Carbon Storage And Evaluation Of Mangrove Wetlands In Dongzhaigang,hainan

Mangrove wetlands are important ecosystem that distribute in tropical and subtropical intertidal. For the purpose of understanding the total carbon storage and its economic value of mangrove wetlands, the distribution, composition and biomass(including aboveground and underground biomass) of 12 communities, the biomass of litters, the amount of carbon storage in vegetation and soil, and the value of carbon storage of mangrove wetlands were studied in Dongzhaigang.The distribution and area of different mangrove communities in Dongzhaigang were analyzed based on Quikbird images. The aboveground biomass(tree height, DBH and intervals) and litters biomass were measured by sampling method. The amount of vegetation carbon storage in different communities was calculated based on photosynthetic reaction formula. The SOCD was measured by potassium dichromate heating method. According to the amount of vegetation and soil carbon storage, the value of mangrove wetlands were evaluated combining with the methods of market value, carbon tax, forestation cost, and the average of carbon tax and forestation cost. The results as followed:1. The total area of mangrove in Dongzhaigang is 1576.24 hm2, mainly composed of 12 communities. The communities and area size by the order are: Bruguiera marina + Bruguiera sexangula var. rhynchopetala+Bruguiera gymnoihiza(484.90hm2), Rhizophora stylosa +Rhizophora apiculata(381.57hm2), Ceriops tagal(376.72hm2), Aegiceras corniculatum(96.7hm2), Kandelia candel(58.01hm2), Avicennia marina(51.8hm2), Sonneratia apetala(38.81hm2), Excoecaria agallocha(30.45hm2), Lumnitzera racemosa(22.60hm2), Pongamia pinnata+Hibiscus tiliaceus(17.04hm2), Sonneratia caseolaris(15.15hm2), and Acrostichum aureum+Acanthus ilicifolius(2.49hm2).2. The aboveground biomass, underground biomass and litters biomass are 40603.88 t, 19908.60 t and 17212.54 t respectively. The amount of vegetation carbon storage of mangrove wetland is 43838.04 t in Dongzhaigang. The largest of biomass per hectare is Sonneratia caseolaris(74108.91±394.72kg/hm2), followed by Aegiceras corniculatum(69030.61±9.72kg/hm2), Bruguiera marina + Bruguiera sexangula var. rhynchopetala + Bruguiera gymnoihiza(54756.57±7.63kg/hm2), Sonneratia apetala(43224.68±480.03kg/hm2), Rhizophora stylosa + Rhizophora apiculata(38508.66±8.51kg/hm2), Kandelia candel(26478.54±5.69kg/hm2), Excoecaria agallocha(21697.87±28.9kg/hm2), Ceriops tagal(17606.79±3.24kg/hm2), Lumnitzera racemosa(12427.88±2.21kg/hm2), Avicennia marina(12376.84±7.53kg/hm2), Acrostichum aureum + Acanthus ilicifolius(2261.04±160.64kg/hm2), Pongamia pinnata+Hibiscus tiliaceus(2051.64±78.05kg/hm2) respectively.3. The amount of soil carbon storage of mangrove wetland is 269037.33 t. There are different in vertical distribution of SOCD in different communities due to different root distribution. According to the average SOCD in different communities, the maximum is 9.83±0.35kg/m2 at layer of 0~20cm, followed by layers of 20~40cm, 40~60cm and 60~80cm are 8.02±0.56kg/m2, 7.17±0.56kg/m2, and 5.25±0.26kg/m2 respectively, and the minimum is 4.85±0.49kg/m2 at layer of 80~100cm. There are no difference between the layer of 0~20cm and 20~40cm(P>0.05), but those of two layers are higher than others layers(P<0.05). The total SOCD in different communities, the highest is Bruguiera marina + Bruguiera sexangula var. rhynchopetala + Bruguiera gymnoihiza(103884.98±906.76t), and followed by Ceriops tagal(74786.45 ±553.78t), Rhizophora stylosa + Rhizophora apiculata(42991.49±553.28t), Aegiceras corniculatum(14990.43±155.69t), Avicennia marina(9894.84±94.79), Kandelia candel(7657.32±102.68t), Excoecaria agallocha(4046.20±49.94t), Sonneratia caseolaris(3069.09±55.90t), Sonneratia apetala(3300.79±169.21t), Lumnitzera racemosa(2957.44±39.10t), Pongamia pinnata+Hibiscus tiliaceus(1327.73±46.18t), and Acrostichum aureum+Acanthus ilicifolius(130.58±4.63t) respectively.4. The total of carbon storage of mangrove wetland is 394951.83 t. Evaluated by the methods of market value, carbon tax, forestation cost, and the average of carbon tax and forestation cost, the values of carbon storage of mangrove wetland are 2.63×107yuan, 3.67×108yuan, 2.92×108yuan and 3.29×108yuan, and range from 2.63×107yuan to 3.67×108yuan. The values of carbon storage of mangrove wetland per hectare are 1.67×104yuan, 2.33×105yuan, 1.85×105yuan and 2.09×105yuan.