Table of Content

    15 September 2015, Volume 30 Issue 9 Previous Issue    Next Issue
    Resource Ecology
    Analysis of the Correlation between NDVI and Climate Factors in the Lancang River Basin
    ZHANG Jing-hua, FENG Zhi-ming, JIANG Lu-guang, YANG Yan-zhao
    2015, 30 (9):  1425-1435.  doi: 10.11849/zrzyxb.2015.09.001
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    Based on MODIS NDVI and meteorological data from 2000 to 2010, this study analyzed the correlation between NDVI and meteorological factors pixel by pixel in the Lancang River Basin, studied the spatial pattern of the relationship between vegetation and climate, and explored the possible influence factors. The study indicated that: 1) Both temperature and precipitation had significant impacts on vegetation growth in the Lancang River Basin, and the temperature’s effect was particularly striking. 2) The response of vegetation growth to climate change showed significant time lag effect, and the lag time shortened as the latitude went up. 3) For different vegetation types, both the orders of influence degree of meteorological factors on NDVI and the sensitive degree of NDVI to climate change were, in turn, grassland, cropland, shrub forest and woodland. For the same vegetation, the impact of temperature was greater than that of precipitation, but NDVI was more sensitive to precipitation. 4) Climate characteristics (perennial mean temperature and multi-year average precipitation) had significant impacts on the response time of NDVI to climate change. There is no significant influence of perennial mean temperature on the relationship between NDVI and temperature, but multi-year average precipitation has impacts on the degree of correlation between NDVI and precipitation.

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    Study on the Variations of Forest Evapotranspiration and Its Components in Eastern China
    LU Qian-qian, HE Hong-lin, ZHU Xian-jin, YU Gui-rui, WANG Hui-min, ZHANG Jun-hui, YAN Jun-hua
    2015, 30 (9):  1436-1448.  doi: 10.11849/zrzyxb.2015.09.002
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    The study of forest evapotranspiration (ET) occupies a significant position in the research of water and energy cycles, owing to the important role of forest ecosystem in the entire terrestrial ecosystem. In this paper, based on Priestley-Taylor Jet Propulsion Laboratory Model (PT-JPL), we simulated ET and its components for the temperate mixed broadleaf-coniferous forest, the artificial evergreen coniferous forest and the subtropical evergreen broad-leaved forest in eastern China from 2003 to 2008, and then validated the accuracy of PT-JPL model with flux data. In addition, seasonal variation characteristics and controlling factors of ET and its components were also studied. The results indicate that PT-JPL model is robust and accurate for estimating forest ET and its components. There are obvious seasonal variation of ET and its components in all three forest ecosystems, with similar variation trends. However, the main controlling factors dominating the seasonal variation of forest ET and its components vary in different forest ecosystems. The seasonal variation of ET and its components for temperate mixed broadleaf-coniferous forest are mainly controlled by net radiation and VPD, while those for artificial evergreen coniferous forest and subtropical evergreen broad-leaved forest are net radiation only. As for seasonal variation of soil evaporation, EVI and VPD are the major contributors in all three forest ecosystems, but when referring to the seasonal change of interception evaporation, VPD is considered as the dominant factor.

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    The Land Use Change and Landscape Pattern Response Driven by YU-YI Expressway (Chongqing Section)
    HUANG Yong, LI Yang-bing, YING Hong
    2015, 30 (9):  1449-1460.  doi: 10.11849/zrzyxb.2015.09.003
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    In order to clarify the influence of roadways on the land use and landscape pattern and the range and intensity of the influence, the 15 km distance’s buffer zones at both sides of the Yu-Yi Expressway from Chongqing to Wushan was chosen as the study area. This section of the road was divided into four segments according to the landform along the road. Based on the data of the remote sensing images in 1986, 2000, 2007 and 2013, and by using ArcGIS software and method of landscape ecology, the paper studied the land use and landscape pattern changes driven by the expressway at three scales. The results show that, in the period from 1986 to 2013, the dispersed land use changed areas developed to an axis along the expressway. The effect zones of the expressway in the west low mountain and hill, the low mountain and strath, and the mid-low mountains gorge area are 10 km, 7 km and 5 km respectively, and it is not obvious in the east middle mountain and valley area. As a whole, the highly explored lands cluster in the 3 km buffer range along the road, and the land use degree decreases from west to east in the study area. The influence of the expressway on landscape structure is within a certain area. In the low mountain and hill at the west and the low mountain and strath area, the changes of landscape pattern mainly happen in the 5 km buffer range, and in 4 km and 3 km buffer range in the middle-low mountain and valley area and middle mountain and valley area, respectively. The landscape structure becomes increasingly fragmented, and the landscape stability within the influenced area decreases greatly, which exposes ecological landscape to more risks. The spatial differences of land use and landscape pattern change are related with the opening time of the expressway, and are also influenced by regional economy, terrain factors, and environmental policy. This research is beneficial for understanding the effect of the road in fragile ecological areas, and the conclusion of this study may provide scientific basis for the regional transportation planning and sustainable land utilization.

