Competitive Exclusion
In ecosystems, competitive exclusion means two species can't coexist if they need the same exact resources; one will eventually outcompete and displace the other.
Competitive exclusion, also known as the competitive exclusion principle, states that two species competing for the exact same limited resources cannot stably coexist in the same ecological niche. Over time, the species with the slight advantage in resource use will dominate, leading to the local extinction or displacement of the other species. This principle is fundamental to understanding niche differentiation and community structure in ecology.
What this means in real life
When grey squirrels were introduced to Britain, they outcompeted native red squirrels for acorns and tree space, causing red squirrel populations to crash in most regions—a real-world example of one species excluding another.
What it isn’t
It is not simply that two species cannot live in the same area; rather, it specifically describes what happens when they compete for identical, limited resources. Species can coexist in the same habitat if they use different food sources or occupy different ecological niches.
Commonly misused online
Often used loosely to mean 'one animal beat another' or 'one species is more successful,' ignoring the precise requirement that both must compete for the exact same scarce resource and one must fully eliminate the other from that space.