Ecological Succession Flashcards
What is primary succession?
Changes in an ecosystem over a period of time when there was previously no life present
When might primary succession occur?
- Following a volcanic eruption
- Following glacial periods
What is secondary succession?
Changes in an ecosystem following a disturbance when there is existing soil
When might secondary succession occur?
- Forest regrowth after logging
- Plant growth after flooding
What is a sere?
The sequence of stages in ecological succession where a habitat develops into the climax community
What are the 3 seres?
- Lithosere (bare rock)
- Hydrosere (water)
- Psammosere (sand)
What are colonisers / pioneer species?
The first organisms to colonise an area during succession
How are pioneer species adapted?
Adapted to the harsh abiotic conditions (e.g. wind speed, temperature)
Which pioneer species are present in a lithosere?
Mosses and lichens
Which pioneer species are present in a hydrosere?
Algae (e.g. blue-green algae)
Which pioneer species are present in a psammosere?
Marram grass
How do pioneer species change abiotic conditions?
Death and decay of species contributes to soil formation
How does soil change as more species colonise an area?
Soil becomes deeper and more fertile
What is the climax community?
The final stage of ecological succession from which there are no further changes
What is the climax community in the UK?
Broadleaf woodland
What happens in a lithosere?
- Mosses and lichens colonise
- Death and decay leads to humus and soil formation
- More plant colonise and outcompete other species
- Climax community is eventually formed
What happens in a hydrosere?
- Algae colonises
- Death and decay leads to organic matter and sediment raising the lakebed
- Continued death and decay dries the soil
- Climax community is eventually formed
What happens in a psammosere?
- Marram grass colonises
- Sand dunes become stabilised
- Death and decay leads to humus and soil formation
- Climax community is eventually formed
What is a plagioclimax community?
An area or habitat in which human influences have prevented further succession
What is another term for plagioclimax?
Deflected succession
What are the 5 most common management practices in plagioclimax communities?
- Grazing (e.g. lowland heathland)
- Burning (e.g. upland moorland)
- Mowing
- Coppicing
- Pollarding
