Assessment of Mangrove in Colanggaman Islet: Basis for Conservation and Management Options
Abstract- Colanggaman once possessed rich diversity of bird species that are dependent in the coastal resources within the islet. Decline of the bird species were recently observed by the coastal dwellers that could be linked to the current condition of the major ecosystem within the islet. However, there is no comprehensive data yet on the mangrove stands of Colanggaman. This paper presented the first detailed assessment of the mangroves in Colanggaman Islet using a modified transect line method. The present survey showed that there were three species of mangrove Rhizophora mucronata (Bakawan babae), Rhizopthora stylosa (Bakawan bangkau), and Rhizophora apiculata (Bakawan lalake). The mean diameter at breast height (DBH) ranges from 8.31-7.77 cm and 4.70-6.10 m describes an intermediate structural development of the identified mangrove species. R. mucronata had the highest relative density (Rd) of 39.65% and dominance (RD) of 38.45. Relative frequencies for all identified species were 33.33% which indicates an overlapping of the species. R. mucronata was also found out to be the most important species of mangroves in Colanggaman in terms of Rd, RD, and Rf. The species diversity (H) of mangroves in Colanggaman Islet was 1.09. The results of this study may assist the decision making processes for management and conservation efforts that are currently needed to protect Colanggaman Islet.