The comparing of species richness and floristic composition of key and critical areas in semi-arid rangeland of Kakouhestan,Qazvin

In this research, species richness, life forms and platability of plant species in the key and critical areas was investigated. Two Whittaker, plots of 0.1-ha were established in each of mentioned areas. In each of Whittaker, plots from 0.1 to 1000 m2 respectively, species name as well as life forms, the number of each species and their palatability classes were recorded. By using linear regression models, two appropriate equations were calculated for species richness in critical and key areas. In order to compare the regression equetions of species richness, the group regression model was used. The results show that the species richness in key area is significantly different from critical area (P<0.05) so the species richness in key area is higher than the critical area. To find the relationships of the life forms and palatability of plant species in the key and critical areas, biplots were provided by using Principal Component Analysis (PCA). The correlation between palatability of species in key and critical areas are positive and negative respectively. Also the phanerophyts and chamaphyts have a positive correlation in key area but the geophytes has a negative correlation in it. This issue in the critical area is vice versa.