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USGS2010

Hydraulic alterations resulting from hydropower development in the Bonneville Reach of the Columbia River

We used a two-dimensional (2D) hydrodynamic model to simulate and compare the hydraulic characteristics in a 74-km reach of the Columbia River (the Bonneville Reach) before and after construction of Bonneville Dam. For hydrodynamic modeling, we created a bathymetric layer of the Bonneville Reach from single-beam and multi-beam echo-sounder surveys, digital elevation models, and navigation surveys. We calibrated the hydrodynamic model at 100 and 300 kcfs with a user-defined roughness layer, a variable-sized mesh, and a U.S. Army Corps of Engineers backwater curve. We verified the 2D model with acoustic Doppler current profiler (ADCP) data at 14 transects and three flows. The 2D model was 88% accurate for water depths, and 77% accurate for velocities. We verified a pre-dam 2D model run at 126 kcfs using pre-dam aerial photos from September 1935. Hydraulic simulations indicated that mean water depths in the Bonneville Reach increased by 34% following dam construction, while mean velocities decreased by 58%. There are numerous activities that would benefit from data output from the 2D model, including biological sampling, bioenergetics, and spatially explicit habitat modeling.

Oregon, Washington↗

USGS2010

Passage and behavior of radio-tagged adult Pacific lampreys (Entosphenus tridentatus) at the Willamette Falls Project, Oregon.

Populations of Pacific lamprey (Entosphenus tridentatus) in the Columbia River basin have declined and passage problems at dams are a contributing factor. We used radio telemetry to monitor the passage of adult Pacific lampreys at the Willamette Falls Project (a hydroelectric dam integrated into a natural falls) on the Willamette River near Portland, Oregon. In 2005 and 2006, fish were captured at the Project, implanted with a radio tag, and released downstream. We tagged 136 lampreys in 2005 and 107 in 2006. Over 90% of the fish returned to the Project in 7 – 9 h and most were detected from 2000 – 2300 h. In 2005, 43 fish (34%) passed the dam via the fishway, with peak passage in August. No fish passed over the falls, but 13% ascended at least partway up the falls. In 2006, 24 fish (23%) passed the Project using the fishway, with most prior to 9 June when the powerhouse was off. Although 19 lampreys ascended the falls, only two passed via this route. The time for fish to pass through the fishway ranged from 4 – 74 h, depending on route. Many fish stayed in the tailrace for hours to almost a year and eventually moved downstream. Our results indicate that passage of lampreys at the Project is lower than that for lampreys at dams on the Columbia River. Low passage success may result from low river flows, impediments in fishways, delayed tagging effects, changing environmental conditions, or performance or behavioral constraints.

Oregon↗

USGS2010

Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead

We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

Northwest Science↗

USGS2011

Persistent effects of wildfire and debris flows on the invertebrate prey base of rainbow trout in Idaho streams

Wildfire and debris flows are important physical and ecological drivers in headwater streams of western North America. Past research has primarily examined short-term effects of these disturbances; less is known about longer-term impacts. We investigated wildfire effects on the invertebrate prey base for drift-feeding rainbow trout (Oncorhynchus mykiss, Walbaum) in Idaho headwater streams a decade after wildfire. Three stream types with different disturbance histories were examined: 1) unburned, 2) burned, and 3) burned followed by debris flows that reset channel morphology and riparian vegetation. The quantity of macroinvertebrate drift (biomass density) was more variable within than among disturbance categories. Average body weight and taxonomic richness of drift were significantly related to water temperature and influenced by disturbance history. During the autumn sampling period, the amount of terrestrial insects in rainbow trout diets varied with disturbance history and the amount of overhead canopy along the stream banks. Results indicate that there are detectable changes to macroinvertebrate drift and trout diet a decade after wildfire, and that these responses are better correlated with specific characteristics of the stream (water temperature, canopy cover) than with broad disturbance classes.

Northwest Science↗

USGS2012

Arrival and expansion of the invasive foraminifera Trochammina hadai Uchio in Padilla Bay, Washington

