Ecological succession
The gradual change in species over time in an area. Primary succession starts on bare ground, such as new volcanic rock. Secondary succession follows a disturbance, such as a fire, on soil that already exists, and is faster.
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Analogy
A new housing estate growing from bare plots into a mature neighbourhood.
In practice
Lichens and mosses colonise bare rock, then grasses, shrubs and finally trees arrive.
Practice
Flashcards
- How does secondary succession differ from primary?It starts on existing soil after a disturbance, so it is faster.
Interview questions
- Discuss the main threats to biodiversity and one strategy for conservation.
- Habitat loss
- Invasive species, pollution, over-harvesting, climate change
- Protected areas or corridors
- Genetic diversity and stability
Questions people ask
What is a climax community?
A climax community is the stable, mature stage that succession tends toward, for example a forest. Ecologists now see this as less fixed than once thought, because disturbances like fires, storms and changing climate keep resetting parts of the landscape, so it is often a patchwork of stages.
What are pioneer species?
Pioneer species are the first to colonise bare or newly disturbed ground, such as lichens, mosses and fast-growing weeds. They tolerate harsh conditions and help create soil as they die and decay. This makes it possible for other plants to arrive and take over.