抄録
Recently evaluation of biodiversity has become more important, because it is necessary for environment assessment, impact assessment and priority assessment for conservation planning. Species diversity is one of the main measures of biodiversity, and has been expressed in various ways such as diversity indices. These indices have been, however, sometimes used inadequately: some authors occasionally ignored, or forgot, the premise of application of such diversity indices. Even when the indices are properly used, we must be careful in interpreting them Many diversity indices are double-faced: species richness and equitability. In recent studies, species richness estimates are often used as more direct measures of species diversity, instead of diversity indices. Such estimates are generally evaluated by nonparametric methods. Both the diversity index and the species richness estimates seem to be influenced by the species-abundance relationship. Diversity evaluation by both methods sometimes shows discrepancies. This paper, reviews the complicated expression and application of species diversity.
