Dynamically evolved community size and stability of random Lotka-Volterra ecosystems

Tobias Galla

doi:10.1209/0295-5075/123/48004

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arXiv · 1808.06660

Dynamically evolved community size and stability of random Lotka-Volterra ecosystems

Tobias Galla

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Abstract

We use dynamical generating functionals to study the stability and size of communities evolving in Lotka-Volterra systems with random interaction coefficients. The size of the eco-system is not set from the beginning. Instead, we start from a set of possible species, which may undergo extinction. How many species survive depends on the properties of the interaction matrix; the size of the resulting food web at stationarity is a property of the system itself in our model, and not a control parameter as in most studies based on random matrix theory. We find that prey-predator relations enhance stability, and that variability of species interactions promotes instability. Complexity of inter-species couplings leads to reduced sizes of ecological communities. Dynamically evolved community size and stability are hence positively correlated.

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Tobias Galla. 2018-08-20. Dynamically evolved community size and stability of random Lotka-Volterra ecosystems. https://doi.org/10.1209/0295-5075%2F123%2F48004

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