1. Succession

2. Succession in Communities
Succession is the process by which communities develop through a series of stages.
New communities replace one another through time in predictable stages.
There are two main types:
1)primary succession
2)secondary succession.

3. Primary succession:
Growth of a community in an area where there was no previous vegetation.
Occurs wherever a volcanic island forms or a glacier melts.
Soil development must happen first and can take many centuries!

4. Primary Succession
There are three types of stages that take place during primary succession:
Pioneer species – colonizers, the first to grow. They survive on very little biomass. They change the conditions of the community so now others can survive.
Ex) lichens, moss, grasses
Seral species – specific intermediate stages of succession identified by the dominant species (always changing).
Ex) grasses, shrubs, pioneer & intermediate trees
Climax community – Stable community of plants and animals with dominant species that maintain dominance.

5. Label:
Pioneer community
Seral community
Climax community
Increasing biomass & biodiversity until levels off in climax community
Decreases temperature and increases fertility of soil
Stabilize environment
Enriches soil, crowds out pioneer species
Shade causes shrubs to die and prevents growth of saplings

6. Secondary succession
Growth of a community after the previous one was destroyed (through fire, forestry, farming)
Soil is already formed, so succession happens much more quickly.

7. Primary succession:
Growth of a community in an area where there was no previous vegetation.
Occurs wherever a volcanic island forms or a glacier melts.
Soil development must happen first and can take many centuries!

8. Using Non-native species as biological control
When pest species overtake an ecosystem, governments try to reduce the population.
One technique is biological control – introducing natural predators to kill the pest
Although biological control can work, sometimes it can get out of control….let’s take a look!

9. Example of Biological Controls that have gone out of control
Cane Toads introduced in Australia for pest control in sugar cane toads (first shipment) became of thousands -They ate everything (small mammals, bugs, other frogs, etc) but the beetles they were brought over to eat

10. Out of Control Species