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    Community structure, biomass and carbon stock assessment of mangrove forest in Poblacion, Batan, Batan Bay, Aklan, Philippines
    Cagalawan, Donna Novei C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2013-04)
    The continued loss of mangroves in Batan Bay, Aklan and elsewhere in the Philippines warrants urgent attention. Appropriate management schemes can only be drawn after a scientific assessment of the remaining mangroves in a given area. This study aimed to 1.) assess the community structure, of mangroves in Poblacion, Batan, Aklan using accepted ecological indicators such as a.) determine the physical and chemical factors such as salinity, temperature of water and soil, pH as well as substrate characterization; b.) identify and classify true mangrove species present in the area; c.) Stand Basal Area, d.) stems per hectare, e.) relative density, f.) relative frequency, g.) relative dominance, h.) importance value, i.) Shannon Index of Dominance and; 2.) determine biomass and carbon density in the above ground pools of mangroves. A total of nineteen (19) true mangrove species represented by six families were identified in Poblacion, Batan, Aklan. The true mangrove species were Aegiceras corniculatum, Avicennia alba, Avicennia marina, Avicennia officinalis, Avicennia rumphiana, Bruguiera cylindrica, Camptostemon philippenensis, Ceriops decandra, Excoecaria agallocha, Lumnitzera littorea, Nypa fruticans, Osbornia octodanta, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Scyphiphora hydrophyllacea, Sonneratia alba, Xylocarpus granatum and Xylocarpus moluccencis. Camptostemon philippenensis had the highest basal area with 103.14 m2/ha and the highest relative dominance with the value of 39.26%. Avicennia marina has the highest stems per hectare in the area with the value of 32, 400. It also recorded the highest average density at 167 trees/ha and was present in all plots with relative frequency of 44.15%. Avicennia marina was the most important species with value of 300.21. Camptostemon philippinensis had the highest seedling density of 586 seedlings per hectare, whereas Avicennia marina had the highest sapling density of 20 saplings per hectare. In terms of biomass, Avicennia marina recorded the greatest biomass at 79.42 tons/ ha and the highest carbon stock of 36.7 tons/ha. A total of 203.87 tons/ha biomass and 91.728 tons/ha carbon stock was determined. Based on the leaf litter fall, Transect 1 has the highest leaf fall at 664.9g.m2. Litter production was highest during November 5, 2012-November 19, 2012 and lowest in December 17, 2012- December 31, 2012 in all three transects.
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    Diversity and structural complexity of mangrove stands in Barangay Mag-aba, Pandan, Antique
    Bolivar, Lucille S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Mangrove forests provide a variety of ecological functions and economic services. However, full realization of these is also hampered by lack of understanding of the structural complexity that brings about a unique ecosystem. There is a need to understand the current status and dynamics of mangroves under threats of both natural and anthropogenic factors. The mangrove forest at Barangay Mag-aba, Pandan, Antique, that is part of the Northwest Panay Peninsula Natural Park, is one of the few patches of mangroves in Antique offering good opportunity to study diversity and stand structure. This study provides an important baseline data for conservation efforts and for comparison with other mangrove stands in the region. This study aimed to assess qualitatively and quantitatively the mangrove community structure of the Mag-aba mangrove forest. Specifically, the objectives of this study included (1) determination of selected physical and chemical factors affecting mangroves, (2) identification and classification of true mangrove species in the area and (3) analysis of the community structure. The modified line plot method for community structure survey was applied. A total of 19 true mangrove species from eight families were recorded in the area with Family Acanthaceae being the most represented. The stand basal area of 35.48 m2/ha was indicative of a mature community system. Structure analysis showed that Excoecaria agallocha (31.31%) was the most dominant species and had the highest importance value (81.29) followed by Bruguiera cylindrica, Xylocarpus granatum and Sonneratia alba. Trees made up 50% of the community composition with a density of 2044.44 t/ha. Barangay Mag-aba had a mean species diversity index (H’) of 0.95 indicating a low number of species present and a mean species evenness value (J’) of 0.38 indicative of an unequal species distribution. High complexity and diversity were observed in the upper intertidal zone where soil salinity is low. These results provide important insights to the underlying ecological functions of the mangroves in the area as basis of a more dynamic and intensive conservation action.