Geology topics

Research about Yellowstone National Park

Source-linked reports with geographic coverage including Yellowstone National Park.

At least 145 records · Page 8Linked to original sources

USGS2006

Assessment of pesticide residues in army cutworm moths (Euxoa auxiliaris) from the Greater Yellowstone Ecosystem and their potential consequences to foraging grizzly bears (Ursus arctos horribilis)

During summer, a grizzly bear ( Ursus arctos horribilis ) in the Greater Yellowstone Ecosystem (GYE) (USA) can excavate and consume millions of army cutworm moths ( Euxoa auxiliaris ) (ACMs) that aggregate in high elevation talus. Grizzly bears in the GYE were listed as threatened by the US Fish and Wildlife Service in 1975 and were proposed for delisting in 2005. However, questions remain about key bear foods. For example, ACMs are agricultural pests and concern exists about whether they contain pesticides that could be toxic to bears. Consequently, we investigated whether ACMs contain and transport pesticides to bear foraging sites and, if so, whether these levels could be toxic to bears. In 1999 we collected and analyzed ACMs from six bear foraging sites. ACMs were screened for 32 pesticides with gas chromatography with electron capture detection (GC–ECD). Because gas chromatography with tandem mass spectrometry (GC–MS/MS) can be more sensitive than GC–ECD for certain pesticides, we revisited one site in 2001 and analyzed these ACMs with GC–MS/MS. ACMs contained trace or undetectable levels of pesticides in 1999 and 2001, respectively. Based on chemical levels in ACMs and numbers of ACMs a bear can consume, we calculated the potential of chemicals to reach physiological toxicity. These calculations indicate bears do not consume physiologically toxic levels of pesticides and allay concerns they are at risk from pesticides transported by ACMs. If chemical control of ACMs changes in the future, screening new ACM samples taken from bear foraging sites may be warranted.

Wyoming↗

USGS2006

Speciation of volatile arsenic at geothermal features in Yellowstone National Park

Geothermal features in the Yellowstone National Park contain up to several milligram per liter of aqueous arsenic. Part of this arsenic is volatilized and released into the atmosphere. Total volatile arsenic concentrations of 0.5–200 mg/m 3 at the surface of the hot springs were found to exceed the previously assumed nanogram per cubic meter range of background concentrations by orders of magnitude. Speciation of the volatile arsenic was performed using solid-phase micro-extraction fibers with analysis by GC–MS. The arsenic species most frequently identified in the samples is (CH 3 ) 2 AsCl, followed by (CH 3 ) 3 As, (CH 3 ) 2 AsSCH 3 , and CH 3 AsCl 2 in decreasing order of frequency. This report contains the first documented occurrence of chloro- and thioarsines in a natural environment. Toxicity, mobility, and degradation products are unknown.

Idaho, Montana, Wyoming↗

USGS2006

Geochemistry of low-temperature springs northwest of Yellowstone caldera: Seeking the link between seismicity, deformation, and fluid flow

A comprehensive geochemical survey of springs outside the northwest margin of the Yellowstone caldera was undertaken in 2003 and 2004. This survey was designed to detect: (1) active leakage from a huge reservoir of CO 2 gas recently postulated to extend from beneath the caldera into this area; and (2) lingering evidence for subsurface flow of magmatic fluids into this area during the 1985 seismic swarm and concomitant caldera subsidence. Spring temperatures are low (< 15 °C), but two large-discharge springs contain 14 C-dead carbon that can be identified as magmatic from calculated end-member values for δ 13 C (dead) and 3 He/C (dead) of − 4&permil; and 1 × 10 − 10 , respectively, similar to values for intra-caldera fumarolic and hot-spring gases. However, the combined discharge of magmatic C is only 5.4 tonnes/day, < 0.1% of the total output from Yellowstone. The two springs have slightly elevated 3 He/ 4 He ratios near 1 R A and anomalous concentrations of Cl, Li, and B, and appear to represent minor leakage of gas-depleted, thermal waters out of the caldera. The small CO 2 signal detected in the springs is difficult to reconcile with a large underlying reservoir of gas in faulted and seismically active terrain. When considered with analyses from previous decades, the results provide no evidence to associate the ten-year period of caldera deflation that began in 1985 with expulsion of magmatic fluids through the caldera rim in this area.

