Gastropod Community Structure in Mangrove Pancer Cengkrong Ecosystem, Trenggalek Regency, East Java

The condition of mangrove vegetation habitat determines the community structure of organisms associated with it, including gastropods. Mangrove Pancer Cengkrong is located in Trenggalek Regency, which is a conservation and ecotourism area. The purpose of this study is the identification of gastropods morphologically and the abundance of gastropod species. The research was conducted in August 2024, using the survey method, at 6 research points using transects, the size transect is 10 x 10 m. Mangrove species found as many as 9 species, with mangrove density ranging from 0.038 - 0.078 ind/m2  . Gastropods found as many as 10 genus, consisting of Cerithidea genus, Littoraria, Faunus, Tarebia, Clypeomorus, Crassispira, Nerita, Terebralia, Neritina, and Cassidula. The abundance of gastropod species ranged from 34.4 - 92.4 ind/m2  , with the highest abundance in the Cerithidea genus and the lowest in the Nerita and Neritina genus. The diversity index ranged from 0.84 to 1.30 (low-medium), the uniformity index ranged from 0.36 to 0.57 (low-medium), and the dominance index ranged from 0.37 to 0.60 (some points had genus dominance). Water temperature (27.2 - 28.8°C), pH (7.2 - 7.8), DO (4.48 - 5.31 mg/L), and salinity (24 - 29 ppt), water quality parameters are considered good for gastropod life. The structure of the gastropod community in the MPC ecosystem is classified as slightly unstable, because there are still several points that have low diversity and uniformity values, and there are points that have a dominance value close to the value of 1, which means there are several genus that dominate. Continuous monitoring and management of mangrove ecosystems are needed so that the gastopod community remains in a balanced condition and there is a need for efforts to utilize Cerithidea gastropods.