Distribution, identification, assessment of mangroves and mangrove communities in Moalboal Coast, Cebu [Philippines]

Findings showed that a total of 318 ha had mangrove vegetation, covering six barangays [village] and divided into three distinct and contiguous areas of the coast. Area 1 covered the Brgy. of Balabagon (8 ha). Area 2 in Brgys. Poblacion East and Tomonoy was composed pf 38 ha and Area 3 in the Brgys. of Saavedra, Tuble, and Tunga covered an area of 272 ha. Mangroves were more concentrated in Brgy. Saavedra, accounting for about 25-30% of the total area. Mangrove conversion into fishponds had been going on for quite sometime in the area. A total of 18 true mangrove species were found in the three mangrove areas. Areas 3 had the greatest number of species at 17 from 11 families followed by Area 2 and Area 1 with 8 species from 4 families, and 8 species from 3 families, respectively. Nypa fruticans was noted as the most dominant vegetation at the landward portion of Area 2. Biodiversity indices revealed that Area 3 was the most diverse among the three areas. From the highest Shannon Index (H) value of 1.00, area 3 obtained a value of 0.808, followed by Area 2 and Area 1 with 0.68 and 0.64, respectively. In terms of regeneration density, Area 1 had the highest regeneration density of 6,084 seedlings/ha, followed by Area 3 and 2 at 869 and 829 seedlings/ha, respectively. As to the species importance value, it was found that Avicennia marina had the highest distribution with a relative frequency of 30.9, followed by Rhizophora apiculata with 24.4, and closely followed by Sonneratia alba with 22.80. In terms of stand structure and characteristics, mangroves in Brgy. Balabagon appeared to be the best among the three sites studied. It obtained an average number of 1,239 trees/ha, a regeneration of 6,084 seedlings/ha, a crown cover of 59.68%, and basal area of 34,528 sq m/ha. Occurrence of most mangrove species in Moalboal Coast was generally very rare with constancy below 5%. These species included: Aegiceras floridum, Camptostemon philippinensis, Xylocorpus granatum, Osboinia octodocta, Exoecaria agallocha, Delichandrone spathecea, Pemphis acidula, Avicennia lanata, Burguiera parviflora, and B. gymnorrhiza. Most of these species were found in Area 2 whose greater part had been converted into fishponds. Said conversion displaced these species, especially that they only occurred at the middle or landward zone of the mangrove forest. Recommendations were presented