2.6.5 Ecological Succession
A good starting point: Equilibrium Theory ď ľ
Ecosystems are stable environments in which the biotic interactions among species determine the structure of the communities present.
Succession and Disturbance ď ľ Ecological
succession: transition between biotic communities 1. Primary: no previous biotic community 2. Secondary: previously occupied by a community 3. Aquatic: transition from pond or lake to terrestrial community
Primary Succession
Mosses invade an area and provide a place for soil to accumulate.
Larger plants germinate in the new soil layer, resulting in additional soil formation.
Eventually shrubs and trees will invade the area.
Primary Succession‌
Primary succession‌
Primary succession‌
K-strategist!
Secondary Succession
Aquatic Succession
Disturbance and Resilience Removes
organisms
Reduces
populations
Creates
opportunities for other species to colonize
Fire and Succession
http://www.fs.fed.us/photovideo/
Ground Fire
Fire and Succession ď ľ
Fire climax ecosystems: dependent upon fire for maintenance of existing balance; e.g., grasslands, pine and redwood forests
ď ľ
What significance does this have for humans and where they live?
Resilience in Ecosystems
Resilience Mechanisms after a Forest Fire Nutrient release to soil Regrowth by remnant roots and seeds Invasions from neighboring ecosystems Rapid restoration of energy flow and nutrient cycling