Evaluation of biodiversity indices during four years in Bagan region of Khuzestan province

The study of vegetation and the measurement of diversity indices are suitable tools for studying the status of forests and rangelands and evaluating them. The purpose of this study is to evaluate the trend of vegetation changes during four consecutive years and in two seasons in the Bagan region. For this purpose, 5 transects of 100 meters with distances of 50 meters in the study area were considered systematically randomly. A total of 30 plots of one fixed square meter were installed along the transects. In two growing seasons, spring and fall, from 2017 to 2020, the type and percentage of cover of native species were harvested. Dominance, uniformity and diversity of Simpson, Shannon and Hill species were measured using PAST and R software. The results of one-way analysis of variance (ANOVA) showed that there is a significant difference between the mean of dominance, Shannon and Simpson indices, percentage of cover, and the number of species in the spring of different harvest years. In fall, except for the dominance index in other indices during July 2019 compared to 2018, there was a significant difference. From the results, it can be concluded that despite the return of some annual or short-lived species such as Bienertia cycloptera Bunge and Salsola jordanicola Eig. following irrigation of cultivated seedlings and rainfall, the study area is still sensitive and fragile and needs to be managed and confined until proper rehabilitation.