Effect of Wastewater Irrigation on Phytosociological Characteristics of the Vegetation: A Case Study in Sistan Region

2 Abstract: The aim of this study is to determine the changes in plant diversity and phytosociological attributes of the vegetation according to the environmental conditions in Sistan Region in the southeast of Iran. For the study of plant communities and quantification of vegetation, quadrate method was used. Quantitative analyses on species diversity in addition to phytosociological attributes analysis were conducted in dry land, agricultural and waste water irrigation area. Data on abundance, density, dominance, frequency, Species Importance Value Indexes, are presented in the study. The plant communities were determined in percentage of frequency, abundance value, relative density and importance value. Based on results of survey that performed in study area, 16 species from 7 botanical families were recorded in all sites. The phytosociological studies reveal in most part of area that the vegetation was characteristically dominated by Tamarix species followed by Aeluropus sp. and Alhagi maurorum, which were the most abundant and frequent species of the study area. The Tamarix species has the highest IVI, in all surveyed areas. Species presenting the highest relative density is Aeluropus littoralis in the agricultural and wastewater area and Aeluropus littoralis in dry land area. It was observed that, wastewater plays an important role in vegetation growth and regeneration. The experiments from wastewater irrigated sites reported maximum number of species, depicting highest diversity among all sites. This clearly indicates that the wastewater can be effectively used in restoration of dry land, since it helps better growth of plants.