Ecological Succession The change in an ecosystem when one community replaces another as a result of biotic & abiotic factors.

Forest Fires: Friend or Foe? Return nutrients to the soil Allow certain seeds to sprout when heated Remove debris from forest floor Fire prevention can lead to higher debris build-up and more intense and dangerous forest fires in the future

Primary Succession establishment of a community in an area of exposed rock with no topsoil. Usually occurs slowly at first.

Lichens A combination of algae and fungus that secrete acids to break down rock and begin soil formation.

Soil Formation Lichens, a combination of algae & fungus, begin to grow on rock Lichens secrete acids that break down the rock Decaying lichens and sediment become the first stages of soil and allow small plants and insects to begin to grow Decaying plants and insects continue to develop soil formation Seeds drift in and grow in new soil allowing trees to grow and larger organisms to survive

Secondary Succession orderly and predictable change that takes place after a community of organisms has been removed but the soil has remained intact. Occurs mainly after disturbances such as fires or floods and begins with pioneer species growth. Usually occurs faster than primary succession because the soil already exists and some species are still present. Nearby undisturbed areas also contribute to a faster growth because seeds and organisms are closer

Pioneer Species Climax Community the earliest species to appear at the beginning of primary succession in order to help create soil by breaking down rocks. Climax Community mature, stable community resulting from little change in the composition of a species. True climax communities are very unlikely due to ever-changing natural disturbances such as climate change.

Where Can We Find A Climax Community? Hard to tell….. Succession is a slow process Human activities affect species success and development