With a brief letter to Nature in 1972, Robert May triggered a worldwide research program in theoretical ecology and complex systems that continues to this day. Building on powerful mathematical results about large random matrices, he argued that systems with sufficiently large numbers of interacting components are generically unstable. In the ecological context, May's thesis directly contradicted the longstanding ecological intuition that diversity promotes stability. In economics and finance, May's work helped to consolidate growing concerns about the fragility of an increasingly interconnected global marketplace. In this Letter , we draw on recent theoretical progress in random matrix theory and statistical physics to fundamentally extend and reinterpret May's theorem. We confirm that a wide range of ecological models become unstable at the point predicted by May , even when the models do not strictly follow his assumptions. Surprisingly, increasing the interaction strength or diversity beyond the May threshold results in a URLanization of the ecosystem -- through extinction of a fixed fraction of species -- into a new stable state whose properties are well described by purely random interactions. This URLanized state remains stable for arbitrarily large ecosystem and suggests a new interpretation of May's original conclusions: when interacting complex systems with many components become sufficiently large, they will generically undergo a transition to a "typical" URLanized, stable state .
In 1972, Robert May triggered a worldwide research program studying ecological communities using random matrix theory. Yet, it remains unclear if and when we can treat real communities as random ecosystems. Here , we draw on recent progress in random matrix theory and statistical physics to extend May's approach to generalized consumer-resource models. We show that in diverse ecosystems adding even modest amounts of noise to consumer preferences results in a transition to "typicality" where macroscopic ecological properties of communities are indistinguishable from those of random ecosystems , even when resource preferences have prominent designed structures. We test these ideas using numerical simulations on a wide variety of ecological models. Our work offers an explanation for the success of random consumer-resource models in reproducing experimentally observed ecological patterns in microbial communities and highlights the difficulty of scaling up bottom-up approaches in synthetic ecology to diverse communities .
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With a brief letter to Nature in
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in theoretical ecology and complex systems that continues to this day. Building on powerful mathematical results about large random matrices, he argued that systems with sufficiently large numbers of interacting components are generically unstable. In the ecological context, May's thesis directly contradicted the longstanding ecological intuition that diversity promotes stability. In economics and finance, May's work helped to consolidate growing concerns about the fragility of an increasingly interconnected global marketplace. In this Letter
studying ecological communities using random matrix theory. Yet, it remains unclear if and when we can treat real communities as random ecosystems. Here
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theoretical
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fundamentally extend and reinterpret
extend
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theorem. We confirm that a wide range of ecological models become unstable at the point predicted by May
approach to generalized consumer-resource models. We show that in diverse ecosystems adding even modest amounts of noise to consumer preferences results in a transition to "typicality" where macroscopic ecological properties of communities are indistinguishable from those of random ecosystems
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the models do not strictly follow his assumptions. Surprisingly, increasing the interaction strength or diversity beyond the May threshold results in a URLanization of the ecosystem -- through extinction of a fixed fraction of species -- into a new stable state whose properties are well described by purely random interactions. This URLanized state remains stable for arbitrarily large ecosystem and suggests a new interpretation of May's original conclusions: when interacting complex systems with many components become sufficiently large, they will generically undergo a transition to a "typical" URLanized, stable state
resource preferences have prominent designed structures. We test these ideas using numerical simulations on a wide variety of ecological models. Our work offers an explanation for the success of random consumer-resource models in reproducing experimentally observed ecological patterns in microbial communities and highlights the difficulty of scaling up bottom-up approaches in synthetic ecology to diverse communities