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    The community structure of mangroves in Barangay Poblacion and Barangay Pinamuk-an, New Washington, Aklan
    Blanco, Florence T. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visaya, 2004-04)
    Mangrove ecosystems presently cover an area of about 20 million hectares worldwide. Mangroves grow in environmental settings ranging from highly humid to extremely arid conditions, and in soils which range from pure clays to peat, sand or coral rubble. This study was conducted to assess the community structure of mangroves in Barangay Poblacion and Barangay Pinamuk-an, New Washington, Aklan, using the transect line method of English et al (1995). Specifically, it aimed to determine selected physical and chemical factors such as salinity, pH, temperature for water and soil as well as characterization of substrates; to identify and classify true mangrove species present in the area; to describe the community structure in terms of stand basal area, stems per hectare, relative density, relative frequency, relative dominance, importance value, shannon index of diversity, zonation patterns, seedling and sapling density. No study had been conducted to document the community structure of mangroves in New Washington, Aklan. This study was done to provide these vital information needed for its proper management. Five stations were selected in Barangay Poblacion and Barangay Pinamuk-an, New Washington, Aklan. Twenty-two (22) species of mangroves were identified belonging to nine (9) families: Avicenniaceae -Avicennia alab, A marina, a officinalis, A rumphiana; Bombaceae - Camptostemon philippinensis; Combretaceae - Lumnitzera littorea, L racemosa; Euphorbiaceae - Exoecaria agallocha; Meliaceae - Xylocarpus granatum, X moluccensis; Myrsinaceae - Aegiceras corniculatum; Myrtaceae - Osbornia octodonta; Palmae - Nypa fruticans; Rhizophoraceae - Bruguiera cylindrica, B parviflora, Ceriops decandra, Rhizophora apiculata, R mucronata; Rubiaceae-Scyphiphora hydrophyllacea; Sonneratiaceae -Sonneratia alba, S caseolaris; Sterculiaceae-Herittiera littoralis. The study area had a water salinity of 6 ppt to 25 ppt ; water temperature of 27 °C to 30 °C ; soil temperature 27°C to 29°C ; water pH 2.29 to 7.80; soil pH 6.30 and 7.59. Basal area ranged from 0.008 m2/ha for Bruguiera parviflora to 114 nr/ha for Sonneratia alba The species with the highest average stems per hectare recorded was Avicennia rumphiana with 3320. The species with the highest average density recorded was Avicennia rumphiana with a value of 54.984. The station with the highest density was Station 3 and 4 while Station 1 and 5 had the lowest. Two species had the highest Relative Frequency. Xylocarpus granatum and Sonneratia alba were in all stations with 100% occurrence. From the 22 true mangrove species recorded, Avicennia rumphiana had the highest relative dominance of 462.30; the least was Bruguiera parviflora (0.06). The most important species was Avicennia rumphiana (118.51) while the least was Sonneratia caseolaris (1.23). The area is considered to be highly diverse at 0.7835. While on a per plot basis, Station 5 had the highest at 0.9439 while least at Station 1 with 0.5709 Index of Diversity.
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    Community structure of riverine mangrove stand in Brgy. Talokgangan, Municipality of Banate, Iloilo Province
    Belaño, Keith Dominador L. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2001-04)
    The community structure of riverine mangrove stand in Brgy. Talokgangan, Municipality of Banate, Iloilo was studied. Ten “true” mangrove species representing seven families were encountered in the “mangals” of Balandra creek community in Brgy. Talokgangan. They were Avicennia marina, Avicennia lanata and Avicennia alba representing Family Avicenniaceae; Rhizophora apiculata and Rhizophora mucronata under Family Rhizophoraceae; Sonneratia alba of the Family Sonneratiaceae; Excoecaria agallocha under Family Euphorbiaceae; Camptostemon philippinense of the Family Bombacaceae; one from the Family Meliaceae namely Xylocarpus granatum, and Family Palmae represented by Nypa fruticans. Stand Basal Area was computed highest in Station 1 with 10.22 m2/ha. Station 1 was also the densest among the four stations with a density value of 2533 trees/ha. In terms of data evaluated per zone, the landward zone has a Stand Basal Area of 10.87 m2/ha which is slightly higher than the middle and riverward zones. The middle zone, however, was found to be the densest with 1850 trees/ha. The most dominant station was Station 1 with the highest Index of Dominance of 0.3319, however, was found to be the least diverse station. The highest Index of Diversity was computed in Stations 2 and 3, with diversity indices of 0.8976 and 0.8989 respectively. Avicennia marina was found common in all stations and the most dominant, making it the most important mangrove species. They were found to occupy the whole site, growing abundantly in wide range of conditions from areas frequently inundated by tidal flow in Station 1 to the firmer muddy substratum in the back mangrove areas. Rhizophora apiculata and Rhizophora mucronata was observed to occupy waterlogged soil conditions. Excoecaria agaliocha tend to flourish in firmer muddy substratum in open sites, whereas, Xylocarpus granatum was observed to occupy zones where salinity is lowest in areas rarely affected by tidal flow. Sonneratia alba and Camptostemon philippinense tend to grow in zones directly inundated by tidal flow.