In ecology, regime shifts are large, abrupt, systemic changes in the structure and function of an ecosystem. Where a regime is a characteristic behavior of a system which is maintained by mutually reinforced processes or feedback loops. The change of regime, or the shift, typically occurs when a continuous smooth change in an internal process or an external variable triggers a completely different system behavior with irreversible consequences. The theory of ecological regime shifts is today understood within the context of nonlinear dynamics, state spaces and attractors that we have previously talked about. The basic theory here is that nonlinear systems like ecosystems can have more than one stable basin of attraction, that we would call a regime, which is stable due to a number of negative feedback loops that hold it within that state. Every time one of these negative feedback loops is broken the system moves farther away from this stable equilibrium attractor, as it moves away it moves towards a critical phase transition area far from its equilibrium, an unstable regime governed by positive feedback where some small event can get amplified rapidly driving the system through the phase transition into another basin of attraction. The system then has two or more basins of attraction and can flip between them, this is called bistability.