Shrub invasion and bacterial community pattern in Swedish pasture soil

Abstract

In arid environments, soil resources accumulate around shrubs to form resource islands. These islands are accompanied by increased bacterial counts and/or increases in microbe mediated processes. The present study investigates the universality of resource islands by measuring bacterial numbers and soil nutrients under and between shrubs invading a Swedish pasture. Substrate utilization patterns were also compared. Neither bacterial count patterns nor soil nutrient measurements supported resource island formation. Analysis of the substrate utilization patterns indicated metabolic differences comparing under- and between-plant communities. The results of this study suggest that resource island formation is not an intrinsic property of shrub invasions but rather may be related to the water harvesting or hydraulic lift associated with shrubs in arid environments.