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

Abstract

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