Arches National Park Research Articles

Mathematical Modeling and Enhancing the Carrying Capacity of National Parks in the United States

A rapid growth in the number of visitors has been observed for many national parks in the United States, examples include Yellowstone National Park, Yosemite National Park, Rocky Mountain National Park and Arches National Park. As a result, public transit and parking resources have been stretched closer and closer to their capacities in these parks. In response, some National Park Services (NPS) have started to implement crowd control measurements, such as the timed entry reservation systems, where visitors have to reserve their slots to visit the park during certain time periods of the year. However, such policy does not touch on the fundamental issue of the subject, that is, the carrying capacity of the park. In this paper, we demonstrate that there will be even greater growth in the number of visitors in the near future, which means that a capacity boost is inevitable. Fortunately, we also observe that if we can fix some key bottlenecks, then we can dramatically increase the capacity of the park without destroying more natural land.

Comparing Visitor Perceptions, Characteristics, and Support for Management Actions before and during a Pilot Timed Entry System at Arches National Park

Over the past decade, many national park units in the United States broke visitation records. Arches National Park (UT, USA) is no exception. Between 2011 and 2021, visitation increased 74%. As part of considering management options to address the issues from sustained and concentrated visitation, Arches implemented a pilot timed entry system from 3 April to 3 October 2022. This article compares visitor perceptions, characteristics, and support for management actions before and during the pilot timed entry system using data from visitor intercept surveys. Findings suggest visitors experience quality improved across the park and on hiking trails during the pilot timed entry system. Visitor characteristics were extremely similar, and there were no differences in local residency, group size, vehicle occupancy, race, ethnicity, first time visitation, education level, or household income. Visitors were more likely to plan for the trip further in advance and were less likely to re-enter the park during the pilot timed entry system. Lastly, visitors demonstrated more support for timed entry and lower levels of support for expanding parking, site specific reservations, and temporary closures during the pilot timed entry system. These results reflect unique insights for managers considering managed access systems like timed entry to sustainably manage visitor use in parks and protected areas.

Finding the right place in Mohr circle space: Geologic evidence and implications for applying a non-linear failure criterion to fractured rock

The ability to relate patterns of brittle rock failure to stress conditions permits geologists to better understand the nature of rock deformation in natural geologic settings. In the field of structural geology, the relationship between shear and normal stress at the time of rock failure, a critical element of any failure criterion, is most commonly assumed to be linear in compressive stress environments. However, derivation and utilization of linear and non-linear failure criteria have been debated and variably invoked in past laboratory, field, and modeling-based analyses. In a study of fractured Jurassic Moab Tongue Member sandstone (Entrada Formation) bordering Arches National Park (Utah), we have documented field evidence for a system of shear fractures whose character and kinematics are best explained by a non-linear failure criterion. This field setting is distinguished by lateral subjacent juxtaposition of a salt-wall diapir (to the northeast) and the fractured sandstone (to the southwest). The shear fracture system reveals conjugate dihedral angles that systematically decrease northeastward reflecting decreasing critical differential stress magnitudes along a non-linear failure criterion, driven by a reduction in mean normal stress closer to the salt-sediment interface. These stress conditions are most likely associated with the mechanical response of the adjacent salt body to tectonic loading. Augmented by experimental rock failure testing, we provide novel field-based evidence that a non-linear failure criterion is most applicable in this natural geologic environment. We also present a pathway to gain insight into paleostress magnitudes utilizing observed failure angles and a geomechanically constrained non-linear failure criterion.

