  Explaining biodiversity in nature is a fundamental problem in ecology. An
outstanding challenge is embodied in the so-called Competitive Exclusion
Principle: two species competing for one limiting resource cannot coexist at
constant population densities, or more generally, the number of consumer
species in steady coexistence cannot exceed that of resources. The fact that
competitive exclusion is rarely observed in natural ecosystems has not been
fully understood. Here we show that by forming chasing triplets among the
consumers and resources in the consumption process, the Competitive Exclusion
Principle can be naturally violated. The modeling framework developed here is
broadly applicable and can be used to explain the biodiversity of many
consumer-resource ecosystems and hence deepens our understanding of
biodiversity in nature.