Montana, Wyoming↗

USGS2006

Temporal, spatial, and environmental influences on the demographics of grizzly bears in the Greater Yellowstone Ecosystem

During the past 2 decades, the grizzly bear ( Ursus arctos ) population in the Greater Yellowstone Ecosystem (GYE) has increased in numbers and expanded in range. Understanding temporal, environmental, and spatial variables responsible for this change is useful in evaluating what likely influenced grizzly bear demographics in the GYE and where future management efforts might benefit conservation and management. We used recent data from radio-marked bears to estimate reproduction (1983–2002) and survival (1983–2001); these we combined into models to evaluate demographic vigor (lambda [λ]). We explored the influence of an array of individual, temporal, and spatial covariates on demographic vigor.

Idaho, Montana, Wyoming↗

USGS2006

Distribution of grizzly bears in the Greater Yellowstone Ecosystem, 2004

The US Fish and Wildlife Service (USFWS) proposed delisting the Yellowstone grizzly bear ( Ursus arctos horribilis ) in November 2005. Part of that process required knowledge of the most current distribution of the species. Here, we update an earlier estimate of occupied range (1990–2000) with data through 2004. We used kernel estimators to develop distribution maps of occupied habitats based on initial sightings of unduplicated females ( n = 481) with cubs of the year, locations of radiomarked bears ( n = 170), and spatially unique locations of conflicts, confrontations, and mortalities ( n = 1,075). Although each data set was constrained by potential sampling bias, together they provided insight into areas in the Greater Yellowstone Ecosystem (GYE) currently occupied by grizzly bears. The current distribution of 37,258 km 2 (1990–2004) extends beyond the distribution map generated with data from 1990–2000 (34,416 km 2 ). Range expansion is particularly evident in parts of the Caribou–Targhee National Forest in Idaho and north of Spanish Peaks on the Gallatin National Forest in Montana.

Wyoming↗

USGS2006

Grizzly bear management in Yellowstone National Park: The heart of recovery in the Yellowstone Ecosystem

Grizzly bear ( Ursus arctos ) management in the Greater Yellowstone Ecosystem (GYE) in the past quarter century has resulted in more than doubling of the population from around 200 to more than 500, expansion of range back into habitats where the bear has extirpated more than a century ago, and a move toward removal from the U.S. Endangered Species list. At the center of this success story are the management programs in Yellowstone National Park (YNP). Regulations that restrict human activity, camping, and food storage, elimination of human food and garbage as attractants, and ranger attendance of roadside bears have all resulted in the population of grizzlies in YNP approaching carrying capacity. Recent studies suggest, however, that YNP alone is too small to support the current population, making management beyond the park boundary important and necessary to the demographics of the population as a whole. Demographic analyses suggest a source-sink dynamic exists within the GYE, with YNP and lands outside the park within the Grizzly Bear Recovery Zone (RZ) representing source habitats, whereas lands beyond the RZ constitute sinks. The source-sink demography in the GYE is indicative of carnivore conservation issues worldwide where many national parks or preserves designed to protect out natural resources are inadequate in size or shape to provide all necessary life history requirements for these wide-ranging species. Additionally, wide-ranging behavior and long-distance dispersal seem inherent to large carnivores, so mortality around the edges is virtually inevitable, and conservation in the GYE is inextricably linked to management regimes not only within YNP, but within the GYE as a whole. We discuss those needs here.

