1. Disturbance and Succession NOTES

2. I. Disturbance An event that causes loss of life in a community
Measured by scale, intensity, and frequency
Moderate disturbance can increase diversity in communities

3. II. Population Growth (post-disturbance and otherwise)
Carrying Capacity: maximum population size an ecosystem can sustain
Limiting Factor/ Resource: factors that influence carrying capacity
limiting factors
carrying capacity
# of organisms
r-strategists
K-strategists
time

4. III. Ecological Succession
Many species of organisms in an area is a community.
1. An existing______________of is
replaced by a different community over periods of time ranging from a few decades to thousands of years.
community
organisms
Secondary succession
Primary succession

5. III. Ecological Succession
Climax stage
III. Ecological Succession
K-strategists
Later seral stages
Early seral stages
r-strategists
Mid seral stages
Pioneer species

6. III. Ecological Succession 2. Disturbance/ uninhabited area
lichens, (produce acids to break down rocks), produce a thin soil,
In primary succession only
mosses, (change soil) ,
weeds, grasses, (pioneer species),
perennial herbs, shrubs, trees,
insects, birds, animals

7. III. Ecological Succession
3. Climax community – stable collection of organisms – which reach a stage stable than those that preceded.
Nature of the climax community depends on climate: varies from rainforest to shrubland to grassland, etc.
more

8. III. Ecological Succession
4. Trends in many successions
Change in community structure: Replacement of opportunistic, early-stage (r-strategists) with late-stage (K-strategists)
Increased nutrients available.
Increased biomass (living material)
Increase in diversity (especially with small, regular disturbances)
Increased complexity (i.e. in food web)
Increased stability between photosynthesis (producers) and respiration (consumers)