Heterogeneous Nonuse Values for Arches and Zion National Parks

Executive Summary This paper identifies several kinds of heterogeneity in nonuse values using a contingent choice experiment about two national parks in Utah. Such heterogeneity has potentially important implications for national park management. When management resources are scarce, it matters that nonuse values differ across park resources or attributes. Resources that generate more nonuse values deserve more protection, including the impacts of visitor activities. Heterogeneity by location implies that management decisions appropriate for one park can’t be adopted in other parks without careful consideration. Heterogeneity of nonuse values matters for management if there are political, equity, or justice reasons to pay more attention to particular groups in society. Heterogeneity by type of nonuse value matters for management, too: existence values have different implications than bequest values since the latter still are generated by (future) visitation. The contingent choice experiment used in this paper asks respondents to compare different potential future scenarios for management of either Zion or Arches National Park. Each scenario is made up of potential changes to seven attributes: wilderness protection, educational outreach, animal conservation, plant conservation, visitation levels, cultural/historical protection, and an annual tax payment. Respondents’ rankings are used to estimate a variety of mixed logit models. In addition, respondents are asked to report what percentage of the total value they receive from each attribute is due to use values, option values, bequest values, and existence values. While some previous researchers used similar questions to decompose nonuse values, this paper uses the decomposition questions differently. First, they are asked separately about each attribute in the experimental design of a contingent choice survey, as opposed to being asked once about total value or total nonuse value. Second, they are used as part of a mixed logit estimation of the relative part-worths of each attribute, rather than being used to decompose the final valuation estimates. Results indicate substantial heterogeneity by park attribute, location, individual, and type of nonuse value. These differences across attributes are largely independent of demographic and socioeconomic variables, though. The paper concludes with a discussion of the implications of the empirical findings for park management.

Biogeochemical and ecosystem properties in three adjacent semi‐arid grasslands are resistant to nitrogen deposition but sensitive to edaphic variability

AbstractDrylands have low nitrogen stocks and are predicted to be sensitive to modest increases in reactive nitrogen availability, but direct evidence that atmospheric nitrogen deposition will have sustained effects on dryland ecosystems is sparse and conflicting.We used three long‐running in situ nitrogen deposition simulation experiments and a complementary laboratory incubation experiment to address fundamental questions about how nitrogen inputs affect drylands: (1) What are the long‐ and short‐term consequences of nitrogen inputs for biogeochemical and ecosystem properties?; (2) Do these consequences depend on soil moisture availability?; and (3) Does soil texture modify the effects of nitrogen inputs and/or soil moisture availability?In 2011, we established three study sites along a soil texture gradient in Arches National Park with plots receiving 0, 2, 5 or 8 kg N ha−1annually (n = 5 per treatment per site). We assessed a suite of biogeochemical metrics over the long term and short term. To assess longer term effects, we sampled annually (2013–2019), just prior to spring nitrogen fertilization. To assess short‐term effects, we sampled immediately before and after spring nitrogen fertilization in 2013. Additionally, we compared foliar chemistry, soil extracellular enzyme activities, heterotrophic respiration rates, and nitrogen trace gas fluxes at select intervals during the study period (2011–2019). Finally, we conducted a laboratory incubation to measure the individual and interacting effects of soil moisture and nitrogen additions on soil microbial activity.We identified some short‐term effects in situ, but no lasting consequences of added nitrogen for any of the metrics measured. In the incubation, soil moisture treatments independently increased heterotrophic respiration rates but did not modify the effects of added nitrogen. In contrast to nitrogen treatments, soil texture was associated with large differences in biogeochemical cycling.Our results oppose the common prediction that coupled dryland biogeochemical cycles are sensitive to nitrogen inputs and suggest that fine‐scale edaphic heterogeneity is a key driver of dryland ecosystem properties.Synthesis. This study synthesizes a rare, long‐term dataset, which provides robust evidence that carbon and nutrient cycling and availability are resistant to realistic levels of atmospheric nitrogen deposition in remote dryland ecosystems.

