Penelitian mengenai struktur komunitas lamun di perairan Muara Binuangeun, Banten, telah dilakukan pada tanggal 6--9 November 2015. Penelitian bertujuan untuk mengetahui struktur komunitas lamun yang mencakup persentase tutupan, frekuensi, kerapatan, indeks nilai kepentingan, indeks keanekaragaman, indeks kemerataan, dan indeks dominansi pada setiap stasiun di Muara Binuangeun. Penentuan lokasi pengambilan sampel dilakukan secara purposive sampling. Hasil penelitian menunjukkan bahwa jumlah jenis lamun yang diperoleh di Muara Binuangeun sebanyak 3 jenis dari 2 suku. Persentase tutupan lamun di setiap stasiun berkisar antara 28,40--61,60%. Kerapatan lamun di setiap stasiun berkisar antara 637--1655 individu/m2. Jenis Thalassia hemprichii memiliki frekuensi tertinggi berkisar 86,67--100%, sedangkan Halodule uninervis merupakan jenis dengan frekuensi terendah berkisar 6,67--20%. Thalassia hemprichii memiliki indeks nilai kepentingan tertinggi di Muara Binuangeun berkisar 138--300%, sedangkan Halodule uninervis memiliki indeks nilai kepentingan terendah yang berkisar antara 4--12%. Nilai indeks keanekaragaman di Muara Binuangeun tergolong rendah berkisar antara 0--0,73, dengan nilai indeks dominansi yang tergolong tinggi pada stasiun 1 dan 2 (1,00), tergolong sedang pada stasiun 3 (0,53) dan tergolong rendah pada stasiun 4 (0,49). Nilai indeks kemerataan pada stasiun 1 dan 2 yang tergolong rendah (0), serta stasiun 3 (0,63) dan 4 (0,67) yang tergolong tinggi. Secara umum, struktur komunitas lamun pada lokasi penelitian tergolong tidak stabil karena tingkat keanekaragaman dan kemerataan yang rendah serta tingkat dominansi yang tinggi.

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Research on community structure of seagrass in waters of Muara Binuangeun, Banten, was conducted on November 6th -- November 9th, 2015. The study aims to determine the community structure of seagrass which includes diversity, cover percentage, frequency, density, importance values, diversity index, evenness index, and dominance index at all of station in Muara Binuangeun. The location of sampling was determined by purposive sampling. The results showed that there are 3 species of seagrass from 2 family in Muara Binuangeun. Percentage seagrass covering in each station ranged from 28,40--61,60%. Seagrass density at each station ranged from 637--1655 individuals/m2. Thalassia hemprichii is the highest frequency (86,67--100%), while Halodule uninervis is the lowest frequency (6,67--20%). Thalassia hemprichii has the highest importance index in Muara Binuangeun (138--300%), while Halodule uninervis has the lowest importance index(4--12%.). The diversity index value in Muara Binuangeun was considered as low (0--0,73), with the dominance index value was high at stations 1 and 2 (1,00), was moderate at station 3 (0,53) and was low in station 4 (0,49). Evenness index values at stations 1 and 2 were considered as low (0), was moderate at station 3 (0,63) and was high at station 4 (0,67). In general, the community structure of seagrass in Muara Binuangeun is unstable because of the diversity and evenness were low, and also dominance were high.