Diversity, density, and Importance Value Index of mangroves in the Segara Anakan lagoon and its surrounding area, Cilacap Regency, Indonesia

Coastal mangrove forest habitats in the Segara Anakan Lagoon have become an important area for estuarine fisheries which should be preserved for sustainability. This study aims to analyze diversity, density, and the importance value index of the mangrove in the area. The method used was a plot and path (combination method). To conduct this study, the nine purposely sampled stations ranged from the western Segara Anakan Lagoon to the eastern mangrove area adjacent to the Donan River. The nine station was grouped into 3 (three areas) namely; Mangrove Eastern Area (river influence), Mangrove Middle Area, Mangrove Western Area (seawater influence. The results show the average mangrove density overall stations were dominated by seedlings with 39881 individuals/ha with fraction 75%, followed by saplings with 12311 individuals/ha (23%), and tree category with 711 individuals/ha (1%). Because of the average mangrove density of tree category less than 1000 trees/ha so, the mangrove forest in the Segara Anakan Lagoon and its surrounding area was categorized to be damaged. Meanwhile, the highest Importance Value Index (IVI) was at 221 for R. apiculata and at 220 for Sonneratia caseolaris for all stations.