Wyoming↗

USGS2006

Grizzly bear nutrition and ecology studies in Yellowstone National Park

T HE CHANCE TO SEE a wild grizzly bear is often the first or second reason people give for visiting Yellow - stone National Park. Public interest in bears is closely coupled with a desire to perpetuate this wild symbol of the American West. Grizzly bears have long been described as a wilderness species requiring large tracts of undisturbed habitat. However, in today’s world, most grizzly bears live in close proximity to humans (Schwartz et al. 2003). Even in Yellowstone National Park, the impacts of humans can affect the long-term survival of bears (Gunther et al. 2002). As a consequence, the park has long supported grizzly bear research in an effort to understand these impacts. Most people are familiar with what happened when the park and the State of Montana closed open-pit garbage dumps in the late 1960s and early 1970s, when at least 229 bears died as a direct result of conflict with humans. However, many may not be as familiar with the ongoing changes in the park’s plant and animal communities that have the potential to further alter the park’s ability to support grizzly bears.

Wyoming↗

USGS2006

The northern Yellowstone elk herd; management policy and natural regulation

No abstract available.

Wyoming↗

USGS2005

Conservation of the Yellowstone grizzly bear

We review literature relevant to the conservation of Yellowstone's grizzly bear population and appraise the bear's long-term viability. We conclude that the population is isolated and vulnerable to epidemic perturbation and that the carrying capacity of the habitat is likely to shift downward under conditions of climate change. Viability analyses based on the assumption that future habitats will closely resemble those existing at present have limited applicability; more information is needed on the autecology of important bear foods and on the implications of landscape-scale changes for bear population dynamics. Optimism over prospects of long-term persistence for Yellowstone's grizzly bears does not seem to be warranted and management of this population should be conservative and not unduly swayed on short-term positive trends.

Yellowstone National Park↗

USGS2005

Consumption of pondweed rhizomes by Yellowstone grizzly bears

Pondweeds ( Potamogeton spp.) are common foods of waterfowl throughout the Northern Hemisphere. However, consumption of pondweeds by bears has been noted only once, in Russia. We documented consumption of pondweed rhizomes by grizzly bears ( Ursus arctos ) in the Yellowstone region, 1977-96, during investigations of telemetry locations obtained from 175 radiomarked bears. We documented pondweed excavations at 25 sites and detected pondweed rhizomes in 18 feces. We observed grizzly bears excavating and consuming pondweed on 2 occasions. All excavations occurred in wetlands that were inundated during and after snowmelt, but dry by late August or early September of most years. These wetlands were typified by the presence of inflated sedge ( Carex vesicaria ) and occurred almost exclusively on plateaus of Pliocene-Pleistocene detrital sediments or volcanic rhyolite flows. Bears excavated wetlands with pondweeds when they were free of standing water, most commonly during October and occasionally during spring prior to the onset of terminal snowmelt. Most excavations were about 4.5 cm deep, 40 cubic decimeter (dm 3 ) in total volume, and targeted the thickened pondweed rhizomes. Starch content of rhizomes collected near grizzly bear excavations averaged 28% (12% SD; n = 6). These results add to the documented diversity of grizzly bear food habits and, because pondweed is distributed circumboreally, also raise the possibility that consumption of pondweed by grizzly bears has been overlooked in other regions.

Idaho, Montana, Wyoming↗

USGS2005

Changing numbers of spawning cutthroat trout in tributary streams of Yellowstone Lake and estimates of grizzly bears visiting streams from DNA

