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At least 847 records · Page 47Linked to original sources

USGS2023

Marmots do not drink coffee: Human urine contributions to the nitrogen budget of a popular national park destination

Reactive nitrogen (Nr) concentrations are higher than expected for mountain lakes in Rocky Mountain National Park, and for many years, high Nr concentrations have been attributed to atmospheric Nr deposition from regional and more distant emission sources, including combustion of fossil fuels and agricultural activities. Here, we estimated the contribution from a very local source, that of human urine, related to intensive use by visitors in Loch Vale Watershed (LVWS). Not only does urine convey hormones, pharmaceuticals, antibiotic-resistant bacteria, and antibiotic-resistant genes to the environment, but it also contributes Nr, which contributes to loss of biodiversity and eutrophication. Using caffeine as a specific marker for human urine, we compared the calculated maximum potential input of urine with that from wet atmospheric Nr deposition. The maximum potential input is a worst-case scenario. Nearly 30,000 and 45,000 people hiked the 4.0 km to the Loch, the lowest lake in LVWS, in June–September 2019 and 2020, respectively. Informal trails and informal latrine sites were mapped, and the contribution of human urine was calculated based on several assumptions, including that each visitor voided their bladder on the ground once per visit somewhere in Loch Vale. The resulting Nr input from urine in Loch Vale for the summer months of June through September was 0.02 kg Nr ha −1 , and prorated to a full year, the 2019 potential contribution of human waste was 0.06 kg ha −1 year −1 . These values are compared with June–September 1.2 kg Nr ha −1 from wet atmospheric deposition or annual measured 2019 deposition of 2.5 kg Nr ha −1 year −1 , to indicate a contribution of 2% Nr to the waters of Loch Vale from local human urine. Most Nr in this alpine and subalpine watershed is still attributable to emissions and subsequent wet atmospheric deposition, but a 2% contribution from human waste is not insignificant. In the very broadest sense, our results document an ecological disturbance from an unprecedented level of human activity in a protected and designated wilderness area. Local solutions to this local problem could include greater outreach to visitors of public lands about the consequences of their activities and installation of latrines.

Colorado↗

USGS2011

Deposition and accumulation of airborne organic contaminants in Yosemite National Park, Calfornia

Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high‐elevation lakes to estimate surface‐water concentrations. Detected compounds included current‐use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane‐related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold‐trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface‐water concentrations inferred from passive samplers were at sub–parts‐per‐trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

California↗

USGS2015

Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14 C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

Rocky Mountain National Park↗

USGS2008

Effects of 2003 wildfires on stream chemistry in Glacier National Park, Montana

Changes in stream chemistry were studied for 4 years following large wildfires that burned in Glacier National Park during the summer of 2003. Burned and unburned drainages were monitored from December 2003 through August 2007 for streamflow, major constituents, nutrients, and suspended sediment following the fires. Stream-water nitrate concentrations showed the greatest response to fire, increasing up to tenfold above those in the unburned drainage just prior to the first post-fire snowmelt season. Concentrations in winter base flow remained elevated during the entire study period, whereas concentrations during the growing season returned to background levels after two snowmelt seasons. Annual export of total nitrogen from the burned drainage ranged from 1·53 to 3·23 kg ha −1 yr −1 compared with 1·01 to 1·39 kg ha −1 yr −1 from the unburned drainage and exceeded atmospheric inputs for the first two post-fire water years. Fire appeared to have minimal long-term effects on other nutrients, dissolved organic carbon, and major constituents with the exception of sulfate and chloride, which showed increased concentrations for 2 years following the fire. There was little evidence that fire affected suspended-sediment concentrations in the burned drainage. Sediment yields in subalpine streams may be less affected by fire than in lower elevation streams because of the slow release rate of water during spring snowmelt.

Hydrological Processes↗

USGS2013

Eruptions at Lone Star Geyser, Yellowstone National Park, USA, part 1: energetics and eruption dynamics

Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a four–day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infraredintensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every three hours. We define four phases in the eruption cycle: 1) a 28 ± 3 minute phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s − 1 , steam mass fraction of less than &sim; 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; 2) a 26 ± 8 minute post–eruption relaxation phase with no discharge from the vent, infrared (IR) and acoustic power oscillations gliding between 30 and 40 s; 3) a 59 ± 13 minute recharge period during which the geyser is quiescent and progressively refills, and 4) a 69 ± 14 minute pre–play period characterized by a series of 5–10 minute–long pulses of steam, small volumes of liquid water discharge and 50–70 s flow oscillations. The erupted waters ascend froma 160 − 170° C reservoir and the volume discharged during the entire eruptive cycle is 20.8 ± 4.1 m 3 . Assuming isentropic expansion, we calculate a heat output from the geyser of 1.4–1.5 MW, which is < 0.1% of the total heat output from Yellowstone Caldera.