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    Assessment on the Rainwater Runoff Detention Produced by Urban Green Spaces within the 6th Ring Road of Beijing
    ZHANG Biao, WANG Shuo, LI Na
    2015, 30 (9):  1461-1471.  doi: 10.11849/zrzyxb.2015.09.004
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    Under the scenario of climate change and rapid urbanization, the effects of urban green spaces on rainwater runoff have attracted special attention. The present studies highlighted the value of urban green spaces in reducing rainwater runoff but failed to consider the effects of landscape patterns (i.e., size, shape, or spatial arrangement of vegetation patches) on runoff reduction. The study mainly focuses on the landscape pattern changes in urban green spaces (including landscape types and metrics) as well as their effects on rainwater runoff detention. This paper investigates the spatial-temporal changes of urban green spaces within the 6th Ring Road of Beijing, and estimates their effects on rainwater runoff detention based on an empirical model. The result indicates that, the urban green space area decreased by 198.49 km2 from 1040.67 km2 in 2000 to 842.18 km2 in 2010, which is mainly attributed to a sharp decrease of farmland and wasteland areas between the 5th and 6th Ring Roads. The largest patch index (LPI) and aggregation index (AI) of urban green spaces consistently decreased from 2000 to 2010, which implied the landscape patches become more isolated and fragmented. The volume of rainwater runoff controlled by urban green spaces slightly increased from 1.32×108 m3 in 2000 to 1.46×108 m3 in 2010 with the increase of summer rainfall, whereas the rainwater detention rate decreased from 23.43% to 16.89%. These changes are closely related to the decreases in green space area and landscape pattern metrics. In addition, the highest rainwater detention rate occurred in the urban green space between the 5th and 6th Ring Roads, however it decreased by 10% from 2000 to 2010. The urban green spaces between the 2nd and 3rd Ring Roads showed the lowest rainwater detention rate, and the flood risk should be paid highly attention. Therefore, an immense regional difference of rainwater runoff reduction is observed among five ring roads, which is closely related to the green space area and patch connectivity in different regions. The green space in the inner part of the 2nd Ring Road was composed primarily of grass and forest, and recorded large LPI and AI values, which promoted its role of rainwater runoff detention. By contrast, the green space between the 2nd and 3rd Ring Roads consisted of grass, forest, farmland, and wasteland, and the landscape metrics of the LPI and AI were relatively small, resulting in the poor capacity of rainwater runoff detention. Therefore, it is a good choice to optimize and adjust the composition and landscape pattern of urban green spaces. The results provide useful information for green space planning and management in highly urbanized areas. City managers should focus greatly on the role of urban green spaces in rainwater regulation and the scientific management of urban green spaces.

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    Resource Evaluation
    Driving Force Analysis and Scenario Simulation of Urban Land Expansion in Ningxia-Inner Mongolia Area along the Yellow River
    LI Jun, DONG Suo-cheng, LI Yu, LI Ze-hong, WANG Jun-ni
    2015, 30 (9):  1472-1485.  doi: 10.11849/zrzyxb.2015.09.005
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    Ningxia-Inner Mongolia Area along the Yellow River (NIMAYR) belongs to China??s fast urbanizing region, and it locates at arid and semi-arid region. The researches on urban land expansion in this area could enrich the theoretical studies on the mechanism of urban land expansion, and make realistic policy suggestion for urbanization in similar areas. Logistic Regression was employed to analyze the main driving force of the urban land expansion. Then urban land transfer matrix was obtained and coupled with CA-Markov, so Logistic-CA-Markov was finally set to simulate urban land expansion. Results showed that arable lands, grasslands, a few rural residential and mineral lands were three main sources of new urban land during 2000-2005. Main driving forces of expansion were the ratio of urban land in the neighborhood, annual precipitation, distance to the national highway, distance to the provincial road, distance to water land, and distance to arable, forest and grass lands. Three scenarios were set to simulate urban land change in 2016. In normal scenario, area of total urban land would be 997 km2, mainly around urbanized areas, including Hohhot, Baotou districts; in planning scenario, area of urban land would be 1525 km2, distributing as same pattern as in normal scenario; in ecological scenario, area of urban land would be 1480 km2, distributing along the main roads. Main conclusions were as follows. The peripheral areas of cities and areas along traffic lines were two main resources where extinct new urban areas generate. Scenario simulation of urban area change on whole NIMAYR showed that given total area of future urban land, distribution pattern of urban areas could be optimized by controlling other land use to transfer to urban land.