Spawning Yellowstone cutthroat trout ( Oncorhynchus clarki ) provide a source of highly digestible energy for grizzly bears ( Ursus arctos ) that visit tributary streams to Yellowstone Lake during the spring and early summer. During 1985–87, research documented grizzly bears fishing on 61% of the 124 tributary streams to the lake. Using track measurements, it was estimated that a minimum of 44 grizzly bears fished those streams annually. During 1994, non-native lake trout ( Salvelinus namaycush ) were discovered in Yellowstone Lake. Lake trout are efficient predators and have the potential to reduce the native cutthroat population and negatively impact terrestrial predators that use cutthroat trout as a food resource. In 1997, we began sampling a subset of streams ( n = 25) from areas of Yellowstone Lake surveyed during the previous study to determine if changes in spawner numbers or bear use had occurred. Comparisons of peak numbers and duration suggested a considerable decline between study periods in streams in the West Thumb area of the lake. The apparent decline may be due to predation by lake trout. Indices of bear use also declined on West Thumb area streams. We used DNA from hair collected near spawning streams to estimate the minimum number of bears visiting the vicinity of spawning streams. Seventy-four individual bears were identified from 429 hair samples. The annual number of individuals detected ranged from 15 in 1997 to 33 in 2000. Seventy percent of genotypes identified were represented by more than 1 sample, but only 31% of bears were documented more than 1 year of the study. Sixty-two (84%) bears were only documented in 1 segment of the lake, whereas 12 (16%) were found in 2–3 lake segments. Twenty-seven bears were identified from hair collected at multiple streams. One bear was identified on 6 streams in 2 segments of the lake and during 3 years of the study. We used encounter histories derived from DNA and the Jolly-Seber procedure in Program MARK to produce annual estimates of grizzly bears visiting streams. Approximately 68 grizzly bears visited the vicinity of cutthroat trout spawning streams annually. Thus, approximately 14–21% of grizzly bears in the Greater Yellowstone Ecosystem (GYE) may have used this threatened food resource annually. Yellowstone National Park (YNP) is attempting to control the lake trout population in Yellowstone Lake; our results underscore the importance of that effort to grizzly bears.

Wyoming↗

USGS2005

Yellowstone bison fetal development and phenology of parturition

Knowledge of Yellowstone bison ( Bison bison ) parturition patterns allows managers to refine risk assessments and manage to reduce the potential for transmission of brucellosis between bison and cattle. We used historical (1941) and contemporary (1989–2002) weights and morphometric measurements of Yellowstone bison fetuses to describe fetal growth and to predict timing and synchrony of parturition. Our method was supported by agreement between our predicted parturition pattern and observed birth dates for bison that were taken in to captivity while pregnant. The distribution of parturition dates in Yellowstone bison is generally right-skewed with a majority of births in April and May and few births in the following months. Predicted timing of parturition was consistently earlier for bison of Yellowstone's northern herd than central herd. The predicted median parturition date for northern herd bison in the historical period was 3 to 12 days earlier than for 2 years in the contemporary period, respectively. Median predicted birth dates and birthing synchrony differed within herds and years in the contemporary period. For a single year of paired data, the predicted median birth date for northern herd bison was 14 days earlier than for central herd bison. This difference is coincident with an earlier onset of spring plant growth on the northern range. Our findings permit refinement of the timing of separation between Yellowstone bison and cattle intended to reduce the probability of transmission of brucellosis from bison to cattle.

Idaho, Montana, Wyoming↗

USGS2005

Incisor wear and age in Yellowstone bison

Biologists commonly use tooth eruption and wear patterns or cementum annuli techniques to estimate age of ungulates. However, in some situations the accuracy or sampling procedures of either approach are undesirable. We investigated the progression of several quantitative measures of wear with age, using permanent first incisors from Yellowstone bison ( Bison bison ), and tested for differences between sexes and herds. We further investigated the relationship of wear and age to explore an age-estimation method. Labial-lingual width (LLW) correlated best with assigned age ( r 2 =0.66, males; r 2 =0.76 females). Labial-lingual width differed between sexes, with females showing &sim;0.2 mm more wear than males. Additionally, differences in rate of wear existed between bison of the northern and central Yellowstone herds (1.2 and 0.9 mm/year, respectively). We developed a regression formula to test the power of LLW as an estimator of Yellowstone bison age. Our method provided estimated ages within 1 year of the assigned age 73% and 82% of the time for female and male bison, respectively.

