Ecological succession

Definition

Ecological succession is the process through which ecosystems change and develop over time, leading to a more stable and mature community. It involves a series of gradual changes in species composition, structure, and function following disturbances or the creation of new habitats. This process can be observed in both primary succession, which occurs in lifeless areas, and secondary succession, which follows disturbances in previously inhabited areas.

5 Must Know Facts For Your Next Test

1. Ecological succession can occur over long periods of time, sometimes taking decades or even centuries to fully establish a mature ecosystem.
2. After mass extinctions, ecological succession plays a significant role in rebuilding biodiversity and restoring ecosystems by allowing new species to fill vacant niches.
3. The stages of ecological succession include pioneer stages, intermediate stages, and climax communities, each characterized by different species compositions and ecological dynamics.
4. Both biotic (living organisms) and abiotic (non-living environmental factors) influences affect the process of ecological succession, such as climate, soil conditions, and existing species interactions.
5. Human activities like deforestation and urban development can initiate secondary succession processes, as these disturbances alter existing ecosystems but often leave behind some soil and seeds for regrowth.

Review Questions

• How does ecological succession contribute to ecosystem resilience following mass extinctions?
  • Ecological succession enhances ecosystem resilience by allowing new species to colonize areas previously affected by mass extinctions. This process facilitates biodiversity recovery as different species adapt to the newly available resources and environmental conditions. The gradual re-establishment of complex food webs and community interactions helps stabilize the ecosystem over time, making it more resistant to future disturbances.
• Compare and contrast primary and secondary ecological succession in terms of their processes and outcomes.
  • Primary ecological succession begins on barren landscapes with no soil, requiring pioneer species to establish the foundation for later communities. In contrast, secondary ecological succession occurs in previously inhabited areas where soil remains intact after disturbances like fires or floods. The outcome for both types often leads to a climax community, but secondary succession typically progresses more rapidly due to existing soil and seed banks.
• Evaluate the implications of human-induced disturbances on the patterns of ecological succession observed in ecosystems.
  • Human-induced disturbances significantly alter natural patterns of ecological succession by introducing changes such as habitat destruction, pollution, or invasive species. These alterations can disrupt the normal progression toward climax communities, leading to simplified ecosystems with reduced biodiversity. Additionally, human activities may create novel environments that require different successional pathways, ultimately impacting the long-term health and stability of ecosystems.

Related terms

primary succession:

The type of ecological succession that occurs in an area where no soil exists, such as after a volcanic eruption or glacier retreat, leading to the gradual establishment of a biological community.

secondary succession:

The type of ecological succession that occurs in an area where a disturbance has destroyed an existing ecosystem but left the soil intact, allowing for a quicker recovery and re-establishment of plant and animal life.

pioneer species: The first species to colonize previously uninhabited or disturbed environments, playing a crucial role in initiating ecological succession by modifying the environment for other species.