Geology topics

Research about Canyonlands National Park

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

13 recordsLinked to original sources

USGS2026

Selective mortality leads to competitive release of a foundational perennial grass in an aridifying grassland

Vegetation dynamics in dryland ecosystems are defined by competition for water, a limiting and increasingly variable resource. As aridification creates warmer and drier conditions, with more frequent and intense droughts, the nature of competitive relationships may be altered, leading to changes in community composition. Reduced water availability is expected to decrease the cover and abundance of cool-season C 3 grasses on the Colorado Plateau, with unknown impacts on other plant functional types, such as drought-tolerant C 4 species. Here, we explore the effects of competitive release on Pleuraphis jamesii , a dominant C 4 grass with rooting and photosynthetic traits that may enable it to capitalize on the mortality of less drought tolerant C 3 species. To accomplish this, we used herbicide to create three removal treatments (C 3 grass and forb removal, C 4 grass removal, and control (no removal)) surrounding P. jamesii focal individuals and measured the subsequent impacts on water availability and plant water relations and growth. The experimentally induced mortality resulted in greater water availability for focal individuals in the C 3 removal treatment. Increased water availability in C 3 removal plots translated to less water stress and greater biomass production of focal P. jamesii plants, suggesting that competitive release can serve as the basis for shifts in community composition towards drought tolerant C 4 plants observed regionally. These responses were not observed in the C 4 removal treatment despite removing roughly equivalent amounts of total plant cover. Our results suggest that reductions in C 3 competitors may benefit drought-tolerant C 4 species through increased resource availability. These findings contribute to a mechanistic understanding of competitive interactions in increasingly water-limited systems.

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USGS2025

Optimizing the effectiveness of connectivity modifiers to reduce dryland degradation

Dryland degradation from unsustainable land use and increasing aridity often manifests as bare, interconnected areas that facilitate the loss or redistribution of resources (soil, seeds, and nutrients) through wind and run-off. Physical structures like branches and stick bundles, which disrupt these pathways and retain resources, are crucial for rehabilitation and restoration. Connectivity modifiers or ConMods, which are galvanized mesh structures that mimic low stature vegetation, are tools specifically designed to interrupt connected pathways and help reinforce overall site stability. Yet, how to effectively and consistently use ConMods to achieve site stability has not been thoroughly tested. Here, we used the Aeolian EROsion model to investigate the combined effects of ConMod height, porosity, and spacing on simulated horizontal sediment flux, a key indicator of site stability. We assessed ConMod performance as percent reduction in predicted sediment flux versus a bare, unvegetated 10,000 m 2 area for a range of horizontal sediment flux. Additionally, in a field experiment, ConMods increased litter retention by up to 15.6 mm compared to bare ground plots, demonstrating their potential to enhance both soil stabilization and resource retention. These findings underscore the potential of ConMods as flexible, cost-effective tools that interrupt positive feedbacks to degradation and provide measurable benchmarks for restoration success.

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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.

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USGS2023

Ecosystem resilience to invasion and drought: Insights after 24 years in a rare never-grazed grassland

Understanding the resilience of ecosystems globally is hampered by the complex and interacting drivers of change characteristic of the Anthropocene. This is true for drylands of the western US, where widespread alteration of disturbance regimes and spread of invasive non-native species occurred with westward expansion during the 1800s, including the introduction of domestic livestock and spread of Bromus tectorum , an invasive non-native annual grass. In addition, this region has experienced a multi-decadal drought not seen for at least 1200 years with potentially large and interacting impacts on native plant communities. Here, we present 24 years of twice-annual plant cover monitoring (1997–2021) from a semiarid grassland never grazed by domestic livestock but subject to a patchy invasion of B. tectorum beginning in ~1994, compare our findings to surveys done in 1967, and examine potential climate drivers of plant community changes. We found a significant warming trend in the study area, with more than 75% of study year temperatures being warmer than average (1966–2021). We observed a native perennial grass community with high resilience to climate forcings with cover values like those in 1967. In invaded patches, B. tectorum cover was greatest in the early years of this study (1997–2001; ~20%–40%) but was subsequently constrained by climate and subtle variation in soils, with limited evidence of long-term impacts to native vegetation, contradicting earlier studies. Our ability to predict year-to-year variation in functional group and species cover with climate metrics varied, with a 12-month integrated index and fall and winter patterns appearing most important. However, declines to near zero live cover in recent years in response to regional drought intensification leave questions regarding the resiliency of intact grasslands to ongoing aridification and whether the vegetation observations reported here may be a leading indicator of impending change in this protected ecosystem.

