2 6 5 ecological succession

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 