Wyoming↗

USGS2019

Fluvial sedimentary history of Arlington Canyon, Channel Islands National Park, California

Arlington Canyon, in the northwest part of Santa Rosa Island, Channel Islands National Park, California, has been the setting for important scientific discoveries over the past half century, including the oldest human remains in North America, several vertebrate fossil sites, and purported evidence of a catastrophic extinction event at the end of the Pleistocene. The canyon is filled with alluvial sediments that date to between 16.4 and 1.1 ka (thousands of calibrated years before present), representing accumulation that occurred primarily in response to rising sea levels during the late Pleistocene and Holocene. The deposits are laterally discontinuous, exhibit a high degree of sedimentary complexity, and contain evidence of past climates and environments, including fossil bones, burned plant macrofossils, and invertebrate microfossils. Here, we show that it is critical to view the observations, data, and conclusions of scientific studies conducted in the canyon within this larger context so that localized facets of the spatially and temporally extensive alluvial deposits are not misinterpreted or misrepresented. By improving the baseline understanding of processes and drivers of sediment accumulation in Arlington Canyon, we hope to offer a solid foundation and better underpinning for future archeological, paleontological, and geochemical studies here and throughout the northern Channel Islands.

California↗

USGS2023

Grizzly bear responses to restrictions of recreation in Yellowstone National Park

Avoiding humans will be more difficult and energetically costly for animals as outdoor recreation increases and people venture farther into wildland areas that provide high-quality habitat for wildlife. Restricting human access can be an attractive management tool to mitigate effects of human recreation activities on wildlife; however, the efficacy of such measures is rarely assessed. In 1982, Yellowstone National Park identified areas important to grizzly bears ( Ursus arctos ) to help protect critical grizzly bear habitat and reduce the likelihood of human injuries by bears. Referred to as bear management areas (BMAs), human access is restricted in these areas for 2–8 months each year, with timing and type of restrictions varying by area. We examined 2 datasets to evaluate grizzly bear selection of BMAs and differences of bear density in BMAs and non-BMAs. First, we used 17 years of recent global positioning system telemetry data for grizzly bears to assess their selection of BMAs during periods when human access was allowed, and when access was restricted. We used step-selection functions to test the hypothesis that bears spend time in places that allow them to avoid people and select quality food sources. There was support that grizzly bears differentially select for BMAs regardless of whether human access was restricted at the time, compared with areas outside BMAs, and that selection changed with sex and season. Only males during the summer and hyperphagic seasons changed their selection of BMAs based on whether access restrictions were in place, and overall, male bears preferred unrestricted BMAs (BMAs without restrictions in place). Females preferentially selected BMAs regardless of whether the area had access restrictions in place only during the mating season. Individuals varied widely in their preference for BMAs and access restrictions. Bears likely choose to spend time in BMAs based on available food resources rather than restrictions to human access. Supporting this interpretation, our analyses indicated that a greater proportion of BMA in an area was associated with higher densities of grizzly bear. Thus, restrictions to human access likely help reduce the potential for human–bear interactions, accomplishing one of the original objectives for establishing the BMAs.

Idaho, Montana, Wyoming↗

USGS2018

Lower lethal temperatures for nonnative freshwater fishes in Everglades National Park, Florida

Temperature is an important factor that shapes biogeography and species composition. In southern Florida, the tolerance of nonnative freshwater fishes to low temperatures is a critical factor in delineating their geographic spread. In this study, we provide empirical information on experimentally derived low-temperature tolerance limits of Banded Cichlid Heros severus and Spotfin Spiny Eel Macrognathus siamensis, two nonnative Everglades fishes that were lacking data, and African Jewelfish Hemichromis letourneuxi and Mayan Cichlid Cichlasoma urophthalmus, species for which previous results were derived from studies with small sample sizes. We also provide a literature review summarizing the current state of knowledge of low-temperature tolerances for all 17 nonnative freshwater fishes that have been found in Everglades National Park. Mean lower lethal temperature tolerances ranged from 4°C (Orinoco Sailfin Catfish Pterygoplichthys multiradiatus) to 16.1°C (Butterfly Peacock Bass Cichla ocellaris). These low-temperature limits may inform the understanding of the ecological role or influence of nonnative fishes and may lead to potential management opportunities and applications.

