Abstract

Utah is a state containing a complexity of landforms in a unique continental setting which results in a variety of climatic and edaphic conditions. The variety, however, is not expressed on a latitudinal plane from north to south but is primarily altitudinal, changing from the playa or valley floors to the mountain tops. The associated arrangement of vegetation, consequently, is usually according to elevation, the elevation generally regulation precipitation and thus edaphic conditions. Slope exposure and position of landforms relative to storm-tracks are modifiers, and prevent fixed posisions for many vegetation types. Vegetation in Utah is as variable as are the physical features. Plant communities range from the salt-tolerant pickleweed types in the Great Basin playas to the alpine grass-carex communities of the upper Uinta Mountains. In the fine textured soils of the playa bottoms deflocculation of colloidal clays due to high salt concentrations is common and prevents water percolation. Up the mountain side the gradient generally increases, salts become less concentrated, soils more coarse or loamy, water percolation increases, temperatures are lower, and precipitation is higher. Plant communities change with these features and can generally be identified with a given environment anywhere in the state. Contemporary vegetation in Utah was divided into two major groups based on location in desert or mountain areas. These major groups were broken into subdivisions according to the general types of vegetation in each, and the subdivision into communities. The breakdown is as follows: I. DESERT VEGETATION TYPES A. Warm Temperate Desert Shrubs Creosotebush - Bursage Community B. Salt Marsh Vegetation Pickleweed Community Saltgrass Community C. Cold Temperate Desert Shrubs 1. Communities on Saline Soils and Regosols Greaseweed Community Shadscale Community Castle Valley Clover Community Mat-Atriplex Community 2. Communities on Non-saline Desert and Sierozem Soils Blackbrush Community Uinta Basin Codominant Community Desert Grass Community Horsebrush Community Winterfat Community Little Rabbitbrush Community Lower Riverbotom Community Sagebrush Community D. Pigmy Conifers Juniper-pinyon COmmunity II. Mountain Vegetation Types E. Mountain Shrubs Mountain brush Community F. Mountain Deciduous Forest Aspen Community G. Mountain Coniferous Forests Ponderosa Pine Community Lodgepole Pine Community Spruce-fir Community

Degree

PhD

College and Department

Life Sciences; Plant and Wildlife Sciences

Rights

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