Changes in ecosystems/succession

• changes that happen in an ecosystem overtime, when the starting point was nothing

• pioneer or colonise species are the first species • early colonisers go through cycle of life, death and decay • they make habitat suitable for more species to thrive

• weathering of exposed rocks • growth of lichen • moss outcompetes lichen • grasses, fern and small herbs colonise • small shrubs such as bramble colonise on the surface • pioneer trees outcompete shrubs • legumes make nitrogen which increases soil fertility • larger trees colonise • creates a climax community

• sediments build up and the water gets shallower • emergent species grow partly in the water • submerged plants establish on the surface • a swamp forms • death and decay of plants lead to rising nutrient levels • species adapted to wet conditions die out • transpiration of plants dries the soil meaning rushes and ferns thrive • small flowering herbs are adapted to wet soils • shrubs form • climax community forms

• mobile dunes in an upper beach accumulate sand • hardy species tolerant of salt, wind such as marram grass colonise the area • vegetation mat develops and the dune system stabilises • accumulating humus changes the soil to allow wild thyme to accumulate • moisture loving plants such as willow colonise followed by woodland

• occurs when there is a disturbance to the natural process of succession

• primary has nothing and secondary has soil • secondary happens much quicker as soil is present

• biodiversity • soil depth • more decay

• deflected or halted succession

• its a volcanic island • in november 1963-1967 surtsey was formed in a volcanic eruption

• stage 1 - soil has poor levels of nitrogen and oxygen • stage 2 - few new colonisers • stage 3 - arrival of gull colony and vegetation enhancement • stage 4 - appearance of first bushy plant