The world around us is slowly and constantly changing. We might never see the small alterations happen, but many years later, changes will surely be visible. Over time small changes add up and soon the whole ecosystem is different. This slow change in the land and habitat is called ecological succession. Animals, plants, and weather are some factors that cause this type of change in an ecosystem. Ecological succession begins with a pioneer community. In many cases lichens are the “pioneers. ” Lichens break down rocks, making soil, so that plants can begin to grow.
The process then continues on; trees grow, decay and then new trees grow back even bigger. Differences in the amount of sunlight, the amount of wind, and the type of soil all influence this changing community of organisms. The number and type of organisms change along with the habitat. Many, many years later the ecosystem becomes relatively stable. This stable condition can last for hundreds of years and is called a climax community. Sometimes nature’s power causes changes that happen more quickly, but not instantly. An example of this is repeated flooding.
In some areas loads happen often, each time new sediment is carried by the water and the deposited. Over time a marsh habitat becomes present, next a grassland and then a forest. At other time nature works backwards by tearing down a climax community with a flood or fire. New kinds of organisms are able to move in and the process repeats itself. This type of major reorganization helps encourage diversity in the environment. The next time you look outside try to picture a changing world. What you see out there today might not be the same in fifty years. Animals will move according to the food supply.
Plants will die if they don’t get the right amount of sunlight and water. The ecosystem will adjust to the new situation As a lake fills with silt it changes gradually from a deep to a shallow lake or pond, then to a marsh, and beyond this, in some cases, to a dry-land forest. When a crop field is deserted or a forest is severely burned over, it is Just like a plot of bare ground and a series of plant communities grow up there and replace one another-? first annual weeds, then perennial weeds and grasses, then shrubs, and trees-?until a forest ends the development.
Likewise, if a landslide exposes a surface of rock in the mountains, the surface may be successively occupied by a sparse cover of lichens; a spreading moss mat; grasses, which enter and become a meadow; a shrub thicket, which oversteps and suppresses the grasses; a first forest stage of smaller trees, which seed into the shrub thicket, grow through it, and replace it; and a final stage of larger trees, which take dominance from the first trees and may form a larger and potentially permanent forest community.
The changes in the structure and composition of the community are rapid at first, slowing gradually until a point of yeoman equilibrium is reached, and the community is more or less stable. Such an orderly and progressive replacement tot one community by another until a relatively stable community, called the climax community, occupies the area is called ecosystem development or ecological succession.
In the first example the principal cause of the change in the community was a physical process-the filling in of the lake with silt. In the second example, a principal cause was the growth of plants on an existing soil. In the third example the succession proceeded by a back-and-forth interplay between organisms and environment: one dominant species modified the soil and micrometers in ways that made possible the entry of a third dominant, which in turn altered its environment.
Causes of succession changes are, to varying degrees, external to the community or internal to the community, many successions involve both kinds of causes and reciprocal influences Succession is the “birth” of an ecosystem and subsequent “aging” process of its biotic and biotic features. The following three parameters are nowadays widely accepted in trying to define ecological succession: (1) It is an orderly process of community development that involves changes in species structure and community processes with time; it is reasonably directional and, therefore, predictable. 2) It results from modification of the physical environment by the community; that is, succession is community- controlled even though the physical environment determines the pattern, the rate of change and often sets limits as to how far development can go. (3) It culminates in a stabilized ecosystem in which maximum biomass (or high information content) and hemolytic function between organisms is maintained per unit of available energy flow.
In fact, ecological succession is a complex dynamic interaction between the community inhabiting the ecosystem, the geological Factors determining the patterns of materials transfer, the current state of the ecosystem as a whole, and time. Insofar as changes in the general state of the ecosystem are related to the community inhabiting it and alteration of the community is a function of the evolution of the general state of the ecosystem, succession proceeds under feedback control