The distribution of theropod-dominated ichnofaunas in the Moab Megatracksite area, Utah: implications for Late Jurassic palaeobiology along an arid coast

ABSTRACT The Late Jurassic, ‘single surface’ Moab Megatracksite between Green River, Utah and the Colorado-Utah State line is associated with the sharp, colour-enhanced, inter-formational contact between white, reworked dune sandstones from the aeolian Moab Member of the Curtis Formation and red, sabkha facies siltstones and sandstones of the upper tongue of the Summerville Formation. Previous studies described theropod (Megalosauripus and Therangospodus) dominated assemblages from ~25 sites in the megatracksite core area around Arches National Park, and briefly interpreted the transgressive mechanisms of the Sundance sea which helped create and preserve the megatracksite. Since the 1990s ~20 newly studied tracksites reveal a cumulative total of ~4,300 tracks and three sites are now designated as, federally managed, interpretative tourist destinations. Similar track assemblages, collectively constituting Megalosauripus-Therangospodus ichnocoenoses have now also been found at lower stratigraphical levels associated with J-3 Unconformity contact zones. These new discoveries relate to stratigraphic studies associated with short-term changes in Sundance Sea level affecting coastal dune facies (Slick Rock and Moab members) across low gradient, inter- and sub-tidal sand flats, and sabkha-like deposits under arid conditions. The multiple (>50) theropod dominated ichnofaunas are integral to palaeobiological understanding of an area from which no body fossils are known.

Integration of tetrapod ichnofaunas and coastal dynamics for paleocommunity reconstruction in the Curtis and Summerville formations (Jurassic), eastern Utah

ABSTRACT The transition between the aeolian Moab Member of the Curtis Formation and the marginal marine upper tongue of the Summerville Formation, in the area of Arches National Park, Utah, facilitated the registration of the distinctive theropod-dominated Moab Megatracksite complex, which is something of an ichnological cause célèbre. The complex reveals three interpenetrating ichnofaunas each with distinctive ichnofacies characteristics. The present study focuses on the small theropod-dominated assemblages from the coastal dune facies and applies Walther’s Law of Facies to the sequence relationship between onshore ichnoassemblages, the late pulse of transgression by the Summerville sea, and the development of the shallow marine Pteraichnus ichnocoenosis. Together, these spatio-temporal facies relationship between onshore terrestrial, shoreline and shallow marine facies and their contained ichnofaunas shed useful light on the Late Jurassic tetrapod ecology of the region, in an area entirely lacking tetrapod body fossils. The small theropod dune ichnofauna has obvious precursors in other Jurassic dune facies. The shoreline and shallow marine ichnocoenosis also fit certain ichnofacies models, despite the lack of comparable ichnofaunas in the area. Abundant trackway size frequency data yield body mass estimates which allow testing of recently proposed palaeobiological theories on theropod ontogeny and community structure based on the skeletal record.

Observing COVID-19 related behaviors in a high visitor use area of Arches National Park.

Visitation to parks and protected areas is a common COVID-19 coping strategy promoted by state and national public health officials and political leadership. Crowding and congestions in parks has been a perennial problem and the ability to socially distance within them is an unproven assumption. Is it possible to socially distance in a busy national park that has been designed to concentrate use? An observational study was conducted in July 2020 at the outside foyer of the Visitor Center of Arches National Park. Motion sensor cameras were placed to record one-minute videos when a person entered the field of view. Number of groups, group size, facial coverings and encounters within 6 feet (1.83 meters) of other groups were recorded. Groups were smaller on average than recorded in previous studies. Approximately 61% of the visitors wore masks. Most groups (69%) were able to experience the visitor center with no intergroup encounters. We model the probability of intergroup encounters and find as group size and number of groups increases, the probability of encounters rises. With four groups present, the probability of one or more encounters ranges from 19% to 40% for common group sizes, while if eight groups are present, the probability of one or more encounters increases from 34% to 64% for common group sizes. Under conditions in which park visitors have the physical space to avoid close encounters with other groups they are taking advantage of the opportunity. Visitors are minimizing group size, wearing masks, and remaining socially distant. However, encounters increase as the number or the size of the groups increases. In other areas of the parks this ability to avoid encounters may not be as possible. We recommend that park managers continue to appeal for compliance with CDC guidelines, especially the wearing of masks and encouraging visitors to split up into small groups when visiting.

