Due to the damages to global biodiversity by human interferences in recent decades and the role of biodiversity in ecosystems sustainability, restoring and protecting of natural resources is a necessity. In order to understand the roles of replanting and protecting natural ecosystems in dry land condition, this research was conducted in the experimental site of the international Carbon Sequestration Project in Hussein Abad rangelands, South Khorasan province, Iran in April and June, 2011. In this study the effects of eight years conservation on biodiversity indices of four vegetation types including Haloxylon persicum, Atriplex canescens, Haloxylon persicum + Atriplex canescens and Zygophyllum eurypterum along with a control type (no regeneration and conservation programs) were investigated. The highest amounts of species number (Hill’s N0) and vegetation cover were observed in Haloxylon persicum + Atriplex canescens type (30 species and 22.5%, respectively) and the lowest amounts were obtained in control type (20 species and 5.5%, respectively). Amount of vegetation percentage in protected areas was on average 3.3 times more than non-protected area. The highest and the lowest values of density were obtained in Atriplex canescens (54 plants m-2) and control (18 plants m-2) vegetation types, respectively. There was not any plant species with frequency of higher than 60% in control, while about 13% of plant species had frequency above 60% in protected vegetation types. The highest and the lowest plant species in all studied vegetation types were belonged to therophytes and phanerophytes groups. The mean Margalef\\\\\\\\\\\\\\\'s richness index in protected vegetation types (4.39) was higher than control (3.62). While, all plant diversity indices were higher in the control type because of more evenness index. Our results indicated that the most of recorded species in the studied area were belong to ephemeral flora. Overall, results showed that vegetation richness and coverage of desert rangelands can be restored with proper management programs.

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