Mutualism and competition between plants and decomposers: implications for nutrient allocation in ecosystems

Area of Science:

• Ecology
• Biogeochemistry
• Soil Science

Background:

• Understanding nutrient allocation in ecosystems is crucial for predicting nutrient cycling dynamics.
• The interplay between plant-microbe mutualism and competition shapes nutrient availability.
• Decomposers play a key role in mineralizing organic matter and releasing nutrients.

Purpose of the Study:

• To investigate nutrient allocation strategies of decomposers in simultaneous mutualism and competition with plants.
• To derive testable predictions regarding nutrient flow rates and fractions in ecosystems.
• To assess the consistency of these predictions with existing ecological data.

Main Methods:

• Developed nutrient-cycle models to simulate plant-decomposer interactions.
• Assumed decomposers allocate mineralized nutrients to maximize their population biomass.
• Analyzed quantitative relationships between nitrogen flow rates and nitrogen fractions in ecosystem components.

Main Results:

• Decomposers prioritize self-growth by retaining the nutrient fraction that maximizes their biomass.
• The remaining mineralized nutrients are made available for plant uptake.
• Observed nitrogen dynamics in diverse ecosystems largely conform to the derived quantitative predictions.

Conclusions:

• Decomposer's growth-maximizing strategy provides a fundamental principle for ecosystem nutrient allocation.
• The model's predictions are robust across different nutrient-cycle model structures.
• This framework offers a powerful tool for understanding and predicting ecosystem nutrient cycling.