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The Seashore

Why not take a look at how Succession works in practice in a Salt Marsh

Competitive Exclusion

In the 1930s a Russian biologist called G.F. Gause did some experiments with small Protozoan creatures called Paramoecia (sometimes called the slipper animal because of its resemblance to a hairy slipper).

Gause kept populations of different species of Paramoecium in centrifuge tubes and monitored how they did. It seemed that if he set the conditions up so that two different species (P. aurelia and P. caudatum) were forced into strong competition, one species always died out.

Gause suggested that this would always happen if two different species were attempting to occupy the same niche at the same time and called the phenomenon the competitive exclusion principle. (Sometimes you hear this called Gauses Law).

It has important implications for multi-species systems. If you've got lots of species living in the same area at the same time and the community is stable (meaning no extinctions) then there can't be strong competition (unless you never, ever have resource limitation). Of course all this depends on what time scale you decide for your definition of stability.

Competitive exclusion is an interesting concept but fiendishly difficult one to prove one way or the other.

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