Florida↗

USGS2018

Quantifying geomorphic and vegetation change at sandbar campsites in response to flow regulation and controlled floods, Grand Canyon National Park, Arizona

Sandbars along the Colorado River in Grand Canyon National Park, USA, are an important recreational resource used as campsites by over 25,000 river runners and hikers annually. The number and size of campsites decreased following the completion of Glen Canyon Dam in 1963 due to reductions of sediment that replenish sandbars and increases in vegetation cover caused by flow regulation. Campsite area continues to decrease despite the use of controlled floods to rebuild sandbars. We quantify the relative magnitude of factors that contribute to changes in campsite size, such as fluvial deposition and erosion, gullying, and vegetation expansion with analysis of four‐band aerial imagery and digital elevation models. Campsite area declined by 37% between 2002 and 2016 (an average of 161 m 2 per site at long‐term monitoring sites). Two drivers contributed to campsite area change: (a) short‐term gains and losses associated with controlled floods and flood‐deposit erosion and (b) long‐term one‐directional loss of campsite area caused by vegetation encroachment. There was more erosion and slope change at sites in critical reaches—sections of river where campsites are infrequent or in high demand—than in noncritical reaches. Vegetation continues to expand at campsites under flow regulation, particularly in noncritical reaches. Although controlled floods have contributed to short‐term increases in sandbar size, long‐term increases in campsite area have not occurred because of sandbar erosion between controlled floods and vegetation expansion. Manual vegetation removal may need to be considered in future management strategies.

Arizona↗

USGS2020

Opportunities and challenges for restoration of the Merced River through Yosemite Valley, Yosemite National Park, USA

Successful river restoration requires understanding and integration of multiple disciplinary perspectives, including evaluations of past and ongoing watershed processes, local geomorphic response, and impacts unique to human activity. Nowhere is this more apparent than along the Merced River in Yosemite National Park, USA, where both an outstanding natural landscape and the consequences of over a century of human disturbances continue to interact. An intact upstream watershed highlights the importance here of local impacts on geomorphic response. Incision and the resulting decoupling of the channel from its adjacent late-Holocene floodplain are consequences of reduced channel roughness, likely from de-snagging the river, and instream gravel mining in the 19th and early 20th century. Riparian-zone disturbance by visitor use has damaged riparian vegetation and soils, inducing channel widening. Revetments and channel-spanning bridges, the latter being visible and oft-cited impacts to fluvial processes, have distorted the natural evolution of meanders and induced local channel narrowing. The historical rate of sediment export from Yosemite Valley has greatly exceeded replenishment from upstream and lateral sources, creating a deficit that now inhibits recovery via passive restoration of more natural channel form and function. Climate change may amplify now-diminished fluvial processes but also exacerbate the rate of sediment export. These conditions, reflecting a complex intersection of geologic history, modern geomorphic processes, and human interactions, demonstrate how a limited influx of sediment coupled with intensive human use can have long-term consequences for riverine conditions, restoration opportunities, and social engagement with the riverine landscape.

California↗

USGS2024

Riparian vegetated area in pre-dam, post-dam, and environmental flow periods in Canyonlands National Park from 1940 to 2022

The Upper Colorado River Basin is the principal water supply of the western United States and includes a series of canyons that provide habitat for disproportionate numbers of flora and fauna. Following the closing of Flaming Gorge and Blue Mesa dams in 1963 and 1966, decreases in peak flows and elevated base flows allowed extensive vegetation encroachment, channel narrowing, and channel simplification. Since 1992, reservoir releases have been modified to increase the ratio of peak to base flows for environmental reasons, including protection of endangered fish. We used remote imagery from 1940 to 2022 to examine rates of vegetation encroachment along three river reaches in Canyonlands National Park during the pre-dam (1940–1966), post-dam (1967–1992), and environmental flows (1993–2022) periods. We found an increase in the vegetated area along the Colorado and Green Rivers upstream of their confluence since 1940. We documented a 6.1% and 4.0% increase in vegetated area in the post-dam period and a 19.5% and 6.5% increase in vegetated area in the environmental flows period on the Colorado and Green Rivers, respectively. The Cataract Canyon reach (Colorado River below the confluence) has been stable since 1966. All three river reaches showed the slowest period of vegetation encroachment, indicative of channel narrowing, in the last 16 years of environmental flows that included a large peakflow in 2011. Environmental flows that mimic the natural hydrograph have not reversed decreases in peak flow and channel width, due in part to decreasing runoff and increasing flow diversion. Flow alterations that reduce the spring peak could cause further narrowing.

