Ecosystems are beautiful manifestations of the tension between the individual species and emerging collective phenomena. For example, in semi-arid grasslands it is possible to run into sudden isolated circles of barren terrain — these are called fairy circles (pictured), a fitting name for a seemingly inexplicable feature, which can be understood only in the context of collective competition.
Now, Daniel Ruiz-Reynés and colleagues have revealed that one needn't travel far to find fairy circles, as they appear underwater all around the Mediterranean Sea. Focusing on P. oceanica and C. nodosa, the researchers used microscopic parameters for growth and death of shoots, apices and rhizome to construct a coarse-grained model for whole meadows. Incorporating nonlinearities to capture saturation effects, and spatial interactions for the description of facilitative and competitive interactions, their model reproduces diverse and complex self-organized vegetation patterns. For intermediate values of growth and death rates, solutions to their model exhibit stripes, dotted or leopard-print patterns, hysteresis and dissipative solitons — all spotted somewhere in the Mediterranean.
Complex dynamical models of plant growth may enable us to infer ecosystem stability and mortality rates from the observed meadow patterns.
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Levi, F. Sea fairies. Nature Phys 13, 824 (2017). https://doi.org/10.1038/nphys4260