Succession Notes

Range of Tolerance

• Optimum Range• Stress Zone• Intolerance Zone

Limiting Factors

–Sunlight–Water/Humidity–Nutrients

Succession

• The change in biological communities of an area over a long period of time

Two Types of Succession:

Primary – Initial establishment & development of a community – occurs on barren rock volcanic eruption, glacial

retreat, pavement

Secondary – Reestablishment of a community – remnants of previous community is still there

abandoned field, after fire, flood, or hurricane

Primary Succession:

Secondary Succession:

Stages of Succession:

• Bare Rock– No soil, no available

nutrients, no active life……not a community

Stages of Succession:

• Lichens & Mosses – Pioneer Species

• First to colonize rocks • secrete acid onto rock

which liberates nutrients that can be absorbed

• catches wind-blown dirt• can take 100s to 1000s

of years• very vulnerable to

erosion• least diverse and least

stable

Stages of Succession:

• Grasses & Shrubs – Early Succession

Plants• don’t need deep soil• like full sun • shrubs move in and

shade out grasses, killing them

Stages of Succession: • Softwood

– Early Mid-succession Plants• trees that need a lot of sunlight• Cedar, pine, aspen, locust • Trees displace grasses and shrubs

Stages of Succession: • Mid-succession Plants

– Tulip, ash, red maple, birch– Displace the soft woods

Stages of Succession: • Mixed Hardwood

Mature Forest– deciduous trees; oaks,

maples, hickories, beech– saplings are shade-tolerant

for the first few years– when an adult tree dies it

leaves a hole in the canopy– saplings race to the top,

grow tall quickly-not widethen grow slowly

– Most Diverse, least likely to erode, very productive

– Dominant species is reproducing, therefore climax stage

Questions

1. What is the difference between primary and secondary succession?

2. What types of events can cause secondary succession?

3. What are some abiotic and biotic factors that play a part in succession?

4. How can humans cause succession?

Big Question

How does the ecosystem change as it moves through the stages of succession?