Download Ecological Succession

Ecological Succession
San Antonio
1800s
San Antonio
Today
What is it?
• Ecological succession – series of predictable
changes that gradually occur in a community over
time
- ecosystems are constantly changing by
natural and human disturbances
- old inhabitants die out and new organisms
move in
- change can take hundreds to thousands of
years
- Can also be immediate in the case of
catastrophic events that destroy ecosystems
Primary Succession
• Primary Succession occurs on surfaces where no
soil exists
* establishment or creation of an ecosystem
Ex: landmasses formed from eruption
of a volcano
or
glaciers melting and exposing rock
• Pioneer species – first species to populate an area
Ex: lichen – made of fungus and algae can
grow on bare rock and break it down to soil
Volcanic & Glacial Succession
Secondary Succession
• Secondary succession takes place when some
kind of disturbance (catastrophic) changes the
community.
- usually rapid and drastic
- examples can be natural such as hurricanes,
volcanic eruptions, wildfires
or
man-made like farming, oil or chemical spills
• Recovery is usually much faster than time frame
of primary succession
Secondary Succession
Climax Communities
• The goal of succession is to reach the point of
a climax community
- stable, almost permanent community that is not
easily replaced
- Point of equilibrium
- Fewer changes occur in the area