Category: Ecology

Summary: Finding when a fungal-detrital nutrient shunt makes a coherent soil food web transiently reactive and shifts the dominant mode onto a producer-fungus-detritus bridge.

Trophic coherence is usually associated with ecological stability, while mycorrhizal networks are known to reshape nutrient exchange between plants, fungi, and detrital pathways. This experiment asks when strengthening that fungal-detrital shunt stops acting as a stabilizing supplement and instead creates a reactive mode concentrated on the producer-fungus-detritus bridge.

The script constructs dense non-symmetric Jacobians for coherent soil food webs, then uses iterative deepening and repeated eigenvalue calculations to bisect the coupling threshold across larger system sizes. Rather than looking only at whether the system is stable or unstable, it measures transient reactivity, bridge dominance, fungal share, and a coherence proxy for the leading mode.

That focus matters because ecosystems can become highly amplifying before they become asymptotically unstable. The experiment is therefore aimed at an earlier structural warning point where a detrital-mycorrhizal pathway begins to dominate the system response.

Method: Dense non-symmetric eigensolves with iterative deepening and bisection on mycorrhizal-detrital coupling in coherent food-web Jacobians.

What is measured: Critical coupling estimate, mean maximum real part, bridge ratio, fungal-detrital share, coherence proxy, passes completed, and bracket width.