Starter What changes do you think will happen to

the following areas within an ecosystem during succession?

Size of organisms Energy flow Soil Biodiversity NPP and GPP

Changes in succession

You should all be able to: Identify changes in energy flow, gross and net

productivity, diversity and mineral cycling at different stages of succession.

Identify different types of climax community

Most of you should be able to: Explain why these changes are happening.

Complete the table

As we go through the different factors complete the table with the changes that happen during succession.

Start now by filling in the “types of vegetation” section in your groups.

Productivity

Describe what is happening in this graph…

Productivity During early stages gross productivity is

because of initial conditions and low density of producers.

The proportion of energy lost through respiration is relatively

So net productivity is

In middle stages gross productivity may be

In later stages, GPP as climax community reaches maturity

Respiration rates are so net productivity is

Productivity

Early Stage Middle Stage

Late Stage

Low GPP

NPP is a high percentage of GPP – low respiration

Little increase in biomass

Gross Productivity high– increased photosynthesis

Increases in biomass as plant forms become bigger

Trees reach their maximum size

Ratio of GPP to R is roughly equal

NPP low

What’s GPP and NPP?

Gross Primary Productivity is low but Net Primary Productivity is a large proportion of GPP because little biomass means respiration is low.

NPP as a percentage of GPP falls because respiration rates increase with more biomass

BiodiversityWhat do you think will happen to biodiversity as succession occurs? Why?

Mineral cycling

At the beginning of succession there are fewer nutrients within the community. Most of these nutrients are held within the soil.

Through the process of succession the level of nutrients within the community increases. Most of these nutrients are held within the vegetation.

Now complete any missing sections in your table…

Disturbance

In pairs try to think of possible disturbances that could cause these set backs…

Checking outcomesCut out the pictures and stick them down to create a diagram showing the process of succession.

Identify the different stages of succession and label your diagram

Annotate how each of the following aspects change through succession:

Size of organisms Energy flow Gross and net productivity Biodiversity Mineral cycling / soil

Now add an explanation for why each of these aspects changes through succession.