Docstoc

Succession

Document Sample
Succession Powered By Docstoc
					Terrestrial Succession




Meredith Burke   June 13, 2002
       DEFINITION




* 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         SECONDARY SUCCESSION
   SUCCESSION
                         Begins with the
Begins with bare
                   disturbance of an existing
  minerals and
  surface water.           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
       The Beginnings of
           Succession
New communities         New communities
  start as the result
  of disturbances in
                         are referred to
  the current            as PIONEER
  environment.           COMMUNITIES:
Changes to an area       a collection of
  often make the
  environment less       organisms able
  suitable for           to “eat” bare
  current organisms      rock (I.E.
  and more suitable
  for others.            lichens)
  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          *Surrounds a
                         kettle lake
stages can be            (MUD Lake)
seen                     created by the
                         glaciers
*Both manmade
and natural              *Bogs, open
                         fields, and
*Considered a            forest are
climax                   present
community                *Consists
                         mainly of
                         deciduous and
                         evergreen trees

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:22
posted:4/24/2012
language:English
pages:11