Succession

What is disturbance?

A relatively discrete event in time that causes an abrupt change in ecosystem, community, or population structure, and changes resource availability, substrate ability, or the physical environment

What is succession?

• The directional change in community composition or structure over time

• Non-seasonal, continuous pattern of local colonization and extinction by different populations

What is primary succession?

Sequence of community change after a catastrophic disturbance

What is secondary succession?

Sequence of community change after less catastrophic disturbances

What is a sere?

Unit of succession

What is a seral stage?

Distinct community within a sere

What is a pioneer community?

Initial seral stage

What is a climax community?

Final seral stage

What is deterministic succession?

• Communities are “superorganisms”

• Each seral stage is a discrete entity

• Predictable and orderly

• From a bare state to a climax community

• Via a series of invasions by “higher forms”

What is contingent succession?

• Communities are a continuum

• A continuous process with no endpoint

• Linked to traits

• Those least tolerant of the changing environment drop out

• Chance colonization events are important

How does facilitation operate during succession?

Early successional species modify the physical environment, making it more conducive for later species

How does tolerance operate during succession?

• Any species that arrive can establish

• r-selected species are gradually outcompeted by K-selected species

How does inhibition operate during succession?

• Any species that arrive can establish

• Early species inhibit later species, slowing succession