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| Understanding The Function of an Ecosystem: Ecological succession or ecosystem development |
Ecological succession is a fundamental process characterized by directional changes in vegetation over time on an ecological scale. It occurs as a series of communities replace one another due to natural or manmade disturbances, ultimately leading to the establishment of a stable climax community.
Key Concepts:
1. Definition and Process:
Ecological succession is the gradual transition of communities, starting from pioneer species and culminating in a climax community. It involves increased productivity, nutrient cycling, organism diversity, and food web complexity.
2. Primary Succession:
This occurs on barren land where pioneer species like microbes, lichens, and mosses colonize the area. These pioneers alter habitat conditions, facilitating the arrival of additional organisms. As the community develops, competition increases, leading to the replacement of pioneer species by others.
Key Points:
- This occurs on bare terrestrial sites initially colonized by hardy pioneer species like microbes, lichens, and mosses.
- Pioneer species alter habitat conditions, facilitating the arrival of additional organisms.
- Their decomposition enriches the soil, creating opportunities for seed germination and growth.
- As the community evolves, competition increases, leading to the replacement of pioneer species by subsequent ones.
3. Secondary Succession:
This occurs on previously inhabited land disrupted by natural events or human activities. Initially, hardy species like grasses colonize the area, followed by taller vegetation and eventually trees. Over time, the area transitions into a forest ecosystem.
Key Points:
- It transpires in areas where the climax community has been disturbed, often due to natural disasters or human activities.
- Begins with the colonization of hardy species like grasses, followed by the establishment of herbaceous plants and eventually trees.
- Over time, the area transitions into a forest ecosystem.
Autogenic and Allogenic Succession:
Autogenic succession is driven by internal factors within the community, while allogenic succession is influenced by external forces.
Autotrophic and Heterotrophic Succession:
Autotrophic succession is characterized by dominance of green plants, while heterotrophic succession involves greater abundance of heterotrophs.
Factors Influencing Succession:
Succession may occur faster in central areas of continents due to faster seed dispersal and establishment of different seres.
Distinguishing Features:
- Primary succession starts on barren land, while secondary succession occurs on previously inhabited land.
- Secondary succession is faster due to the presence of developed soil.
- Autogenic succession is driven by internal factors, whereas allogenic succession is influenced by external forces.
- Autotrophic succession is dominated by green plants, whereas heterotrophic succession involves more heterotrophs.
Understanding ecological succession is crucial for comprehending ecosystem dynamics and management strategies.