MUTUALISM AND COMPETITION BETWEEN PLANTS AND DECOMPOSERS - IMPLICATIONS FOR NUTRIENT ALLOCATION IN ECOSYSTEMS

By examining the consequences of simultaneous mutualism and competitio n between plants and decomposers, we show that testable predictions ab out nutrient allocation in ecosystems follow from the assumption that decomposers allocate for their own growth the fraction of mineralized nutrient that maximizes their population biomass, leaving the remainde r available for plant uptake. Available data for a wide variety of eco systems are nearly all consistent with the predicted quantitative rela tionships among nitrogen flow rates and nitrogen fractions in plants, decomposers, and nonliving organic matter. Our predictions are robust against changes in the detailed structure of the nutrient-cycle models we use for our derivations.