Mangrove Community Structure in Papuan Small Islands, Case Study in Biak Regency

Abstract

Mangrove plays the importance of roles for the small island sustainability, both physically and ecologically. In the high-risk Pacific Ocean's islands, small islands in Biak face typhoons, earthquakes, high waves, and tsunami effects. The study was conducted at 100 10mx10m-quadratic-plots scattered on seven small islands in Biak-Numfor Regency. Research objectives were to investigate the mangrove community structure of each island, i.e., canopy coverage, density, and morphological size, and to analyze the correlation among those parameters. The result found that mangrove was in pristine condition, large individual size with low anthropogenic threats. They were covered by a medium and dense canopy from 61.32±3.04% in Pasi to 93.88±0.14% in Meos Mangguandi. Substrate significantly influenced the level of canopy coverage and the MDS ordination of species composition. Sonneratia alba tended to be dominant in rocky sand in Pasi, Owi, Padaidori, and Wundi, while Ceriops and Rhizophora were mostly occupied the muddy sand, or Bruguiera gymnorrhiza has the highest domination in sandy mud substrate in Auki, Pai, and Meos. The canopy coverage had a significant correlation only with total density but none with the others. The height of the tree (up to 21.2 m) was found highly related to the diameter size (max: 124 cm).