Phytosociological Analysis and Species Diversity of Herbaceous Layer in Rashad and Alabassia Localities, South Kordofan State, Sudan

The objective of the present study is to analyze the phytosociological characteristics and the diversity patterns of herbaceous plants in Rashad and Alabassia localities. The study was conducted in selected 14 vegetation sites. Important Value Index (IVI) was used to estimate the phytosociological characteristics, the Shannon index to measure the plant diversity and the Pielou index for species evenness. During the study period, a total of 48 species, representing 42 genera from 20 families, were recorded. The phytosociological characteristics revealed that Tetrapogon cenchriformis dominated herbaceous species in sites 1, 7, 10, 11 with IVI values 139.3, 113, 70.3 and 95.8, respectively, followed by Spermacoce pusilla dominating sites 3, 4, 5 and 6 with IVI values 65.1, 50.4, 104.2 and 133.5, respectively. The distribution pattern revealed that 87.5% species showed aggregated distribution, while 12.5% were randomly distributed. The highest density was 110 plants/m2 recorded in site 4. Species richness varied through different sites; the highest number of species was 19, recorded in site 2. The highest values of Shannon diversity index and evenness index were in site 12. The highest similarity was recorded between site 9 and site 10 (73.39%) and the lowest (41.83%) between site 1 and site 3. The herbaceous flora of the area indicated its importance as one of the productive range region.