Limiting Factor - Ecosystem

In all ecosystems one factor, usually abiotic, limits the growth of organisms and is therefore called a limiting factor. The limiting factor is one that outweighs all the other factors that are necessary for the growth of organisms. It is the primary determinant for growth because it lies beyond the minimum and maximum limits o the range of tolerance. For example, phosphorus is a limiting factor in certain aquatic ecosystem. It is the first to be used up. When phosphorus is reduced, the growth of algae is impaired. So, this is an example, where pho3phorus is in short supply and is thus a limiting factor. As mentioned above just as the shortage of any abiotic factor impairs the survival of organisms In an ecosystem, so can an excess.

Any factor that is in excess may b detrimental for the living organisms, directly or indirectly. You may be wondering how' Let us consider an example of a power plan1 from where the hot water pours into a nearby stream. As a result, the temperature or water in the area nearby shoots up from 10° C to 30° C. This sudden therryal vhock IS fatal for many fish and other aquatic organisms. The above example, illustrates the direct effect of excess of a factor. How the factors indirectly affect living beings is illustrated by the following example. If we over-water or flood a patch of land having trees on a prolonged basis then the excess water saturates, the soil by displacing air needed by the trees from the soil pores, thus creating anaerobic conditions. As a result, the roots get deprived of oxygen leading to the death of the trees. The excess of the water thus indirectly affect the survival of trees adversely.