Succession in Environment
Definition:
Succession is a sequence of modifications and changes in the community structure of an ecosystem over some time.
OR
A change in the community and its non-living environment over a period of time is called succession.
Community changes the environment in ways that favour the competitors and species replace one another and their predecessors in somewhat foreseeable manner until a stable, self-sustaining climax community is reached. Succession is a sort of “community relay” in which assemblages of plants and animals change the earlier ones in a sequence that is at least somewhat predictable.
The accurate changes occurring throughout succession are as varied as the environments in which succession occurs, however particular general phases can be acknowledged.
- 1) Pioneers and Climax Community
- 2) Two Significant Forms of Succession on Dry Land
- 3) Types of Primary succession
- 4) Xerophytes
- 5) Stages of Xerosere
- 6) Climax forests
- 7) Frequently Asked Questions (FAQs) on Ecological Succession
- 8) Multiple Choice Questions (MCQs) with Answers
- 9) Summarizing Ecological Succession
- 10) You may also like to learn:
Pioneers and Climax Community
In each case, succession is initiated by a few hardy invaders called pioneers and it ends with a varied and fairly steady climax community.
Two Significant Forms of Succession on Dry Land
Succession on dry land are of two major types,
- Primary succession
- Secondary succession
Primary succession
Throughout primary succession, an ecosystem is forged from bare rock, sand or clear glacial pool where there was no trace of the previous life. The development of a community from scratch is a procedure often needing thousands of years.
Secondary succession
During secondary succession, a new ecosystem develops after an existing ecosystem is interrupted as in case of forced fire or an abandoned farm field. Secondary succession happens far more quickly than primary succession due to the fact that the previous community has actually left its mark in the form of enhanced soil and seeds and other traces of living life.
Types of Primary succession
Primary succession maybe
- Hydrosere
- Xerosere
- Derosere
Hydrosere
Primary succession beginning in a pond is called hydrosere.
Xerosere
Primary succession starting on dry soil or environment or habitat is called xerosere.
Derosere
Primary succession starting on dry soil or rock is called derosere.
Xerophytes
Plants growing in xeric conditions are called xerophytes, which have the ability to withstand extended periods of water lack and extreme temperature levels. Succulent plants such as the cacti have water stored in large parenchyma tissue, others have leaf modification.
Stages of Xerosere
Following are the stages of xerosere
Crustose lichen stage
Crustose refers to land lifeless structure and any external protective surface on the rock and crustose implies crusts on the substratum. Special types of lichens get impregnated in the form of crust. They can live in extreme conditions. Often, their surface is wet due to rain and dew- drops. They take in water during the dry season. They are quiescent or dormant, generally desiccated throughout the dry season.
Common Examples are: Bacidia and Leucanor
Foliage lichen stage
In this stage, the lichens are just similar to crumpled leaves connected at one point. It produces shade to the crustose lichens as a result of which their growth is lowered or reduced. The area becomes rough, as increasingly more fissures and depressions develop. At this phase, other plants invade called moss stage, due to the fact that now the soil is more permeable with some litter of lichens.
Typical examples are: Dermatocarpon, Parmelia, etc.
Moss stage
This is the third stage with mosses. They compete with lichens for water and penetrate much deeper into the soil as compared to the lichens, adding more humus to the soil.
Common examples are: Polytrichum, Tortula, and so on.
Herbaceous (plant) stage
Little seedling of herbaceous plants now establishes due to the more availability of moisture, humus, and soil for anchorage.
Shrub stage
Shrubby plants now start growing, controlling, and shadowing herbaceous plants which pass away to include more humus to the soil.
Climax forests
The soil is improved to a level that it now allows the growth and establishment of woody plants. The shade of these plants prevents the development of many plants other than mosses, lichens, a couple of ferns etc.
Woody plants control and this phase in succession remain basically the very same if nothing changes in the environment to disturb the balance. Because it is a stable stage in succession, the woody forest is considered to be the climax phase for this area.