Trochammina hadai Uchio, a benthic foraminifera native to Japanese estuaries, was first identified as an invasive in 1995 in San Francisco Bay and later in 16 other west coast estuaries. To investigate the timing of the arrival and expansion of this invasive species in Padilla Bay, Washington, we analyzed the distribution of foraminifera in two surface samples collected in 1971, in nine surface samples collected by Scott in 1972–1973, as well as in two cores (Padilla Flats 3 and Padilla V1/V2) obtained in 2004. Trochanimina hadai , originally identified as the native Trochammina pacifica Cushman in several early foraminiferal studies, dominates the assemblage of most of the surface samples. In the Padilla V1/V2 and Padilla Flats 3 cores, the species' abundance follows a pattern of absence, first appearance, rapid expansion commonly seen shortly after the arrival of a successful biological invasion, setback, and second expansion. Using Q-mode cluster analysis, pre-expansion and expansion assemblages were identified. Pb-210 dating of these cores proved unsuccessful. However, based on T. hadai's first appearance occurring stratigraphically well above sedimentological changes in the cores that reflect deposition of sediments in the bay due to previous diversions of the Skagit River, and its dominance in the early 1970s surface samples, we conclude that the species arrived in Padilla Bay somewhere between the late 1800s and 1971. Trochammina hadai may have been introduced into the bay in the 1930s when oyster culturing began there or, at a minimum, ten years prior to its appearance in San Francisco Bay.

Washington↗

USGS2012

Temporal genetic monitoring of hybridization between native westslope cutthroat trout and introduced rainbow trout in the Stehekin River, Washington

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.

Washington↗

USGS2012

Recent population trends of mountain goats in the Olympic Mountains, Washington

Mountain goats ( Oreamnos americanus ) were introduced in Washington's Olympic Mountains during the 1920s. The population subsequently increased in numbers and expanded in range, leading to concerns by the 1970s over the potential effects of non-native mountain goats on high-elevation plant communities in Olympic National Park. The National Park Service (NPS) transplanted mountain goats from the Olympic Mountains to other ranges between 1981 and 1989 as a means to manage overabundant populations, and began monitoring population trends of mountain goats in 1983. We estimated population abundance of mountain goats during 18–25 July 2011, the sixth survey of the time series, to assess current population status and responses of the population to past management. We surveyed 39 sample units, comprising 39% of the 59,615-ha survey area. We estimated a population of 344 ± 72 (90% confidence interval [CI]) mountain goats in the survey area. Retrospective analysis of the 2004 survey, accounting for differences in survey area boundaries and methods of estimating aerial detection biases, indicated that the population increased at an average annual rate of 4.9% since the last survey. That is the first population growth observed since the cessation of population control measures in 1990. We postulate that differences in population trends observed in western, eastern, and southern sections of the survey zone reflected, in part, a variable influence of climate change across the precipitation gradient in the Olympic Mountains.

Washington↗

USGS2013

Factors influencing the distribution of native bull trout and westslope cutthroat trout in western Glacier National Park, Montana

The widespread declines of native bull trout ( Salvelinus confluentus ) and westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) populations prompted researchers to investigate factors influencing their distribution and status in western Glacier National Park, Montana. We evaluated the association of a suite of abiotic factors (stream width, elevation, gradient, large woody debris density, pool density, August mean stream temperature, reach surface area) with the occurrence (presence or absence) of bull trout and westslope cutthroat trout in 79 stream reaches in five sub-drainages containing glacial lakes. We modeled the occurrence of each species using logistic regression and evaluated competing models using an information theoretic approach. Westslope cutthroat trout were widely distributed (47 of 79 reaches), and there appeared to be no restrictions on their distribution other than physical barriers. Westslope cutthroat trout were most commonly found in relatively warm reaches downstream of lakes and in headwater reaches with large amounts of large woody debris and abundant pools. By contrast, bull trout were infrequently detected (10 of 79 reaches), with 7 of the 10 (70%) detections in sub-drainages that have not been compromised by non-native lake trout ( S. namaycush ). Bull trout were most often found in cold, low-gradient reaches upstream of glacial lakes. Our results indicate that complex stream habitats in sub-drainages free of non-native species are important to the persistence of native salmonids in western Glacier National Park. Results from this study may help managers monitor and protect important habitats and populations, inform conservation and recovery programs, and guide non-native species suppression efforts in Glacier National Park and elsewhere.

Montana↗

USGS2013

Distribution of Pacific lamprey Entosphenus tridentatus in watersheds of Puget Sound Based on smolt monitoring data

Lamprey populations are in decline worldwide and the status of Pacific lamprey ( Entosphenus tridentatus ) is a topic of current interest. They and other lamprey species cycle nutrients and serve as prey in riverine ecosystems. To determine the current distribution of Pacific lamprey in major watersheds flowing into Puget Sound, Washington, we sampled lamprey captured during salmonid smolt monitoring that occurred from late winter to mid-summer. We found Pacific lamprey in 12 of 18 watersheds and they were most common in southern Puget Sound watersheds and in watersheds draining western Puget Sound (Hood Canal). Two additional species, western brook lamprey ( Lampetra richardsoni ) and river lamprey ( L. ayresii ) were more common in eastern Puget Sound watersheds. Few Pacific lamprey macrophthalmia were found, suggesting that the majority of juveniles migrated seaward during other time periods. In addition, “dwarf” adult Pacific lamprey (< 300 mm) were observed in several watersheds and may represent an alternate life history for some Puget Sound populations. Based on genetic data, the use of visual techniques to identify lamprey ammocoetes as Entosphenus or Lampetra was successful for 97% (34 of 35) of the samples we evaluated.

