Keberadaan hutan mangrove adalah sebagai salah satu pembentuk ekosistem di Kawasan Konservasi Mangrove yang ada di Kota Tarakan. Pesatnya pembangunan di Kota Tarakan menyebabkan hilang atau berkurangnya luasan hutan mangrove. Penelitian bertujuan untuk menganalisis struktur komunitas dan kerapatan mangrove di Kawasan Konservasi Mangrove dan Kepiting Kelurahan Pamusian Kota Tarakan. Penelitian ini dilaksanakan pada bulan November- Desember 2020 di Kawasan Konservasi Mangrove dan Kepiting Kelurahan Pamusian Kota Tarakan. Metode pengambilan sampel yang digunakan adalah metode purposive sampling. Pengamatan dilakukan pada 3 (Tiga) titik stasiun dan masing-masing stasiun terdiri dari 3 plot dengan ukuran 10m x 10m untuk pohon, 5m x 5m untuk anakan dan 1m x 1m untuk semai. Penelitian ini menggunakan analisis data vegetasi mangrove meliputi Kerapatan jenis, Kerapatan Relatif, Frekuensi jenis, Frekuensi Relatif, penutupan jenis atau Dominansi, Dominansi Relatif, Indeks Nilai Penting dan Struktur Komunitas. Jenis mangrove yang didapatkan di Kawasan Konservasi Mangrove dan Kepiting Kelurahan Pamusian Kota Tarakan adalah Avicennia alba, Avicennia marina, Lumnitzera racemosa, Rhizophora apiculata, Rhizophora mucronata, Sonneratia alba, Xylocarpus granatum dan Nypa fruticants. Nilai kerapatan jenis berkisar 1.800 – 9.333, nilai frekuensi jenis berkisar 16 - 25, nilai dominansi jenis sebesar 1.775.745 dan nilai indeks nilai penting berkisar 200 - 300%. Struktur Komunitas di Kawasan Konservasi Mangrove dan Kepiting Kelurahan Pamusian Kota Tarakan sangat padat.
Kata Kunci: Kerapatan, Mangrove, Struktur komunitas

The existence of mangrove forests is one of the ecosystem building blocks in the Mangrove Conservation Area in Tarakan City. The rapid development in Tarakan City has caused the loss or reduction of the mangrove forest area. This study aims to analyze the community structure and density of mangroves in the Mangrove and Crab Conservation Area, Pamusian Village, Tarakan City. This research was conducted in November-December 2020 in the Mangrove and Crab Conservation Area, Pamusian Village, Tarakan City. The sampling method used is purposive sampling method. Observations were made at 3 (three) station points and each station consisted of 3 plots with a size of 10m x 10m for trees, 5m x 5m for tillers and 1m x 1m for seedlings. This study uses data analysis of mangrove vegetation including species density, relative density, species frequency, relative frequency, species cover or dominance, relative dominance, significant value index and Community Structure. The types of mangroves found in the Mangrove and Crab Conservation Area, Pamusian Village, Tarakan City are Avicennia alba, Avicennia marina, Lumnitzera racemosa, Rhizophora apiculata, Rhizophora mucronata, Sonneratia alba, Xylocarpus granatum and Nypa fruticants. Species density values ranged from 1.800 – 9.333, species frequency values ranged from 16-25, species dominance values were 1.775745 and important value index values ranged from 200 - 300%. The structure of the mangrove and crab conservation area, pamusian sub-district, Tarakan city is very dense. Keywords: Density, Mangrove, Community Structure