Species Diversity of Gastropods Along a Disturbance Gradient in Rambungan Mangrove

Gastropods are diverse in mangrove habitat and the major group in the phylum Mollusca that inhabit both aquatic and terrestrial habitats. However, Rambungan mangrove are currently converted to aquaculture activities and affected by anthropogenic activities such as artisanal fishing, construction of Rambungan bridge, agriculture and coastal road in the area, which poses negative impacts on the environment and gastropod fauna. Hence, the objective of this research is to determine species richness and abundance of gastropods along a disturbance gradient in mangrove habitats and to assess the environmental variables. The gastropods were sampled using the line transect with quadrat approach, with distances of 10 m, 25 m, and 30 m along the river. The species richness and abundance of the gastropods along the disturbance gradient was determined using diversity indices (Shannon-Weiner, Margalef, Pielou and Jaccard index) and statistical test (Mann-Whitney, Independent t-test, factorial ANOVA, and linear correlation) was done in JASP software. Species of gastropods that was collected were Pirenella sp., Bulla ampulla sp., Assiminea sp., Indothais sp., Cerithium sp., Littorina sp., and Littoraria sp. The results show that there were low species in this area and H’ value range of 0.436 and 0.558 which indicates low diversity value in this Rambungan mangrove. Soil pH is the most affected by aquaculture ponds among three environmental variables measured (salinity, pH and light intensity) and the effect of aquaculture ponds is random and even across the sampling area. The findings of this study on the abundance and distribution of gastropods in a disturbance gradient can serve as reference for future study in the are