Ecological Succession
- Created by: bethanymcguire
- Created on: 18-05-17 13:37
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- Ecological Succession
- a process where an ecosystem changes over time, the biotic factors change as the abiotic factors change
- occurs in stages called seres, at each stage, the wildlife is better adapted to the environment.
- as the succession continues, the ecosystem becomes more complex. new species inhabit the area and the species biodiversity increase
- the final sere is called the climatic climax.
- the ecosystem supports the largest amount of diversity it can while the abiotic and biotic factors are in balance
- Primary Succession
- happens on surfaces which have never had vegetation on them, such as new rock surface following a volcanic eruption or bare rock exposed by retreating galciers
- 1. the abiotic conditions are poor, seeds and spores are blown by the wind to the area
- 2.the first species which colonise the area(pioneer species) they grow because they are specialised and well adapted to cope here such as lichens/mosses
- GROUND LAYER
- 3. the pioneer species change the abiotic factors. they die and then decompose. this forms humus (creates an immature soil) for new species to establish on as well as creating nutrients
- HERBS GROW, THE FIELD LAYER
- 4. the conditions become less hostile. the immature soil helps to retain water which allows different species to grow. these die and release different nutrients back into the soil, now different plants can grow such as shrubs.
- SHRUB LAYER
- Priseres
- 5. The shrub layer will be taken over by the tree layer, if environmental factors do not change, it will eventually reach a state of equilibrium (balance)
- Temperate Deciduous Woodlands UK
- Dynamic equilibrium; because any change in climate or soil changes the characteristics of the vegetation and animal life.
- Brown soil
- usually deep, well drained, fertile and supports a large amount of fauna
- decomposers break down the thick layer of litter to create a rich dark brown humus. rodents and earthworms mix into the layers to help aerate the soil
- slightly acidic, unless there is heavy precipitation there is little leeching. nutrient recycling is efficient
- Canopy Layer- layer of tree tops which grow to around 30m. they lose their leaves in autumn to reduce water loss by transpiration
- shrub layer which has small trees such as rowan holly and hazel
- tree layer which consists of lime, elm, beech, oak and
- field layer which consists of brambles, grasses and flowering plants
- ground layer- mosses, lichens and litter
- Light availability depends on seasonality
- Secondary Succession
- occur on surfaces which have already been colonised
- but have since been changed or destroyed
- such as deforestation/ human activities or fire from lightnig strikes or landslides
- occur on surfaces which have already been colonised
- Things which could affect a succession
- Farming
- Invading Species
- Extreme weather, drought, lightning, snow...
- Deforestation
- Waste management -Toxic
- Flooding
- Water extraction may affect forest growth
- Xeroseres (found on dry land)
- Lithosere
- when bare rock is progressively colonised by plants as soils develop
- Raised beach on the west coast of Scotland formed since the last ice age
- Lithosere
- Hydroseres (formed in water)
- Halosere
- salt water environment like salt marshes also undergo a succession
- Hydrosere
- where fresh water environments such as ponds and lakes silt up over time. the spores of algae/mosses blow onto the water. creating a pioneer community
- floating and submerged water weeds including lillies can then develop trapping sediment at the water edge
- Halosere
- From the ground to the tree layer. the height increases, and the number of species increases
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