Effects of Soil Disturbance on Plant Succession and Levels of Mycorrhizal Fungi in a Sagebrush-Grassland Community

Abstract

A 5-year study was conducted to determine the effects of soil disturbance on plant succession and the relationship between plant succession and mycorrhizal inoculum potential (MIP) in a big sagebrush-grassland vegetation type. Disturbed plots, consisting of 4 levels of soil disturbance, were established in 1976, 1977, and 1979 to evaluate environmental fluctuations. Perennial grass canopy cover and aboveground biomass production were positively correlated with MIP and negatively correlated with disturbance treatments. Annual forb canopy cover (primarily nonmycorrhizal species) and aboveground biomass were negatively correlated with MIP and positively correlated with level of soil disturbance. Weather fluctuations had a greater effect on annual plants than perennial plants after the perennial species were established. MIP values appeared to be a general indicator of the type and rate of plant succession that will evolve following soil disturbance.