Application of numerical indices "Rarefaction and Jackknife" to evaluate oak forest plant richness

In order to investigate the application of Rarefaction and Jackknife numerical methods to assess the species richness Bane oak forests in Kurdistan province, three less disturbed, moderate and severe disturbed areas were selected. Three forest patches with similar physiographic conditions of each region were selected and in each patch, 3 plots of 400 square meters (on transects and at a distance of 100 meters) were taken to record the floristic information. Type and abundance of understory species in 5 micro plots with 1.5 × 1.5 m dimensions were recorded in each sample. Rarefaction and Jackknife methods as well as Margalef, Menhinic and amount of species indices were applied and were compared using of Tukey test. Margalef index mean were 6.254, 4.803, and 2 and Menhinic index mean were 1.628,1.263 and 0.794 and number of species index mean were 41.56, 32.11, 18.33 in less disturbed forest, mid-disturbed forest and severe disturbed forest, respectively. Also significant differences of abovementioned indices were observed amongst treatments. The species richness estimated through Rarefaction method 40.56, 30.99, and 17.96 for less disturbed forest, medium disturbed and severe disturbed forest, respectively and the species richness estimated by Jackknife method was 116.91, 110.114 and 69.62, respectively. Differences in the above indices between less disturbed forest and mid-disturbed forests and severe disturbed forests were significantly different. In general, according to the different sampling efforts, Rarefaction and Jackknife methods would present more accurate estimation of the species richness.