Sustainable Heritage Tourism: Native American Preservation Recommendations at Arches, Canyonlands, and Hovenweep National Parks

The sustainable use of Native American heritage places is viewed in this analysis as serving to preserve their traditional purposes and sustaining the cultural landscapes that give them heritage meaning. The research concerns the potential impacts of heritage tourism to selected Native American places at Arches National Park, Canyonlands National Park, and Hovenweep National Monument. The impacts of tourists on a heritage place must be understood as having both potential effects on the place itself and on an integrated cultural landscape. Impacts to one place potentially change other places. Their functions in a Native American landscape, and the integrity of the landscape itself. The analysis is based on 696 interviews with representatives from nine tribes and pueblos, who, in addition to defining the cultural meaning of places, officially made 349 heritage management recommendations. The U.S. National Park Service interprets Natives American resources and then brings millions of tourists to these through museums, brochures, outdoor displays, and ranger-guided tours. Native American ethnographic study participants argued that tourist education and regulation can increase the sustainability of Native American places in a park and can help protect related places beyond the park.

Managing Carrying Capacity at Arches National Park

Abstract Visitor use of Arches National Park has grown dramatically in the past few decades and now exceeds 1 million visits annually. This has led to the trampling of fragile soils and vegetation, as well as crowding on trails and at attraction sites. The National Park Service developed and applied its Visitor Experience and Resource Protection framework to measure and manage carrying capacity at Arches; the first national park to use a management-by-objectives framework for this purpose. The process has led to an insightful exploration of the balance between preservation of the environment and visitor experience. Information Adapted from ‘Chapter 8 – How Many Visitors is Too Many at Arches?’. In: Manning R.E. and Anderson L.E (eds) Managing outdoor recreation: case studies in the National Parks . CABI, pp. 71-75. © CAB International 2012

Exploring the Case: Managing Carrying Capacity at Arches National Park

Introduction The question of carrying capacity is one faced by many protected natural areas. It might appear simple: if the number of visitors is such that it risks damaging the environment or biodiversity, then that number should be restricted or the visitor flow modified. On closer examination, the issues raised are complex. How do you define ‘damage’? How do you establish that a number is too high? Is it too high only at certain moments or in certain places? Can visitor behaviour be influenced? If one imposes restrictions, should all visitors be treated alike, or should some have priority? The more we consider carrying capacity, the more we realize that it is connected to many other issues. The case of Arches gives us an insight, therefore, on how a National Park Authority approaches visitor management as a whole.

Landscape Arch, Delicate Arch, and Double Arch in Arches National Park, Southeastern Utah

Arches National Park in southeastern Utah has the greatest concentration of natural rock arches in the world. The park is located in a geologic region called the Paradox fold and fault belt in the northern Paradox Basin and showcases spectacular and classic Colorado Plateau geology with its colorful sedimentary rocks, ancient sand dunes, cliffs, domes, fins, and pinnacles, as well as the arches. The arches in the park and the surrounding region were formed by a unique set of circumstances involving Middle Pennsylvanian (about 308 million years ago [Ma]) to Late Triassic (200 Ma) movement of subsurface salt layers, Middle Pennsylvanian to Late Cretaceous (about 70 Ma) deposition, and Tertiary and Quaternary (23 Ma to the present) folding, faulting, erosion, and salt dissolution. Massive, hard, brittle sandstones jointed by folding, resting on or containing soft layers or partings, and located near fold structures such as salt-cored anticlines undergoing dissolution, and a dry climate, all favor the formation of arches. Rarely do all these phenomena occur in one place, but they do in Arches National Park.The Natural Arch and Bridge Society (NABS) stated, “A natural arch is a rock exposure that has a hole completely through it formed by the natural, selective removal of rock, leaving a relatively intact frame.” They also make it clear that a natural bridge (which is at least partially formed by flowing water) is one type of natural arch (NABS website) (see A Bit of Perspective, below, for more explanation). Using their own criteria, Stevens and McCarrick (1988) catalogued over 2000 natural arches in Arches National Park; most have unique characteristics that could qualify them as geosites. However, the three most famous arches in the park, and perhaps the world, are Landscape Arch, Delicate Arch, and Double Arch, and thus these were selected as the geosites for this paper.

