Floristic composition and diversity of mangroves in selected sites in the province of Antique, Panay Island, Philippines.

Abstract

Mangroves in the Philippines are in constant danger due to innumerable disturbances in the environment. The study endeavored to assess the floristic composition and diversity of the mangroves in the province of Antique through transect and ocular survey in the randomly selected sites throughout the province. Diversity in the region is high with the presence of 3 1 true mangrove species represented by 16 families and 14 genera. The species include <i>Acanthus ebracteatus, A. ilicifolius,</i> and <i>A. volubilis</i> from Family Acanthaceae, <i>Avicennia alba, A. marina. A. officinalis, and A. rhumphiana</i> from Family Avicenniaceae, <i>Camptostemon philippinensis</i> from Family Bombaceae, <i>Lumnitzera littorea</i> and <i>Lumnitzera racemosa</i> from Family Combretaceae, <i>Excoecaria agallocha</i> from Family Euphorbiaceae, <i>Pemphis acidula</i> from Family Lythraceae, <i>Xylocarpus granatum</i> and <i>Xylocarpus moluccensis</i> from Family Meliaceae, <i>Aegiceras corniculatum</i> and <i>Aegiceras floridum</i> from Family Myrsinaceae, <i>Osbornia octodonta</i> of Family Myrtaceae, <i>Nypa fruticans</i> of Family Palmae, <i>Bruguieria cvlindrica. B. gymnorrhiza, and B. sexangula, Ceriops decandra, C. tagal, Rhizophora apiculata. R. mucronata and R. stylosa</i> from Family Rhizophoraceae, <i>Scyphiphora hydrophvllaceae</i> from Family Rubiaceae, <i>Sonneratia alba, S. caseolaris and S. ovata</i> from Family Sonneratiaceae, and <i>Heritiera littoralis</i> from Family Sterculiaceae . The Shannon Index of Diversity used to determine the measure of diversity in the area is correlated with Pielou's Equitability Index for Evenness. The measures of indices showed that diversity and evenness of the mangal area in the province are directly related, with values of 0.73232 and 0.51163, respectively. Caluya showed the highest diversity index of 1.0132, which consisted of 28 species from 13 families and 15 genera, while Bugasong has a relatively low diversity of 0.0486, denoted by 6 species from 4 families and 4 genera. In general, the high variations in the geomorphology of coastal areas in Antique provided a wide range of substrata for colonization of mangroves that contributed to the high species diversity.