Pioneer VS Climax species/ Primary VS Secondary su
Pioneer species: Climax species:
- e.g. lichens, algae, moss. - e.g. bigger plants, woodland.
- Opportunistic. - Better competitors
- Short lived. - Long lived.
- Grow rapidly. - Dominant species.
- Unstable. - Stable.
- Plants grow where no plants have grown before.
- Plants grow where there has been a previous population of plants that were destroyed e.g. in a fire.
Succession description and examples
SUCCESSION is a predictable and gradual change in plant and animal communities at a site over time, leading to the development of a climax state.
- The first species to colonise are called pioneer species and the ultimate, last species to colonise are called the climax community.
- Once the climax community has been reached, the succession will not proceed any further, however there will still be changes to the environment.
- Each next set of colonisers are known as seres.
- Each new community will be better adapted to the changed environment provided by the previous community.
- No plants are in bare rock as it is exposed and the heat is reflected/absorbed by the rock.
Examples of a succession: Psammosere (Sand dune succession):
Pioneer species e.g. sea rocket.
- These are able to tolerate salt water and unstable sand.
Climax species reached e.g. woodland.
- Sand is more stable, increased humus levels and fresh water.
Changes shown through succession over time.
- No plant competition for light, water, space and nutrients.
- Soil mobile and liable to erosion/loss.
- More extreme surface microclimate as bare soil absorbs and reflects more heat.
- A drier environment, no plant cover to hold moisture above ground and little humus to hold it in the soil.
- Lower nutrient levels in the soil.
2 years later:
- Intense plant competition for space and resources.
- Soil bound by roots and plant cover.
- Plant cover provides a certain amount of ground insulation from extremes of temperature - variety of microclimates.
- Plant cover and increasing humus levels help to retain water.
- Nutrient levels in the soil will have increased.