Mangrove and soil characteristics investigation

Table 2. Tree and sapling density; sum of species; important value IV index of tree and canopy coverage 128 percentage of mangrove plant community on three study zones in Kelong Island. 129 NO PARAMETERS ZONATION LANDWARD MIDDLEZONE SEAWARD 1 Tree Density tree ha -1 2175 ± 222 a 1800 ± 141 b 1550 ± 191 b Rhizophoraapiculata 425 ± 544 1425 ± 126 1475 ± 171 Brugueiragymnorrhiza na 100 ± 82 na Xylocarpusgranatum 1750 ± 332 200 ± 82 na X. mollucensis na 75 ± 50 75 ± 50 2 Sapling Density id.ha -1 975 ± 287 a 925 ± 150 a 1875 ± 50 b R. apiculata 325 ± 330 850 ± 191 1875 ± 50 B. gymnorrhiza na 200 ± 115 na X. granatum 525 ± 171 75 ± 96 na X. mollucensis na na na Aegicerascorniculatum 125 ± 96 na na 3 Sum of Species 3 4 2 4 Tree IV index Highest XG: 232.42 RA: 177.32 RA: 237.53 Lowest RA: 67.58 XM : 30.60 XM: 62.47 XG = X. granatum; RA = R. apiculata; XM = X. mollucensis. Different letters indicated significant differences 130 among treatments at p _ 0.05 according to ANOVA. na: not available. 131 132 133 134 135 136 137 138 139 140 Figure 2. Multidimensional scaling analysis of plots based on tree species abundance. 141

3.2. Greenhouse gas GHGs fluxes

142 Generally, Kelong mangrove had low GHGs fluxes from its soil Figure 3, Spatially, CH 4 and N 2 O gas 143 fluxes had not significant difference among the three stations and their fluxes ranged from 0.52 0.92 to 2.544.17 144 μmol m −2 h −1 , and from -0.56 0.61 to -0.060.13 μmol m −2 h −1 , respectively. However, CO 2 flux was found to 145 significantly different among the stations P0.05, and the value decreased from LW station 4.35 2.04 mmol 146 m −2 h −1 to seaward 0.48 0.1.38 mmol m −2 h −1 . Correlation among GHGs fluxes, vegetation and environmental 147 data was showed on Table 3. Pore water salinity, TDS and conductivity, as well as soil pH were found to 148 significantly and negatively correlate to CO 2 flux. 149 150 151 152 Figure 3. Soil-to-atmosphere GHGs fluxes on each zone of mangrove forest in Kelong Island. 153 154 Table 3. Pearson correlation among environmental parameters water and substrate with tree abundance TA 155 and greenhouse gases fluxes. 156 CO 2 CH 4 N 2 O Soil pH -0.864 0.509 -0.412 Soil Temperature -0.483 0.373 -0.162 Soil OC 0.735 0.244 0.476 Soil TP -0.633 0.372 -0.024 Soil TKN 0.566 0.497 0.488 Water salinity -0.686 0.262 -0.489 Water total dissolved solid -0.643 0.266 -0.454 Water conductivity -0.692 0.288 -0.479 Tree abundance 0.464 -0.094 0.498 indicates p 0.05; indicates p 0.01. 157 158 159 160 161 162 163 164 165