Idaho, Montana, Wyoming↗

USGS2005

Water-chemistry data for selected springs, geysers, and streams in Yellowstone National Park Wyoming, 2001-2002

Water analyses are reported for one-hundred-twenty-one samples collected from hot springs and their overflow drainages, the Gibbon River, and one ambient-temperature acid stream in Yellowstone National Park (YNP) during 2001-2002. Twenty-five analyses are reported for samples collected during May 2001, fifty analyses are reported for samples collected during September 2001, eleven analyses are reported for samples collected during October 2001, and thirty-five analyses are reported for samples collected during June and July 2002. Water samples were collected and analyzed for major and trace constituents from nine areas of YNP including Norris Geyser Basin, Nymph Lake and Roadside Springs, Lower Geyser Basin, Washburn Springs, Calcite Springs, Crater Hills, Mammoth Hot Springs, West Thumb Geyser Basin, and Brimstone Basin. These water samples were collected and analyzed as part of research investigations in YNP on arsenic redox distribution in hot springs and overflow drainages, the occurrence and distribution of dissolved mercury, and sulfur redox speciation. Most samples were analyzed for major cations and anions, trace metals, and iron, arsenic, nitrogen, and sulfur redox species. Only mercury concentration, pH, and specific conductance were determined for samples collected in October 2001 as they were collected during a reconnaissance field trip. Analyses were performed at the sampling site, in an onsite mobile laboratory, or later in a U.S. Geological Survey laboratory, depending on stability of the constituent and whether it could be preserved effectively. Water samples were filtered and preserved onsite. Water temperature, specific conductance, pH, Eh, and dissolved hydrogen sulfide were measured onsite at the time of sampling. Alkalinity and acidity were determined by titration, usually within a few days of sample collection. Concentrations of thiosulfate (S 2 O 3 ) and polythionate (S n O 6 ) were determined as soon as possible (generally minutes to hours after sample collection) by ion chromatography in an onsite mobile laboratory vehicle. Total dissolved iron and ferrous iron concentrations often were measured onsite in the mobile laboratory. Concentrations of aluminum, arsenic, barium, beryllium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, nickel, potassium, selenium, silica, sodium, strontium, vanadium, and zinc were determined by inductively coupled plasma-optical emission spectrometry. Trace concentrations of antimony, cadmium, chromium, cobalt, copper, lead, and selenium were determined by Zeeman-corrected graphite-furnace atomic-absorption spectrometry. Concentrations of total arsenic and arsenite were determined by hydride-generation atomic-absorption spectrometry using a flow-injection analysis system. Concentrations of total mercury were determined by cold-vapor atomic fluorescence spectrometry. Concentrations of bromide, chloride, nitrate, and sulfate were determined by ion chromatography. Concentrations of ferrous and total iron were determined by the FerroZine colorimetric method. Concentrations of nitrite were determined by colorimetry or chemiluminescence. Concentrations of ammonia were determined by ion chromatography, with reanalysis by colorimetry when separation of sodium and ammonia peaks was poor. Dissolved organic carbon concentrations were determined by the wet persulfate oxidation method.

Wyoming↗

USGS2005

Ground water to surface water: Chemistry of thermal outflows in Yellowstone National Park

