Zion National Park Research Articles

Plant Species Coalition Groups of Zion National Park: An Individualistic, Floristic Alternative to Vegetation Classification

Vegetation surveys at Zion National Park (Zion), Utah, have contributed to our understanding of plant community patterns and their relationship to environmental factors. Previous authors used vegetation plot data to characterize vegetation types at Zion following conventional procedures that emphasize spatial discreteness and dominant species. We developed and applied an alternative approach for community characterization that emphasizes nondiscrete presence-absence patterns and is compatible with the individualistic concept. We reanalyzed existing plot data from Zion using coalition clustering, an algorithm that identifies groups of positively-associated species referred to as coalition groups. Each species and plot in the data set was linked to each coalition group via an “affinity” value obtained through weighted averaging. Affinity values were used to characterize environmental affinities of coalition groups through regression tree modeling and predictive mapping. We also identified species that frequently co-occurred with coalition groups (affiliate species) and those that frequently co-occurred with high cover (dominant-affiliates), viewing these as alternatives to conventional prevalent and dominant species. Following this approach, we identified 10 coalition groups at Zion that overlapped compositionally and spatially to differing degrees. Mesic environments on a gradient from low-elevation riparian zones through mid-elevation narrow canyons to high-elevation plateaus were represented by 3 overlapping groups. Two groups occupying slickrock and sand environments were detected on the Navajo Sandstone, as well as 2 on mesa tops above it. At lower elevations, 3 intergrading xeric coalition groups were distinguished. When previously classified associations of the National Vegetation Classification were clustered based on shared affinities to coalition groups, the arrangement differed from existing classification schemes but was environmentally interpretable. Although these patterns are contingent on conditions at the time of data collection, they provide a baseline that could be used for evaluating and predicting plant community change in the park. With proper attention to sampling and analysis issues, our community characterization approach could be applied in other settings as an alternative or supplement to conventional vegetation classification.

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.

Recognition of a highly restricted freshwater snail lineage (Physidae: Physella) in southeastern Oregon: convergent evolution, historical context, and conservation considerations

Non-marine mollusks have the highest number of documented extinctions of any major taxonomic group. Given their conservation status and the numerous cases of taxonomic uncertainty concerning freshwater mollusks in particular, the recognition of potentially endangered species is critically important. Here, we evaluate the genetic distinctiveness and phylogenetic position of a freshwater snail restricted to a series of geothermal springs within the Owyhee River drainage in Oregon (the ‘Owyhee wet-rock physa’). Because these snails closely resemble Physella (Petrophysa) zionis, a wet-rock physa that occurs in a small area in Zion National Park (Utah), the Owyhee wet-rock physa is presumably either closely related to or represents a disjunct population of P. zionis. However, phylogenetic analyses of sequences of mitochondrial cytochrome oxidase I and nuclear first and second internal transcribed spacer gene regions indicate that the Owyhee wet-rock physa is genetically distinct from other physid species. Despite exhibiting similar morphologies, the Owyhee wet-rock physa and P. zionis are distantly related physids; instead, the Owyhee wet-rock physa is most closely related to a population of physids from central California. These results suggest that convergent evolution may be responsible for the similar shell morphologies of the Owyhee wet-rock physa and P. zionis. Furthermore, the close relationship between physid populations in southeastern Oregon and central California suggests a historical connection between the Owyhee River and river drainages to the south. Finally, we recommend that the Owyhee wet-rock physa be considered critically endangered based on its extremely limited distribution.

Editorial: third international tenebrionoidea symposium.

Editorial: third international tenebrionoidea symposium.

A geospatial model of ambient sound pressure levels in the contiguous United States.

This paper presents a model that predicts measured sound pressure levels using geospatial features such as topography, climate, hydrology, and anthropogenic activity. The model utilizes random forest, a tree-based machine learning algorithm, which does not incorporate a priori knowledge of source characteristics or propagation mechanics. The response data encompasses 270 000 h of acoustical measurements from 190 sites located in National Parks across the contiguous United States. The explanatory variables were derived from national geospatial data layers and cross validation procedures were used to evaluate model performance and identify variables with predictive power. Using the model, the effects of individual explanatory variables on sound pressure level were isolated and quantified to reveal systematic trends across environmental gradients. Model performance varies by the acoustical metric of interest; the seasonal L50 can be predicted with a median absolute deviation of approximately 3 dB. The primary application for this model is to generalize point measurements to maps expressing spatial variation in ambient sound levels. An example of this mapping capability is presented for Zion National Park and Cedar Breaks National Monument in southwestern Utah.

