Struktur Komunitas Gastropoda Pada Ekosistem Mangrove Di Muara Sungai Batang Ogan Komering Ilir Sumatera Selatan

River Estuary is a mixing place of two mass of water such as the freshwater mass and seawater which is influenced by the physical characteristics of water such as seasons, tide, current, temperature, and salinity. Estuary area is one of the area for the mangrove ecosystem where mangrove ecosystem are habitat from kind of benthic organism, one of the kind is gastropods. Gastropod density on mangrove ecosystem was influenced by the activity which was found in mangrove ecosystem, where, it could be giving an effect of gastropod living cause gastropod tend to live staying with limited moving. The aim of this research was to know mangrove density, community gastropods structure and relation between biota(gastropods) and their habitat (mangrove) in river estuary Batang Village which was conducted on October 2009, using method to determine monitoring station was purposive random sampling technique in order to represent research area and to take data by using square transect method. Based on the result of research, the total of gastropod which were achieved on mangrove ecosystem of river estuary Batang Village 10 species from 7 families. The most species were Syncera brevicula. Density of gastropod at research location gyrate from 32-78 individual/m².The high density of gastropoda were getting in stasiun 1 with the total 78 ind/m², where as the low density of gastropoda were getting in stasiun 3 with the total 32 ind/m². Diversity index were range between 1,21-1,50, uniformity ondex in the research location were range between 0,55-0,81 and Domination index were range between 0,29-0,43 which have meaning that there was no domination spesies in the research location. To mangrove vegetatiom in research location of river estuary Batang Village, generally it were founded 6 species from 3 families where the family Rhizoporaceae were mangrove family which dominated the research location. Keyword : Batang River, Estuary, Gastopod and Mangrove Muara sungai adalah tempat bercampurnya dua massa air yaitu massa air tawar dan air laut yang masih dipengaruhi oleh sifat-sifat fisik perairan seperti musim, pasang surut, arus, suhu, dan salinitas. Daerah muara adalah salah satu habitat dari berbagai macam organisme hewan bentik, salah satunya adalah gastropoda. Kepadatan gastropoda pada ekosistem mangrove sangat dipengaruhi oleh kegiatan yang terdapat pada ekosistem mangrove dimana hal ini akan memberikan efek terhadap kelangsungan hidup gastropoda karena gastropoda hidup cenderung menetap dengan pergerakan yang terbatas. Tujuan penelitian ini adalah untuk mengetahui kerapatan mangrove, struktur komunitas gastropoda dan hubungan antara biota (gastropoda) dengan habitatnya (mangrove) di muara Desa Sungai Batang yang dilaksanakan pada bulan Oktober 2009 dengan metode yang digunakan untuk penentuan stasiun pengamatan yakni teknik purposive random sampling sehinggga dapat mewakili daerah penelitian dan untuk pengambilan data menggunakan metode transek kuadrat. Berdasarkan hasil penelitian jumlah gastropoda yang ditemukan pada ekosistem mangrove di muara Sungai Batang sebanyak 10 spesies dari 7 famili. Spesies yang paling banyak ditemukan adalah Syncera brevicula. Kepadatan gastropoda pada lokasi penelitian berkisar dari 32-78 individu/m². Kepadatan gastropoda tertinggi terdapat pada stasiun 1 yaitu 78 individu/m², sedangkan yang memiliki kepadatan terendah terletak pada stasiun 3 yaitu 32 individu/m². Indeks keanekaragaman berkisar antara 1,21-1,50, indeks keseragaman pada lokasi penelitian berkisar antara 0,55-0,81 dan indeks dominansi spesies berkisar antara 0,29-0,43 yang berarti tidak ada spesies yang mendominasi pada stasiun penelitian. Untuk vegetasi mangrove di daerah penelitian di muara desa Sungai Batang, secara umum ditemukan 6 spesies dari 3 famili dimana famili Rhizoporaceae merupakan famili mangrove yang mendominasi pada lokasi penelitian