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    Spatiotemporal Evolution of Salt Marsh and Influential Analysis of Reclamation of Jiangsu Middle Coast in Recent 25 Years
    SUN Chao, LIU Yong-xue, LI Man-chun, ZHAO Sai-shuai, ZHOU Min-xi
    2015, 30 (9):  1486-1498.  doi: 10.11849/zrzyxb.2015.09.006
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    There are a variety of salt marshes in wide tideland of Jiangsu coast. In recent years, the distribution pattern of salt marshes has changed dramatically caused by reclamation activities on a large scale. Deep understanding on the distribution and expansion of salt marshes under the impact of reclamation will help us propose corresponding decisions supporting resource development and environment protection of tideland. Taking above into account, we identified salt marshes along middle segment of Jiangsu coast using remote sensing images and NDVI with local OTSU method as well as digitized reclamation from images, and obtained the information of salt marshes and reclamation at 7 time points in recent 25 years. And then we analyzed spatiotemporal evolution of salt marshes and their response to the reclamation based on a variety of GIS methods. The main results showed that: 1) The area of salt marshes experienced a slight increase and then followed by a sharp decrease with almost 10% (324.40 km2 in 1987, 291.04 km2 in 2013) total area reduce. After 2000, with the rapid disappearance of salt marshes, the width of salt marshes outside dim became narrower gradually. The overall pattern of distribution also changed: the majority of salt marshes distributed north to the Jiang Harbor before 2000, but more and more concentrated on the coast between Xinyang Harbor and Doulong Harbor in recent years. 2) The area of disappeared salt marshes, which resulted from reclamation, reached 569.47 km2 in the past 26 years, accounting for 85.4% of the total disappearance. The intense reclamation activities impacted greatly on the native salt marshes in the coast area north to the Jiang Hrabor. Nowadays, the most part of middle segment of Jiangsu coastal area was only covered by Spartina alterniflora. 3) Reclamation in intertidal region could change surrounding sedimental environment, which played a certain role in the expansion of salt marshes. That means salt marshes may be restored after the reclamation. Nevertheless, if remained salt marshes outside dim were too less, the restoration would be unsustainable. Therefore, we had better slow down the speed as well as limit the size of reclamation, and pay more attentions on some fragile coasts, in order to achieve the sustainable development and utilization of tidal flat in the future.
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    Health Assessment and Driving Mechanism Analysis of Cultivated Land in the Township Enterprises Developed Region
    LI Qiang, PENG Wen-ying, WANG Jian-qiang, ZHAO Ye
    2015, 30 (9):  1499-1510.  doi: 10.11849/zrzyxb.2015.09.007
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    The rapid development of township enterprises in the region will bring a direct influence on cultivated land’s use and protection, and cause a conspicuous change of the cultivated land health. This paper selected the cultivated land of township enterprises developed regions for the case study. A composite evaluation model was used to evaluate the cultivated land health index (CLHI), which is developed from the cultivated land emergy index with multi-level fuzzy evaluation model. A fuzzy assessing system including quality, productivity and soil environment was used to evaluate the health of cultivated land, and the fuzzy decision result were revised by the agricultural land emergy index which was comprised of the emergy utilization coefficient and the cultivated land pressure index based on the emergy analysis theory. The basic data were acquired by household survey, sampling and testing analysis, and the health status of cultivated land in this study region was assessed by using the platform of GIS. The evaluation results show that the health of cultivated land in the township enterprises developed area is worth of worrying about, the composite index of cultivated land health being in the range of 0.412-0.677. The result of composite index was divided into three classes, namely in normal health, sub-health and poor health in the study area, and the area proportions of them are 35.23%, 41.55% and 23.22%, respectively. This study indicates that the direct harm has been brought to the soil environment of farmland by the pollutant emitted from the adjacent township enterprises and the pollutant diffused along the river. With development of township enterprises, the farmers become to pay more emphasis on non-agricultural production, and the productivity of cultivated land were reduced. This study can provided reference for the assessment method selection in similar areas, and for the improvement of science adjustment and mechanism study of the health of cultivated land in the township enterprises developed region.

