Eight (8) BCWERC technical staff from the project “Benchmarking and Impact Assessment of Mangrove and Beach Forest Rehabilitation in Disaster-Affected Areas” revisited the benchmarked site in Lava Island, Barangay Day-as, Cordova last March 8-9, 2016 to monitor any significant improvement from last year’s findings as well as to gather additional data on the condition of the mangrove ecosystem.
Three transect lines were established during the assessment having seaward, middle-ward and landward plots where six (6) mangrove species were identified such as: bakauan bato (Rhizophora stylosa), bakauan lalaki (Rhizophora apiculata), bungalon (Avicennia marina), pagatpat (Sonneratia alba), tabigi (Xylocarpus granatum), and malatangal (Ceriops decandra). Among the six species, R. stylosa was found to be dominant in each transect and also has a greater stem diameter than all other mangrove species in the area. In general, the mangrove forest is healthy as there are only few occurrences of individual trees with pest and disease. Macrobenthic organisms dwelling below the water column which are visible to the naked eye were also collected and mostly composed of gastropods (snails).
A total of 22 species of gastropods were found in the island. In addition, Bivalves were also observed in the area with a total of five identified species and one of them was Gafrarium tumidum locally known as balisa, a commercially valuable species. Five crab species were identified, three of which belongs to genus Uca, one belongs to genus Perisesarma and another to genus Ozius (forceps crab). Avifaunal survey recorded four species of birds in the area. Interestingly wild ducks (Anas luzonica) were noted and the local residents have attested to the sightings of this species only recently.
The said activity was ERDB-BCWERC’s response to the oil-spill incident brought about by the collision of 2GO cargo ship and MV St. Thomas Aquinas off the coast of Talisay City which caused the sinking of the former. The southern sea of Mactan Island was heavily affected since the currents brought the oil to the mangrove forest in the area and paralyzed the livelihood of the coastal municipality of Cordova for months.
The survey results show that the area is diverse in mangroves and animal species. The mangrove ecosystem was observed to be healthy and shows signs of recovery from oil-spill. Mangrove forests are very efficient coastal protection agent against physical disturbances such as wind and storm surges as well as chemical disturbances and pollution. However, the rich assemblages of species in the mangrove areas and the nature of its hydrology makes them fragile and vulnerable to such disturbances (oil-spill). Jamiel R. Rosales, BCWERC