Variety of gastropods biodiversity associated with natural and anthropogenic factors in Mangrove Forests located at border of Iran and Pakistan

Abstract

This research was conducted to evaluate the gastropods diversity in mangrove forests located in Iranian part of the Govater Gulf in southern border of Iran and Pakistan. Three transects were selected at the water interface vertically to the end of forest stand. In each transect, samples of sediments containing gastropods were taken at the beginning (lower zones), the middle, and the end (upper zone) points during four continued seasons. Biodiversity (Shannon–Wiener index), dominance (Simpson’s dominance index), species evenness (Smith and Wilson evenness index), richness (number of species), and density (number in m3) were calculated for each season in sampling points. Data analysis results showed that biodiversity and richness indices changed significantly among different transects. Shannon–Wiener diversity index in transect one (1.90 ± 0.69) was significantly higher than transect two (1.26 ± 0.67) and three (1.19 ± 0.68). Similarly, richness index was the highest in transect one (7.58 ± 1.53) rather than transect two (4.42 ± 1.15) and three (3.92 ± 0.94). Density index changed differently between lower zone (2318.02 ± 987.76), middle zone (2318.01 ± 605.75) and upper zone (13,420.71 ± 176.50). Species evenness showed significant differences between lower (0.65 ± 0.15) to middle (0.46 ± 0.20) and upper (0.30 ± 0.32) zones. Different seasons had no significant effect on richness, density, diversity, and evenness of gastropod species. Consequently, among the natural factors, it is the intertidal zones which increases the environmental stresses such as salinity and humidity was considered, and surprisingly, weak anthropogenic factors, for example, the effect of the transect was positive due to providing nutrient.