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    Scale Adaptability of the Large-Scale Vegetation Reducing Sediment Equation in the Loess Hilly Region
    LUO Ya, YANG Sheng-tian, ZHOU Qiu-wen, CHEN Ke, WANG Zhi-wei
    2015, 30 (9):  1511-1522.  doi: 10.11849/zrzyxb.2015.09.008
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    The large- scale vegetation reducing sediment equation in the loess hilly region (LVRSE) is one of the efficient tools for analyzing the effect of vegetation change on sediment yield in the Loess Plateau, and its adaptability at different spatial scales is very important to study the water and sediment changes of Yellow River. This research uses a numericalexperimental method to study the adaptability of LVRSE at small basin, sub- basin and grid scales. The result shows that the overall estimation bias (D) of LVRSE at different spatial scales ranks in the following order: small basin (D=52.26%), sub-basin (D=60.07%), grid (D= 92.17%); the Nash- Sutcliffe model efficiency coefficient (NSE) of the LVRSE at different spatial scales ranks in the following order: small basin (NSE =0.21), sub-basin (NSE=-0.31), grid (NSE=-0.80). This result indicates that the LVRSE is more applicable to small basins of more than about 500 km2, and not applicable to the sub-basins and grids of less than 500 km2. These findings can provide reference for the popularization and application of the LVRSE.

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    Green GDPAccounting Research Based on Emergy Analysis Method: A Case Study of Shangluo City in Shaanxi Province
    A Case Study of Shangluo City in Shaanxi Province
    2015, 30 (9):  1523-1533.  doi: 10.11849/zrzyxb.2015.09.009
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    In recent years, the rising environmental loading ratio indicates an increasing pressure of economic activities on the environment, and the economic development achieved at the cost of over-exploitation of resources and environment deterioration. The development of regional economy is becoming a sharp contradiction with ecological environment and resources conservation. In some regions, economic issues and environmental problems have become major social focus. We have been using GDP to measure the level of economic development for a long time. However, economic growth cannot be achieved without the consumption of resources and environment. It is necessary to explore a method that can correctly measure the relationship between the economic development (including the quality and quantity of economic development) and the resource and environment consumption. This will make a great contribution to the protection of resources and environment. Currently, there are lots of researches of Green GDP, and some countries have gradually built up resource checking account, but the accounting methods of Green GDP are not uniform, and the accounting system has some defects. This paper provides an integrated study on the Green GDP account for Shangluo City in Shaanxi Province from 2003 to 2012 based on Emergy Synthesis Theory. An emergy-based multiple spatial scale analysis framework and a rigorous accounting method that can quantify the values of human-made and natural capital losses were proposed in this study. The advantage of Emergy Theory Method is that it has unified dimension measuring unit for natural and environmental resource, and there are more index range can be selected to expand. The green GDP accounting tends to be more accurate, more reasonable and scientific. According to Odum’s emergy theory and method of economic system, we conduct a research on quantitative Green GDP accounting for Shangluo City from 2003 to 2012. We find: 1) The GDP values of Shangluo from 2003 to 2012 are between 1.12×109 and 6.72×109 $; the green GDP in the same years are in the range of 9.80×108-3.35×109 $; and green GDP/GDP (%) are at 49.85%-87.50%. 2) From 2003 to 2012, along with the development of economy in Shangluo City, the consumption of natural resources and environment resources increased quickly, resulting the green GDP varied greatly from 2003 to 2012. The annual consumption of environmental resources accounted for 5.18%-24.39% of GDP, and the effect of the environmental resources value loss is greater than that of the loss of natural resource on the green GDP accounting in 2008 and 2009, while it is on the contrary in the rest of the years. 3) Input resources, include petrol, diesel oil, chemical fertilizer, pesticide etc, have little effect on the green GDP accounting, accounting 0.83%-1.30% of GDP every year. In short, because of the excessive dependence on resources and the environment, the economic development model of Shangluo is not sustainable, which will get the local economy into a vicious spiral. In addition, green GDP accounting based on Emergy Theory shows great advantage, and regional transmission of various ecological flows is one of the biggest challenges in further studying.

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    Study on Spatial Structure and Form of Rural Residential Based on Fractal Theory: A Case Study on Pinggu District in Beijing
    ZHUANG Zhi-feng, JIANG Guang-hui, HE Xin, QU Yan-bo, ZHANG Cui-yu
    2015, 30 (9):  1534-1546.  doi: 10.11849/zrzyxb.2015.09.010
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    Based on the fractal theory, this paper measured and analyzed the change of spatial structure and spatial form of rural residential lands in Pinggu District of Beijing from 2004 to 2012, and put forward countermeasures for optimizing the spatial structure and increasing the stability of its spatial from. Results showed that spatial structure and form of rural residential lands in Pinggu District took on fractal characteristics. On regional scale, the aggregation dimension and correlation dimension decreases as the time went on, and the form dimension continues to increase. And the spatial structure of rural settlement in Pinggu District conforms to the agglomeration development theory, while the spatial form became increasingly complex. So we need to strengthen the construction of transportation infrastructure, enhance the correlation degree of each element of the rural residential land system, so as to promote the spatial structure optimization. Also, the rural land use should be planned scientifically to reduce the randomness of spatial development of land use and realize the sustainable development of rural residential land in Pinggu District. This study can provide an academic basis for the layout adjustment and consolidation of rural residential land in practice.

