Mangroves of Naawan, Libertad and Laguindingan, Misamis Oriental, Philippines: Community Structure and Health Using Sponges as Bioindicator Vannisa Lou Wagas1, Anna Arlene Eya2, Angeli Valera-Mag-Aso3 and Ma. Reina Suzette Madamba4 MSU-Iligan Institute of Technology, Philippines [email protected], [email protected] Abstract - Mangrove forests, or mangal, are characterized by one or more species of salt-tolerant trees that form distinct monospecific zones along tropical protected coastlines. Mangrove forests support a diverse range of animals and plants and are important breeding ground for a vast array of organisms. Sponge associations in mangrove systems are spatially heterogenous. An ocular inspection was conducted initially in the mangrove forest along the intertidal zone of Laguindingan, Libertad and Naawan, Misamis Oriental to determine the community structure and health of mangrove species using sponges as bioindicator. A total of 30 quadrats with 10 x 10 m were established in each of the three sampling areas. The species composition, DBH and growth stage of each mangrove was also determined in every quadrat. The relative abundance of sponges per mangrove species and per growth stage of each mangrove was also determined. Results showed that there are two species of mangroves found in Laguindingan. These species includes Rhizophora apiculata and Rhizophora mucronata. There are four mangrove species in Libertad. These are Avicennia lanata, Rhizophora apiculata, Rhizophora mucronata and Sonneratia alba. On the other hand, the mangrove forest of Naawan is also dominated by species of Avicennia rumphiana, Rhizophora apiculata and Rhizophora mucronata. Sponges only associate in the pseudo roots of mangrove species in Laguindingan. This study shows that the presence and abundance of certain sponge species in the saplings and trees could serve as biological indicators of mangrove health. Keywords - Mangrove Community Structure, Health, Sponges, Bioindicator Remark: The full paper may be found in www.inrit2013.com The Third International Congress on Interdisciplinary Research and Development, 30 - 31 May 2013, Thailand 33.1 .