Rubidium content of plants, fungi and animals closely reflects potassium and acidity conditions of forest soils

Rubidium concentrations in tissues of organisms (vascular plants, fungus, insect, bird, rodents) were closely related to soil chemical properties (K+ saturation as % cation exchange capacity, and pH) at repeated sampling of 30 beech forest sites in south Sweden. The Rb+ concentration of organisms, representing a variety of tropic levels, was a sensitive measure of the K+ status of acid soil ecosystems. Low K+ status (pool of exchangeable K+) in the soil, usually aggravated by high soil acidity which causes K+ leaching losses, is compensated by greatly increased uptake of Rb+ by plants and fungi and these elevated Rb+ levels are propagated in the food web. The relationship between Rbi concentration in the tissues of organisms and soil chemical properties was not erased through the food web. (C) 2000 Elsevier Science B.V. All rights reserved