ABSTRACT
The responses of ecosystems to small environmental changes are generally divided into two categories, small and reversible, or large, abrupt, and irreversible. Various examples of the latter response, commonly termed as a “critical transition” or “regime shift,” have been reported, including sudden loss of transparency and vegetation in shallow lakes subject to human-induced eutrophication, coral reefs overgrown by fleshy macroalgae, and desertification induced by climate changes or human disturbances [270]. The abrupt response is often detrimental to the ecosystem, involving loss of biodiversity and bioproductivity [181, 71]. Using a simple dynamical system we first explain the conceptual view of regime shifts as transitions between two alternative stable states (Section 11.1.1), and then describe a few indicators that have been proposed as early warning signals for impending regime shifts (Section 11.1.2).
