Aspen paper birch
black spruce
jach plne
tehen
and
grasses
farbe
shruba
tree seedling
exposed
rock
planeer
community
climax
community
Time
A.
B.
Ecological succession leads to the sustainability of life in an ecosystem. Succession is the
observed process of change in the species structure of an ecosystem. The community
begins with relatively few ploneering plants and animals and develops through stages of
increasing complexity until it becomes stable. Succession may be initiated either by the
formation of new, unoccupled habitat such as the formation of an island or by some
form of disturbance such as a fire in an existing ecosystem. Succession that begins in
new habitats, uninfluenced by pre-existing communities is called primary succession,
whereas succession that follows disruption of a pre-existing community is called
secondary succession
Consider this northem site of primary succession following the retreat of a glacier, Plant
species at location B. would eventually change to the species seen at location C
because of what factor?