Proper indices for species diversity studies in four range sites in Isfahan province

Irrational human activities such as wars, high fossil fuel consumption, deforestation, desertification, chemical pollution and some environmental disasters are important factors for environmental and biological diversity degradations. Biological diversity is based on species diversity which makes gene pools, so any decline in species diversity leads to genetic chute. In this study species diversity was studied by nonparametric methods in 2 steppe and 2 semi-steppe range sites in Isfahan province during 6 years (2002-2007). Species richness, heterogeneity and evenness indices were calculated from density data during study period. In steppe sites because of high species dominance (Hill) index and in semi-steppe sites (Hill) index seemed to be suitable to determine species diversity. Generally statistical test indicated that species richness, evenness and diversity between semi-steppe and steppe vegetations are significantly different. Results indicated that species richness and diversity of Aghcheh and Vardasht sites were significantly different, while evenness was not significantly different in mentioned sites. In steppe sites of Shadian and Khondab evenness and diversity were significantly different but species richness was similar. Ttherefore, based on this study findings, species richness in semi-steppe and evenness in steppe sites were more effective in creation of diversity index.