Geothermal waters in the earth’s subsurface boil with steam separation and may mix with dilute ground waters (that may or may not contain sulfuric acid from sulfur oxidation), resulting in a wide range of compositions when they discharge and emerge at the surface. As they discharge onto the ground surface they undergo evaporative cooling, degassing, oxidation, and mineral precipitation. Within this aquatic environment of rapidly changing physical and chemical parameters, numerous microbial communities develop—some of which affect oxidation and mineral precipitation. Microbes are responsible for rapid oxidation of iron and arsenic in thermal outflows, and for catalyzing the production of sulfuric acid from the oxidation of elemental sulfur. The attractive visual display of colors observed in Yellowstone’s geothermal waters reflects this interplay of physical, chemical, and biological phenomena. Oxidation of dissolved sulfide to thiosulfate occurs abiotically, and thiosulfate can be found in many of Yellowstone’s thermal waters—at any pH, temperature, and composition. Polythionates, on the other hand, are rarely found in Yellowstone waters but are associated with sulfur hydrolysis in Cinder Pool. Oxidation rates of iron and arsenic in overflows have been estimated at 1-3 mM/h and 0.04-0.1 mM/h, respectively—orders of magnitude faster than the abiotic rate. The abiotic production of thiosulfate from oxidation of dissolved sulfi de at Angel Terrace and Ojo Caliente is about 3-30 µM/min, faster by 2-3 orders of magnitude than the laboratory rate at 25°C. The partitioning of dissolved sulfide between that volatilized to the air and that oxidized to thiosulfate has been estimated at Angel Terrace and at Ojo Caliente. For the pH range of 6-8 and the temperature range of 50-93°C, 67-86% of the dissolved sulfide is lost to the atmosphere and 10-33% is oxidized to thiosulfate. Only a very small percentage, if any, forms elemental sulfur under these conditions.

Wyoming↗

USGS2004

Unusual behavior by Bison, Bison bison, toward Elk, Cervus elaphus, and wolves, Canis lupus

Incidents are described of Bison ( Bison bison ) in Yellowstone National Park mauling and possibly killing a young Elk ( Cervus elaphus ) calf, chasing wolves ( Canis lupus ) off Elk they had just killed or were killing, and keeping the wolves away for extended periods. During one of the latter cases, the Bison knocked a wolf-wounded Elk down. Bison were also seen approaching wolves that were resting and sleeping, rousting them, following them to new resting places and repeating this behavior. These behaviors might represent some type of generalized hyper-defensiveness that functions as an anti-predator strategy.

Idaho, Montana, Wyoming↗

USGS2004

Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears

Spawning cutthroat trout ( Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears ( Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized ( i ) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ± 93 ppb) and its virtual absence in all other bear foods ( 6 ppb), ( ii ) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, ( iii ) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, ( iv ) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and ( v ) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

Wyoming, Montana, Idaho↗

USGS2004

Grizzly bear-human conflicts in the Yellowstone ecosystem, 1992-2000

For many years, the primary strategy for managing grizzly bears ( Ursus arctos ) that came into conflict with humans in the Greater Yellowstone Ecosystem (GYE) was to capture and translocate the offending bears away from conflict sites. Translocation usually only temporarily alleviated the problems and most often did not result in long-term solutions. Wildlife managers needed to be able to predict the causes, types, locations, and trends of conflicts to more efficiently allocate resources for pro-active rather than reactive management actions. To address this need, we recorded all grizzly bear-human conflicts reported in the GYE during 1992-2000. We analyzed trends in conflicts over time (increasing or decreasing), geographic location on macro- (inside or outside of the designated Yellowstone Grizzly Bear Recovery Zone [YGBRZ]) and micro- (geographic location) scales, land ownership (public or private), and relationship to the seasonal availability of bear foods. We recorded 995 grizzly bear-human conflicts in the GYE. Fifty-three percent of the conflicts occurred outside and 47% inside the YGBRZ boundary. Fifty-nine percent of the conflicts occurred on public and 41% on private land. Incidents of bears damaging property and obtaining anthropogenic foods were inversely correlated to the abundance of naturally occurring bear foods. Livestock depredations occurred independent of the availability of bear foods. To further aid in prioritizing management strategies to reduce conflicts, we also analyzed conflicts in relation to subsequent human-caused grizzly bear mortality. There were 74 human-caused grizzly bear mortalities during the study, primarily from killing bears in defense of life and property (43%) and management removal of bears involved in bear-human conflicts (28%). Other sources of human-caused mortality included illegal kills, electrocution by downed power-lines, mistaken identification by American black bear ( Ursus americanus ) hunters, and vehicle strikes. This analysis will help provide wildlife managers the information necessary to develop strategies designed to prevent conflicts from occurring rather than reacting to conflicts after they occur.

Wyoming↗