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USGS2020

The roles of flood magnitude and duration in controlling channel width and complexity on the Green River in Canyonlands, Utah, USA

Predictions of river channel adjustment to changes in streamflow regime based on relations between mean channel characteristics and mean flood magnitude can be useful to evaluate average channel response. However, because these relations assume equilibrium sediment transport, their applicability to cases where streamflow and sediment transport are decoupled may be limited. These general relations also lack the specificity that is required to connect specific characteristics of the streamflow and sediment regime with the dynamics of channel morphological change that create channel complexity, which is often of ecological interest. We integrate historical records of channel change, observations of scour and fill during a snowmelt flood, measurements of sediment transport, and predictions from a two-dimensional streamflow model to describe how annual peak flow magnitude and peak-flow duration interact with the upstream sediment supply to control channel form for a 15-km study reach on the regulated Green River in Canyonlands National Park, Utah. Two major decadal-scale episodes of channel narrowing have occurred within the study area. For each of these episodes, the reduction in average channel width was consistent with the change predicted by hydraulic geometry relations as a function of average flood magnitude. However, channel narrowing occurred during periods of exceptionally low annual floods. The most recent episode of channel narrowing occurred between 1988 and 2009, during low-flow cycles when the 5-yr mean peak flow was less than 60% of the long-term (1959–2016) mean peak flow. These findings, together with findings from previous studies, demonstrate that decreases in peak-flow magnitude caused by streamflow regulation, climate change, or a combination of those factors have driven episodes of channel narrowing on the Green River. Observations of streamflow, sediment-transport, and morphologic change coupled with predictions from a two-dimensional streamflow model indicate that peak flow magnitudes of at least 75% of the long-term mean peak flow are required to transport bed-material sand in suspension in all regions of the multi-thread channel and that the ~2-month duration of the snowmelt flood played an important role in creating conditions necessary to maintain channel conveyance. These results indicate that detailed characterizations of channel response such as these are needed to predict how river channels will respond to changes in streamflow regime that affect annual peak flow magnitude and duration.

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USGS2013

Dryland soil microbial communities display spatial biogeographic patterns associated with soil depth and soil parent material

Biological soil crusts (biocrusts) are common to drylands worldwide. We employed replicated, spatially nested sampling and 16S rRNA gene sequencing to describe the soil microbial communities in three soils derived from different parent material (sandstone, shale, and gypsum). For each soil type, two depths (biocrusts, 0–1 cm; below-crust soils, 2–5 cm) and two horizontal spatial scales (15 cm and 5 m) were sampled. In all three soils, Cyanobacteria and Proteobacteria demonstrated significantly higher relative abundance in the biocrusts, while Chloroflexi and Archaea were significantly enriched in the below-crust soils. Biomass and diversity of the communities in biocrusts or below-crust soils did not differ with soil type. However, biocrusts on gypsum soil harbored significantly larger populations of Actinobacteria and Proteobacteria and lower populations of Cyanobacteria. Numerically dominant operational taxonomic units (OTU; 97% sequence identity) in the biocrusts were conserved across the soil types, whereas two dominant OTUs in the below-crust sand and shale soils were not identified in the gypsum soil. The uniformity with which small-scale vertical community differences are maintained across larger horizontal spatial scales and soil types is a feature of dryland ecosystems that should be considered when designing management plans and determining the response of biocrusts to environmental disturbances.