미국 유타 아치스국립공원 내에 발달하는 아치형태의 분류와 발달원인 분석

모아브의 아치스국립공원에는 유타주의 상징인 델리커트아치(Delicate Arch)를 비롯하여 수천 개의 생성중이거나 풍화에 의해 소멸되고 있는 아치들이 발달하고 있다. 본 연구에서는 아치들의 주변에서 관찰되는 지질구조요소들이 아치의 형성과 형태의 변화에 어떠한 요인으로 작용하였는지에 초점을 맞추어 아치들을 분류하고 그 형성원인을 이해하고자 하였다. 분류를 위하여 아치가 발달하는 층의 위치에 따라 슬리크암층원(Slick Rock Member)을 하부, 중부, 그리고 상부로 나누어 분석하였다. 아치의 형태에 영향을 미친 지질요소는 크게 4가지로 구분되었다. 슬리크암층원의 하부에 발달한 아치는 듀이브릿지층원(Dewey Bridge Member)의 완만한 습곡에 의한 인장단열의 발달로 아치들이 형성된 것으로 해석되었으며, 슬리크암층원의 중부에서는 지하심부 암염돔의 영향으로 발달한 습곡과 이에 수반된 암석지느러미(rock fins)뿐만 아니라 변형띠, 층리, 단열 등 다양한 요인이 복합적으로 작용하여 다양한 형태의 아치를 형성하였음이 밝혀졌다. 이 지역에 집중적으로 아치들이 발달하는 이유는 이 지역에 적당하게 변형을 받은 지층들이 적절한 높이로 융기하여 차별적인 풍화침식을 받았기 때문으로 판단된다.

The Sublimity of Great Landscapes

A personal evocation of one of the glories of the US National Park system: Delicate Arch in Arches National Park, Utah.

The impact of faults and fluid flow on seismic images of a relay ramp over production time

Relay ramps can act as conduits for fluid flow in producing hydrocarbon reservoirs, but the two bounding faults are often at the limit of seismic resolution. To study the impact of relay ramps and their fluid composition on seismic data, we present an integrated workflow combining flow simulation in a geomodel of an outcrop relay ramp, forward seismic modelling and seismic-attribute-based volume extraction. In the chosen outcrop of the Arches National Park (Utah, USA), the petrophysical properties are conditioned by deformation bands present in the sandstone, and are used to run a simple water injector–oil producer fluid-flow simulation. Pre-stack depth-migration seismic images are obtained at t = 0, t 1 = 10 and t 2 = 20 years of the flow simulation. The seismic image porosity changes at t = 0 when the model is oil-saturated, whereas the water–oil contacts have stronger amplitude contrasts at later stages. With an adapted attribute-based workflow, we are able to extract geobodies corresponding to the faults and the relay ramp from the three seismic cubes. By varying workflow parameters, we also show reservoir and acquisition conditions that can affect the resolution of the relay ramp on the seismic image either positively or negatively.

