Carbon Storage Of Forested Wetland Ecosystems In The Permafrost Region,in Daxing’anling Mountains Of China

Wetlands play an important role in the global carbon cycle,but there are still many uncertainties in the estimation of wetland carbon stocks.The ecosystem carbon storage(vegetation C storage and soil organic C storage),net primary productivity(NPP)and annual net carbon sequestration(ANCS)of seven kinds of natural wetlands(tussock swamp-C,shrub swamp-G,Alnus sibirica swamp-M,Be tula platyphylla swamp-B and Larix gmelinii-Carex schmidtii swamp-LT,Larix gmelinii-Moss swamp-LX,Larix gmelinii-Sphagnum spp swamp-LN)were measured by using relative growth equations and Multi N/C 3100,HT 1300 Solids Module(Analytik Jena AG,Germany),in order to quantify ecosystem carbon storage and sequestration capacity of seven natural wetlands and reveal the spatial distribution of them along the environmental gradient of transition in the permafrost region,northeast of China.The results showed that:①The vegetation carbon storage(VCS)of seven wetland types varied from 3.60 to 62.18 t.hnm-2,which took on a skewing trend of first rising and then decreasing along the water environmental gradient from marsh to forest;②The soil organic carbon storage(SOCS)of seven wetland types varied from 179.47 to 320.81 t.hm-2,and SOCS of forested wetlands(except M)and shrub wetlands were significantly higher than that of C by 56.4～78.8%(P<0.05)and M by 32.0%～50.9%(P<0.05);③The ecosystem carbon storage(ECS)of these wetland types varied from 183.07 to 347.14 t.ha-2,and ECS of forested wetlands(except M)and shrub wetlands were significantly higher than that of C by 64.0～89.6%(P<0.05)and M by 28.1%～48.1%(p<0.05),yet the proportion of soil carbon stocks in forested wetlands(82.1～96.4%)was lower than that of C and G(98.0～98.3%);④NPP and ANCS of seven wetland types varied from 6.76 to 11.22 t hm-2·a-1 and 2.97 to 5.37 t hm-2·a-1,and NPP and ANCS of forested wetlands(except LN)were significantly higher than those of C by 26.9～61.4% and 30.5～66.0% and of G by38.6～77.2% and 41.4～80.8%(P<0.05),respectively.Therefore,the ecosystem carbon stocks of forested wetlands(except M),shrub swamps and marsh in the frozen permafrost region of the were equivalent to 82.6-89.0%,76.9% and 46.9% of the lower limit values of northern peat land carbon reserves(390-1364 t·hm-2·a-1),respectively.The vegetation annual net carbon sequestration of forested wetlands(except LN)was slightly higher than the estimated value of global land vegetation ANCS(4.1 t·hm-2·a-1),while those of marsh and shrub swamps were about 3/4 of it.