Ecological succesion Flashcards
What is a sere
The sequence of stages in ecological succession during which an uncolonised habitat develops into the climax community
What is secondary succession
Ecological succession that takes place in an area where the existing climax community has been disturbed or destroyed.
What is primary succession
Changes in an ecosystem over time when the starting point was nothing (no soil just bare rock, sand or water)
What are the three types of seres
- Hydrosere
- Lithosere
- Psammosere
What are pioneer species
One of the first species to colonise an area at the start of ecological succession. They are usually well adapted to extreme abiotic factors.
What is a hydrosere
Succession where the first stage or sere is freshwater
What is a lithosere
Succession where the first stage or sere is bare rock
What is a psammosere
Succession where the first stage or sere is on sand
What is a plagioclimax
Community maintained by human activity where succession/ the climax community was deflected or stopped
What is deflected succession
Natural ecological succession is stopped by human actions. Long-term continuation of the actions that deflect succession will create a plagioclimax.
What is a climax community
The relatively stable community of species present at the end of ecological succession.
The species that make up the community are controlled by the climate, so it is often called the climatic climax community
What is the main difference between primary and secondary succession
Primary succession occurs in an environment without previous life. Secondary succession occurs in an area that had previously been inhabited but experienced a disturbance, such as a wildfire or human activities such as grazing livestock or coppicing
During the succession process what increases over time
- Biodiversity
- Soil depth
- Complexity (plants develop)
- Plants become taller (supported by deeper soil = deeper roots)
- Shade
- Decay and decomposition
What are 6 plagioclimaxes in the UK
- Lowland heath
- Upland moor
- Chalk grassland
- Hay meadows
- Water meadows
- Coppiced woodland
What is the management practice in lowland heath
- Burn it (controlled burning)
- Grazing
What is the management practice in upland moor
- Burn it (controlled burning)
- Grazing
What is the management practice in chalk grassland
Grazing
What is the management practice in hay meadows
Mowing / harvesting the hay
What is the management practice in water meadows
Grazing
What is the management practice in coppiced woodland
Coppicing (cut trees down to a stump at intervals every 10 years)
How do early colonisers change abiotic conditions to enable more and more species to thrive
Early colonisers (pioneer species) go through the cycle of death and decay which helps with the production of soil and makes the habitat suitable for new species to thrive
How does lithosere develop
Developed by a cliff fall, glacier retreat or a volcanic eruption
What are the abiotic conditions usually like before succession of a lithosere
Abiotic conditions are usually harsh and unsuitable.
- Extreme temperatures
- Limited water availability
- No soil
What happens in stage 1 of primary succession of a lithosere
The ground surface consists of ash and bare rock and pioneer species usually lichen and moss colonise.