First 231 words of the document:
PRIMARY SUCCESSION occurs when an area which is devoid of life is first colonised by PIONEER SPECIES e.g. lichen and algae that can cope in
the harsh conditions.
These species alter the environment in a way that makes it an unsuitable home for them, but suitable for a new species to establish. The
new species often replaces the existing species. A similar process occurs over time through stages (SERES) until a stable community is reached
the CLIMAX COMMUNITY e.g. woodland.
The dominant species of a community is the one that excerpts an overriding influence over the rest of the species. The dominant species is
usually the largest and/or most abundant plant species in the community.
As succession progresses, the number of niches increases, as does the number of species present. However, it is not unusual for the climax
community to have lower biodiversity than preceding stages in the succession.
The climax community is not always trees e.g. tundra and moss bogs.
SECONDARY SUCCESSION occurs in an area where living things already exist e.g. on bare soil where an existing community has been cleared.
DEFLECTED SUCCESSION is when a community remains stable because human activity prevents succession from running its course. E.g. sheep
grazing prevents woodland to grow in fields.