<![CDATA[The mangrove ecosystem in the conservation area of Besi Administrative Village, North Seram, serves an essential role as a natural habitat for mollusk communities (gastropods and bivalves). This study aimed to analyze mangrove density, evaluate mollusk community structure, and assess the relationship between mangrove density and mollusk community structure in the Mangrove Conservation Area of Besi Administrative Village. The research was conducted from October to November 2025 in the Mangrove Conservation Area of Besi Administrative Village, North Seram District, Central Maluku Regency. Data were collected using simple random sampling across Zone 1 (Stations I and II) and Zone 2 (Stations III and IV). Mangrove data were sampled using the line transect plot method, whereas mollusk data (gastropods and bivalves) were obtained by excavating the substrate. Data analysis for mangrove and mollusk community structure included species composition, abundance, density, frequency, similarity, diversity, and dominance. The relationship between mangrove density and mollusk community structure was analyzed using simple linear regression. The results revealed 10 mangrove species and 19 mollusk species (18 gastropods and 1 bivalve). In Zone 1, Rhizophora apiculata and Faunus ater were identified as the dominant species, exhibiting moderate mollusk diversity (H' = 1.281). In Zone 2, Rhizophora stylosa and Littoraria scabra dominated, with low diversity (H' = 0.539). The dominance index was low in both zones. The relationship between mangrove density and mollusk abundance was non-linear: displaying a negative correlation in Zone 1 (overcrowding effect) and a positive correlation in Zone 2 (ecosystem engineer effect). Consequently, coastal ecosystem management efforts particularly for mangroves must be tailored to specific habitat conditions. ABSTRAK Ekosistem mangrove di kawasan Konservasi Negeri Administratif Besi, Seram Utara berfungsi esensial sebagai alam asli bagi komunitas moluska (gastropoda dan bivalvia). Penelitian ini bertujuan menganalisis kerapatan mangrove, menganalisis struktur komunitas moluska, dan menganalisis hubungan kerapatan mangrove dengan struktur komunitas moluska di Kawasan Konservasi Mangrove Negeri Administratif Besi. Penelitian dilakukan di Kawasan Konservasi Mangrove Negeri Administratif Besi, Kecamatan Seram Utara, Kabupaten Maluku Tengah pada Oktober-November 2025. Pengambilan data dilakukan secara simple random sampling pada zona 1 (stasiun I dan II) serta zona 2 (stasiun III dan IV). Pengambilan data mangrove menggunakan line transect plot method, sedangkan data moluska (gastropoda dan bivalvia) dilakukan dengan cara menggali pada substrat. Analisa data struktur komunitas mangrove dan moluska meliputi komposisi, kelimpahan, kerapatan, frekuensi, kesamaan, keanekaragaman, serta dominansi. Hubungan antara kerapatan mangrove dan struktur komunitas moluska dianalisis menggunakan regresi linear sederhana. Berdasarkan hasil penelitian diperoleh 10 jenis mangrove dan 19 jenis moluska (18 gastropoda dan 1 bivalvia). Teridentifikasi di zona 1 terdapat jenis yang mendominasi yaitu Rhizophora apiculata dan Faunus ater dengan keanekaragaman moluska sedang (H’ = 1,281), sedangkan jenis yang mendominasi di zona 2 yaitu Rhizophora stylosa dan Littoraria scabra dengan keanekaragaman rendah (H’ = 0,539). Indeks dominansi pada kedua zona tergolong rendah. Hubungan antara kerapatan mangrove dan kelimpahan moluska bersifat non-linear: bernilai negatif di zona 1 (over crowding effect) dan positif di zona 2 (ecosystem engineer effect). Perlu dilakukan upaya pengelolaan ekosistem pesisir khususnya mangrove disesuaikan dengan kondisi habitat. Kata Kunci: Mangrove, moluska, kerapatan, struktur komunitas, kawasan konservasi]]>
