ABSTRAK
Lamun atau disebut juga ilalang laut atau yar merupakan tumbuhan berbunga (Angiospermae; monokotil), memiliki rhizome, berbuah, berdaun dan berakar sejati yang tumbuh pada substrat berlumpur, berpasir sampai berbatu yang hidup terendam di dalam air laut dangkal dan jernih, dengan sirkulasi air yang baik.Tujuan dari penelitian ini untuk mengetahui dan mengkaji karakteristik jenis-jenis lamun serta struktur komunitas (diversitas, frekuensi, densitas, dominansi,indeks nilai penting)lamundi daerah  intertidal pantai Litianak dan pantai Oeseli di Kabupaten Rote Ndao Nusa Tenggara Timur.
Penelitianmenggunakan metode transek kuadrat.Pengamatan dilakukan dengan berpatokan pada heterogenitas(keanekaragaman) dan homogenitas vegetasi (persamaan jenis).Ulangan pengamatan sebanyak 3 kali dengan jarak masing-masing ulangan (transek kuadran) sejauh 10 meter.Data dianalisis menggunakan Indeks Diversitas Shannon-Wienner, frekuensi, kerapatan, penutupan, dan indeks nilai penting.
Hasil penelitian menunjukkan karakteristik lamun di pantai Litianak dan pantai Oeseli mempunyai karakteristik yang hampir sama yang membedakan hanya pada ukuran panjang, lebar, dan warna daun, di pantai Litianak ukuran panjang dan lebar daun lebih kecil dibandingkan yang ada di pantai Oeseli begitu juga warna daun di pantai Litianak berwarna hijau muda sedangkan di pantai Oeseli warna daun hijau tua.Indeks Diversitas di pantai Litianak 0,98  dan di  pantai Oeseli 1,789 dengan tingkat keanekaragaman rendah,Indeks Nilai Penting di pantai Litianak tertinggi pada jenis lamun Halodule uninervis (1,11)dan terendah jenis lamun Cymodocea rotundata(0,4). Sedangkan indeks nilai penting lamun pada pantai Oeseli tertinggi jenis lamun Enhalus acoroides(1,2) dan terendah jenis lamun Cymodocea rotundata (0,42).
Kata kunci :Karakteristik, struktur komunitas, lamun, intertidal, Pantai Litianak, Pantai
Oeseli
ABSTRACT
Seagrass also called reed sea or water is a flowering plant (Angiospermae; monocots), has a rhizome, fruit, leafy and rooted true that grew on the substrate muddy, sandy to rocky live submerged in shallow sea water and clear, with a circulation water good. The aim of this study was to determine and assess the characteristics of the types of seagrass and community structure (diversity, frequency, density, dominance, importance value index) of seagrass in the intertidal beach and coastal Litianak Oeseli in Rote Ndao East.
The study used a transect method of squares. Based on the observations made by the heterogeneity (diversity) and homogeneity of vegetation (common type).Deuteronomy observation 3 times the distance of each replicate (transect quadrant) as far as 10 meters. Data were analyzed using the Shannon diversity index-Wienner, frequency, density, closing, and the index value is important.
The results show the characteristics of seagrass on the beach Litianak and beach Oeseli have similar characteristics that differed only in the length, width, and color of the leaves, on the beach Litianak the length and width of leaves are smaller than those of the beach Oeseli so is the color of the leaves in beach Litianak light green color, while at the beach Oeseli dark green leaves. Litianak diversity index on the beach at the beach Oeseli 0.98 and 1.789 with a low level of diversity, importance value index was at its highest Litianak coast seagrass species Halodule uninervis (1.11) and the lowest type of seagrass Cymodocea rotundata (0.4). While the index value on the importance of seagrass highest Oeseli coast seagrass species Enhalus acoroides (1.2) and the lowest type of seagrass Cymodocea rotundata (0.42).
Keywords: Characteristics, community structure, seagrasses, intertidal, Litianak Beach, Beach Oeseli