| Studies were conducted on the relationships of halophytic species distribution and chemical and physical soil characteristics in saline-alkali habitats of Red Desert, Wyoming. Vegetation types of the study area which consist of baltic rush, saltgrass, greasewood, and sagebrush were mapped by a reconnaissance method with references to climatic and edaphic factors. In each type, vegetation parameters such as cover, density, and frequency were recorded and soil characteristics such as pH, conductivity, soluble salts, and soil texture and moisture were determined. A significant difference between plant types was found for conductivity, exchangeable sodium, and soil moisture. Greasewood and saltgrass were found on soils with highest salt content with averages of 12.5 and 12.2 mmhos/cm, respectively, and sagebrush occurred on soils of the lowest salt content with an average of 7 mmhos/cm. Soils under saltgrass had the highest mean value for exchangeable sodium percentage but had narrower ranges than the greasewood. Sagebrush had the lowest mean and range of exchangeable sodium percentages. A gradient of water from more xeric to more mesic, and a gradation of soil texture from more coarse and sandy to finer textured clay loam were found along the study area's outer perimeter inward to the margin of the saline lakes. Saltgrass and sagebrush showed relatively high correlations (r = 0.75 and 0.77) with soil water and no correlations were found between the pH, soil texture, and vegetation parameters. The high negative correlation between the cover of sagebrush and conductivity and exchangeable sodium (r = -0.89 and -9.97) indicate adverse effects of salt to the survival of this species, while the low negative correlations between the cover percentages of saltgrass and greasewood and these soil factors confirm the better adaptation of these species in saline environments. Clustering of vegetation types showed high similarities of stands of the same type (50 to 90 percent) and the results of ordination of stands along the water gradient further confirmed the validity of initial vegetation mapping of the study area. |
