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Why can secondary succession begin sooner than primary succession?
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ecological disturbance
Aerial view of the remains of trees on a hillside after a forest fire.
Secondary succession can begin sooner than primary succession because it occurs in environments where a disturbance has not eliminated all life and nutrients. Unlike primary succession, which starts in essentially lifeless areas lacking soil—such as those created by lava flows or retreating glaciers—secondary succession takes place in habitats where biological remnants persist.123
Key factors that allow for a faster start include:
- Soil and Nutrients: The existing soil remains intact, retaining the necessary nutrients to support plant growth immediately following a disturbance.1
- Biological Legacies: The presence of a soil seed bank allows buried seeds to sprout shortly after the disturbance passes.13
- Reduced Competition: Surviving organisms may experience faster growth due to reduced competition and shading from previously dominant species.1
In contrast, primary succession must first undergo a slow process of soil formation, often initiated by pioneer species like lichens that create the initial layers of soil as they decompose.2