Effects of Semi- Circular Bunds on Composition, Biodiversity and Biomass changes of Vegetation in Semi-arid Rangelands of Bushehr Province

Abstract

Semi-circular bunds are one of the useful rainwaters harvesting methods in arid and semi-arid areas for restoration and reclamation of rangelands. The aim of the present study was to evaluate the effects of semi-circular bunds on vegetation indices in semi-arid rangelands of Dashtestan county in Bushehr province. For this purpose, a systematic-randomized sampling method was conducted in the restoration (semi-circular bunds) area and control area. In each plot, the vegetation cover percentage was estimated. To compare the different indices such as species composition, biomass, diversity, and species richness between two areas, a t-test was used. The results showed a significant difference between the two areas in terms of all indices (P<0.05). The mean comparison showed that these practices had a significant effect on 31 plant species. In addition, comparing the means of indices including the number of species, Simpson and Shannon-Wiener diversity indices and Margalef richness indices showed that the restoration practices led to a significant increase in these indices. However, the Pielou evenness index increased significantly in the control area. Generally, in the semi-circular bunds area, the biomass of grasses, forbs, and total biomass was significantly higher than those of the control area. The RDA analysis showed that valuable species such as Atriplex leucoclada, Hippocrepis unisiliquosa, Medicago polymorpha, Medicago rigidula, and Medicago raditaa were more present in the semi-circular bund’s areas. The results showed that constructing semi-circular bunds had a positive effect on the vegetation indices of semi-arid rangelands in Bushehr province.