The Stones I Carry

The Stones I Carry Reg Darling (bio) The stones in my pocket help keep me honest by being stronger and truer than my words. They tether me to places that seem radiant with spirit and resonant with truths that cannot be uttered. [I don’t know what “spirit” fully means, but in the absence of a better word, I accept its ambiguity. The difference between a mossy, water-smoothed and -shaped marble boulder in southwestern Vermont and a paved parking lot anywhere transcends both semantics and philosophy. That difference is what I call spirit, and it keeps me alive. Spirit’s manifestations are many, and I can’t perceive them all, which is why I decline the violent exclusivity of belief. Instead, I try to live in the confluence of my heart’s strange mysteries and the land’s implacable wildness.] In a sense, I carry those places in my pocket, and that helps me to carry them in my heart. Weminuche Wilderness Area Schoodic Peninsula Rio Grande Gorge [End Page 135] Arches National Park Taconic Range Green Mountains [Colorado, Maine, New Mexico, Utah, Vermont.] One morning in the mid-1990s, when I was getting ready for a busy office day and had to teach in the evening, I was suffering from a lingering cold and felt harried and overwhelmed. My weary distress was pretty obvious. As I was leaving, my son Oren, eleven years old then, gave me a white pebble. “Here, carry this with you. It’s from Gifford Woods,” he said. And through that weary stressful day and many days to come, it was a comforting presence. [Gifford Woods State Park, near Killington, Vermont, was a favorite camping place on the summer wanders that gave me lifesaving respite from a stressful career, and rendered Oren’s vision of the world both broader and more intimate.] I carried the stone Oren gave me in my pocket for a dozen years. Its sharp edges were worn smooth by coins, keys, pens, and the smooth, rounded quartz pebble from my ancestral territory that soon joined it in my pocket. [The Tionesta watershed of the Allegheny Plateau.] Once, I left Oren’s stone in a special place in the woods (where the resident ravens knew me and I became acquainted with a large, ghost-like coyote whom I regarded as brethren) for most of a summer. [Nowadays one must hike through an oil field to get there.] When I retrieved it, I imagined it to be somehow infused with the spirit of that place mingled with the spirit of the Green Mountains. [End Page 136] [It became poetry made of stone.] When Oren was fifteen, a floatplane carried us far out into the tundra of northern Quebec, where we hunted caribou with longbows and homemade arrows. Sitting near a well-used caribou trail on a large island in the Pons River, I felt an unexpected wave of deep, childlike homesickness. [We were so incredibly far from everything known and dearly loved in a staggeringly beautiful, but also incredibly harsh, land.] Holding the quartz pebble from the beloved landscape of my ancestry and birth transformed poignancy into comfort and fond nostalgia. The pastoral gentleness of my native Alleghenies seemed alive in that smooth, round piece of white quartz. After I killed a caribou on the island a few days later, I left the pebble there. It seemed intuitively necessary. [We brought home our winter’s meat and through it took the tundra into our blood, muscles, and bones.] The pebble I left on the island was soon replaced by another that was, in turn, left in a faraway place. I began gathering pebbles on my wandering hikes (often retracing routes gleaned from my great-grandfather’s journals) for the purpose of leaving them on my travels beyond my homeland. There are quartz pebbles from the Tionesta watershed in Arkansas, Colorado, Delaware, Florida, District of Columbia, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Brunswick, New Hampshire, New Mexico, New York, North Carolina, Oklahoma, Ontario, Quebec, South Carolina, Tennessee, Texas, Utah, Vermont, [End Page 137] Virginia, and West Virginia. There are stones from all those places...

Examining crowding among winter recreationists in Rocky Mountain National Park

ABSTRACTCrowding in America’s national parks is a severe problem. Places like Arches National Park are witnessing such an influx of tourism that they are considering new management techniques. Understanding the social science of the situation through crowding studies assists park management in developing strategies for resource protection, recreation management, conflict prevention, and user satisfaction. The purpose of this research was to explore feelings and perceptions of crowding at the Bear Lake trailhead in Rocky Mountain National Park (RMNP). The main goals of the study were to obtain information about visitors of RMNP during the winter season while examining the type(s) of activities they were engaging in along with exploring any feelings of crowding they might have felt. There were 428 completed questionnaires for this study. Results showed fewer conditions of crowding compared to summer users at the park. However, the results of this study also show that some individuals did experience crowding and even conflict during their visit. Such results are valuable as a complementary source of information to the summer studies that have already been concluded. Photo elicitation methods also supported normative standards of low user encounters on the trail in order to deter greater feelings of crowding.