Back Cover: Regeneration of a Conjugated sp2Graphene System through Selective Defunctionalization of Epoxides by Using a Proven Synthetic Chemistry Mechanism (Chem. Eur. J. 7/2014)

Selective defunctionalization of epoxides on graphene oxide using proven synthetic chemistry is shown on the background of layered rock structures in Zion National Park. For more details, see the Full Paper by M. Pumera and C. K. Chua on page 1871 ff.

Adaptive Restoration of River Terrace Vegetation through Iterative Experiments

ABSTRACT Restoration projects can involve a high degree of uncertainty and risk, which can ultimately result in failure. An adaptive restoration approach can reduce uncertainty through controlled, replicated experiments designed to test specific hypotheses and alternative management approaches. Key components of adaptive restoration include willingness of project managers to accept the risk inherent in experimentation, interest of researchers, availability of funding for experimentation and monitoring, and ability to restore sites as iterative experiments where results from early efforts can inform the design of later phases. This paper highlights an ongoing adaptive restoration project at Zion National Park (ZNP), aimed at reducing the cover of exotic annual Bromus on riparian terraces, and revegetating these areas with native plant species. Rather than using a trial-and-error approach, ZNP staff partnered with academic, government, and private-sector collaborators to conduct small-scale experiments to e...

Interpretation of Geoheritage for Geotourism – a Comparison of Chinese geoparks and National Parks in the United States

Abstract This study presents an interpretation system model of geoheritage to facilitate the understanding of geoscience knowledge by the common lay person. Interpretation system construction is crucial to geoparks and is a shared value. The improvement of the effectiveness of geoheritage interpretation is still under exploration. Therefore, the interpretation systems of two global geoparks in China are outlined and compared with the interpretation system in Zion National Park in the United States. From lessons and experiences, this paper suggests utilizing geotourism as a complete contextual communication system, in which a geopark (source) delivers information about its unique cultural and natural values to target tourists (receivers) through tourism activities (channels). The communication effect of geotourism is monitored by feedback from tourists through the post-travel surveys or activities. We expect that this model will provide a better interpretation of geoheritage with a new perspective.

Jurassic earthquake sequence recorded by multiple generations of sand blows, Zion National Park, Utah

Earthquakes along convergent plate boundaries commonly occur in sequences that are complete within 1 yr, and may include 8–10 events strong enough to generate sand blows. Dune crossbeds within the Jurassic Navajo Sandstone of Utah (western United States) enclose intact and truncated sand blows, and the intrusive structures that fed them. We mapped the distribution of more than 800 soft-sediment dikes and pipes at two small sites. All water-escape structures intersect a single paleo-surface, and are limited to the upper portion of the underlying set of cross-strata and the lower portion of the overlying set. A small portion of one set of crossbeds that represents ∼1 yr of dune migration encloses eight generations of eruptive events. We interpret these superimposed depositional and deformational structures as the record of a single shock-aftershock earthquake sequence. The completeness and temporal detail of this paleoseismic record are unique, and were made possible when sand blows repeatedly erupted onto lee slopes of migrating dunes. Similar records should be sought in modern dunefields with shallow water tables.

Visitor Assessment of the Mandatory Alternative Transportation System at Zion National Park

Transportation infrastructure in national parks has historically been designed for the automobile. With more vehicles in the parks, visitors found themselves in circumstances more reminiscent of a city than a park. Traffic jams, overcrowding, illegal parking, horn honking, and idling vehicles became common, creating stress and contributing to air and noise pollution, the very things visitors were hoping to get away from. Park managers began searching for alternatives, including shuttle systems. Many national parks have implemented optional shuttle systems, but relatively few have completely closed roads to vehicles, transporting visitors on mandatory shuttles. Zion National Park instituted a mandatory shuttle system in May 2000 to relieve crowding and congestion in the main canyon and to protect natural resources. Taking a longitudinal approach, attributes of the shuttle (e.g., crowding, accessibility, freedom, efficiency, preference, and success) were assessed with experiential park factors (e.g., scenic beauty, naturalness, solitude, tranquility, air quality, and soundscape) in 2000, 2003, and 2010 by surveying shuttle-riding park visitors. While visitors initially reported a few reservations about the shuttle system, by 2003, the majority rated the system successful. Ratings of all shuttle-related variables, except crowding, improved over the decade. Improvements were greatest for freedom, accessibility, and efficiency. Multiple regression found overall shuttle success to be mediated by preference, freedom, accessibility, efficiency, and comfort. Experiential variables assessing park conditions followed a similar pattern, with improved ratings as the decade progressed. Results provide important insights into the visitor experience with mandatory alternative shuttle systems in national parks.

