Gause's principle

Definition

The ecological proposition that two species exploiting the same limiting resource in the same way cannot coexist at stable population densities indefinitely; the superior competitor will eventually exclude the inferior one through competitive superiority, or the inferior competitor must diverge in resource use, habitat, or phenology to persist.

Etymology

Named for Russian ecologist Georgy Gause, who demonstrated the principle experimentally in 1934 using competing Paramecium species.

Example

Two ant species foraging on identical sugar baits in a forest understory illustrate Gause's principle: unless one species shifts to nocturnal foraging or discovers alternative carbohydrate sources, the more aggressive or efficient species will monopolize baits and numerically dominate, potentially leading to local exclusion of the inferior competitor.

Synonyms

• competitive exclusion principle
• Gause's law

Related Terms

• niche differentiation
• resource partitioning
• character displacement
• limiting similarity
• ecological release
• Interspecific competition
• Lotka-Volterra competition model

Usage Notes

Often misapplied as absolute; modern understanding recognizes that coexistence of close competitors is possible through spatial heterogeneity, temporal variability, or weak competition relative to other factors. The principle predicts outcome under sustained, intense competition for a single resource, not instantaneous exclusion. Contrast with niche theory: Gause's principle explains why niche differentiation is evolutionarily favored, not why species are pre-adapted to different niches.