AACL Bioflux, 2017, Volume 10, Issue 6. http://www.bioflux.com.ro/aacl 1569 Diversity of mangrove species in three municipalities of Davao del Norte, Philippines Brian L. Pototan, Neil C. Capin, Myla Ross M. Tinoy, Annabelle U. Novero Phil-LiDAR 2 Research Project, College of Science and Mathematics, University of the Philippines Mindanao, Mintal, Tugbok District Davao City 8022, Philippines. Corresponding author: A. U. Novero, aunovero@up.edu.ph Abstract . This study assessed mangrove forest diversity in Carmen, Panabo and Tagum, Davao del Norte, Philippines. Among parameters calculated were rank abundance and diversity index. There were 12 species representing 8 families of mangroves in Carmen, 11 species from 9 families in Tagum, and 16 species from 10 families in Panabo, repesctively. Species dominance values were low at 0.1596 (Carmen), 0.1836 (Tagum), and 0.2333 (Panabo). The Shannon H indices were low: 2.067 (Carmen), 1.968 (Tagum), and 1.906 (Panabo). Species evenness was highest in Carmen (0.6584) and lowest in Panabo (0.425). Rhizophora mucronata (Rhizophoraceae) and Avicennia marina (Avicenniaceae) were the top species found in the three municipalities. Both are species of Least Concern under IUCN classification. Ceriops decandra (Rhizophoraceae), a Near Threatened species was recorded in Panabo, whereas Avicennia rumphiana (Avicenniaceae), a Vulnerable species was recorded from all three municipalities. Majority of the species noted were of Least Concern. The assessment of mangrove forest species is important because mangroves help protect the coastline, provide food resources to communities as well as help maintain the health of the ecosystem. Key Words: mangrove, diversity, conservation status, Shannon index, Philippines. Introduction . Mangroves are one of the most exceptional floras in the world. They grow in the coastlines of tropical and sub-tropical countries and are well adapted to extreme conditions such as high salinity and temperature (Kathiresan & Bingham 2001). Mangroves could be utilized in a lot of practical ways like for firewood, charcoal and thatching for construction (Brown & Fischer 1918; Spalding et al 1997; Long & Giri 2011). Moreover, they provide other services such as coastal protection. Certain mangrove species help prevent flooding and erosion of unconsolidated coastlines by breaking the force of waves (FAO 1994). Mangroves are suitable homes for epibenthic, infaunal and meiofaunal invertebrates and are able to support communities of phytoplanktons, zooplanktons and fishes due to the unique environment they create (Cañizares & Seronay 2016). Mangroves are also nurseries and feeding sites for some marine species (Rönnback 1999; Long & Giri 2011) and nesting grounds for hundreds of bird species (Nagelkerken et al 2008; Garcia et al 2014). The Philippines has been constantly listed as one of the top biodiversity hotspots of the world (Myers 1988, 1990; Myers et al 2000; Mittermeier et al 2004; Mittermeier et al 2011; Marchese 2015). This is due to its archipelagic orientation and tropical climate. Its coastline stretches to about 36,000 km covering more than 7,000 islands (Garcia et al 2014). All these intrinsic features of Philippines help make it a very adaptable location for mangroves to thrive in. In 1920, assessment of the total mangrove coverage for the entire country amassed an estimated total of 400,000-500,000 hectares (Brown & Fischer 1918; Chapman 1976; Primavera 2000; Garcia et al 2014). Furthermore, the Philippines holds approximately 50% of the known mangrove species in the world (Primavera et al 2004; Garcia et al 2014) including endangered, vulnerable and threatened ones (Spalding et al 2010). Regardless of how critically important and beneficial mangroves are, there has been a continuous and profound decline in their population. The Philippines lost about 75% of its mangrove habitats over the past few decades with the majority of it gone