Frequently Asked Questions (FAQs) on Ecological Succession
1. What is ecological succession?
- Definition: Ecological succession refers to a sequence of modifications and changes in the community structure of an ecosystem over a period of time.
2. How is succession initiated, and what does it lead to?
- Succession is initiated by hardy invaders known as pioneers. It leads to the development of a varied and stable climax community.
3. What are the two significant forms of succession on dry land?
- There are two major types: Primary succession and Secondary succession.
4. What is primary succession?
- Definition: Primary succession involves the formation of an ecosystem on bare rock, sand, or a clear glacial pool where there was no previous life.
5. What is secondary succession?
- Definition: Secondary succession occurs when a new ecosystem develops after an existing one is disrupted, such as in the case of a forced fire or an abandoned farm field.
6. What are the types of primary succession?
- Primary succession can be classified into three types: Hydrosere, Xerosere, and Derosere.
7. What are xerophytes?
- Xerophytes are plants that can withstand extended periods of water lack and extreme temperatures, often found in dry conditions. Examples include succulent plants like cacti.
8. What are the stages of Xerosere?
- The stages of Xerosere include:
- Crustose lichen stage
- Foliage lichen stage
- Moss stage
- Herbaceous (plant) stage
- Shrub stage
9. What is a climax forest?
- Definition: A climax forest is a stable and self-sustaining community of woody plants that dominates a particular area. It represents the final stage in ecological succession if the environment remains undisturbed.
10. Why does secondary succession happen more quickly than primary succession?
- Secondary succession occurs more rapidly because the previous community leaves behind soil, seeds, and other traces of life, facilitating the establishment of a new ecosystem.
11. What are some examples of plants in the crustose lichen stage?
- Common examples include Bacidia and Leucanor.
12. What characterizes the foliage lichen stage in Xerosere?
- In this stage, lichens resemble crumpled leaves connected at one point, creating shade for crustose lichens, and the area becomes rough with fissures and depressions.
13. How do shrubby plants contribute to the Xerosere succession?
- Shrubby plants grow, control, and shadow herbaceous plants, which eventually die, adding more humus to the soil.
14. Why is the woody forest considered the climax phase in ecological succession?
- The woody forest is considered the climax phase because it represents a stable stage where the balance is maintained, and the soil allows the growth of woody plants, preventing the development of many other plant species.
15. How long does primary succession typically take to form an ecosystem?
- Primary succession often requires thousands of years to develop an ecosystem from bare rock, sand, or a clear glacial pool where there was no trace of previous life.
