7. Ecological Succession 7.1 Succession

Starter Match up the key word to the definition Ecosystem Biotic Abiotic Community An ecological factor that makes up part of the non-biological environment More or less self-contained functional unit in ecology made up of all the interacting biotic and abiotic factors in an area The organisms of all species that live in the same area An ecological factor that makes up part of the living environment of an organism

Learning Objectives Describe changes that occur in the variety of species occupying an area over time Define succession and climax community Success Criteria You can describe the order of plant succession and explain common features of succession

Succession The changes, over time, in the species that occupy a particular area

Succession of bare rock or barren land Succession happens when an area is first colonised. What might happen to cause this?  A retreating glacier depositing rock  Wind or sea piling sand into dunes  Volcanoes erupting and depositing lava  Land subsiding and creating lakes or ponds  Silt and mud being deposited at river estuaries

Pioneer Species The first stage of succession involves pioneer species colonising an inhospitable environment Pioneer species have features that suit them to colonisation

Task In pairs, come up with a list of features that pioneer species may have, which would help them to colonise inhospitable environments

Features of Pioneer Species Production of a lot of wind-dispersed seeds to easily reach isolated areas Rapid germination of seeds The ability to photosynthesise The ability to fix nitrogen from the atmosphere Tolerance to extreme conditions

Stages of Plant Succession

Colonisers (lichens): when they die, they release nutrients. This changes the abiotic environment by creating soil. Mosses, then Ferns: rock is continually eroded, as these die organic matter increases, building up soil Small flowering plants, shrubs then trees establish

Climax Community The organisms that make up the final stage of ecological succession A balanced equilibrium In the UK, this is deciduous woodland

Animal Succession Animal species present depend on the plant species found in the area For example, mosses and grasses provide food and habitats for insects and worms. These can then support secondary consumers.

Common features in any succession The non-living environment becomes less hostile A greater number and variety of habitats Increased biodiversity More complex food webs Increased biomass

Land alteration Succession also occurs when land is suddenly altered e.g. from a fire The area will then undergo succession to return to a stable, climax community This type of succession doesn’t begin with a pioneer species

Learning Objectives Describe changes that occur in the variety of species occupying an area over time Define succession and climax community Success Criteria You can describe the order of plant succession and explain common features of succession