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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...
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Over the past several decades, the expansion and thickening of woodlands in the western United States has caused a range of ecological changes. Woody expansion often leads to increases in soil organic matter (SOM) pools with implications for both biogeochemical cycling and ecological responses to management strategies aimed at restoration of rangeland ecosystems. Here we directly measure C and N stocks and use simple non-steady-state models to quantify the dynamics of soil C accumulation under and around trees of varied ages in southern Utah woodlands. In the two pinyon-juniper forests of Grand Staircase Escalante National Monument studied here, we found approximately 3 kg C/m2 and approximately 0.12 kg N/m2 larger...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecological Applications,
Grand Staircase Escalante National Monument,
USA,
Utah,
arid, All tags...
carbon,
grazing,
nitrogen,
pinyon–juniper forest,
soil,
woody encroachment, Fewer tags
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Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of the Colorado Plateau. We also evaluated differences in plant ground cover and the spatial distribution of soil resources. Results show that areas used by domestic livestock have 20% less plant cover and 100% less soil organic carbon and nitrogen compared to relict sites browsed by native ungulates. In actively grazed sites, domestic livestock grazing also appears to lead to clustered, rather...
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