The Six Stages of Succession on a Newly Exposed Suface
A simple model of succession on a surface which has recently become exposed (secodary succession)
Refers to AQA A2 Geography, Ecosystems, Change and Challenge Unit
- Created by: Bethany
- Created on: 19-03-14 17:42
STAGE 1
- LICHENS colonise the rock
- These LICHENS produce acids.
- The acids begin to WEATHER the rock.
- This begins to form an embryonic SOIL
Lichens colonise a wall (souce: FSC)
STAGE 2
- If the material is POROUS enough (e.g. brick), or when some rock has WEATHERED enough to hold WATER and SOIL particles, SEEDS of more advance plants may colonise.
- MOSS is commonly found at this stage.
Moss on an abandoned car park
STAGE 3
- Dead moss and the minerals begin to form a SOIL.
- This provides STABILITY, WATER and NUTRIENTS for the roots of more ADVANCED SPECIES to develop, for example OXFORD RAGWORT and NETTLES.
- These RUDERAL SPECIES can tolerate the rubbish and debries found on the wasteland.
- Plant succession is RAPID and plants have features of WEEDS.
Oxford Ragwort colonsies at Stage 3
STAGE 4
- Plant cover INCREASES and COMPETITION becomes more intense as colonisation proceeds.
- Rapidly growing ANNUAL plants are replaced by PERRENNIAL GRASSES.
- NETTLES and DANDELIONS, which are longer-living, invade.
Perrennial Grasses Dominate
STAGE 5
- In time, dense thickets of BRAMBLE, HAWTHORN and ELDER develop.
- SMALL SHRUBS become established in the cracks in the rock as soil gets deeper.
- IVY and BRAMBLE can out-compete smaller plants as their roots grow into deeper crevices in the rock.
Brambles on wasteland
STAGE 6
- Trees can only survive in DEEP SOILS, but some trees such as YEWS can grow on walls, even though their growth is stunted.
Yew trees growing from walls
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