Washington↗

USGS2013

Book review: Biology and conservation of martens, sables, and fishers: A new synthesis

Mammals of the genus Martes , including martens, sables, and fishers, are mid-sized carnivores inhabiting many forested ecosystems throughout regions of North America, Europe, and Asia. This volume provides a comprehensive synthesis of the current state of knowledge pertaining to the biology and conservation of Martes species throughout the world. This volume will be an essential resource for mammalogists, resource managers, and applied ecologists involved in research or conservation of martens, sables, and fishers. For that matter, anyone seeking a full immersion in the modern world of Martes biology and conservation will not be disappointed. The volume has been carefully edited and reviewed, and the thoroughness with which the authors present and interpret recent advances in their specialty areas is really quite impressive. Review info: Biology and conservation of martens, sables, and fishers: A new synthesis. Edited by K.B. Aubry, W.J. Zielinski, M.G. Raphael, G. Proulx, and S.W. Buskirk, 2012. ISBN: 978-08014, 580pp.

Northwest Science↗

USGS2013

Effects of summer drawdown on the fishes and larval chironomids in Beulah Reservoir, Oregon

Summer drawdown of Beulah Reservoir, Oregon, could adversely affect fish and invertebrate production, limit sport fishing opportunities, and hinder the recovery of threatened species. To assess the impacts of drawdown, we sampled fish and Chironomidae larvae in Beulah Reservoir in the springs of 2006 to 2008. The reservoir was reduced to 68% of full pool in 2006 and to run-of-river level in 2007. From spring 2006 to spring 2007, the catch per unit effort (CPUE) of fyke nets decreased significantly for dace [Rhinichthys spp.] and northern pikeminnow [Ptychocheilus oregonensis], increased significantly for suckers [Catastomus spp.] and white crappies [Pomoxis nigromaculatus], and was similar for redside shiners [Richardsonius balteatus]. CPUE of gillnets either increased significantly or remained similar depending on genera, and the size structure of redside shiners, suckers, and white crappies changed appreciably. From 2007 to 2008, the CPUE of northern pikeminnow, redside shiners, suckers, and white crappies decreased significantly depending on gear and the size structure of most fishes changed. Springtime densities of chironomid larvae in the water column were significantly higher in 2006 than in 2008, but other comparisons were similar. The densities of benthic chironomids were significantly lower in substrates that were frequently dewatered compared to areas that were partially or usually not dewatered. Individuals from frequently dewatered areas were significantly smaller than those from other areas and the densities of benthic chironomids in 2008 were significantly lower than other years. Summer drawdown can reduce the catch and alter the size structure of fishes and chironomid larvae in Beulah Reservoir.

Oregon↗

USGS2014

Efficacy of plastic mesh tubes in reducing herbivory damage by the invasive nutria ( Myocastor coypus ) in an urban restoration site

The restoration of stream corridors is becoming an increasingly important component of urban landscape planning, and the high cost of these projects necessitates the need to understand and address potential ecological obstacles to project success. The nutria (Myocastor coypus) is an invasive, semi-aquatic rodent native to South America that causes detrimental ecological impacts in riparian and wetland habitats throughout its introduced range, and techniques are needed to reduce nutria herbivory damage to urban stream restoration projects. We assessed the efficacy of standard Vexar® plastic mesh tubes in reducing nutria herbivory damage to newly established woody plants. The study was conducted in winter-spring 2009 at Delta Ponds, a 60-ha urban waterway in Eugene, Oregon. Woody plants protected by Vexar® tubes demonstrated 100% survival over the 3-month initial establishment period, while only 17% of unprotected plantings survived. Nutria demonstrated a preference for black cottonwood (Populus balsamifera ssp trichocarpa ) over red osier dogwood ( Cornus sericea) and willow ( Salix spp). Camera surveillance showed that nutria were more active in unprotected rather than protected treatments. Our results suggest that Vexar® plastic mesh tubing can be an effective short-term herbivory mitigation tool when habitat use by nutria is low. Additionally, planting functionally equivalent woody plant species that are less preferred by nutria, and other herbivores, may be another method for reducing herbivory and improving revegetation success. This study highlights the need to address potential wildlife damage conflicts in the planning process for stream restoration in urban landscapes.