Utah↗

USGS2013

Black bear density in Glacier National Park, Montana

We report the first abundance and density estimates for American black bears ( Ursus americanus ) in Glacier National Park (NP),Montana, USA.We used data from 2 independent and concurrent noninvasive genetic sampling methods—hair traps and bear rubs—collected during 2004 to generate individual black bear encounter histories for use in closed population mark–recapture models. We improved the precision of our abundance estimate by using noninvasive genetic detection events to develop individual-level covariates of sampling effort within the full and one-half mean maximum distance moved (MMDM) from each bear’s estimated activity center to explain capture probability heterogeneity and inform our estimate of the effective sampling area.Models including the one-halfMMDMcovariate received overwhelming Akaike’s Information Criterion support suggesting that buffering our study area by this distance would be more appropriate than no buffer or the full MMDM buffer for estimating the effectively sampled area and thereby density. Our modelaveraged super-population abundance estimate was 603 (95% CI¼522–684) black bears for Glacier NP. Our black bear density estimate (11.4 bears/100 km2, 95% CI¼9.9–13.0) was consistent with published estimates for populations that are sympatric with grizzly bears (U. arctos) and without access to spawning salmonids. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Montana↗

USGS2016

Age-specific survival of reintroduced swift fox in Badlands National Park and surrounding lands

In 2003, a reintroduction program was initiated at Badlands National Park (BNP), South Dakota, USA, with swift foxes ( Vulpes velox ) translocated from Colorado and Wyoming, USA, as part of a restoration effort to recover declining swift fox populations throughout its historical range. Estimates of age-specific survival are necessary to evaluate the potential for population growth of reintroduced populations. We used 7 years (2003–2009) of capture–recapture data of 243 pups, 29 yearlings, and 69 adult swift foxes at BNP and the surrounding area to construct Cormack–Jolly–Seber model estimates of apparent survival within a capture–mark–recapture framework using Program MARK. The best model for estimating recapture probabilities included no differences among age classes, greater recapture probabilities during early years of the monitoring effort than later years, and variation among spring, winter, and summer. Our top ranked survival model indicated pup survival differed from that of yearlings and adults and varied by month and year. The apparent annual survival probability of pups (0.47, SE = 0.10) in our study area was greater than the apparent annual survival probability of yearlings and adults (0.27, SE = 0.08). Our results indicate low survival probabilities for a reintroduced population of swift foxes in the BNP and surrounding areas. Management of reintroduced populations and future reintroductions of swift foxes should consider the effects of relative low annual survival on population demography.

Wildlife Society Bulletin↗

USGS2001

Egg parasitoids of Sophonia rufofascia (Homoptera: Cicadellidae) in Hawaii Volcanoes National Park

Parasitism of the leafhopper Sophonia rufofascia (Kuoh and Kuoh), a recent immigrant that has become a widespread pest in Hawaii, was examined in a 1-year survey in Hawaii Volcanoes National Park. Samples of young leaves of four plant species infested with eggs of S. rufofascia were collected at five sites ranging from 880 to 1190 m in elevation. Leafhopper eggs were parasitized principally by three species of Mymaridae (Hymenoptera): Polynema sp., Schizophragma sp. probably bicolor (Dozier), and Chaetomymar sp. Although parasitism by each species fluctuated at levels usually below 10%, all three were detected consistently across most host plants, sites, and sample periods. Total parasitism differed at a marginally significant level among host plants and sites, but not among sample periods. Total parasitism averaged 14.3% (maximum: 26.3%) on Dodonaea viscosa Jacquin, 10.6% (maximum: 17.5%) on Myrica faya Aiton, 8.7% (maximum: 29.5%) on Metrosideros polymorpha Gaudich-Beaupre, and 1.6% (maximum: 4.3%) on Vaccinium reticulatum Smith. Parasitism was generally higher at sites lower in elevation. Further monitoring is recommended to determine whether parasitism will increase to levels that can effectively suppress S. rufofascia populations. The efficacy of natural enemies already present in Hawaii is important because concern over nontarget impacts on endemic leafhoppers makes introduction of new biological control agents difficult. ?? 2001 Academic Press.

