Warm-Up 10/2 - Adam Hardtke.com
Download
Report
Transcript Warm-Up 10/2 - Adam Hardtke.com
Succession
How do ecosystems recover from
disturbances?
Succession
Succession is the process of life taking
over disrupted ecosystems
Primary succession occurs in barren
areas with no soil (eruptions, glaciers)
Secondary succession occurs where soil
is still intact (grazing, logging, etc.)
Primary Succession
With no soil, bare ecosystems are very hostile to life
Pioneer species are first to colonize
Pioneer species need little water, shade
Typically small weeds, lichens
R-selected and/or type III species
Who lives and who dies?
Competition for resources determines who takes over
the new land
Species that reproduce fast and don’t need many
resources survive best, become pioneer species
Over time, less weedy species arrive and outcompete
the first colonizers
Later Succession
As soil appears, larger grasses, shrubs, and shade-
intolerant trees appear
The species that appear depend on the climate
Results of Succession
Primary and secondary succession result in a climax
community
Maintain species for a long period of time
Sustainable (in energy balance)
More organism symbioses than a changing community
May 18, 1980
Spirit Lake, before eruption
Spirit Lake, after and now
Windy Ridge Old
Growth Forest,
above Spirit
Lake
(before eruption)
Windy Ridge Old
Growth Forest,
after eruption
and now