Oregon↗

USGS2014

A legacy of divergent fishery management regimes and the resilience of rainbow and cutthroat trout populations in Lake Crescent, Olympic National Park, Washington

As a means to increase visitation, early fisheries management in the National Park Service (NPS) promoted sport harvest and hatchery supplementation. Today, NPS management objectives focus on the preservation of native fish. We summarized management regimes of Olympic National Park's Lake Crescent, which included decades of liberal sport harvest and hatchery releases of 14.3 million salmonids. Notably, nonnative species failed to persist in the lake. Complementary analyses of annual redd counts (1989–2012) and genetics data delineated three sympatric trout (one rainbow; two cutthroat) populations that exhibited distinct spatial and temporal spawning patterns, variable emergence timings, and genetic distinctiveness. Allacustrine rainbow trout spawned in the lake outlet from January to May. Cutthroat trout spawned in the major inlet tributary (Barnes Creek) from February to June and in the outlet river (Lyre) from September to March, an unusual timing for coastal cutthroat trout. Redd counts for each species were initially low (rainbow = mean 89; range 37–159; cutthroat = mean 93; range 18–180), and significantly increased for rainbow trout (mean 306; range 254–352) after implementation of catch-and-release regulations. Rainbow and cutthroat trout reached maximum sizes of 10.4 kg and 5.4 kg, respectively, and are among the largest throughout their native ranges. Morphometric analyses revealed interspecific differences but no intraspecific differences between the two cutthroat populations. Genetic analyses identified three distinct populations and low levels (9–17%) of interspecific hybridization. Lake Crescent rainbow trout were genetically divergent from 24 nearby Oncorhynchus mykiss populations, and represented a unique evolutionary legacy worthy of protection. The indigenous and geographically isolated Lake Crescent trout populations were resilient to overharvest and potential interactions with introduced fish species.

Washington↗

USGS2014

Demographics of piscivorous colonial waterbirds and management implications for ESA-listed salmonids on the Columbia Plateau

We investigated colony size, productivity, and limiting factors for five piscivorous waterbird species nesting at 18 locations on the Columbia Plateau (Washington) during 2004–2010 with emphasis on species with a history of salmonid ( Oncorhynchus spp.) depredation. Numbers of nesting Caspian terns ( Hydroprogne caspia ) and double-crested cormorants ( Phalacrocorax auritus ) were stable at about 700–1,000 breeding pairs at five colonies and about 1,200–1,500 breeding pairs at four colonies, respectively. Numbers of American white pelicans ( Pelecanus erythrorhynchos ) increased at Badger Island, the sole breeding colony for the species on the Columbia Plateau, from about 900 individuals in 2007 to over 2,000 individuals in 2010. Overall numbers of breeding California gulls ( Larus californicus ) and ring-billed gulls ( L. delawarensis ) declined during the study, mostly because of the abandonment of a large colony in the mid-Columbia River. Three gull colonies below the confluence of the Snake and Columbia rivers increased substantially, however. Factors that may limit colony size and productivity for piscivorous waterbirds nesting on the Columbia Plateau included availability of suitable nesting habitat, interspecific competition for nest sites, predation, gull kleptoparasitism, food availability, and human disturbance. Based on observed population trends alone, there is little reason to project increased impacts to juvenile salmonid survival from tern and cormorant populations. Additional monitoring and evaluation may be warranted to assess future impacts of the growing Badger Island American white pelican colony and those gull colonies located near mainstem dams or associated with Caspian tern colonies where kleptoparasitism is common.

Columbia Plateau↗

USGS2015

Biotic and abiotic influences on abundance and distribution of nonnative Chinook salmon and native ESA-listed steelhead in the Wind River, Washington

