Succession

Community EcologyRemember: Community: a group of interacting populations that occupy the same area at the same time.

Limiting FactorsBiotic or Abiotic factors that restrict the existence, numbers, reproduction, or distribution of organisms.

2How might a cold climate be a limiting factor?Dry climate?Salt water?

LimitationsTemperatureElevationWindsSoil

Vegetation is limited to shallow rooted plants like lichen, ferns, and mosses

Animals must have adaptations to survive and thrive in cold, harsh environments4Why do organisms live where they do?Tolerance range: the ability of an organism to adjust to environmental fluctuations-Catfish need little oxygen and can live in warmer water-Bass/Trout need more oxygen and need much colder water

ToleranceSalt Marsh:

Near the shore, a few salt-tolerant species form salt marshes

6SuccessionThe natural changes and species replacements that take place in the communities of an ecosystem over time.

7SuccessionPrimary succession: the colonization of new areas by organisms-pioneer species: the first organisms to colonize an area (usually mosses and lichens)The decay of pioneer species produces soilWith soil comes the ability to sustain larger species

Occurs where a glacier hasreceded.Anywhere there is exposed rock and no soil.

9SuccessionSecondary succession: the community changes that occur after it has been destroyed by a natural disaster or human activityThe land already contains soilThe pioneer species will differ from that in primary succession

TypesSecondary Examplesa hurricanea farmer abandons a fielda building is demolished and left alone

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Final ResultClimax CommunityA stable, mature community that undergoes little or no change.12Succession Observed in Glacier Bay National Park

Lichen and moss have special adaptations to tolerate extreme conditions. Despite limiting factors, the fireweed seeds are well adapted so that they are easily spread by wind.

13Dryas is very good at enriching the soil with nitrogen. The moss grows close to the ground around the dryas mat and the cottonwood trees grow up in the middle.

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A spruce tree growing under an alder thicket15A mature Spruce and Hemlock Forest

16SuccessionWill the climax community be the same in all areas? Why or why not?

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