Gardner volumes and self-organization in a minimal model of complex ecosystems

Fuente: arXiv
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Autores principales: Thomsen, Frederik J., Dubbeldam, Johan L. A., Hanel, Rudolf
Formato: Preprint
Publicado: 2026
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author Thomsen, Frederik J.
Dubbeldam, Johan L. A.
Hanel, Rudolf
author_facet Thomsen, Frederik J.
Dubbeldam, Johan L. A.
Hanel, Rudolf
contents We study self-organization in a minimally nonlinear model of large random ecosystems. Populations evolve over time according to a piecewise linear system of ordinary differential equations subject to a non-negativity constraint resulting in discrete time extinction and revival events. The dynamics are generated by a random elliptic community matrix with tunable correlation strength. We show that, independent of the correlation strength, solutions of the system are confined to subsets of the phase space that can be cast as time-varying Gardner volumes from the theory of learning in neural networks. These volumes decrease with the diversity (i.e. the fraction of extant species) and become exponentially small in the long-time limit. Using standard results from random matrix theory, the changing diversity is then linked to a sequence of contractions and expansions in the spectrum of the community matrix over time, resulting in a sequence of May-type stability problems determining whether the total population evolves toward complete extinction or unbounded growth. In the case of unbounded growth, we show the model allows for a particularly simple nonlinear extension in which the solutions instead evolve towards a new attractor.
format Preprint
id arxiv_https___arxiv_org_abs_2601_00707
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Gardner volumes and self-organization in a minimal model of complex ecosystems
Thomsen, Frederik J.
Dubbeldam, Johan L. A.
Hanel, Rudolf
Adaptation and Self-Organizing Systems
Dynamical Systems
Populations and Evolution
We study self-organization in a minimally nonlinear model of large random ecosystems. Populations evolve over time according to a piecewise linear system of ordinary differential equations subject to a non-negativity constraint resulting in discrete time extinction and revival events. The dynamics are generated by a random elliptic community matrix with tunable correlation strength. We show that, independent of the correlation strength, solutions of the system are confined to subsets of the phase space that can be cast as time-varying Gardner volumes from the theory of learning in neural networks. These volumes decrease with the diversity (i.e. the fraction of extant species) and become exponentially small in the long-time limit. Using standard results from random matrix theory, the changing diversity is then linked to a sequence of contractions and expansions in the spectrum of the community matrix over time, resulting in a sequence of May-type stability problems determining whether the total population evolves toward complete extinction or unbounded growth. In the case of unbounded growth, we show the model allows for a particularly simple nonlinear extension in which the solutions instead evolve towards a new attractor.
title Gardner volumes and self-organization in a minimal model of complex ecosystems
topic Adaptation and Self-Organizing Systems
Dynamical Systems
Populations and Evolution
url https://arxiv.org/abs/2601.00707