APES 2.5: Natural Disruptions to Ecosystems

natural disturbance

a natural event that disrupts the structure and/or function of an ecosystem, ex. tornados, hurricanes, asteroids, forest fires, drought

periodic

occurs with regular frequency (ex. dry-wet seasons)

episodic

occasional events with irregular frequency (ex. hurricanes, droughts, fires)

random

no regular frequency (volcanoes, earthquakes, asteroids)

Earth's climate has varied over geologic time for numerous reasons, ex.

slight changes in Earth's orbit and tilt cause mini ice ages and warmer periods as earth shifts slightly closer to and further from the sun

sea level has varied over geological time as:

glacial ice on earth melts and forms

major environmental disturbances result in:

widespread habitat changes or loss, ex. rising sea level floods coastal and estuary habitats

migration

wildlife may migrate to a new habitat as the result of natural disruptions

examples of migration

1. wildbeests migrating to follow rain patterns of African savanna
2. ocean species moving further north as water temperature warms
3. bird migration and breeding shifting earlier as insect hatching shifts earlier with warming climate