Canyonlands Research Bibliography


Environment and Communiy Organization in Grasslands of Canyonlands National Park

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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 texture, bulk density, pH organic matter, total nitrogen, and available K^+, PO"4@?, and Ca^+^+. Although the parks are similar in gross environment and vascular plant cover, cryptogamic vegetation and community structure differ markedly between the areas. Many vascular species occur in greater abundance in one park than the other. Floristically, Virginia was much richer than Chesler Park. Cryptogamic cover was about seven times greater in the ungrazed park. The lichen and moss ground cover is apparently important in stabilization of the highly erodable, sandy soils against wind and water erosion. Cryptogams also have a important influence on chemical characteristics of the surface 5 cm of soil, and the difference in surface soils between the parks may be related to the presence of these species. Community pattern in the virgin park is more definite than in the adjacent, grazed park, a condition which is contrary to the concept that minimum association between species (pattern) is to be expected in stable as opposed to successional vegetations.

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