Community Ecology Notes – Module 2
Succession in communities
Learning Outcomes of Module:
1. Understand what succession is
2. Identify the different types of succession
Succession in communities
Succession: Change in structure of a community over time
Figure 1: Representation of succession in communities
Primary succession: A series of changes that occur in an area where no ecosystem previously existed
• Conditions for growth are extreme and challenging
• e.g. Newly formed volcanic island
• e.g. New sand dune
• e.g. Newly formed pond
Pioneer species: Pioneer species are adapted to survive and thrive in harsh environments and are
therefore the first species to colonize a new habitat.
• e.g. Lichen - Able to grow on bare rocks, produce acidic compounds which break down the
rock over time, creating soil for other plants to grow in
• Characteristics of a pioneer species:
o The first species to populate a new/disturbed area
o In a primary succession system, pioneer species need to be small, simple, and
capable of producing their own food
, ▪ e.g. photosynthetic plants, algae, lichen. - plants with adaptations such as
long roots or root nodes containing nitrogen fixing bacteria.
• In the case of primary succession, pioneer species are needed to build the soil for
subsequent plants to grow in
o e.g. Lichen → moss
• Pioneer species will eventually disappear/decrease in the landscape as succession tends
towards a climax community
Figure 2: Primary succession
Secondary succession: A series of changes that occur after a disturbance in an ecosystem
• e.g. Fire and flood
• e.g. Overgrazing
• e.g. Extreme weather event
• e.g. Human activity such as tree felling
Pioneer species in secondary succession
• Pioneer species in secondary succession systems are not necessarily building the soil, they
might already be present,
o e.g. as seeds in a soil seed bank or they might migrate into the area,
o e.g. Seeds/plants dispersed by animals or the wind
• Where a gap has been created in a forest, the pioneer species will be a fast growing
tree/shrub species that quickly takes advantage of the increased light
• After a fire in a grassland ecosystem the pioneer species may be a fast growing grass that
will take advantage of the nutrients released into the soil by the fire
o Fynbos is a fire-adapted vegetation type that requires regular burning to maintain
the high diversity and community structure. Optimal fire-cycle: 10 -1 4 years. Shorter
fire cycles destroy slow maturing species while long intervals between fires lead to a
loss of species as the vegetation becomes moribund
Succession in communities
Learning Outcomes of Module:
1. Understand what succession is
2. Identify the different types of succession
Succession in communities
Succession: Change in structure of a community over time
Figure 1: Representation of succession in communities
Primary succession: A series of changes that occur in an area where no ecosystem previously existed
• Conditions for growth are extreme and challenging
• e.g. Newly formed volcanic island
• e.g. New sand dune
• e.g. Newly formed pond
Pioneer species: Pioneer species are adapted to survive and thrive in harsh environments and are
therefore the first species to colonize a new habitat.
• e.g. Lichen - Able to grow on bare rocks, produce acidic compounds which break down the
rock over time, creating soil for other plants to grow in
• Characteristics of a pioneer species:
o The first species to populate a new/disturbed area
o In a primary succession system, pioneer species need to be small, simple, and
capable of producing their own food
, ▪ e.g. photosynthetic plants, algae, lichen. - plants with adaptations such as
long roots or root nodes containing nitrogen fixing bacteria.
• In the case of primary succession, pioneer species are needed to build the soil for
subsequent plants to grow in
o e.g. Lichen → moss
• Pioneer species will eventually disappear/decrease in the landscape as succession tends
towards a climax community
Figure 2: Primary succession
Secondary succession: A series of changes that occur after a disturbance in an ecosystem
• e.g. Fire and flood
• e.g. Overgrazing
• e.g. Extreme weather event
• e.g. Human activity such as tree felling
Pioneer species in secondary succession
• Pioneer species in secondary succession systems are not necessarily building the soil, they
might already be present,
o e.g. as seeds in a soil seed bank or they might migrate into the area,
o e.g. Seeds/plants dispersed by animals or the wind
• Where a gap has been created in a forest, the pioneer species will be a fast growing
tree/shrub species that quickly takes advantage of the increased light
• After a fire in a grassland ecosystem the pioneer species may be a fast growing grass that
will take advantage of the nutrients released into the soil by the fire
o Fynbos is a fire-adapted vegetation type that requires regular burning to maintain
the high diversity and community structure. Optimal fire-cycle: 10 -1 4 years. Shorter
fire cycles destroy slow maturing species while long intervals between fires lead to a
loss of species as the vegetation becomes moribund
