ECOLOGY OF SUCCESSION

ECOLOGICAL SUCCESSION

CONTENT

• Introduction
• Types of Succession
• Differences Between Successions
• Characteristics of Succession
• Outcome of Succession

 

ECOLOGICAL SUCCESSION

The orderly change in the inhabitants of an area over time is called succession. It can also be defined as the step by step orderly and gradual replacement of communities of organisms that leads to a climax community.

An illustration of succession is that of a pond. Rain carries sediment from surrounding land into the pond, filling it and making it shallower. Algae that live in the pond die and eventually fall to the bottom, adding organic materials to the sediment.

Some plants such as pond weeds grow at the bottom. These plants make up the pioneer community. The pioneer plants are the first to inhabit the changing environment. The roots of these underwater plants hold much silt, quickly building up the bottom cover of the pond. As they die, their organic matter accumulates at the bottom. The water along the edges becomes so shallow that water lilies and other floating plants replace the pioneer plants.

The final stage of succession in a particular area is called climax community. The species that constitute the climax community differs from biome to biome. A climax community is also a stable community because its appearance and species composition are stable. To become climax, the community would have gone through a sequence of species.

 

TYPES OF SUCCESSION

Basically, there are two types of succession; these are

• Primary succession
• Secondary succession

 

Ecological succession ; ecological Ecological succession happens when new life takes over an environment. ...

• Primary successionPrimary succession begins in barren areas, such as on bare rock exposed by a retreating glacier. ...  Secondary succession; Secondary succession follows a major disturbance, such as a fire or a flood

Factors that can cause ecological succession 

The main causes of ecological succession include the biotic and climatic factors that can destroy the populations of an area. 

Wind,fire,soil erosion and 

natural disasters include the climatic factors.

PRIMARY SUCCESSION

This is a type of succession that begins from bare ground, bare rock or bare body of water.

Primary succession on land may be studied on a building site where a heap of sub-soil, stones or cement block is left over after construction. In an aquatic habitat, primary succession may be observed in a new artificial pond.

 

The first in any succession are called primary colonizers and are usually autotrophic plants. These have simple requirements for life and can withstand exposures. By the second year of the primary succession in addition to more algae and lichens, mosses may begin to grow. As they grow, they wear out some soil and some of them die and decay, creating more soil for their successor.

 

By the third year, small herbaceous plants may be present. These in turn help to change the habitat by overshadowing the smaller plants, causing them to die out and dropping their leaves, and thus making the soil suitable for other organisms. As years pass by, more species come into the habitat, while some face out. Succession of species continues till the climax is reached. Then, bigger life forms like shrubs and trees are found growing.

 

SECONDARY SUCCESSION

Secondary succession is a succession that occurs when an area has not been totally stripped of soil and vegetation. It occurs more rapidly than primary succession because soil has already been formed. It also occurs when a farmer abandon old field. Secondary succession begins from an existing community which has been interfered with by man and other factors. Fire, drought and floods can cause secondary succession.

 

Personal Drill;           

1. Define pioneer community.

 

2. How is a stable community reached

 



Succession in aquatic ecosystem 




2. 
   
3. SUCCESSION CAN ALSO OCCUR  IN AQUATIC ENVIRONMENT;

SUCCESSION IN A POND FOR INSTANCE

Pond Succession A geological event, such as a glacier or sink hole, can create a pond. Ponds are nothing more than shallow holes where water collects. Yet, if left alone, ponds will fill in with dirt and debris until they become land. It often takes hundreds of years for a pond to be transformed from a body of clear water into soil. The Four Stages of Pond Succession 1) As a pond develops seeds are flown in by birds and land animals come to inhabit the pond. These are the pond pioneers. 2) As more creatures arrive the debris on the bottom increases. Pondweed, and other submergent vegetation, appears and soon grow all along the bottom. Emergent plants have roots under water while part of their bodies resides above the water line. 3) Emergents then appear on the edges of the pond. Over time, sometimes hundreds of years, as ponds plants grow, die and decompose, layers of debris build up. These layers of decaying matter raise the pond floor over the years. 4) After some time, the pond floor is close enough to the bottom that emergents can grow all the way across the floor. When this happens, the ponds becomes a marsh. Many interesting creatures can reside in the shallow muddy waters of marshes. (Marshes can be created in other ways also.) The marsh continues to fill in with dirt and debris. Eventually trees grow in the water. It is now a swamp. Over time, the swamp may dry out. Land that was once a pond, may become a forest or grassland. CHARACTERISTICS OF SUCCESSION Plants form pioneer organisms being the producers The number of organisms is usually increased from year to year until a climax is reached. Diversity of organisms species increase from year to year. Succession is orderly and progressive starting with microscopic green plants and ending with big trees. Each generation of species alters the habitat by making more soil, and when they die the soil becomes more fertile. There is competition among organisms in that the various species present compete for the available resources such water, CO2, O­­2, light and space. The plants that are more able to compete displace other. Changes in species composition as the fittest survive and the unfit fade out.     OUTCOME OF SUCCESSION Changes in the physical environment due to structural changes of the species and the activities in the community. Simple organisms which start the succession are usually replaced by more complex ones in an evolutionary trend Equilibrium point is attained through colonization of abandoned farmland by a wide variety of organisms The final outcome of succession is the climax or stable community.

FURTHER  EVALUATION    

What is ecological succession?

Write short note on primary succession

Differentiate between primary and secondary succession.

Define stable community.

State the outcome of succession.

Compiled by  Ayo-Ben-Niji

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