Category: Ecology

Summary: Estimating when omnivory shortcuts become strong enough to trigger transient amplification in a food web that is already close to a nonreciprocal reactivity onset.

Food webs can remain linearly stable yet still amplify perturbations for a while, a phenomenon called reactivity. This experiment asks whether omnivory links can push a trophically structured system into that transient-amplification regime when latent nonreciprocity has already brought the web close to onset.

The simulation builds dense trophically coherent operators with heavy-tailed heterogeneity, fixed subcritical nonreciprocity, and a tunable omnivory component. GPU eigensolves, iterative deepening, and bisection are then used to locate the omnivory level where the symmetric reactivity operator first becomes positive.

The scientific value is that the project isolates an interaction between two mechanisms that are often discussed separately. Rather than asking whether omnivory or nonreciprocity matters in isolation, it measures when their combination changes the food web's short-time response.

Method: GPU dense symmetric eigensolve with iterative deepening and bisection on omnivory strength in trophically coherent food-web reactivity operators.

What is measured: Critical omnivory threshold, onset of positive reactivity, support of the reactive mode on middle trophic levels, system size reached, and bracket width.