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Today’s Outline
Ecology (BIOL 250)
Lecture 19: Succession and Stability
Announcements
Introduction
Primary Succession
Secondary Succession
Disturbance
Ecosystem Recovery
Mechanisms of Succession
Community and Ecosystem Stability
!Succession: Gradual change in plant and
animal communities in an area following
disturbance.
"Primary succession on newly exposed geological
substrates.
"Secondary succession following disturbance that
does not destroy soil.
!Climax Community: Late successional
community that remains stable until disrupted
by disturbance.
Introduction
!Reiners et.al. studied changes
in plant diversity during
succession.
"Total number of plant species
increased with plot age.
"Species richness increased
rapidly in early years of
succession and more slowly
during later stages.
!Not all groups increased in density
throughout succession.
Primary Succession
at Glacier Bay
Primary Succession
at Glacier Bay
Primary Succession
at Glacier Bay
!Chapin documented substantial changes in
ecosystem structure during succession at
Glacier Bay.
"Total soil depth and depth of all major soil horizons
show significant increase from pioneer community.
!In addition, organic content, moisture, and N
concentrations all increased.
•Physical and biological systems are inseparable.
!Oosting found number of woody plant species
increased during secondary succession at
Piedmont Plateau.
"A separate study found increase in bird diversity
across successional sequence closely paralleled
increase in woody plant diversity observed by
Oosting.
Secondary Succession
in Temperate Forests
