Terrestrial Succession Meredith Burke June 13, 2002.
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Transcript of Terrestrial Succession Meredith Burke June 13, 2002.
Terrestrial SuccessionTerrestrial Succession
Meredith Burke June 13, 2002Meredith Burke June 13, 2002
DEFINITIONDEFINITION
* A series of regular, predictable changes in the structure of a community over time.
Succession begins with a simple change. Two types of
succession are…
PRIMARY SUCCESSIONBegins with bare minerals
and surface water.
SECONDARY SUCCESSIONBegins with the disturbance of
an existing ecosystem.
Stages of Primary Succession
Pioneer Stages:Bare rock, lichens, small annual plants, perennial herbs, grasses
Intermediate Stages:Grasses, shrubs, shade-intolerant trees
Climax Stages:Shade-tolerant trees, climax community
Factors affecting the rate of succession…
1) Competitive abilities of the species involved.
2) Tolerance to the environmental conditions brought about by changes in vegetation
3) The interaction with animals (particularly grazing herbivores)
4) Fire
New communities start as the result of disturbances in the current environment.
Changes to an area often make the environment less suitable for current organisms and more suitable for others.
New communities are referred to as PIONEER COMMUNITIES:a collection of organisms able to “eat” bare rock (I.E. lichens)
The Beginnings of Succession
Timeline of Terrestrial Primary Succession
1) Primary Community: colonization of organisms on bare rock
2) Lichens break down the rock and and accumulate debris creating a thin layer of soil
3) Small life forms are supported in the soil layer
4) Life forms replace the lichen community
Timeline Continued…
5) New community replaced by perennial plant community
6) Shrubs replaced by shade intolerant trees
7) Shade intolerant trees replaced by shade tolerant trees
8) Climax community is reached
Climax Communities
*Stable and long lasting*Larger more diverse
populations* Extensive and well defined (AKA a
biome)* Results from pioneer and transitional organisms as
well as cycling* Changes occur very slowly
Terrestrial Succession At Beaver Lake
*Many different stages can be seen
*Both manmade and natural
*Considered a climax community
*Surrounds a kettle lake (MUD Lake) created by the glaciers
*Bogs, open fields, and forest are present
*Consists mainly of deciduous and evergreen trees