ECOLOGICAL SUCCESSION

Ecosystems tend to

change with time

until a stable system

is formed.

The stable system that

will form depends on

climatic limitations.

Ecological Succession

The replacement of one

community by another

until a stable stage is

reached is called

ecological succession.

a series of changes in a

community in which new

populations of organisms

gradually replace existing

ones

Climax Community

The final stage of

succession is called

the climax

community.

The climax

community in New

York State is an oak-

hickory forest or a

maple-beech forest.

Primary Succession

Primary succession

occurs where there

was no previous

community, such as

on bare rock or sand.

Primary succession

begins with pioneer

organisms.

Pioneer Organisms

Pioneer organisms

can tolerate extreme

conditions: hot and

cold; dry and wet.

Moss, dune grass, and

lichens are pioneer

organisms.

Lichens

Lichens are algae and

fungus growing

together in a

mutualistic

relationship. Algae

make the food;

fungus anchor and

capture water.

Pioneer organisms

Soil is produced over hundreds of years by pioneer organisms.

These organisms break apart rock, add humus as they die and decompose, and hold water

This allows other organisms to grow there.

Succession occurs BECAUSE

Each community changes the conditions so that they are more favorable to other organisms that replace them.

For example, some types of trees need a lot of sun and their saplings cannot grow under the shade of their own species.

They will be replaced by the types of trees whose saplings cangrow in shade of other trees.

Secondary Succession

When a community is

disrupted and

succession occurs

again, it is called

secondary

succession.

Disruption may be

from fire, farming,

wind, foresting

Secondary Succession

The community

begins again where

the former

community was

disrupted.

Soil is already

present.

A community is still undergoing

succession

As long as the species

keep changing:

Here, the plants

growing under the

pine trees are NOT

small pine trees, so

the species will be

changing as the old

pine trees fall.

Climax Community

The same climax

community will

develop unless the

abiotic conditions

have changed.

We can tell it’s a climax

community-

A climax community

replaces itself with

more of itself:

Under sugar maple

trees, we will see

sugar maple saplings-

that shows that it is a

climax community

Climax Community

The climax community will be part of the BIOME of that area.

Our climax community-oak/hickory forest-is part of the temperate deciduous forest biome