Evaluation of biodiversity of plant species in Arasbaran area using non-parametric measures with respect to topographic factor of slope: a case study of aquiferous land of Ilgina and Kaleibar rivers

For achievement tosustainable development and conservation of natural ecosystems and their biodiversity,study on topographic factors and their effects is necessary.Regarding to topographical condition of Arasbaran forests of Iran,slope is an important ecological factor controlling many other dependant variables.So the inventory grid was designed by a random-systematic method with dimension of 300×300 meter and 160 sample circle plot with 314 square meters area were taken in Arasbaranforests.Shrub and arborous species were measured in main sample plot.Species,the percentage of coverage crown and the number of basis were considered as the measurement standards of plant coverage.Grassy species were measured in micro sample plots each with3.14 square meter.In micro sample plots,species and the percentage of the grass coverage were both determined.Site slope weredividedtothree classes including(0-25,25-50,and over50percent)in order to determined the biodiversity of plant species in different slope classes,and then indices of Margalef,Menhinick,Modified Nee, SmithandWilson,Simpson and Shanon-Wiener was calculated in each class.To determine the difference between slope classes we used one-way variance analysis and multi range comparing Duncan test.The results show evenness index of the range of plant do not have significant impact, however, its effect on the richness and heterogeneity index is a mean.Also the results showed that the index of species richness has a significant role in increasing biodiversityof region studied with increasing slope.Coefficient of variation toidentify the best indicator of the statistics and Pearson correlation coefficient was used.The result showed that to measure of richness,Margalef index,to measure of the evenness,Modified index and to measure of the heterogeneity,the Shanon-Wiener index,are the best indicators.