Ecological collapse

Ecological collapse refers to a situation where an ecosystem suffers a drastic, possibly permanent, reduction in carrying capacity for all organisms, often resulting in mass extinction. Usually, an ecological collapse is precipitated by a disastrous event occurring on a short time scale. Ecological collapse can be considered as a consequence of ecosystem collapse on the biotic elements that depended on the original ecosystem. Ecosystems have the ability to rebound from a disruptive agent. The difference between collapse or a gentle rebound is determined by two factors—the toxicity of the introduced element and the resiliency of the original ecosystem. Through natural selection the planet's species have continuously adapted to change through variation in their biological composition and distribution. Mathematically it can be demonstrated that greater numbers of different biological factors tend to dampen fluctuations in each of the individual factors. Scientists can predict tipping points for ecological collapse. The most frequently used model for predicting food web collapse is called R50, which is a reliable measurement model for food web robustness. Although there is no single cause for ecological collapse, attributing factors include asteroid impacts, extremely large volcanic eruptions, and abrupt climate change. The snowball effect of these attributing factors and ecological collapse are demonstrated within the fossil record. Prehistoric examples include the Carboniferous Rainforest Collapse, the Cretaceous–Paleogene extinction event, the Permian–Triassic extinction event, and other mass extinctions. For example, effects of climate change as a contributing factor towards ecological collapse are demonstrated in the Ordovician–Silurian extinction events. A possible cause of the Ordovician Extinction was global cooling which affected the habitats of marine life. Consequently, sea creatures such as trilobites, brachiopods, and graptolites became extinct.