Biotic and abiotic factors influence fish populations and distributions. Concerns have been raised about the influence of hatchery fish on wild populations. Carson National Fish Hatchery produces spring Chinook salmon Oncorhynchus tshawytscha in the Wind River, Washington, and some spawn in the river. Managers were concerned that Chinook salmon could negatively affect wild steelhead O. mykiss and that a self-sustaining population of Chinook salmon may develop. Our objectives were to assess: 1) the distribution and populations of juvenile spring Chinook salmon and juvenile steelhead in the upper Wind River; 2) the influence of stream flow and of each population on the other; and 3) if Chinook salmon populations were self-sustaining. We snorkeled to determine distribution and abundance. Flow in the fall influenced upstream distribution and abundance of juvenile Chinook salmon. Juvenile Chinook salmon densities were consistently low (range 0.0 to 5.7 fish 100 m -2 ) and not influenced by number of spawners, winter flow magnitude, or steelhead abundance. Juvenile steelhead were distributed through the study section each year. Age-0 and age-1 steelhead densities (age-0 range: 0.04 to 37.0 fish 100 m -2 ; age-1 range: 0.02 to 6.21 fish 100 m -2 ) were consistently higher than for juvenile Chinook salmon. Steelhead spawner abundance positively influenced juvenile steelhead abundance. During this study, Chinook salmon in the Wind River appear to have had little effect on steelhead. Low juvenile Chinook salmon abundance and a lack of a spawner-to-juvenile relationship suggest Chinook salmon are not self-sustaining and potential for such a population is low under current conditions.

Northwest Science↗

USGS2015

Vegetation community response to tidal marsh restoration of a large river estuary

Estuaries are biologically productive and diverse ecosystems that provide ecosystem services including protection of inland areas from flooding, filtering freshwater outflows, and providing habitats for fish and wildlife. Alteration of historic habitats, including diking for agriculture, has decreased the function of many estuarine systems, and recent conservation efforts have been directed at restoring these degraded areas to reestablish their natural resource function. The Nisqually Delta in southern Puget Sound is an estuary that has been highly modified by restricting tidal flow, and recent restoration of the delta contributed to one of the largest tidal salt marsh restorations in the Pacific Northwest. We correlated the response of nine major tidal marsh species to salinities at different elevation zones. Our results indicated that wetland species richness was not related to soil pore-water salinity (R2 = 0.03), but were stratified into different elevation zones (R2 = 0.47). Thus, restoration that fosters a wide range of elevations will provide the most diverse plant habitat, and potentially, the greatest resilience to environmental change.

Washington↗

USGS2015

Structure, diversity, and biophysical properties of old-growth forestsin the Klamath region, USA

The diverse old-growth forests in Klamath region of northern California and southern Oregon provide valuable ecosystem services (e.g., maintaining watersheds, wildlife habitat, recreation), but may be vulnerable to a wide range of stressors, including invasive species, disrupted disturbance regimes, and climatic change. Yet our understanding of how forest structure in the Klamath region relates to the current physical environment is limited. Here we provide present-day benchmarks for old-growth forest structure across a climatic gradient ranging from coastal to dry interior sites. We established 16 large (1 ha) forest plots where all stems > 5 cm in diameter were identified to species and mapped. Climate across these sites was highly variable, with estimated actual evapotranspiration correlated to several basic measures of forest structure, including plot basal area, stem size-class inequality, tree species diversity and, to a lesser extent, tree species richness. Analyses of the spatial arrangement of stems indicated a high degree of non-uniformity, with 75% of plots showing significant stem clumping at small spatial scales (0 to 10 m). Downscaled predictions of future site water balance suggest changes will be dominated by rapidly increasing climatic water deficit (D, a biologically meaningful index of drought). While these plots give a picture of current conditions, continued monitoring of these stands is needed to describe forest dynamics and to detect forest responses to ongoing and future stressors.

Klamath region↗

USGS2015

Population structure and dynamics of northern pike and smallmouth bass in Coeur d’Alene Lake, Idaho.

Numerous species have been introduced to Coeur d'Alene Lake, Idaho over the last century, but minimal research has been completed to understand their population dynamics. The objective of this study was to describe the population demographics and dynamics of northern pike ( Esox lucius ) and smallmouth bass ( Micropterus dolomieu ), two important nonnative sport fishes in the system to provide information that will assist with guiding management decisions. The oldest northern pike was age 7 and the oldest smallmouth bass was age 11. Populations of both species exhibited very stable recruitment with a recruitment coefficient of determination of 0.99 for northern pike and 0.98 for smallmouth bass. Total annual mortality was estimated as 66% for northern pike and 42% for smallmouth bass. Growth of northern pike in Coeur d'Alene Lake was comparable to the 50–75th percentiles of growth exhibited by lentic northern pike populations across North America. Northern pike in Coeur d'Alene Lake were most similar to populations in the north-central and northeast United States with fast growth rates and short life spans. In contrast, smallmouth bass grew slowly and generally fell within the 5th percentile of lentic smallmouth bass populations in North America. Smallmouth bass in Coeur d'Alene Lake were similar to other populations in northern regions of the United States displaying slow growth rates with high longevity. Results of this study provide important insight on nonnative northern pike and smallmouth bass population dynamics.

Idaho↗