Ekosistem mangrove terdapat di seluruh pantai maupun pulau-pulau kecil Indonesia yang terpengaruh oleh pasang surut. Kajian pola sebaran, indikator kualitas lingkungan dan ekologi komunitas mangrove Pulau Tunda dilakukan pada bulan Januari 2014 dengan tujuan untuk mengetahui pola sebaran, indikator kualitas lingkungan dan ekologi komunitas mangrovenya. Sampel mangrove diambil menggunakan transek garis dan plot yang ditarik dari titik acuan (tegakan mangrove terluar) serta tegak lurus garis pantai sampai ke daratan. Kemudian transek garis tersebut dibuat petak-petak contoh (plot) yang berukuran 10 x 10 m2 untuk kategori pohon dan di dalam ukuran 10 x 10 m2 dibuat plot berukuran 1 x 1 m2 untuk kategori semai. Pola penyebaran mangrove Pulau Tunda dianalisis berdasarkan indeks Morisita. Sementara kualitas lingkungan hutan mangrove dianalisis menggunakan tutupan pohon, tutupan semai dan jumlah jenis semai yang ditemukan. Kemudian ekologi komunitas mangrove Pulau Tunda dianalisis berdasarkan indeks keanekaragaman, dominansi dan keseragaman. Hasil penelitian menunjukan bahwa pola penyebaran mangrove Pulau Tunda tergolong beraturan (regular), dimana terjadi interaksi negatif antar individu dalam memperebutkan ruang, unsur hara maupun cahaya matahari. Selain itu, kondisi hutan mangrove Pulau Tunda masih tergolong baik dengan tingkat kualitas lingkungan vegetasi mangrove 73.74%, keanekaragaman dan dominansi mangrovenya tergolong rendah (1.20 dan 0.52) dan keseragamannya tergolong labil (0.60). Mangrove ecosystems are found throughout the coast and small islands of Indonesia which are affected by tides. Distribution pattern studies, environmental quality indicators and the ecological mangrove community of Tunda Island were carried out in January 2014 with the aim to determine distribution patterns, indicators of environmental quality and ecology of the mangroves community. Mangrove samples were taken using line transects and plots drawn from reference points (outer mangrove stands) and perpendicular to the coastline to the mainland. The line transect is made of plots of sample size 10 x 10 m2 for the category of trees and in a size of 10 x 10 m2 a plot of 1 x 1 m2 is made in the seedling category. The pattern of distribution of mangroves of Tunda Island was analyzed based on the Morisita index. While the environmental quality of mangrove forests was analyzed using tree cover, seedling cover and number of seedlings found. The ecology of the Tunda Island mangrove forest community was analyzed based on the diversity index, dominance and uniformity. The results showed that the pattern of mangrove distribution of Tunda Island was regular, where there was a negative interaction between individuals in fighting over space, nutrients and sunlight. In addition, the condition of the Tunda Island mangrove forest is still relatively good with the level of environmental quality of mangrove vegetation 73.74%, the diversity and dominance of mangroves are relatively low (1.20 and 0.52) and uniformity is classified as unstable (0.60).