (I?g / g wet weight) of DDE (0.11 to 0.95), polychlorinated biphenyls (no residue detected [ND] to 1.1), mercury (0.60 to 1.8), and lead (ND to 0.85) in livers and cadmium (9.1 to 21.9) in kidneys were similar in each colony. All concentrations were less than known effect levels.

Northwestern Naturalist↗
USGS2001

Declining ring-necked pheasants in the Klamath Basin, California: II. Survival, productivity, and cover

Cover condition and its influence on nesting success, survival, and body condition of ring-necked pheasants (Phasianus colchicus) were evaluated at Tule Lake National Wildlife Refuge (TLNWR) and Lower Klamath National Wildlife Refuge (LKNWR). Inadequate nesting cover was responsible for extremely low nest success early in the nesting season at TLNWR. Later in the season at TLNWR, spring-planted crops provided cover to conceal nesting and renesting hens; however, only 0.07 young were produced (to 1 August) per hen during the study. The extremely low reproductive rates were well below those required to maintain a stable population. At TLNWR, most adult mortality during spring and early summer (before crops provided adequate cover) apparently resulted from predation by golden eagles (Aquila chrysaetos). This mortality occurred weeks before insecticide applications. Hard winters (cold temperatures and heavy snowfall) periodically reduce the pheasant population in the Klamath Basin and again greatly reduced numbers during the last year of this study. Unfortunately, pheasant populations declined under the conditions found during this study and were unable to recover from the hard winter of 1992 to 1993. Mean body mass and tarsal length of adult hen pheasants at TLNWR, which is intensively farmed, were less than those for hens at LKNWR, which is not intensively farmed. Results of our study suggest that TLNWR hens may have been nutritionally stressed, and that the amount and distribution of vegetative cover needs to be improved at TLNWR. Habitat management of edge cover along agricultural crops should feature perennial grasses and legumes with small tracts of land interspersed throughout the agricultural fields to provide alternative cover for wildlife in general including pheasants.

Northwestern Naturalist↗
USGS1994

Partial migration and wintering localities of American kestrels nesting in the Pacific northwest

Based on banding recoveries, an estimated 89.5% of American kestrels (Falco sparverius) nesting in eastern Oregon, eastern Washington, and Idaho (excluding the Snake River Plain) are migratory and primarily migrate to western Mexico for the winter. Band recoveries from Mexico may be biased; however, we do not know whether the bias is toward more or fewer recoveries. The banding data imply that the remaining kestrels from the region (10.5%) are permanent residents, and we found 2.8% of a northeastern Oregon population on nesting territories in January 1981 (permanent residents). A higher percentage of the nesting population appears to be permanent residents in the valleys along the Snake River Plain than in the remainder of Idaho, eastern Oregon, and eastern Washington (p = 0.02). Limited evidence shows that permanent resident kestrels in eastern Oregon nest earlier than migrants. Information available for the population west of the Cascade Mountains in Oregon and Washington was limited.

Northwestern Naturalist↗
USGS1991

Accumulation of trace elements and organochlorines by surf scoters wintering in the Pacific northwest

Selenium, cadmium, mercury, copper, manganese, zinc, aluminum, lead, PCBs and DDE were accumulated by segments of the surf scoter (Melanitta perspicillata) population that winters in the Pacific Northwest, but whether the uptake occurred on breeding and/or wintering grounds was uncertain for some contaminants. Surf scoters collected in Puget Sound and San Francisco Bay (in another study) during the same period (January 1985) contained similar concentrations of cadmium, but Alsea Bay scoters contained more. Cadmium was inversely related to both liver and body weights of Northwest scoters in January; similar weight losses were reported in experimental laboratory studies. Northwest and north San Francisco Bay scoters contained similar mercury concentrations, but those in south San Francisco Bay contained higher concentrations. San Francisco Bay scoters contained higher arsenic and selenium concentrations than those in the Northwest; however, the 43.4 ppm (geometric mean, dry wt) selenium in livers at Commencement Bay in January was above levels associated with the reproductive problems in aquatic birds at Kesterson National Wildlife Refuge. Even higher concentrations of some elements may be found in surf scoters in March, because a later collection (March) at San Francisco Bay yielded higher concentrations than found there in January. Trace element concentrations in birds at a given wintering location are variable among species and may be influenced by diet, breeding grounds, and physiology (e.g., at Commencement Bay surf scoters with a sediment-associated diet contained 50X more cadmium in their kidneys than did fish-eating western grebes [Aechmophorus occidentalis]). The numerous wildlife species that live on estuaries require further attention.

Northwestern Naturalist↗
USGS2010

Scale-dependent associations of Band-tailed Pigeon counts at mineral sites

The abundance of Band-tailed Pigeons ( Patagioenas fasciata monilis ) has declined substantially from historic numbers along the Pacific Coast. Identification of patterns and causative factors of this decline are hampered because habitat use data are limited, and temporal and spatial variability patterns associated with population indices are not known. Furthermore, counts are influenced not only by pigeon abundance but also by rate of visitation to mineral sites, which may not be consistent. To address these issues, we conducted mineral site counts during 2001 and 2002 at 20 locations from 4 regions in the Pacific Northwest, including central Oregon and western Washington, USA, and British Columbia, Canada. We developed inference models that consisted of environmental factors and spatial characteristics at multiple spatial scales. Based on information theory, we compared models within a final set that included variables measured at 3 spatial scales (0.03 ha, 3.14 ha, and 7850 ha). Pigeon counts increased from central Oregon through northern Oregon and decreased into British Columbia. After accounting for this spatial pattern, we found that pigeon counts increased 12% ± 2.7 with a 10% increase in the amount of deciduous forested area within 100 m from a mineral site. Also, distance from the mineral site of interest to the nearest known mineral site was positively related to pigeon counts. These findings provide direction for future research focusing on understanding the relationships between indices of relative abundance and complete counts (censuses) of pigeon populations by identifying habitat characteristics that might influence visitation rates. Furthermore, our results suggest that spatial arrangement of mineral sites influences Band-tailed Pigeon counts and the populations which those counts represent.

Pacific Northwest↗