Coral Reef SuccessionCoral Reef Succession

Ecological SuccessionEcological Succession

The progressive change in the species composition of an ecosystem.

Ecological SuccessionEcological

Succession

Climax StageClimax Stage

New Bare SubstrateNew Bare Substrate

Colonizing StageColonizing Stage

Successionist StageSuccessionist Stage

PRIMARY SECONDARY

Growth occurs on newly exposed surfaces where no soil exists

Ex. Surfaces of volcanic eruptions

Growth occurring after a disturbance changes a community without removing the soil

2 types of succession

• For example, new land created by a volcanic eruption is colonized by various living organisms

• For example, new land created by a volcanic eruption is colonized by various living organisms

• Disturbances responsible can include cleared and plowed land, burned woodlands

• Disturbances responsible can include cleared and plowed land, burned woodlands

Mount St. Helens

prior 1980

Mount St. Helens

May 18, 1980

Sep. 24, 1980

Mount St. Helens

Fireweed 1980 after eruption

2004

2012

Hanauma Bay Tuff Ring(shield volcano)

Succession after Volcanic Eruption

What organisms would appear first?

How do organisms arrive, i.e., methods for dispersal?

Volcanic eruption creates sterile environment

Mechanisms of Succession

Facilitation

Inhibition

Tolerance

Early species improve habitat.

Ex. Early marine colonists provide a substrate conducive for settling of later arriving species.

As resources become scarce due to depletion and competition, species capable of tolerating the lowest resource levels will survive.

Competition for space, nutrients and light; allopathic chemicals.

First arrivals take precedence.

r & K Selected Species

Pioneer species- 1st species to colonize a newly disturbed area

r selected

Late successional species

K selected

low competitive abilityshort life spanhigh growth rate

higher maternal investment per offspringlow reproductive output

high reproductive output

slow growth ratelong life spanhigh competitive ability

r & K refer to parameters in logistic growth

equation

Ecological Succession on a Coral Reef

Ecological Succession on a Coral Reef

Successional Models and their Impacts (p.133)

Successional Models and their Impacts (p.133)

• Case 1: No Disturbance (Competitive Exclusion Model)

• Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model)

• Case 3: Constant Strong Disturbance (Colonial Model)

• Case 1: No Disturbance (Competitive Exclusion Model)

• Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model)

• Case 3: Constant Strong Disturbance (Colonial Model)

Case 1: No Disturbance(Competitive Exclusion Model)

• As the reef becomes complex, organisms compete for space.• Dominant organism outcompetes other species.• Occurs in stable environments. • Results in low species diversity.• Highly protected patch reefs within lagoons or protected bays• Deeper water

Case 2: Occasional Strong Disturbance(Intermediate Disturbance Model)

• Storms and hurricanes allow for other species to move in• Dominant species would not be allowed to reach competitive exclusion• After each disturbance have a recovery period• Area of high diversity

Case 3: Constant Strong Disturbance(Colonial Model)

• Constant exposure to disturbance• Shallow environment• High turnover of species• r-selected species

Reef

Case 3

Case 2

Case 1Deep reef slope

Reef slope beneath reef crest

Near reef crest

Ecological Succession on a Coral ReefThe Big Island

Ecological Succession on a Coral ReefThe Big Island

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Ecological Succession on a Coral ReefEcological Succession on a Coral Reef

Successional Models and their Impacts

Successional Models and their Impacts

a) The slopes of a newly formed volcanic island

b) Wetlands in Texas, following Hurricane Rita

c) A receding glacier

d) A dried up lake

e) Primary succession would not occur on any of these.

a) The slopes of a newly formed volcanic island

b) Wetlands in Texas, following Hurricane Rita

c) A receding glacier

d) A dried up lake

e) Primary succession would not occur on any of these.

Primary succession would take place on all of the following EXCEPT:

QUESTION: Review

A “K” selected species generally has all of the following characteristics EXCEPT:

a) Large sizeb) Short-livedc) Good competitord) Constant population sizee) Slow population growth