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Undergraduate Special Problem

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    Mangrove community structure survey in Iloilo River
    Bayate, Bryna Kimberly L. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2004-04)
    Mangroves are highly productive forests growing along tropical tidal mudflats and shallow water coastal areas where water is generally brackish. The structure of the mangrove stand in the Iloilo River was studied using the transect line plot method with 55 plots established in the 3 out of 4 stations of the river. Community Structure is described in terms of the following parameters: basal area, stems per hectare, relative density, relative frequency, relative dominance and importance value of the species and the Shannon Index of Diversity. Variations in these parameters are correlated with certain physico-chemical factors- soil and water temperature, soil and water pH, and water salinity.Nineteen(19) true mangrove species were found in the area belonging to 10 families. These include Mysinaceae family represented by Aegiceras corniculatum ; Avicenniaceae family represented by Avicennia alba, Avicennia marina, Avicennia officinalis and Avicennia rumphiana; Euphorbiaceae family represented by Excoecaria agallocha; Sterculiaceae family represented by Heritiera littoralis; Combretaceae family represented by Lumnitzera racemosa; Palmae family represented by Nypa fruticans; Rhizophoraceae family represented by Bruguiera cylindrica Rhizophora apiculata, Rhizophora mucronata, and Rhizophora stylosa; Sonneratiaceae family represented by Sonneratia alba, Sonneratia caseolaris, and Sonneratia ovata.Ruciaceae family represented by Scyphiphora hydrophyllacea and Meliaceae family represented by Xylocarpus granatum, and Xylocarpus meckongensis. Avicennia officinalis has the highest total basal area of 650.69m2/ha, Avicennia alba, Aegiceras corniculatum, Avicennia marina, Avicennia officinalis, Avicennia rumphiana, Exoecaria agallocha, Lumnitzera racemosa, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia alba and Xylocarpus moluccensis have equal relative frequency of 0.074. Avicennia marina obtained the highest stems per hectare with a value of 38933.33, relative density of 0.405 relative dominance of 0.332 and importance value of 0.913. The index of diversity is 1.010, indicating that the area is diverse.
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    Fungal pathogen associated with Rhizophora stylosa: A comparative study between oiled and unoiled sites within Taklong Island National Marine Reserve (TINMAR), Nueva Valencia, Guimaras
    Balanga-an, Kristoffer (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2009-03)
    Mangroves, refer to an assemblage of trees and shrubs that inhabit the coastal intertidal zone in tropical and subtropical regions. They help in the soil formation, protection, and stabilization of our coastal environment as well as serve as shelter and breeding grounds for some of our marine organisms. A mangrove habitat represents the borderline between land and sea and is considered as one of the principal places where spilled oil and associated impacts converge. Oil spill threaten mangroves by predisposing the plants to fungal attacks thereby reducing their resistance to stress and diseases. Studies also show that certain fungi species are able to utilize oil in contaminated mangrove species. This study generally aims to compare the fungal population found on the diseased leaves of Rhizophora stylosa between oiled and unoiled sites in the Taklong Island National Marine Reserve (TINMAR). It also aims to isolate, characterize and identify fungi present in diseased leaves of Rhizophora stylosa using potato dextrose agar (PDA) culture media and determine their frequency of occurrence. Leaf samples were collected from two sites in TINMAR, one of which was contaminated by oil and the other one was not. Three trees were selected to represent each of the two sampling sites (oiled and unoiled), and to each of the selected trees, three diseased leaves were collected. The results of this study showed the dominance of some species of fungi namely, Aspergillus (40%), Penicillium (20%), Cladosporium (13.33%), Monilia (6.67%), Mycelia (6.67%), Humicola (6.67%), and Pestalotiopsis (6.67%). Five out of these seven genera were isolated from the unoiled site while six of these were isolated from the oiled site. Generally, the fungal population was observed to be greater in the oiled site than in the unoiled. This preliminary data indicate that R. stylosa might still be undergoing stress due to the remaining components of the spilled oil in the area. However, this can only be resolved by further monitoring.