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USGS2010

Chemical and textural controls on phosphorus mobility in drylands of southeastern Utah

We investigated several forms of phosphorus (P) in dryland soils to examine the chemical and textural controls on P stabilization on a diverse set of substrates. We examined three P fractions including labile, moderately labile, and occluded as determined by a modified Hedley fractionation technique. The P fractions were compared to texture measurements and total elemental concentrations determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Labile P related to the absence of materials involved in P sorption. Moderately labile P was most strongly associated with high total Al & Fe content that we interpret to represent oxides and 1:1 clay minerals. The occluded P fraction was strongly associated with low total Al & Fe environments and interpreted to represent 2:1 clay minerals where ligand exchange tightly sequesters P. The results indicate that the controls on P fraction distribution are initially closely tied to the chemical and physical properties of the bedrock units that contribute to soil formation. Further, these results suggest that the progression of stabilized P forms in dryland areas differs from the progression observed in mesic environments. Soil development in dryland settings, such as the formation of pedogenic carbonates, may lead to differing controls on P availability and the proportional size of the moderately labile fraction.

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USGS2006

Controls of bedrock geochemistry on soil and plant nutrients in Southeastern Utah

The cold deserts of the Colorado Plateau contain numerous geologically and geochemically distinct sedimentary bedrock types. In the area near Canyonlands National Park in Southeastern Utah, geochemical variation in geologic substrates is related to the depositional environment with higher concentrations of Fe, Al, P, K, and Mg in sediments deposited in alluvial or marine environments and lower concentrations in bedrock derived from eolian sand dunes. Availability of soil nutrients to vegetation is also controlled by the formation of secondary minerals, particularly for P and Ca availability, which, in some geologic settings, appears closely related to variation of CaCO3 and Ca-phosphates in soils. However, the results of this study also indicate that P content is related to bedrock and soil Fe and Al content suggesting that the deposition history of the bedrock and the presence of P-bearing Fe and Al minerals, is important to contemporary P cycling in this region. The relation between bedrock type and exchangeable Mg and K is less clear-cut, despite large variation in bedrock concentrations of these elements. We examined soil nutrient concentrations and foliar nutrient concentration of grasses, shrubs, conifers, and forbs in four geochemically distinct field sites. All four of the functional plant groups had similar proportional responses to variation in soil nutrient availability despite large absolute differences in foliar nutrient concentrations and stoichiometry across species. Foliar P concentration (normalized to N) in particular showed relatively small variation across different geochemical settings despite large variation in soil P availability in these study sites. The limited foliar variation in bedrock-derived nutrients suggests that the dominant plant species in this dryland setting have a remarkably strong capacity to maintain foliar chemistry ratios despite large underlying differences in soil nutrient availability.

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USGS2006

Performance of Bromus tectorum L. in relation to soil properties, water additions, and chemical amendments in calcareous soils of southeastern Utah, USA

In drylands of southeastern Utah, USA, the invasive exotic grass Bromus tectorum L. occurs in distinct spatial patterns suggesting soil control of ecosystem susceptibility to invasion. To improve our understanding of these patterns, we examined performance of B. tectorum in relation to additions of water, KCl, MgO, and CaO at seventeen 1600 m 2 sites distributed across a calcareous soil gradient in Canyonlands National Park. Water additions resulted in a 57% increase in B. tectorum establishment. Fall establishment was significantly correlated with silt and clay content in wet plots but not in dry plots, suggesting that texture effects on B. tectorum establishment patterns may be greater in wet years than in dry years. Applications of MgO resulted in a 49% decrease in B. tectorum establishment, although MgO had no effect on whole-plot biomass at the end of the growing season. B. tectorum –soil relations were strongest during winter (December–March) when relative growth rates were negatively related to soil acid-neutralizing potential, sand and CaCO 3 content, and a measure of bioavailable Mg; and positively related to silt and clay content, total N, measures of bioavailable Mn, P, and K, and a measure of magnetite indicating distributional patterns of eolian dust. As soils were persistently moist during this period, we attribute strong B. tectorum –soil patterns in winter to effects of low temperature on diffusion, microbial activity, and/or production of root exudates important for nutrient mobilization and uptake. In spring, there was a reversal in B. tectorum –soil relations such that loamy soils with higher B. tectorum densities were unfavorable for growth relative to sandy soils with higher warm-season water potentials. We conclude that resource limitations for B. tectorum in this study area shift seasonally, from water limitation of fall establishment, to nutrient limitation of winter growth, and back to water limitation of spring growth. Because study sites generally were arrayed along a hillslope gradient with downslope trends in soil vtexture and nutrient content, close B. tectorum –soil relations documented in this study indicate that a geomorphic framework is useful for understanding and predicting B. tectorum invasion patterns in dryland ecosystems of this region.

