Undergraduate Special Problem

Mangroves are important ecologically and economically in coastal areas in tropica] and sub-tropical areas in the world. However, they continue to be under threat from various human activities either directly or indirectly. The recent oil spill off the coast of southern Guimaras has brought numerous damages to these critical habitats including the mangroves in Taklong Island National Marine Reserve. This study is part of the over all Oil Spill Assessment program conducted by University of the Philippines in the Visayas following the sinking of M.T. Solar 1. This study aimed to determine the effect of oil spill on shoot development as an indicator of health conditions of trees and seedlings of selected mangroves such as Aegiceras floridum, Avicenia marina, Rhizophora apiculata Rhizophora , Rhizophora stylosa, and Sonneratia alba, in Taklong Island National Marine Reserve. Specifically, it aims to determine 1) standing leaves, 2) new leaves, 3) leaf scars of trees and seedlings. Results showed that shoot development among trees were not significantly different between oiled and unoiled sites but closer examination of species response revealed significant differences on standing leaves and new leaves only. Seedling shoot development showed a consistent significant difference among species and between sites. Aegiceras floridum and Sonneratia alba were least affected as shown by the higher number of standing leaves and least number of leaf scar while the Rhizophora spp. and Avicennia marina had the greatest number of leaf scars and least number of standing leaves. Results of this study showed that seedlings are clearly under stress and are more sensitive to oiling than trees although species response also varied individually. While tree species such as the Rhizophora spp. (e.g. R. apiculata, R. stylosa and R. mucronata) appear to be the most sensitive compared with Aegiceras floridum, Avicennia marina and Sonneratia alba. Results of this study will be useful in providing new knowledge on the evaluation of impacts of oil spills on mangroves.

Mangrove forests are unique inter-tidal ecosystems comprised of taxonomically diverse, salt-tolerant tree and other plant species that are primarily found o.i relatively sheltered coastlines, deltas, estuaries, and lagoons in tropical and subtropical regions of the world. The objective of this study is to generally determine the physicochemical factors influencing the distribution and occurrence of mangroves in selected sites in the Province of Antique and to specifically measure selected physicochemical factors influencing the distribution and occurrence per species per municipality and correlate selected physicochemical factors like soil and water salinity, soil and water pH, and soil and water temperature influencing the distribution and occurrence per species per municipality using Pearson Correlation Coefficient. There were 224 plots established in 11 municipalities in the province of Antique. Twenty-five plots were established in Anini-y, 44 in Hamtic, 11 in San Jose, 5 in Belison, 18 in Patnongon, 23 in Bugasong, 11 in Barbaza, 9 in Tibiao, 26 in Culasi, 23 in Pandan, and 29 in Semirara. A total of 27 true mangrove species belonging to 12 families were found in the 11 municipalities of Antique. The 12 families are Family Avicenniaceae represented by Avicennia alba , Avicennia marina, Avicennia officinales, and Avicennia rumphiana', Family Combretaceae represented by Lumnitzera racemosa and Lumnitzera littorea; Family Euphorbiaceae represented by Excoecaria agallocha; Family Lythraceae represented by Pemphis acidula; Family Meliaceae represented by Xylocarpus granatum and Xylocarpus moluccensis; Family Myrsinaceae represented by Aegiceras coniculatum and Aegiceras floridum; Family Myrtaceae represented by Osbornia octodonta; Family Arecaeae (Palmae) represented by Nypa fruticans; Family Rhizophoraceae represented by Bruguiera cylindrica, Bruguiera gymnorrhiza, Bruguiera sexangula, Ceriops decandra, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata, and Rhizophora stylosa; Family Rubiaceae represented by Scyphiphora hydrophyllacea; Family Sonneratiaceae presented by Sonneratia alba, Sonneratia caseolaris, Sonneratia ovata; and Family Sterculiaceae represented by Heritiera littoralis. For Soil pH, the highest value of 8.87 was observed in the municipality of Hamtic and the lowest at 6.32 in the municipality of Semirara. Overall mean soil pH was 7.31. For Water pH, the highest value of 8.96 was observed in the municipality of San Jose, and the lowest value of 6.29 in the municipality of Tibiao. Overall mean water pH was 7.23. For salinity, it ranged from 3.1 ppt (Tibiao) to 27.47 (Semirara) and the overall mean was 13.37 ppt For Water Temperature, the highest value of 29.48 °C was observed in Anini-y & the lowest value of 24.74 °C in the municipality of Semirara with an overall mean of 27.40 °C. For Soil Temperature, the highest value of 30.2 °C was observed in the municipality of Belison & the lowest value of 24.97 °C in the municipality of Semirara with an overall mean of 27.50 °C. Among the species present, Aegiceras floridum showed significant correlation with Soil pH (favor low soil pH), water pH ( favor low water pH), salinity ( favor high salinity), soil temperature (favor high soil temperature) and water temperature (low water temperature), A. rumphiana showed significant correlation with water pH (favor low water pH) and soil temperature ( favor low soil temperature), B. cylindrica showed significant correlation with soil pH ( favor high soil pH), C. decandra showed significant correlation with water pH (favor low water pH) and salinity (favor high salinity), L. littorea showed significant correlation with soil pH (favor high soil pH), water pH (favor high water pH), salinity (favor high salinity), soil temperature (favor high soil temperature) and water temperature (favor high water temperature), O. octodonta showed significant correlation with soil pH (favor high soil pH), water pH (favor low water pH), salinity ( favor low salinity), soil temperature (favor high soil temperature) and water temperature (favor low water temperature), S. caseolaris showed significant correlation with water pH (favor low water pH), salinity (favor low salinity), soil temperature (favor low soil temperature) and water temperature (favor low water temperature) and S. ovata showed significant correlation with soil pH ( low soil pH), salinity (favor low salinity) and water temperature (favor low water temperature). Species like A. corniculatum, A. alba, A. marina, B. sexxangula, E agallocha, H. littoralis, L racemosa, N. fruticans, R apiculata, R mucronata, R stylosa, S. alba, X. granatum and X. moluccencis showed wide tolerance (no correlation) in all physicochemical factors (Soil Salinity, Water pH, Soil pH, Soil Temperature and Water Temperature).

Undergraduate Special Problem

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