Preliminary Study On Wetland Vegetation Carbon Storage Of Nansihu Lake In Shandong Province

Wetland is one of the highest productive force's ecosystems in the world, riches in animal, plant resource and unique ecological features,and is very sensitive to the global changes. Because of the primary production capacity and a low rate of decomposition of the wetland vegetation it has become an important CO₂ sink, and the carbon storage of the wetland vegetation reserves its the function of carbon sink. However, in recent years, because of the over-exploitation and irrational use of wetlands, which greatly affect the function of wetland vegetation carbon reserves, the wetland vegetation has begun to degradate. The study is an important infrastructure for the hold wetland ecosystems studys ,specially for the study of carbon cycle, and is also an important part of the global change research. In the background of Global Change, the study of the wetland vegetation carbon reserves has become very important.This paper is based on personal interest and a project of my academic adviser.It makes ShanDong NanSihu lake as a typical area,in which the human impacts greatly.Using three TM images of NanSihu lake in 1987, 1997&2008,and many relevant research data, the wetland remote sensing information was extracted. At the same time, the biomass of three types plant in the field ,including reed, lotus & water plant, gained by the field gathering law.The unit density of carbon of reed and lotus were gained by chemical experiment.Based on the two sides data,the paper deeply analyse the landscape pattern changes of wetland vegetation, changes in carbon reserves of wetland vegetation and the change's driving force , the change of the carbon reserves'value, and has proposed the development and protection of wetlands.The main contents and results of this paper include the following four parts.Firstly, after the range of NanSihu lake was redefined, I used the technology of GIS and RS to deal with the three TM images,including classification and information extraction and used the software fragstats3. 3. to calculate the landscape pattern indexes.I used the related functions of ArcGIS to do the landscape pattern transition matrix analysis.These analysis showed that,in the recent twenty years, NanSihu lake wetland vegetation features and landscape pattern has changed enormously. Wetland landscape express more features of human impact; the natural attribution reduces and human activities increases. In the area of wetland, AREA_MN of Patch decreased;Patch Number increased and landscape fragmentation got worse.The matrix of the wetland has changed from wetland vegetation nature state to the artificial state.Secondly, by the way of field gathering and the way potassium dichromate external heating, three types of the community's biomass above water and the unit density of carbon were gained.The paper showed water percentage of reed is during 44.4%—73.5%,and the water percentage of lotus 79.4%—85.3%,and the water plants during 64.1 %—84.5%. we have found the uint biomass of reed is heavier than lotus's,and lotus's heavier than water plant. Not only different plants have different carbon density,but also the different module of the same plant have different carbon density.Thirdly, using two parts of data above,I calculate the wetland vegetation carbon reserves of three relevant years in NanSihu lake,and analysis changes of carbon reserves in serveal aspects. Analysis showed that ,in recent twenty years, the standpoint of wetland vegetation carbon reserves and the average of the overall value of the reserves level are in a downward trend. In particular, in the latter half research phase of the study (1997 - 2008 ), the decrease rate has become faster than in the form half research phase of the study (1987 - 1997 ).The carbon pattern of wetland vegetation enhances on the part and weakens in the whole. The carbon sink capacity of the wetland vegetation in 1987 is more close to the carbon sink capacity of savanna. The carbon sink capacity in 1997 is still higher than the ability of to 1997, a wetland'carbon sink capacity is higher than carbon sink capacity of temperate grassland.But the carbon sink capacity of the wetland vegetation in 2008 has decreased sharply,and its carbon sink capacity is as same as desert vegetation's.Fourthly, Based on the price of carbon sequestration mechanisms, the economic value of carbon sequestration of NanSihu lake wetland vegetation was fulfilled and evaluated paper showed the economic value of carbon sequestration has been in a downward trend ,and the reason of the trend is closely related to human destruction of wetland vegetation.