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The ecology and phytosociology of a virgin grassland community (Virginia Park, Canyonlands National Park, Utah) have been investigated. Based on the use of C × F index, Hilaria jamesii and Stipa comata are the most abundant of the four major perennial grasses. Oryzopsis hymenoides and Sporobolus cryptandrus are less abundant in decreasing order. The sites dominated by Hilaria are characterized by soils with finer texture, slightly warmer average temperature and higher surface K+ and organic matter compared to sites dominated by Stipa comata. In addition, frequency of both vascular and cryptogamic species is greater on sites dominated by Hilaria. Published in Journal of Range Management, volume 30, issue 4, on pages...
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A comparative study was made of the soils of a virgin grassland and an adjacent grazed area in Canyonlands National Park. Soils from the virgin site were finer textured than those of the grazed area, and the surface 5 cm contains a significantly lower amount of calcium. In addition, the surface 5 cm of the virgin site contains significantly greater amounts of phosphorus, potassium, and organic matter. Subsurface soils in the two parks are less dissimilar. Cryptogams on the virgin grassland appear to have an important influence on chemical characteristics of the surface 5 cm of soil. The difference in surface soils between the parks may be related to the presence of these species. Data point strongly to light winter...
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Sixty uniformly distributed stands in adjacent areas, 40 in Virginia Park (virgin) and 20 in Chesler Park (grazed), were analyzed. Cryptogamic and vascular species were recorded; cover was analyzed by the point sampling method, and frequency by means of 25 quadrats (each 0.125 m^2) per stand. The prevalent species (26 in Virginia, 23 in Chesler) were selected on the basis of a constancy-times-frequency index. Interspecific association patterns were determined by means of simple procedures based on quadrat frequency values for each species in the individual stands. Major environmental variables were recorded at each stand, and soil samples from four depths were collected at each site. Soil samples were analyzed for...
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A study has been made of the vegetational condition of two graben valleys in Canyonlands National Park. The sites, formerly subjected to relatively heavy grazing pressure, were originally investigated in 1970 and analyzed again in 1981, providing an eleven-year record of succession. Comparisons are made to successional trends noted in related studies of disturbed and pristine areas. The graben valleys, with few exceptions, show a successional trend over eleven years toward the climax vegetational condition of an area that has never been disturbed. Published in Proceedings of the American Philosophical Society, volume 126, issue 6, on pages 520 - 526, in 1982.
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A study has been made of the vegetational condition of a formerly grazed area, Chesler Park, in Canyonlands National Park. A comparison was made with the same area 10 years earlier. The 10-year successional changes are also compared to baseline data of 10 years earlier from Virginia Park, an adjacent ungrazed area. Because of inaccessibility and long isolation from disturbances, Virginia Park is presumed to be in climax condition and is the control for this study. Chesler Park shows a successional trend after 10 years toward the vegetational condition of Virginia Park. This is exemplified, with only one major exception (Hilaria jamesii), by responses of the perennial grasses (Stipa comata, Oryzopsis hymenoides,...
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