UPV Theses and Dissertations
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Item Diversity and structural complexity of mangrove stands in Barangay Mag-aba, Pandan, AntiqueBolivar, 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.Item Economic analysis of rice farming under differential tenurial arrangements in Sibalom, AntiqueBasañes, Lorvi Ann A.; Rondrique, Clyde G. (Division of Social Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1997-03)This study was undertaken in order to acquire informations about the effects of tenurial arrangments on the productivity and profitability of rice farms in Sibalom, Antique, from the operators view point. The study found out that the practices of rice farms did not essentially vary among farms of different tenure arrangements, though some slight differences had been discovered. Furthermore, it was also discovered that tenurial arrangement greatly affected the distribution of gains from farming. Though share-tenanted farms proved to be the most profitable from the operators point of view, the conpensation that the operators received were quite inadequate to compensate the cost in using owned inputs. Moreover, other tenurial arrangements, leasehold and owner-operated, revealed to be less profitable than the one mentioned earlier. In terms of its effect on productivity, tenurial arrangements were found to explain an insignificant variation in the farms output. The study concluded that tenurial arrangements did really have a significant effect on productivity and the production practices of rice farmers, though in the profitability side, it proved to be otherwise. Of the problems presented, the emergence of rats and the golden kuhol pestilence in the rice fields were pointed out as the primary reasons for the decline in the productivity of rice farms in Sibalom, Antique. Aside from the propagation of government support programs and the transformation and empowerment of rice farmer cooperatives, the study also recommended that a closer look on share-tenancy must be done by the goverment so as to eliminate its equity undesirability, instead of outlawing the said tenurial arrangement which proved, in this study, to be the most efficient tenurial arrangement in rice farming.Item Density of mangrove trees in selected municipalities in the Province of Antique, Panay Island, PhilippinesArelis, Ian Jerwin C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2006-03)Mangroves line one quarter of the world’s tropical coastlines, and approximately 117 countries and territories have mangrove resources within their borders. Although over recent years mangrove deforestation has occurred at a phenomenal rate worldwide, constant assessment in the Philippines has been made to monitor its current status. To characterize the density of mangrove trees better in Panay Island, surveys were undertaken within the coastal and riverine estuaries in the 11 municipalities of the province of Antique. Detailed records were taken by transect and ocular surveys along 40 barangays with 75 transects and 223 plots established. The mangroves of Antique were composed of 31 species of true mangroves belonging to 14 families and a total of 16 generas. Considerable values in terms of relative density and stems per hectare were found with Nypa fruticans as the highest, with a relative density of 70.372% trees per hectare and an average stem density of 4,457.249 stems/ha. Other significant species included Sonneratia alba (4.534%; 625 stems/ha), Avicennia marina (4.524%; 1,525 stems/ha), and Rhizophora apiculata (4.232%; 50 stems/ha). Close examination of the data suggested the variability of distribution patterns and density to be attributable to the differing responses of individual species to the environmental factors and other human activities. It was also concluded that habitat classification and topography could directly affect mangrove distribution and also capable of altering basic zonation patterns.