Ecological threshold is the point at which a relatively small change or
disturbance in external conditions causes a rapid change in an
ecosystem. When an ecological threshold has been passed, the ecosystem may no longer be able to return to its state by means of its inherent
resilience . Crossing an ecological threshold often leads to rapid change of
ecosystem health. Ecological threshold represent a non-linearity of the responses in ecological or biological systems to pressures caused by human activities or natural processes.
Critical load,
tipping point and
regime shift are examples of other closely related terms.