Malacological survey along the intertidal zone of Las Piñas-Paranaque Critical Habitat and Ecotourism Area

Abstract

Background: One of the eight Ramsar sites in the Philippines is the Las Piňas – Parañaque Critical Habitat and Ecotourism Area(LPPCHEA), and it plays a significant role in the East Asian-Australian Flyway as a stopover site. The migratory birds coming from the north of Asia and Alaska feed on the molluscs in this area. However, there is paucity of literature on the species composition of molluscs found in this critical habitat. Baseline information on these organisms is essential as they are subject to the effects of anthropogenic activities close to and in the wetland, which in turn can have an impact on the ecosystem, particularly the birds foraging in this location.

Methodology: The Natural Geography of in-Shore areas (NaGISA) protocol was used for the study. Transects were laid in three sampling sites in Freedom Island and Long Island. The sampling sites were GPS-referenced. A cylinder corer was used to collect mudflat soil, with the corer pushed into the sediment. Soil samples were sieved using a 0.5mm stainless mesh sieve pan, leaving shells and larger sand grains. The molluscs were sorted and identified through taxonomic keys. Sampling was done once for each site in November 2012.

Results and Discussion: A total of 61 molluscan species belonging to two classes, 14 orders, and 33 molluscan families were identified and recorded. There were 34 species under the Class Gastropoda that belong to 5 orders and 18 families. For Class Bivalvia, there were 27 species belonging to 8 orders and 15 families. Among the molluscs recorded, 10 species were identified as non-indigenous. It is important to monitor molluscan species as anthropogenic activities may affect these organisms, and in turn, affect the wetland's function for migratory birds. The presence of non-indigenous species may be a potential threat to the ecosystem.

Conclusion: Baseline information of the molluscan community in the LPPCHEA was provided by the study. These species provide diet to the endemic and migratory birds in the area. There is a need to monitor these molluscs due to the effects of the man-caused activities close to the area. Also, the non-indigenous species should be studied for their potential to be invasive.