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Undergraduate Special Problem

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

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    Community structure, biomass and carbon stock assessment of mangrove forest in Poblacion, Batan, Batan Bay, Aklan, Philippines
    Cagalawan, Donna Novei C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2013-04)
    The continued loss of mangroves in Batan Bay, Aklan and elsewhere in the Philippines warrants urgent attention. Appropriate management schemes can only be drawn after a scientific assessment of the remaining mangroves in a given area. This study aimed to 1.) assess the community structure, of mangroves in Poblacion, Batan, Aklan using accepted ecological indicators such as a.) determine the physical and chemical factors such as salinity, temperature of water and soil, pH as well as substrate characterization; b.) identify and classify true mangrove species present in the area; c.) Stand Basal Area, d.) stems per hectare, e.) relative density, f.) relative frequency, g.) relative dominance, h.) importance value, i.) Shannon Index of Dominance and; 2.) determine biomass and carbon density in the above ground pools of mangroves. A total of nineteen (19) true mangrove species represented by six families were identified in Poblacion, Batan, Aklan. The true mangrove species were Aegiceras corniculatum, Avicennia alba, Avicennia marina, Avicennia officinalis, Avicennia rumphiana, Bruguiera cylindrica, Camptostemon philippenensis, Ceriops decandra, Excoecaria agallocha, Lumnitzera littorea, Nypa fruticans, Osbornia octodanta, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Scyphiphora hydrophyllacea, Sonneratia alba, Xylocarpus granatum and Xylocarpus moluccencis. Camptostemon philippenensis had the highest basal area with 103.14 m2/ha and the highest relative dominance with the value of 39.26%. Avicennia marina has the highest stems per hectare in the area with the value of 32, 400. It also recorded the highest average density at 167 trees/ha and was present in all plots with relative frequency of 44.15%. Avicennia marina was the most important species with value of 300.21. Camptostemon philippinensis had the highest seedling density of 586 seedlings per hectare, whereas Avicennia marina had the highest sapling density of 20 saplings per hectare. In terms of biomass, Avicennia marina recorded the greatest biomass at 79.42 tons/ ha and the highest carbon stock of 36.7 tons/ha. A total of 203.87 tons/ha biomass and 91.728 tons/ha carbon stock was determined. Based on the leaf litter fall, Transect 1 has the highest leaf fall at 664.9g.m2. Litter production was highest during November 5, 2012-November 19, 2012 and lowest in December 17, 2012- December 31, 2012 in all three transects.
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    Temporal variation in the subtidal macroinfaunal composition of a NaGISA seagrass bed in southern Guimaras, Philippines between 2015 and 2016
    Bacabac, Earl Jeroh I. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Seagrass meadows are amongst the most abundant and diverse ecosystems when it comes to biodiversity but due to stress induced by natural and anthropogenic factors, a worldwide decline threatens the vital ecological functions of these habitats. Studying the infauna provides clues and information about the complexity of seagrass ecosystems and provides information that would facilitate better seagrass area management and associated conservation efforts. The NaGISA sampling protocol was conducted in Calaparan seagrass bed in TINMAR, Guimaras, Philippines between Sept. 2015 and 2016. Overall macrofaunal density was recorded at 21,954.80 ± 36,109.62 ind.m'2 with macrofaunal density higher in 2015 than in 2016 albeit, insignificant except for capitellid polychaetes. Community structure analysis also found similarity in dominance patterns in the subtidal zone with other soft-bottom macrofaunal studies in the Philippines with polychaetes, nematodes, and crustaceans as the respective dominant macrofaunal groups observed. Dominant polychaete families were also found to be cosmopolitan and opportunistic. Granulometric analysis characterized the sediment as pebble to medium sand with mid phi values ranging from -3.69 to 1.10 but poor sorting in all sampling points was observed. Cymodoceaceans dominated the subtidal zone in both years (Halodule pinnifolia in 2015; Cymodocea rotundata in 2016). Correlation analysis showed macrofaunal densities to have a significantly strong negative relationship with sorting index and percent gravel while a strong positive relationship with percent seagrass cover. The poor sediment sorting, coarse sediment character, and seagrass cover were the primary factors influencing the observed decrease in macrofaunal density but the decrease is considered normal for the variability of macrofauna in the area. A clearer picture of macrofaunal interactions would be provided with comparison to intertidal macrofauna of the area in the sampling years and data on additional factors that were not measured in the study.