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USGS2006

Soil respiration in the cold desert environment of the Colorado Plateau (USA): Abiotic regulators and thresholds

Decomposition is central to understanding ecosystem carbon exchange and nutrient-release processes. Unlike mesic ecosystems, which have been extensively studied, xeric landscapes have received little attention; as a result, abiotic soil-respiration regulatory processes are poorly understood in xeric environments. To provide a more complete and quantitative understanding about how abiotic factors influence soil respiration in xeric ecosystems, we conducted soil- respiration and decomposition-cloth measurements in the cold desert of southeast Utah. Our study evaluated when and to what extent soil texture, moisture, temperature, organic carbon, and nitrogen influence soil respiration and examined whether the inverse-texture hypothesis applies to decomposition. Within our study site, the effect of texture on moisture, as described by the inverse texture hypothesis, was evident, but its effect on decomposition was not. Our results show temperature and moisture to be the dominant abiotic controls of soil respiration. Specifically, temporal offsets in temperature and moisture conditions appear to have a strong control on soil respiration, with the highest fluxes occurring in spring when temperature and moisture were favorable. These temporal offsets resulted in decomposition rates that were controlled by soil moisture and temperature thresholds. The highest fluxes of CO 2 occurred when soil temperature was between 10 and 16 °C and volumetric soil moisture was greater than 10%. Decomposition-cloth results, which integrate decomposition processes across several months, support the soil-respiration results and further illustrate the seasonal patterns of high respiration rates during spring and low rates during summer and fall. Results from this study suggest that the parameters used to predict soil respiration in mesic ecosystems likely do not apply in cold-desert environments.

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USGS2006

Atmospheric dust in modern soil on aeolian sandstone, Colorado Plateau (USA): Variation with landscape position and contribution to potential plant nutrients

Rock-derived nutrients in soils originate from both local bedrock and atmospheric dust, including dust from far-distant sources. Distinction between fine particles derived from local bedrock and from dust provides better understanding of the landscape-scale distribution and abundance of soil nutrients. Sandy surficial deposits over dominantly sandstone substrates, covering vast upland areas of the central Colorado Plateau, typically contain 5-40% silt plus clay, depending on geomorphic setting and slope (excluding drainages and depressions). Aeolian dust in these deposits is indicated by the presence of titanium-bearing magnetite grains that are absent in the sedimentary rocks of the region. Thus, contents of far-traveled aeolian dust can be estimated from magnetic properties that primarily reflect magnetite content, such as isothermal remanent magnetization (IRM). Isothermal remanent magnetization was measured on bulk sediment samples taken along two transects in surficial sediment down gentle slopes away from sandstone headwalls. One transect was in undisturbed surficial sediment, the other in a setting that was grazed by domestic livestock until 1974. Calculation of far-traveled dust contents of the surficial deposits is based on measurements of the magnetic properties of rock, surficial deposits, and modern dust using a binary mixing model. At the undisturbed site, IRM-based calculations show a systematic down-slope increase in aeolian dust (ranging from 2% to 18% of the surface soil mass), similar to the down-slope increase in total fines (18-39% of surface soil mass). A combination of winnowing by wind during the past and down-slope movement of sediment likely accounts for the modern distribution of aeolian dust and associated nutrients. At the previously grazed site, dust also increases down slope (5-11%) in sediment with corresponding abundances of 13-25% fines. Estimates of the contributions of aeolian dust to the total soil nutrients range widely, depending on assumptions about grain-size partitioning of potential nutrients in weathered bedrock. Nevertheless, aeolian dust is important for this setting, contributing roughly 40-80% of the rock-derived nutrient stocks (P, K, Na, Mn, Zn, and Fe) in uppermost soil over most of the sampled slope at the undisturbed site, which shows no evidence of recent wind erosion.