Tramways, Draw Works and Flumes

The settlement of the American West was directly dependent on the extraction of resources including minerals, precious metals, timber, and the commerce that resulted. The infrastructure that developed around these extraction activities was intended to be merely functional, and therefore temporary. Readily available forest resources made timber structures relatively inexpensive and easy to build; they could be put into service quickly and were adequate to immediate needs. Many of these structures survive today at former mining and milling sites, along with remnants of the railroad lines that served them. Together they provide a compelling picture of the development of the American West and the technologies used to extract, refine, and transport the materials that initiated settlement of the region. Preservation of these sites and structures poses many interesting problems: Most of the structures were designed to meet short-term needs and have already outlasted their intended service life; Most of the structures were strictly utilitarian, and maintenance of them was discontinued when mining or logging operations ceased; Exposure of these structures to severe weather conditions is typical. The structures are at remote sites and access is extremely limited; Many of the structures are dangerous due to the extent of deterioration and proximity to open mines, adits, and industrial waste. In this presentation, the authors will use three case studies to illustrate preservation issues common to remote resource extraction sites, techniques used to access the timber structures, and some of the stabilization strategies implemented at each of the sites. The case studies include the aerial tramway of the Keane Wonder Mine in Death Valley National Park, the Cable Mountain Draw Works in Zion National Park, and the Hanging Flume in Colorado.

Materializing Tensions: How Maps and Trails Mediate Nature

Before visitors to national parks take their first steps of a hike, maps shape their perceptions of nature. Additionally, on the trail, the landscapes organize visitors' experiences by concealing and revealing the trail itself. Focusing on one Zion National Park hiking trail, Hidden Canyon, as a rhetorical artifact, I argue that maps and trails materialize tensions of access–preservation and safety–risk, functioning as mediators between recreators and nature. My analysis employs the concept of landscape to connect maps and trails with our understanding of nature, foregrounding the consequences of material rhetoric in environmental communication.

Soil Seed Bank Responses to Postfire Herbicide and Native Seeding Treatments Designed to Control Bromus tectorum in a Pinyon–Juniper Woodland at Zion National Park, USA

AbstractThe continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.

Downslope coarsening in aeolian grainflows of the Navajo Sandstone

Downslope coarsening in grainflows has been observed on present-day dunes and generated in labs, but few previous studies have examined vertical sorting in ancient aeolian grainflows. We studied the grainflow strata of the Jurassic Navajo Sandstone in the southern Utah portion of its outcrop belt from Zion National Park (west) to Coyote Buttes and The Dive (east). At each study site, thick sets of grainflow-dominated cross-strata that were deposited by large transverse dunes comprise the bulk of the Navajo Sandstone. We studied three stratigraphic columns, one per site, composed almost exclusively of aeolian cross-strata. For each column, samples were obtained from one grainflow stratum in each consecutive set of the column, for a total of 139 samples from thirty-two sets of cross-strata. To investigate grading perpendicular to bedding within individual grainflows, we collected fourteen samples from four superimposed grainflow strata at The Dive. Samples were analyzed with a Malvern Mastersizer 2000 laser diffraction particle analyser. The median grain size of grainflow samples ranges from fine sand (164μm) to coarse sand (617μm). Using Folk and Ward criteria, samples are well-sorted to moderately-well-sorted. All but one of the twenty-eight sets showed at least slight downslope coarsening, but in general, downslope coarsening was not as well-developed or as consistent as that reported in laboratory subaqueous grainflows. Because coarse sand should be quickly sequestered within preserved cross-strata when bedforms climb, grain-size studies may help to test hypotheses for the stacking of sets of cross-strata.

The role of large predators in maintaining riparian plant communities and river morphology

Studies assessing the potential for large predators to affect, via trophic cascades, the dynamics of riparian plant communities and the morphology of river channels have been largely absent in the scientific literature. Herein, we consider the results of recent studies involving three national parks in the western United States: Yellowstone, Olympic, and Zion. Within each park, key large predators were extirpated or displaced in the early 1900s and subsequent browsing pressure by native ungulates initiated long-term declines in recruitment (i.e., growth of seedlings/sprouts into tall saplings and trees) of palatable woody species and impairment of other resources. Channel responses to browsing-suppressed riparian vegetation included increased widths of active channels via accelerated bank erosion, erosion of floodplains and erraces, increased area of unvegetated alluvium, channel incision, and increased braiding. A reduced frequency of overbank flows indicated these rivers have become increasingly disconnected from historical floodplains because of channel widening/incision. Results from Zion National Park also identified major biodiversity affects (e.g., reduced abundance of plant and animal species). Although these studies were conducted in national parks, results may have implications concerning riparian plant communities, biodiversity, and channel morphology for streams and rivers draining other public lands in the western US. It is on these lands that native and introduced ungulates have often heavily utilized riparian areas, largely in the absence of key predators, with significant consequences to plant communities and channels.

