Microhabitat Relationships of Six Major Shrubs in Navajo National Monument, Arizona

Abstract

Six shrub species were studied to determine their microhabitat relationships as well as their effect on the immediate environment. Analysis of site characteristics and mineral composition of soils in open areas adjacent to shrubs and beneath shrubs allowed for comparison of the different habitats following shrub establishment. Soil pH differs beneath the various shrubs and all six species tended to create more alkaline soils beneath their canopy. All species showed increased soil salinity beneath their canopy. However, the concentration of total soluble salts in the soil surface beneath the shrubs varied with the species and was highest beneath fourwing saltbush. Significant increases in the concentration of magnesium and potassium ions beneath shrubs were observed. Nitrogen and phosphorus were also found in greater concentration beneath the shrub canopy. Soil depth differed beneath the shrub species, with sagebrush and fourwing saltbush growing on the deeper more highly developed types. There was a positive relationship between the presence of shrubs and the depth of the soil profile.