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Environmental Fluctuations on South‐Facing Slopes in the Santa Catalina Mountains of Arizona

Haase, Edward F.
Ecology 1970 v.51 no.6 pp. 959-974
drought, environmental factors, evaporation, hills, mountains, soil temperature, soil water, solar radiation, spring, summer, vegetation, wet season, Arizona
Solar radiation, evaporation, air— and soil—temperature extremes, soil moisture, and precipitation were measured on four aspects (SSE, S, SSW, SW) of constant slope in the desert foothills of the Santa Catalina Mountains over a 1—year period. The sequence of warmest and driest aspects based upon annual means was S, SSW, SW, SSE. The warmest and driest aspect may change with the environmental factor considered or the time of year. Drought extremes reached a high peak on the SW aspect during the arid spring, although during all other seasons the SW aspect had the mildest drought conditions. The warmest and driest aspect during the summer rainy season was SSE, during the winter rainy season it was S, and during the fall arid season S and SSE were nearly equal. Few significant differences were found throughout the year between S and SSW aspects. When vegetation and environment are considered, the warmest and driest aspect may also change with the species because plants may utilize different microenvironments at different seasons and vary in their response to similar environmental changes.