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USGS2005

Soil biota can change after exotic plant invasion: Does this affect ecosystem processes?

Invasion of the exotic annual grass Bromus tectorum into stands of the native perennial grass Hilaria jamesii significantly reduced the abundance of soil biota, especially microarthropods and nematodes. Effects of invasion on active and total bacterial and fungal biomass were variable, although populations generally increased after 50+ years of invasion. The invasion of Bromus also resulted in a decrease in richness and a species shift in plants, microarthropods, fungi, and nematodes. However, despite the depauperate soil fauna at the invaded sites, no effects were seen on cellulose decomposition rates, nitrogen mineralization rates, or vascular plant growth. When Hilaria was planted into soils from not-invaded, recently invaded, and historically invaded sites (all currently or once dominated by Hilaria), germination and survivorship were not affected. In contrast, aboveground Hilaria biomass was significantly greater in recently invaded soils than in the other two soils. We attributed the Hilaria response to differences in soil nutrients present before the invasion, especially soil nitrogen, phosphorus, and potassium, as these nutrients were elevated in the soils that produced the greatest Hilaria biomass. Our data suggest that it is not soil biotic richness per se that determines soil process rates or plant productivity, but instead that either (1) the presence of a few critical soil food web taxa can keep ecosystem function high, (2) nutrient loss is very slow in this ecosystem, and/or (3) these processes are microbially driven. However, the presence of Bromus may reduce key soil nutrients over time and thus may eventually suppress native plant success.

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USGS1972

Water resources of part of Canyonlands National Park, southeastern Utah

Canyonlands National Park is in about the center of the Canyon Lands section of the Colorado Plateaus physiographic province in southeastern Utah. The part of the park discussed embraces an area of about 400 square miles comprising isolated mesas, precipitous canyons, and dissected broad benches near the confluence of the Green and Colorado Rivers, the only perennial streams in the area. The climate is arid to semiarid; normal annual precipitation ranges from less than 8 to about 10 inches. Potential evapotranspiration is about 41 inches annually. Geology of the park is characterized by nearly horizontal strata that dip gently northward. Exposed rock formations and deposits range in age from Middle Pennsylvanian to Holocene. Owing to the elevated and deeply dissected topography, only parts of the Cedar Mesa and White Rim Sandstone Members of the Cutler Formation of Permian age have potential for development of wells. Strata above and below them support only small springs, are dry, or contain brine. In the northwest part of the park, the Green River at Taylor Canyon is a potential source of surface water for public supplies for the Island In The Sky area and a small part of the northwest White Rim area. It will require filtration and treatment before use. In the same area, two unused wells in Taylor Canyon will supply enough water for present requirements from the White Rim Sandstone Member of the Cutler Formation, about 140 gallons per minute combined, but yield mineralized water that will require treatment before use. Springs yielding good water at the Island In The Sky and White Rim are mostly intermittent and too small for public-water supply. Most of the White Rim area is dry, having no usable ground water. In The Needles area, wells provide water of good quality from the Cedar Mesa Sandstone Member of the Cutler Formation. Springs yielding good water in the same area are available for supplementary supplies. West of The Needles, The Grabens area is without springs or potential aquifers bearing usable water. During 1970 about 510,000 gallons of water was used in Canyonlands National Park. Of this amount, 110,000 gallons was supplied to Island In The Sky by tank truck from a source outside the park, and about 400,000 gallons was withdrawn from the well in use at The Needles. Estimated total annual requirements in 10 years (1980) may be as much as 6 million gallons. Sources of water supplies within the park now in use and potential sources of surface water or ground water outlined by this investigation will meet the estimated requirements. Development of rainfall-collection and cistern-storage systems could furnish small emergency sources of water for waterless areas on the White Rim and in The Grabens.

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