Investigating the Effects of Soil Factors on Biodiversity in Plant Communities of Karvan Rangeland (Case Study: Isfahan Province, Iran)

Understanding the plant species diversity could be used as an importantindicator applied for the natural areas management. The aim of this study was toinvestigate the relationships between soil characterizes with distribution and diversity ofplant in vegetation types in Karvan district (located in west of Isfahan province). For thispurpose, three vegetation types were selected as follows: Scariola orientalis-Astragalusgossypinus (Sc.or-As.go), Hordeum fragile-Astragalus gossypinus (Ho.fr-As.go) andCousinia bachtiarica-Astragalus gossypinus (Cu.ba-As.go). Then, four transects randomsampling - systematic bias to the general and lateral slope of the region in each vegetationtype were placed and the name and other characterize of the plants were recorded by 90 ofrandomly quadrate one m2, also the soil samples of the start and end of each transect fromtwo different depths (0-20 and 20-75 cm) of soil were taken. Soil samples were analyzedand the physicochemical factors were measured. Diversity indices such as Menhinick,Margalef and Fisher alpha were analyzed by VMSP software and soil data were analyzedby PC-ORD software. The results of numerical indices showed a different diversity indexin vegetation types and there were significant correlation between some soil properties anddiversity index. It was concluded that the Sc.or-As.go type had the highest diversity incomparison with the other vegetation types (Ho.fr-As.go and Cu.ba-As.go). Finally soilproperties such as organic matter, clay and soil depth had positive and the amount of limeand gypsum had negative correlation with species diversity.