B-6.3: Illustrate the processes of succession in ecosystems. Ecology: Succession

What is Succession? Ecological succession is the series of changes in an ecosystem when one community is replaced by another as a result of changes in abiotic and biotic factors There are 2 types of succession: Primary secondary

Primary Succession Begins in a place without soil, such as: Volcanic lava flows Pavement Bare rock The first organisms to colonize the bare rock are called pioneer species, which do not need soil to survive Examples: mosses and lichens

Primary Succession Mosses and lichens among most important pioneer species (first organisms) The mosses and lichens help to break apart the rocks into smaller pieces, which begins the process of soil formation Erosion by wind and water also helps to break down the rock When lichens and mosses die, they decompose and add small amounts of organic matter and nutrients to the newly forming soil

Primary Succession After mosses and lichens, then the other plants like annual grasses, weeds and ferns can grow in the newly formed soil Continue to break down rock and provide more soil Soil layer thickens

Primary Succession After the ferns, seeds of other plants and small trees are able to germinate and grow Over time more species grow and die Their decomposed bodies add nutrients to the soil and larger plants are able to populate the area

Primary Succession As species of plants change, species of animals that can inhabit area change Organisms in each stage may alter ecosystem in ways that may hinder their own survival but benefit future organisms This is how one community replaces another over time

Primary Succession The climax community is the final stage of succession, which is considered stable and permanent (unless a disturbance occurs, such as a forest fire) The climax community is determined by the limiting factors of the area Scientists have found that the processes of succession are always changing ecosystems

Primary Succession

Secondary Succession Begins in a place that already has soil and once had living organisms For example, secondary succession would occur after a forest fire Abandoned farmland, vacant lots, clear-cut forest areas Because soil is already present, wildflowers, bushes and tree seedlings can quickly grow back These would be the pioneer species

Secondary Succession

Secondary Succession Similar to primary succession in later stages after soil has been formed Something halts the succession, such as a fire, a hurricane or human activities, and destroys the established community but soil remains intact When disturbance is over, ecosystem interacts to restore the original condition of the community

Where does Succession Happen? Succession can occur in any environment, such as a forest, grassland, beach, coral reef, desert) Each biome has a different type of climax community

Succession Continual process Some stages may last for a short period of time, while others may last for hundreds of years Any disturbance will affect rate of succession. Usually secondary succession occurs faster than primary because it already has soil present When disturbances are frequent or intense, area has species that are present early on in succession When disturbances are moderate, area is composed of habitats in different stages of succession

What would be the order of the stages of succession? 3 1 4 2