Linking climate to changing discharge at springs in Arches National Park, Utah, USA

AbstractGroundwater‐fed springs are essential habitat for many dryland species. Climate projections forecast an increasingly arid climate for the southwestern United States. Therefore, an understanding of the relationships between climate and spring discharge is increasingly important. Monthly discharge measurements were recorded from 2001 to 2014 at three jointed bedrock springs in and near Arches National Park, Utah, United States. Discharge was compared with the potential evapotranspiration (PET) and precipitation derived from Daymet gridded climate data. Despite the similarities in location, aquifer type, and climate exposure, all three springs showed different responses to local climate. Two springs emerging from the western aquifer had decreases in discharge during differing portions of their record, while the eastern aquifer spring had stable discharge. At the monthly scale, there was a strong inverse relationship between measured discharge and PET at all three springs, likely due to vegetation accessing the water prior to its surface expression. Annual average winter discharge from both western aquifer springs responded to reductions in 10‐year cumulative winter precipitation, while discharge from the eastern aquifer spring did not correspond well to precipitation within the period of record. Uncertainty in climate projections for aquifer recharge remains high, but increasing air temperatures will likely lead to increased PET and reduced spring surface flow. Better characterization of climate and spring discharge relationships will help managers protect contributing areas that may be more susceptible to groundwater withdrawal and better understand the available habitat for groundwater‐dependent ecosystems and species.

A mast-seeding desert shrub regulates population dynamics and behavior of its heteromyid dispersers.

Granivorous rodent populations in deserts are primarily regulated through precipitation‐driven resource pulses rather than pulses associated with mast‐seeding, a pattern more common in mesic habitats. We studied heteromyid responses to mast‐seeding in the desert shrub blackbrush (Coleogyne ramosissima), a regionally dominant species in the Mojave–Great Basin Desert transition zone. In a 5‐year study at Arches National Park, Utah, USA, we quantified spatiotemporal variation in seed resources in mast and intermast years in blackbrush‐dominated and mixed desert vegetation and measured responses of Dipodomys ordii (Ord's kangaroo rat) and Perognathus flavescens (plains pocket mouse). In blackbrush‐dominated vegetation, blackbrush seeds comprised >79% of seed production in a mast year, but 0% in the first postmast year. Kangaroo rat abundance in blackbrush‐dominated vegetation was highest in the mast year, declined sharply at the end of the first postmast summer, and then remained at low levels for 3 years. Pocket mouse abundance was not as strongly associated with blackbrush seed production. In mixed desert vegetation, kangaroo rat abundance was higher and more uniform through time. Kangaroo rats excluded the smaller pocket mice from resource‐rich patches including a pipeline disturbance and also moved their home range centers closer to this disturbance in a year of low blackbrush seed production. Home range size for kangaroo rats was unrelated to seed resource density in the mast year, but resource‐poor home ranges were larger (P < 0.001) in the first postmast year, when resources were limiting. Blackbrush seeds are higher in protein and fat but lower in carbohydrates than the more highly preferred seeds of Indian ricegrass (Achnatherum hymenoides) and have similar energy value per unit of handling time. Kangaroo rats cached seeds of these two species in similar spatial configurations, implying that they were equally valued as stored food resources. Blackbrush mast is a key resource regulating populations of kangaroo rats in this ecosystem.

Five Tectonic Settings in Five National Parks and Forests: A Field Camp Experience

In summer 2014, Southern Utah University’s field camp visited five national parks and forests to study five different tectonic settings in five weeks. These included: thick-skinned contraction of the Laramide Orogeny at Capitol Reef National Park; normal faulting due to salt tectonics of the Paradox Formation at Arches National Park; thin-skinned folding and thrusting of the Sevier Orogeny at Fish Lake National Forest and Kolob Canyon of Zion National Park; foreland sedimentary transitions in the Book’s Cliffs areas of Utah; thrusting and conjugate fracture development due to the gravitational collapse of the Marysvale volcanic field at Bryce Canyon National Park; and a metamorphic core complex at Great Basin National Park and Hendry’s Creek in the Northern Snake Range of Nevada. This article provides a brief summary and photographic tour of the students’ experiences studying each tectonic environment, and it highlights wonderful geological features exposed in our national parks.