| The soil, water and vegetation of Mangrove wetland are three vital factors of mangrovewetland ecosystem. This study is aiming at the variation and the co-relationship amongfactors (soil, water and vegetation) of mangrove wetland in the process of restoration bymeasuring total microbial DNA, soil organic carbon (SOC), carbon-nitrogen ratio (C/N), totalnitrogen (TN), total phosphorus (TP), total potassium (TK), pH, salinity, moisture content offive types of surface soil of those ponds, the height, basal diameter, relative chlorophyllcontent of vegetation in those sites, the chemical oxygen demand (COD), total nitrogen (TN),total phosphorus (TP), temperature, pH, salinity of water from shrimp ponds and duck ponds,and the price differences of water from those five sample sites. Based on which we get theimpact from recovery process of Mangrove on the repairation of factors of shrimp pond. Thisis meaningful to ecological restoration theoretical system. The results showed that:1）The water quality indicators changed significantly after Mangrove wetland was used foraquaculture. Water COD, TP, NQI, significantly increased,but pH and N/P declined. Thephenomenon of water acidification, salinization, eutrophication are serious concerning to theduck ponds, while the temperature and TN did not change significantly. By the coefficient ofvariation analysis (CV), we found that COD, TP and TN are three vital factors leading fromthis functional transformation of Mangrove wetland.2）SOC, TN and C/N decreased after the transformation, and soil salinization is serious. TP inaquaculture areas is higher than that in Mangrove original habitat, but lower in abandonshrimp pond. In Mangrove wetland, there are moderate soil microbes, which enabled thenormal soil nutrient cycling and energy flow. The high water-contained ratio made theaeration condition in a bad mode concerning soil of shrimp pond and duck-pond, and theorganic acids and chlorinated substances from slow decomposition of organic matter result inlower soil pH of the circumstances. By the coefficient of variation analysis (C.V), total massof microbial DNA changed significantly, followed by TN, SOC, TP and TK minor changes.3）In the one year consistent observation about the water quality after vegetation restorationon abandoned shrimp ponds, the COD, TN, TP of the pond water declined significantly, the state of eutrophication lowed down. Results from N/P analysis showed that water quality arein nitrogen restrictions status during the phase of late vegetation restoration, PH and salinitychanged in a overall declined state, water temperature stayed in a moderate state, comparedwith which in Dong zhai gang are higher in2.5-3.6℃.6）.Besides,The compare result got byfuzzy mathematical model about water resource prices of5type of sites showed that waterresource prices of abandoned shrimp sites A and B as well as native forest were mostly in thesame level which goes, in order,2.733￥/m3,2.674￥/m3and2.688￥/m3, while for theon-using shrimp pond and duck pond, the prices were relatively low, only for1.994￥/m3and1.930￥/m3respectively. In a word, during the recovery time, vegetation played a role inimproving water quality reflected in a higher water price.4）The process of Mangrove recovery has positive effect on the soil of the abandoned pond. Inthe restored abandoned shrimp ponds, soil organic carbon, TN, TP and moisture content aresignificantly increased, while the content of NaCl and pH decreased, which implied recoveryof soil in Mangrove wetland and alleviation of soil salinization. During this recovery process,TN and TP are both increased, but the average level is lower than that of primeval Mangrovewetland. As for SOC, it rose first and then declined; TK declined first and then rose. In thelate period, SOC and TN are both declined because of the lower vegetation survival rate.5）In the restored abandoned shrimp ponds, Rhizophora apiculata Blume, Avicennia marinaand Aegiceras corniculatum have good reparation effect in survival rate, height, basaldiameter, chlorophyll content comparing with Ceriops tagal and Bruguiera sexangula.Rhizophora apiculata Blume and Avicennia marina have a good recovery effect, whileCeriops tagal and Bruguiera sexangula are not. As for Bruguiera sexangula, the recoverycession went much better when plumular axis were used than seedings were used. Theanalysis found that during the restoration time the survival rate of Mangrove plants hadsignificant negative relationship with their drowning time and drowning hight, butsignificantly positive corelated with salinity of the water... |
PDF Full Text Request