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Undergraduate Special Problem

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/30

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Keyword: search.filters.keyword.Community structureSDG: search.filters.sdg.SDG 15 - Life on land

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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.
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    Community structure of mangroves in selected barangays in Sebaste, Antique
    Alorro, Mary Juandin Grace F. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2007-03)
    Mangroves are higher plants that are primarily found predominantly in the intertidal areas such as estuaries and lagoons of the tropical and subtropical shorelines. This study was conducted to assess the community structure of mangroves in Barangay Callan, Barangay Idio, Barangay Poblacion, Barangay Abiera, and Barangay Bacalan, Sebaste, Antique, using the transect line method. Specifically, it aimed to determine selected physical and chemical factors such as salinity, pH, temperature for water and soil as well as characterization of the substrate; identify and classify true mangrove species present in the area; and 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 has been done to document the community structure of mangroves in Sebaste, Antique thus, this study was done to provide vital information needed for its proper management. Three stations were selected in Sebaste, Antique. Four (4) species of true mangroves were identified, belonging to three (3) families: Palmae - Nypa fruticans; Rhizophoraceae - Rhizophora apiculata, Bruguiera gymnorrhiza; and Euphorbiaceae - Excoecaria agallocha. The study area had a water salinity range of 0.6 ppt to 15.3 ppt; water temperature range of 28.3°C to 35.4°C; water pH range of 7.1 to 7.7; soil temperature range of 28.3°C to 34.7°C; and soil pH range of 6.5 to 7.2. Basal area ranges from 3.16 m2/ha (Rhizophora apiculata) to 5.88 m2/ha (Excoecaria agallochd) to 8.19 m2/ha (Bruguiera gymnorrhiza) . The species with the highest average of stems per hectare were Excoecaria agallocha and Bruguiera gymnorrhiza with 300 as well as the highest average density value of 100 for Excoecaria agallocha. Nypa fruticans had the highest relative frequency and relative dominance. Among the four species, the most important species was Nypa fruticans. The Shannon Index of Dominance was 0.403 which was quite low in terms of diversity as influenced by the dominance of Nypa fruticans.