Effects Of Foreign Species Introduction On An

Ecosystem Essay, Research Paper

The effects of foreign species introduction on an ecosystem

The effects of foreign species introduction into an ecosystem are very profound. From small microorganisms to species of large mammals, many foreign species introductions occur every day. New implications of their introduction are found just as often.

When a foreign species is introduced into an ecosystem, often the ecosystem contains no natural predators for the new species. This lack of predators sometimes leads to; in conjunction with a supply of food suitable for the new species, a period of exponential growth of the species. This growth and severe increase in the size of the population can cause a shortage of food for native species. When this occurs, the native species disappear and the biodiversity in the ecosystem is reduced. The carrying capacity is also reduced because the ecosystem will not be capable of supporting the same amount of life. If one species hogs the food and does not contribute itself to the food chain, the balance is disrupted and there will be less available for the native species. Once the new species has found its ecological niche however, balance begins to restore itself.

When the biodiversity in the ecosystem is reduced, the ability of the ecosystem to grow, or the biotic potential, is as well reduced. More species residing in an ecosystem which depend on each other allows for a greater chance of survival and perpetuation. This may occur for several reasons, for example a bee and a flower. The bee requires the pollen of the flower to make its honey. However, while gathering the pollen from the flowers, it transfers some of the pollen to female flowers, allowing them to make seeds and spawn further generations. However, a foreign species may, for example, eat the bees therefore allowing for decreased fecundity of the flowers.

Another implication of the introduction of foreign species into an ecosystem is the

potential for toxins to be spread up the species chain is increased. For example, in ports all over the world, ships empty their ballast tanks containing large amounts of sea water, often laced with organisms not naturally found in their new region. The zebra mussel provides food for a certain type of fish, and also contains several toxins because it is a filter feeder. The level of toxins in the fish due to the biological amplification is high. But if and when a new type of fish are introduced, which eats zebra mussels and provides a more preferred food for the fish which formerly ate the mussels, a new level of biological amplification is inserted. This results in the higher levels containing more toxins than they previously did, which can lead to higher death rates, and lower birth rates, which is an example of a lower biotic potential.

Finally, abiotic factors may not be prepared for the new species introduction. If, for example, a forest has a certain amount of rocks suitable for the construction of shelter by certain animals, and a new species moves in which also utilizes the same material for its shelter. The rocks will be in short supply. They are an abiotic factor, without which, animals have no shelter. The animal which takes up the building supplies but does not provide back to the ecosystem will thrive, however the rest of the ecosystem which depends on the native animal which is harmed, will not thrive and have a decreased biotic potential.

In conclusion, if a foreign species is introduced, the ecosystem is often not prepared to deal with the new competition. Because the predator-prey relationship is important in controlling the population, and the new species may not have any predators, the population may explode. The materials available may be compromised for the more beneficial organisms, and overall the biotic potential and carrying capacity will decrease. At least, until the new organism finds its niche and can contribute to the ecological community.