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标题：Experimental support for alternative attractors on coral reefs
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作者：Russell J. Schmitt ; Sally J. Holbrook ; Samantha L. Davis 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：10
页码：4372-4381
DOI：10.1073/pnas.1812412116
出版社：The National Academy of Sciences of the United States of America
摘要：Ecological theory predicts that ecosystems with multiple basins of attraction can get locked in an undesired state, which has profound ecological and management implications. Despite their significance, alternative attractors have proven to be challenging to detect and characterize in natural communities. On coral reefs, it has been hypothesized that persistent coral-to-macroalgae “phase shifts” that can result from overfishing of herbivores and/or nutrient enrichment may reflect a regime shift to an alternate attractor, but, to date, the evidence has been equivocal. Our field experiments in Moorea, French Polynesia, revealed the following: ( i ) hysteresis existed in the herbivory–macroalgae relationship, creating the potential for coral–macroalgae bistability at some levels of herbivory, and ( ii ) macroalgae were an alternative attractor under prevailing conditions in the lagoon but not on the fore reef, where ambient herbivory fell outside the experimentally delineated region of hysteresis. These findings help explain the different community responses to disturbances between lagoon and fore reef habitats of Moorea over the past several decades and reinforce the idea that reversing an undesired shift on coral reefs can be difficult. Our experimental framework represents a powerful diagnostic tool to probe for multiple attractors in ecological systems and, as such, can inform management strategies needed to maintain critical ecosystem functions in the face of escalating stresses.
关键词：bistability ; hysteresis ; resilience ; coral–algae phase shift ; alternative stable states