  Explaining biodiversity is a fundamental issue in ecology. A long-standing
puzzle lies in the paradox of the plankton: many species of plankton feeding on
a limited variety of resources coexist, apparently flouting the competitive
exclusion principle (CEP), which holds that the number of predator (consumer)
species cannot exceed that of the resources at a steady state. Here, we present
a mechanistic model and demonstrate that intraspecific interference among the
consumers enables a plethora of consumer species to coexist at constant
population densities with only one or a handful of resource species. This
facilitated biodiversity is resistant to stochasticity, either with the
stochastic simulation algorithm or individual-based modeling. Our model
naturally explains the classical experiments that invalidate the CEP,
quantitatively illustrates the universal S-shaped pattern of the rank-abundance
curves across a wide range of ecological communities, and can be broadly used
to resolve the mystery of biodiversity in many natural ecosystems.
