Download Ecological Succession

Ecological Succession
3.
4.
Objectives
1.
Explain what succession is
2.
Explain the process of ecological succession
Explain the role that plants play in maintaining biodiversity
Explain how organisms survive after their ecosystem has
been disturbed.
Definitions…
Succession: A series of gradual changes in the
vegetation of an area followed by gradual changes
in the animals in the area.
Primary Succession: Succession in an area that has
no plants, animals, or soil.
Pioneer Species: The first species to colonize an
area during succession.
Secondary Succession: Succession in an
ecosystem that has been disturbed by a natural
event or human activity.
Ecosystem: All living and non living components in
an area.
Ecological Succession…
• Succession is influenced by..
1) Biotic (living) factors
2) Abiotic (nonliving) factors
Succession occurs in stages or steps.
However, these steps are not always
distinct and can often blend into each
other..
Primary Succession…
• Takes place on
completely barren
rock.
•
•
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•
•
•
No plants
No animals
No soil
No shade
No shelter
Nothing!!!!
…and then
Pioneer organisms start to grow.
Grasses, lichens start to grow on rocks.
Form soil and create conditions that allow more
vegetation to grow.
Still no shade or
shelter.
Mosses and other small plants colonize the area.
They help keep water in soil and reduce erosion.
Attract insects, birds and other small animals
which feed on plants and eventually
decompose to build more soil.
Soil becomes
thicker and full of
nutrients.
Plants provide
shelter to small
organisms.
Small plants and soft
wood trees (pine trees
and larger shrubs) grow.
These plants can survive
in harsh conditions.
Roots break up rock and help add nutrients to soil
when they decompose.
Plants provide shelter for more species of insects,
birds and small mammals.
• Bigger plants and hard
wood trees grow
• Provide more shelter
and shade
• Provide food and
habitat for a wider
range of mammals
• Their droppings and
remains enrich the
soil
• Soil continues to
become deeper and
richer; retains more
water
Climax Community
• All ages of plants and hard wood trees grow.
• Many shrubs, saplings and herbaceous plants
grow.
• High biodiversity
• Complex food webs
• Diversity of plant life provides food and habitat
for a wide range of other organisms
Ecological Succession
Secondary Succession
This usually happens more quickly and occurs after
an existing community has been disturbed by
natural events or human activity (e.g. forest fire).
Competition and Succession
• Succession is a long-term process driven
by interspecific and intraspecific
competition.
• Competition for water, sunlight, nutrients,
etc.
• Winners and losers