Ecological Succession Science 10

Ecological succession  refers to the series of ecological changes that every community undergoes over long periods of time.  From the Latin, succedere, to follow after.  This process begins with pioneer organisms.

What does pioneer mean?  The one who goes before to prepare the way for others.  The first one.  Like the “pioneers” or early settlers of Canada.  What are the pioneers of an ecosystem?

Pioneer Organisms  Early settlers of a new region.  Such as bacteria, lichens, or fungi  We know that they add organic matter to the “primitive” (crude, or simple) soil.  This allows the first plants, or primitive plants, to grow.  They include mosses and ferns.

Order of growth 1.Primitive plants 2.Grasses 3.Shrubs 4.Trees 5.Seedling of various trees 6.Succession stops with the formation of a climax community.

Climax Community  Is the final stage of ecological succession.

Two stages of Succession 1.Primary Succession 2.Secondary Succession

Primary Succession  Occurs when a community begins to form in an area where there is no soil or living material.  Occurs in a area where a disturbance has occurred.

Disturbance  Is a change in environmental conditions which causes a profound (significant, or important) change in an ecosystem.  There are 2 types of disturbances:  Natural  Man-made

Natural Disturbance  Are “nature” made catastrophic events such as flood, fire, volcanic activity, climate change, species extinction.

Man-Made Disturbance  Or human influenced such as acid rain, ozone depletion, enhanced global warming, pollution, habitat destruction, monoculture farming, clear-cut logging, over-fishing.

 In terrestrial habitats, primary succession is a slow process because it begins with the formation of soil, or Pedogenesis.

Pedogenesis  Term to describe “making soil”  Soil is usually made from weathering and the action of pioneer organisms (lichens, fungi)

Weathering  Occurs when large rocks are broken down into pieces through natural, chemical, or biological processes.

 Rounded boulders in Joshua Tree National Monument, in California.  Rounded boulders like these reflect long-term erosion of granitic rocks by frost wedging and chemical weathering.

 A bizarre form of mechanical weathering: Mushroom Rock, Death Valley National Park.  Mushroom Rock was carved by blowing sand.  The upper part of the rock is relatively uneroded because the windblown sand is densest a few feet above the surface.  This rock which was about 2 meters tall, has since fallen down.

Secondary Succession  Occurs in an area where the existing community has been destroyed such as a manmade fire or clearcutting.  Soil is already present so plants can grow quite quickly (opposite of primary succession).

Factors That Help Ecological Succession 1.Climate 2.Soil 3.Geographical Features

Climate Includes: 1.Temperature 2.Precipitation 3.Amount of available sunlight

Soil Includes: 1.salinity (amount of dissolved salt) 2.fertility (how things grow) 3.moisture (how much H 2 O it can hold) 4.texture

Geographical Features 1.Latitude: position north or south of the equator 2.Altitude: height above sea level 3.Proximity or nearness to mountain ranges or bodies of water

Remediate  To restore a disturbed or contaminated area of land to a natural state

Phytoremediation  The use of plants, which can collect toxic compounds in their tissues, to clean the soil of its contaminants.  To collect uranium after the Chernobyl disaster sunflowers were used.

Bioremediation  Using bacteria or microbes to clean up or remove chemicals in the soil.  Such as pesticides, PCBs (poly- chlorinated biphenyls), detergents, oil (as seen in the diagram)