Study And Application On The Theory Of Fuzzy Hypervolume Niche

Fuzzy hypervolume niche was proposed to overcome the limitation of Hutchinson's niche concept and the formulas to measure two important indexes—niche width and niche overlap which can be easily applied in practice. Further researches show that multi-dimensional niche overlap is usually bigger than the product of one-dimensional niche overlap when each dimension of resources which the species utilizes is independent from others.Niche which many ecologists have become interested in is an important concept in ecology. The main definitions of niche are the habitat niche of Grinnell (1917), the functional niche of Elton (1933) and the hypervolume niche of Hutchinson (1957) whose concept has by far the largest influence on niche. For overcoming localization of the Hutchinson's definition, Guangxia Cao (1995) initiated a new definition of niche in which only one-dimensional resources is considered by the theory of fuzzy sets.Based on Hutchinson niche and Guangxia Cao's definition, Fuzzy hypervolume niche evolves the theory of fuzzy niche: the niche is a fuzzy hypervolume; the niche of the species is a hypervolume with fuzzy boundary which is formed by the n-dimensional resources (time, space, temperature, humid, trophic, ...) necessary for the species' continuous existing and multiplying; membership of a point in the niche is equivalent to the adaptive degree of the species to the point of the environmental resources. All these push forward the development of the research of niche.