Diversity and species richness along an altitudinal gradient in the Gharabagh rangelands of west Azerbaijan province

Species diversity is one of the complex ecological concepts. The causes of these changes and their mechanisms were an outstanding ecological question. Biodiversity conservation is the ultimate goal of natural resources management. In this study, the relationship between species diversity and species richness were determined in Gharabagh rangelands along the altitudinal gradient using Simpsons, Shannon-Wiener, Margalef and Menhenic indices in Gharabagh rangelands. To measure vegetation parameters, the sampling was done in seven elevation classes with100m distance between, by randomly systematic method. Then, the number and canopy cover of species was recorded in ten plots in each elevation class. The result showed that there is a nonlinear and signicant relationship between Simpson's and Shannon–Wiener and Margalef and Menhenic indices with altitude increasing. So that species diversity, richness and numbers decreased above 1600 m altitude variation. R-square of the regression equations indicate that the dependent variable changes included Simpson, Shannon-Wiener, species number Margalef and Menhenic respectively with coefficient of 71, 68, 43, 49 and 63 percent are explained by the independent variable. In general we can say that, due to livestock and humans at low altitude decreased the species diversity and richness, while in mid altitude due to reduction of livestock population and improving climate increase species diversity and richness.