The definition of the niche by fuzzy set theory

A new fuzzy niche concept is proposed to overcome the limitation of Hutchinsonʹs niche concept. The index α that makes a α-level set of the fuzzy set of the niche is a nice measure for intercompetition, and further discussions showed that α can serve as an index for measuring the existing status of a species in the community: if α exceeds its threshold value, the species may be excluded from the community; otherwise the species coexists with other species in the community.