An ecosystem, short for ecological system, is defined as a collection of interacting organisms within a biophysical environment. Ecosystems are never static, and are continually subject to both stabilizing and destabilizing processes. Stabilizing processes allow ecosystems to adequately respond to destabilizing changes, or perturbations, in ecological conditions, or to recover from degradation induced by them. Yet, if destabilizing processes become strong enough or fast enough to cross a critical threshold within that ecosystem, often described as an ecological 'tipping point', then an ecosystem collapse (sometimes also termed ecological collapse) occurs.
Ecosystem collapse does not mean total disappearance of life from the area, but it does result in the loss of the original ecosystem's defining characteristics, typically including the ecosystem services it may have provided. Collapse of an ecosystem is effectively irreversible more often than not, and even if the reversal is possible, it tends to be slow and difficult. Ecosystems with low resilience may collapse even during a comparatively stable time, which then typically leads to their replacement with a more resilient system in the biosphere. However, even resilient ecosystems may disappear during the times of rapid environmental change, and study of the fossil record was able to identify how certain ecosystems went through a collapse, such as with the Carboniferous rainforest collapse or the collapse of Lake Baikal and Lake Hovsgol ecosystems during the Last Glacial Maximum.
