Succession is the change in the species composition of a community over time. Ecosystems are dynamic, and each community changes the conditions around it in a way that allows new species to move in.The general pattern is the same in every succession:1. Pioneer species are the first to colonise an area. They are adapted to survive harsh, hostile conditions, such as bare rock or sand with little water or few nutrients.
2. The pioneer species change the abiotic conditions, making them less hostile. For example, when they die and decompose they add organic matter, which helps soil form and hold water and mineral ions.
3. The new conditions allow other species to survive. These species may be better competitors, so they outcompete and replace the earlier ones.
4. Each new community changes the conditions again, and so on, until a stable final community, the climax community, is reached.At each stage, each group of organisms changes the environment so that it becomes more suitable for other species and often less suitable for itself.As succession proceeds, there are usually:
• more species, so biodiversity increases;
• more complex food webs, with more niches;
• more biomass, as larger plants such as shrubs and trees become established;
• less hostile, more stable abiotic conditions, such as deeper soil with more water and minerals.
Succession starting on bare ground with no soil is called primary succession; succession where soil is already present is called secondary succession.
2. The pioneer species change the abiotic conditions, making them less hostile. For example, when they die and decompose they add organic matter, which helps soil form and hold water and mineral ions.
3. The new conditions allow other species to survive. These species may be better competitors, so they outcompete and replace the earlier ones.
4. Each new community changes the conditions again, and so on, until a stable final community, the climax community, is reached.At each stage, each group of organisms changes the environment so that it becomes more suitable for other species and often less suitable for itself.As succession proceeds, there are usually:
• more species, so biodiversity increases;
• more complex food webs, with more niches;
• more biomass, as larger plants such as shrubs and trees become established;
• less hostile, more stable abiotic conditions, such as deeper soil with more water and minerals.
Succession starting on bare ground with no soil is called primary succession; succession where soil is already present is called secondary succession.