Climax Communities

1
Climax Communities

• A climax community is one that has passed through
  all of the stages of succession
• The community is stable and the species that
  exist replace themselves instead of being
  replaced by other species

2
Is there only one climax community possible per
location?

• Originally it was thought--gt YES
• Now we think --gt NO
• It depends upon original pioneer species and
  interaction among later species

3
Is there really such a thing as a climax
community?

• Some communities never return to their former
  state
• How do you know when you have a climax community?
• Succession is not an orderly process pieces of a
  community can be in different stages at different
  times

4
Successional Patterns
5
Successional Patterns
6
Why is disturbance important?

• In many communities, species richness is highest
  in the midsuccessional stage (e.g. Chaparral)
• This is due to the fact that, in some
  environments, climax communities are dominated by
  a small number of species
• Having an intermediate amount of disturbance can
  allow the persistence of early, middle and late
  successional spp. (habitat heterogeneity over
  time)

7
Peat Bog to a Lake
8
Fireweed against a charred trunk
9
Succession in Deciduous Forest
10
Types of Succession

• Primary succession
• begins with bare rock exposed by geologic
  activity
• example sere rock -gt lichen -gt moss -gt grass -gt
  shrub -gt trees -gt oak hickory forest
• Secondary succession
• begins on soil from which previous community has
  been removed (by fire, agriculture, etc.)
• old field succession
• example sere grass -gt shrub -gt trees -gt oak
  hickory forest
• secondary succession can proceed much faster
  because the soil has been prepared by the
  previous community

11
Differences

• Pioneer Community Climax Community Harsh
  environment favorable environment biomass
  increasing biomass stable
• energy consumption energy consumption
  inefficient efficient
• some nutrient loss nutrient cycling
• low species diversity high species
  diversity fluctuations common fluctuations less
  common r - adapted K - adapted