VI. Ecological Succession The replacement of one type of community by another over time.

A. Primary Succession The establishment of vegetation in an area previously uncolonized by organisms. May begin with bare rock Ex. New island formed after volcanic eruption

2. Pioneer Community first established group of organisms to inhabit an area help to break down rock and add nutrients to soil Examples: lichens - mutualistic relationship between: Algae Fungus & Photosynthesis provides food for the fungus Provides protection/support for algae, breaks down rock to expose minerals

3. Thin soil begins to accumulate and weeds will grow. 4. Weeds die, decompose and create more (fertile) soil so that grasses can grow. 5.  Shrubs 6.  Conifers 7.  Hardwoods (deciduous trees)

Mature, stable community (Depends on Biome) 8. Climax Community Mature, stable community (Depends on Biome) Remains until disrupted by a natural disaster or human activities (fire, flood, volcanic eruption, deforestation, etc.)  Secondary Succession

B. Secondary Succession Occurs after an existing (previously inhabited) ecosystem was disrupted (fire, hurricane, tornado, farming, logging) Takes less time than primary succession because soil is already there and ash/detritus supply nutrients Similar to primary succession, except for lichen stage

C. Pond Succession- 1. Sediments accumulate and fill in a pond, decreasing its depth and supporting plant growth 2. Aquatic pond community is eventually replaced by a terrestrial community.