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Although mathematical models and laboratory experiments have shown that species interactions can generate chaos, field evidence of chaos in natural ecosystems is rare. We report on a pristine rocky intertidal community located in one of the world’s oldest marine reserves that has displayed a complex cyclic succession for more than 20 y. Bare rock was colonized by barnacles and crustose algae, they were overgrown by mussels, and the subsequent detachment of the mussels returned bare rock again. These processes generated irregular species fluctuations, such that the species coexisted over many generations without ever approaching a stable equilibrium state. Analysis of the species fluctuations revealed a dominant periodicity of about 2 y, a global Lyapunov exponent statistically indistinguishable from zero, and local Lyapunov exponents that alternated systematically between negative and positive values. This pattern indicates that the community moved back and forth between stabilizing and chaotic dynamics during the cyclic succession. The results are supported by a patch-occupancy model predicting similar patterns when the species interactions were exposed to seasonal variation. Our findings show that natural ecosystems can sustain continued changes in species abundances and that seasonal forcing may push these nonequilibrium dynamics to the edge of chaos. Significance The intuitive and popular idea of a balance of nature has been criticized, because species interactions may generate nonequilibrium dynamics, such as oscillations and chaos. However, field evidence of chaos in ecosystems is rare. We report on a coastal community that has displayed striking fluctuations in the abundances of barnacles, mussels, and algae for more than 20 y. Data analysis reveals that these fluctuations reflect a cyclic succession alternating between stabilizing and chaotic dynamics during the species replacement. These results are supported by a simple patch-occupancy model, which predicts very similar dynamics when exposed to seasonal variation. Our findings provide a field demonstration of nonequilibrium coexistence of competing species through a cyclic succession at the edge of chaos.

Last fall, John Ringling North and associated stockholders sold Ringling Bros. and Barnum & Bailey Circus to the Feld Bros., Irvin and Israel, theatrical entrepreneurs of Washington, D.C., and Judge Roy Hofheinz, owner of the Houston Astrodome. Hofheinz is a sports impresario of...

New York's International Airport is a sprawling Jet Age giant that covers 4,900 acres, has 22,725 employees, handles 7,000,000 passengers a year-- and is still growing.

Bears are the most viciously dangerous wild animals in captivity, and polar bears are the worst. A lion will usually whip a tiger in a really serious big-cat fight.

Here it is, the incredible story of the state that has become, in one explosive decade, America's playground and one of our boomingest industrial frontiers

ALTHOUGH I was a latterday canvas-covered trouper, come late to the spangled feast, I have absorbed many...

IN a world in which nearly everything is rapidly being discovered or exposed, clowns are still mighty mysterious creatures. And clowning remains one of man's weirdest occupations -- not completely art, nor craft, nor profession, but a remarkable combination of all three heavily larded with large chunks of pure hokum and sheer nonsense.

Manual Medicine 101: Manual Medicine Approach to the Sports Medicine Patient features an overview of the key factors involved in manual medicine from two fundamental perspectives— osteopathic medicine and chiropractic medicine. The video looks at the two respective professions, the philosophies upon which they are established, and the differences between the two approaches to medicine. The video defines basic terminology associated with osteopathy, discusses somatic dysfunction, and reviews the core techniques that are used in its diagnosis and treatment. The video also details the terminology and techniques of chiropractic medicine, as well as discusses the need.