sdfs
Multiple Choice Questions (MCQs) with Answers
1. What is ecological succession?
- A. A series of modifications in an ecosystem
- B. A sequence of changes in community structure over time
- C. Both A and B
- D. None of the above
Answer: C. Both A and B
2. What initiates succession in an ecosystem?
- A. Climax community
- B. Pioneers
- C. Xerophytes
- D. Mosses
Answer: B. Pioneers
3. How does secondary succession differ from primary succession?
- A. It occurs more slowly
- B. It happens on bare rock
- C. It occurs after an existing ecosystem is disrupted
- D. Both A and B
Answer: C. It occurs after an existing ecosystem is disrupted
4. What is the primary difference between hydrosere and xerosere?
- A. The type of vegetation
- B. The starting point of succession
- C. The presence of water
- D. The duration of the process
Answer: B. The starting point of succession
5. What are plants growing in xeric conditions called?
- A. Hydrophytes
- B. Xerophytes
- C. Mesophytes
- D. Halophytes
Answer: B. Xerophytes
6. During which stage of xerosere do lichens resemble crumpled leaves connected at one point?
- A. Crustose lichen stage
- B. Foliage lichen stage
- C. Moss stage
- D. Shrub stage
Answer: B. Foliage lichen stage
7. What occurs in the moss stage of xerosere?
- A. Development of shrubby plants
- B. Competition with lichens for water
- C. Increase in humus content in the soil
- D. Seedling establishment of herbaceous plants
Answer: C. Increase in humus content in the soil
8. Why does secondary succession happen more quickly than primary succession?
- A. Enhanced soil and seeds from the previous community
- B. Rapid growth of pioneers
- C. Increased sunlight availability
- D. Absence of competitors
Answer: A. Enhanced soil and seeds from the previous community
9. What is the final stage in ecological succession called?
- A. Pioneer community
- B. Climax community
- C. Xerophyte stage
- D. Hydrosere
Answer: B. Climax community
10. What is the role of shrubby plants in the xerosere succession?
- A. Increase soil fertility
- B. Add more humus to the soil
- C. Control and shade herbaceous plants
- D. Enhance water availability
Answer: C. Control and shade herbaceous plants
11. What is the primary focus of primary succession?
- A. Enhancement of existing ecosystem
- B. Formation of an ecosystem from scratch
- C. Rapid development of vegetation
- D. Introduction of xerophytes
Answer: B. Formation of an ecosystem from scratch
12. What do lichens contribute to the crustose lichen stage in xerosere?
- A. Increased soil permeability
- B. Shade to other plants
- C. Deep penetration into the soil
- D. Humus enrichment
Answer: B. Shade to other plants
13. What characterizes the climax forest stage?
- A. Rapid plant growth
- B. Enhanced soil fertility
- C. Stable and self-sustaining community
- D. Increased competition among species
Answer: C. Stable and self-sustaining community
14. What is the significance of pioneers in ecological succession?
- A. They initiate the succession
- B. They represent the climax community
- C. They enhance soil fertility
- D. They control shrubby plants
Answer: A. They initiate the succession
15. What is the primary factor influencing the speed of secondary succession?
- A. Climate
- B. Soil composition
- C. Previous community’s influence
- D. Availability of water
Answer: C. Previous community’s influence
Summarizing Ecological Succession
The concluding section of the tutorial on Ecological Succession emphasizes the fundamental principles and stages involved in the dynamic process of ecosystem development over time.
- Definition of Succession:
- Succession is defined as a sequence of modifications and changes in the community structure of an ecosystem over a period of time. It involves both living and non-living components of the environment.
- Phases of Succession:
- Succession leads to changes in the community structure, favoring competitors and leading to the replacement of species in a somewhat predictable manner. The process ultimately culminates in the establishment of a stable, self-sustaining climax community.
- Role of Pioneers and Climax Community:
- Succession in any case is initiated by hardy invaders known as pioneers, and it concludes with the establishment of a diverse and relatively stable climax community.
- Forms of Succession on Dry Land:
- Two major types of succession on dry land are highlighted – Primary succession and Secondary succession, each with distinct characteristics.
- Primary Succession:
- Primary succession involves the gradual formation of an ecosystem on barren substrates, such as bare rock, sand, or clear glacial pools, over an extended period, often spanning thousands of years.
- Secondary Succession:
- Secondary succession occurs more rapidly as it follows the disturbance of an existing ecosystem, such as through forced fires or abandoned farm fields. The previous community leaves its mark in the form of enhanced soil, seeds, and other traces of living life.
- Types of Primary Succession:
- Three main types of primary succession are introduced – Hydrosere (pond initiation), Xerosere (on dry soil or habitat), and Derosere (on dry soil or rock).
- Xerophytes:
- Plants adapted to xeric conditions, called xerophytes, possess mechanisms to withstand prolonged water scarcity and extreme temperatures.
- Stages of Xerosere:
- The tutorial outlines key stages in xerosere, including Crustose Lichen, Foliage Lichen, Moss, Herbaceous, Shrub, and Climax Forests. Each stage contributes to the development and transformation of the ecosystem.
- Climax Forests:
- The final stage, Climax Forests, represents a stable phase where the soil is improved to allow the growth and establishment of woody plants. This stage remains relatively unchanged unless environmental disturbances occur.
The tutorial provides a comprehensive overview of ecological succession, elucidating the intricate processes that shape the development of ecosystems, from the initiation by pioneers to the establishment of a climax community.