Ecological Succession (Unit 4)

• Succession: describes the changes, over time, in the species that occupy a particular area. The first stage of succession is the colonisation of an inhospitable environment by organisms known as pioneer species. These organisms have the following features
                     - Production of wind-dispersed seeds that can reach isolated situations
                     - Rapid germination of seeds on arrival
                     - The ability to photosynthesise
                     - The ability to fix nitrogen due to there being few/no nutrients
                     - Tolerance of extreme conditions
• At each stage a different species is present which alters the environment, especially the soil, and is then out-competed by new species, forming a new community.
• In the UK, the ultimate community will most likely be deciduous oak woodland. This stable state is known as the climax community.
• Common features during succession- Non-living environment becomes less hostile
                                                            - A greater variety of habitats= greater biodiversity
                                                            - More complex food webs= increased biomass
• Secondary succession: Land that has already sustained life is suddenly altered. This type does not start with a pioneer species and returns to the climax community much faster. 

Conservation
The management of the Earth's natural resources in such a way that maximum use can be made of them in the future. This involves active intervention by humans to maintain the ecosystems and biodiversity. The main reasons for conservation is down to ethics, economy and culture/aesthetic.

Conserving habitats by managing succession
One way of conserving habitats is preventing a climax communtity from forming which causes a diminish in habitats and hence biodiversity. An example where this method is used is in moorland where the burning and grazing of heather prevents the land reaching a climax community. If the factor that is prventing further succession is removed, then the ecosystem will develop naturally into its climatic climax (secondary succession).