Selling a State to the Nation

After gaining statehood in 1896, Utah struggled to overcome perceptions of its un-Americanness. Mormons (members of the Church of Jesus Christ of Latter-day Saints) made up the majority of the population and held most political offices, and the practice of polygamy and the threat of theocracy from the dominant religion fueled perceptions that Utah was an outsider in the Union. The national park movement provided a means for the state to promote its landscape as a contribution to the country and to prove its worth to America. Journalism associated with the designation of Zion National Park (1919) shows how Utah's reporters used landscape to fuel a booster press in a struggle to bridge the chasm that separated the state from the rest of the country. Much like the nation used the early national parks as a means of establishing national identity, Utah's press used the parks to establish the state's Americanness.

Impacts of Hikers on Aquatic Invertebrates in the North Fork of the Virgin River, Utah

Abstract Effects of in-stream hiking on benthic standing stocks and drifting aquatic invertebrates and on organic matter were examined in the North Fork of the Virgin River, Zion National Park, Washington County, Utah. Densities of drifting aquatic invertebrates and organic matter increased with increasing numbers of hikers and reached a threshold level at high numbers of hikers. However, there was no apparent longer-term effect on standing stocks of benthic invertebrates or on organic matter. Densities of benthic invertebrates and organic matter did not differ among sites. Results suggest that in-stream hiking in the North Fork of the Virgin River increases drifting by invertebrates, but invertebrates from nearby undisturbed patches readily colonize impacted reaches.

Restoring Burned Areas at Zion National Park (Utah)

Restoring Burned Areas at Zion National Park (Utah)

Estimating aboveground forest biomass carbon and fire consumption in the U.S. Utah High Plateaus using data from the Forest Inventory and Analysis Program, Landsat, and LANDFIRE

Abstract The concentrations of CO 2 and other greenhouse gases in the atmosphere have been increasing and greatly affecting global climate and socio-economic systems. Actively growing forests are generally considered to be a major carbon sink, but forest wildfires lead to large releases of biomass carbon into the atmosphere. Aboveground forest biomass carbon (AFBC), an important ecological indicator, and fire-induced carbon emissions at regional scales are highly relevant to forest sustainable management and climate change. It is challenging to accurately estimate the spatial distribution of AFBC across large areas because of the spatial heterogeneity of forest cover types and canopy structure. In this study, Forest Inventory and Analysis (FIA) data, Landsat, and Landscape Fire and Resource Management Planning Tools Project (LANDFIRE) data were integrated in a regression tree model for estimating AFBC at a 30-m resolution in the Utah High Plateaus. AFBC were calculated from 225 FIA field plots and used as the dependent variable in the model. Of these plots, 10% were held out for model evaluation with stratified random sampling, and the other 90% were used as training data to develop the regression tree model. Independent variable layers included Landsat imagery and the derived spectral indicators, digital elevation model (DEM) data and derivatives, biophysical gradient data, existing vegetation cover type and vegetation structure. The cross-validation correlation coefficient ( r value) was 0.81 for the training model. Independent validation using withheld plot data was similar with r value of 0.82. This validated regression tree model was applied to map AFBC in the Utah High Plateaus and then combined with burn severity information to estimate loss of AFBC in the Longston fire of Zion National Park in 2001. The final dataset represented 24 forest cover types for a 4 million ha forested area. We estimated a total of 353 Tg AFBC with an average of 87 MgC/ha in the Utah High Plateaus. We also estimated that 8054 Mg AFBC were released from 2.24 km 2 burned forest area in the Longston fire. These results demonstrate that an AFBC spatial map and estimated biomass carbon consumption can readily be generated using existing database. The methodology provides a consistent, practical, and inexpensive way for estimating AFBC at 30-m resolution over large areas throughout the United States.

Hikers Impact on the North Fork of the Virgin River, Zion National Park, Utah

The research studied the benthic algal cyanobacterial community and ecological and physical characteristics to determine whether recreational hiking impacts the Virgin River in Zion National Park, Utah. Sampling occurred on 10 August 2001 of three cobblestones from 11 different riffle locations. The null hypothesis is the algal community will change in assemblage structure and function along a hikers gradient. This hypothesis predicts that lower or no visitor use sites will have lower algal species diversity, average cell biovolume, cell density, total biomass, chlorophyll a, AFDM, and ash weight and percentage. There were 99 benthic algal and cyanobacteria species identified from the Virgin River. The benthic flora and ecological/physical parameters were examined to assess the impact of hiking. Canonical correspondence analyses of the species data separated sites into 2-groups (impacted and none to low impact). The first and second axes of the ecological/physical variables explained 67% of the variation. The average cell biovolume and species diversity were positively aligned to the first axis, while cell density was slightly negatively aligned. The data suggests the ecological threshold had been reached lowering the relative abundance of diatoms and increasing cyanobacteria contribution. Further research needs to be accomplished determine exact cause.