Ecological Succession Ecological Succession - The gradual change of a community over time. Ecological succession may occur when the conditions of an environment suddenly and drastically change by: Forest fire Wind storms Volcanic eruption Human activities like agriculture

Primary Succession Primary Succession is the series of community changes which occur on an entirely new habitat which has never been colonized by life before.

Primary Succession Primary Succession follows the formation of new land surfaces caused by landslides or avalanches, volcanic activity, & glaciation.

Steps of Primary Succession Primary succession begins when bare rock is exposed where nothing lives. Most primary succession begins with lichens. The lichens help to begin soil formation. Lichens are considered to a pioneer species A pioneer species is the first species to occupy a new area

Steps of Primary Succession After many years the soil will become deep enough for mosses to grow. Over time the soil layer thickens & the mosses will be replaced by ferns, which will then be replaced by wild grasses. Eventually small trees & shrubs will come into the area.

Steps of Primary Succession After hundreds of years, the soil will become deep enough to support an entire forest. Finally, a community emerges that is not replaced. This community is called the climax community.

Primary Succession A volcanic eruption on Mt. O-Usu in Japan

Secondary Succession Secondary succession follows the destruction or partial destruction of a vegetation area by some sort of disturbance, like a fire, windstorm, or flood that leaves the soil intact.

Steps of Secondary Succession A disturbance such as a fire destroys all the plants & trees in a forest, leaving the soil still intact. 2. Crabgrass is usually one of the first weeds to grow with horseweed starting to show in the second season.

Steps of Secondary Succession 3. In 5-15 years, small pine trees may start to grow amongst the weeds. 4. Over time, hardwoods such as oaks & maples replace older pines.

Steps of Secondary Succession Secondary succession usually occurs more quickly since the soil was still intact & may only take a few decades to rebuild the area. 0 yrs 10 yrs 15 yrs 20yrs

Steps of Succession video clip