Biological Control↗

USGS1999

Characterizing backcountry camping impacts in Great Smoky Mountains National Park

This investigates resource impacts on backcounty campsites in the Great Smoky Mountains National Park, USA. Study objectives were to enhance our understanding of camping impacts and to improve campsite impact assessment procedures by means of multivariate techniques. Three-hundred and eight campsites at designated backcountry campgrounds, and 69 additional unofficial campsites were assessed. Factor analysis of 195 established campsites on eight impact indicator variables revealed three dimensions of campsite impact: area disturbance, soil and groundcover damage, and tree-related damage. Four distinctive backcountry campsite types were identified, three of which were derived from cluster analyses of factor scores. These four backcountry campsite types characterize the intensity and areal extent of resource impacts, and they vary in locational and environmental attributes. At an aggregate level, different campsite types contributed unequally to the cumulative level of impact. The dimensional structure and typology developed in this study demonstrates that campsite impacts can be viewed and examined holistically with the use of multivariate methods. Implications for assessment procedures, management and further research are discussed.

Journal of Environmental Management↗

USGS2002

Management practices that concentrate visitor activities: Camping impact management at Isle Royale National Park, USA

This study assessed campsite conditions and the effectiveness of campsite impact management strategies at Isle Royale National Park, USA. Protocols for assessing indicators of vegetation and soil conditions were developed and applied to 156 campsites and 88 shelters within 36 backcountry campgrounds. The average site was 68 m 2 and 83% of sites lost vegetation over areas less than 47 m 2 . We believe that management actions implemented to spatially concentrate camping activities and reduce camping disturbance have been highly successful. Comparisons of disturbed area/overnight stay among other protected areas reinforces this assertion. These reductions in area of camping disturbance are attributed to a designated site camping policy, limitation on site numbers, construction of sites in sloping terrain, use of facilities, and an ongoing program of campsite maintenance. Such actions are most appropriate in higher use backcountry and wilderness settings.

Isle Royale National Park↗

USGS2016

Lake transparency: a window into decadal variations in dissolved organic carbon concentrations in Lakes of Acadia National Park, Maine

A forty year time series of Secchi depth observations from approximately 25 lakes in Acadia National Park, Maine, USA, evidences large variations in transparency between lakes but relatively little seasonal cycle within lakes. However, there are coherent patterns over the time series, suggesting large scale processes are responsible. It has been suggested that variations in colored dissolved organic matter (CDOM) are primarily responsible for the variations in transparency, both between lakes and over time and further that CDOM is a robust optical proxy for dissolved organic carbon (DOC). Here we present a forward model of Secchi depth as a function of DOC based upon first principles and bio-optical relationships. Inverting the model to estimate DOC concentration from Secchi depth observations compared well with the measured DOC concentrations collected since 1995 (RMS error < 1.3 mg C l-1). This inverse model allows the time series of DOC to be extended back to the mid 1970s when only Secchi depth observations were collected, and thus provides a means for investigating lake response to climate forcing, changing atmospheric chemistry and watershed characteristics, including land cover and land use.

Book chapter↗

USGS1991

Sources of dissolved and particulate organic material in Loch Vale Watershed, Rocky Mountain National Park, Colorado, USA

The sources of both dissolved organic carbon (DOC) and particulate organic carbon (POC) to an alpine (Sky Pond) and a subalpine lake (The Loch) in Rocky Mountain National Park were explored for four years. The importance of both autochthonous and allochthonous sources of organic matter differ, not only between alpine and subalpine locations, but also seasonally. Overall, autochthonous sources dominate the organic carbon of the alpine lake, while allochthonous sources are a more significant source of organic carbon to the subalpine lake. In the alpine lake, Sky Pond, POC makes up greater than one third of the total organic matter content of the water column, and is related to phytoplankton abundance. Dissolved organic carbon is a product of within-lake activity in Sky Pond except during spring snowmelt and early summer (May–July), when stable carbon isotope ratios suggest a terrestrial source. In the subalpine lake, The Loch, DOC is a much more important constituent of water column organic material than POC, comprising greater than 90% of the spring snowmelt organic matter, and greater than 75% of the organic matter over the rest of the year. Stable carbon isotope ratios and a very strong relation of DOC with soluble Al (tot) indicate DOC concentrations are almost entirely related to flushing of soil water from the surrounding watershed during spring snowmelt. Stable carbon isotope ratios indicate that, for both lakes, phytoplankton is an important source of DOC in the winter, while terrestrial material of plant or microbial origin contributes DOC during snowmelt and summer.

Colorado↗