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    Spatio-temporal Variation Characteristics of Spring and Summer Meteorological Drought and Its Relationship with Circulation Factors in Hedong Maize Planting Areas of Gansu Province
    JI Ding-min, ZHANG Bo, WANG Dong, MA Qiong, ZHANG Yao-zong, ZHAO Yi-fei, Yousif Elnour Yagoub
    2015, 30 (9):  1547-1559.  doi: 10.11849/zrzyxb.2015.09.011
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    Crop growth in Hedong rain fed agricultural region of Gansu Province mainly rely on the natural rain. Spring and summer drought is the main factor affecting the growth of maize. The monthly meteorological data of 13 meteorological stations in Hedong region from 1957 to 2012 were acquired. To investigate the temporal and spatial distribution of spring and summer drought in Hedong maize planting areas, we used SPEI index to reveal the trend, cycle, spatial change of drought and its relation with circulation in recent 56 years. The results show that: Both the spring and summer season in Hedong maize planting areas become dryer in recent 56 years, and the situation was aggravating since the mid 1990s. The variation of drought underwent three phases. Both the spring and summer season were slightly arid before the 1980s. Summer droughts were more severe than spring drought from 1980s to 1990s. After 2000s, spring droughts were more severe than summer drought. The drought cycles of spring and summer are 20 years and 14 years respectively. The periodicities of drought were mainly affected by the sunspot. There was a significant difference in the spatial distribution of drought frequencies before and after SPEI mutation. Low drought frequency area transformed into high frequency area after the abrupt change of SPEI, and the draught prone areas expanded. The main circulation factor influencing spring and summer drought in this area was ENSO events, especially on summer drought. The significant increase of ENSO events were the main reason of more serious drought in Hedong region in recent 20 years. When ENSO warm events occur, it tends to be drought in spring and summer in this area; when ENSO cold events occur, it turns from dry to wet in spring and summer in this area.

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    Study on the Near SurfaceWind Shear Characteristics in Liaoning Province
    GONG Qiang, WANG Hong-yu, ZHU Ling, LIN Na, GU Zheng-qiang, CHAO Hua, XU Hong
    2015, 30 (9):  1560-1569.  doi: 10.11849/zrzyxb.2015.09.012
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    The near surface wind shear characteristics were analyzed using 10 m to 70 m (100 m) hourly gradient wind observation data of 26 wind towers from June 2009 to May 2010. The results are as follows. The variation of wind speed with height accords with exponential function. The yearly wind shear indices at different wind tower vary remarkably from 0.0244 to 0.4050, with no obvious spatial characteristics, which is affected by local terrain and physiognomy. The wind shear indexes at 11 wind towers are more than 0.15 (standard B,came from GB 50009-2012) and 0.143(reference value came from GB/T 18710-2002). The spatial average yearly wind shear index of 26 wind towers is 0.1551, which is also a little more than standard B and 0.143 (reference value came from GB/T 18710-2002). So it needs to pay attention when quoting the reference values directly in the wind engineering if there is no local observation. The obvious daily variations of wind shear index show that large wind shear index occurs before sunrise and after sunset, and it gradually drops with the increase of near surface temperature. The wind shear index is the lowest in spring comparing with other seasons. The wind shear index under neutral atmospheric condition approaches to the yearly average wind shear index, and it is higher under stable condition and lower under unstable condition. The average wind shear index decreases with the increase of wind speed, which is lower than the yearly average wind shear index under strong wind condition. For a great number of wind towers, the wind shear index is less than 0.1 when wind speed is more than ≥15 m/s.

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    Study on the “Four-water” Transformation on North Shore of Middle Reaches of the Huaihe River
    LIU Jin, LI Hui, FANG Tao, SUN Qing-yan
    2015, 30 (9):  1570-1581.  doi: 10.11849/zrzyxb.2015.09.013
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    In view of the strong impact of human activities on the regional water cycle in recent years, the transformation among four types of water needs to be well studied. A typical area on the north shore of middle reaches of the Huaihe River was selected as the study region, and a distributed hydrological model was used to study the quantitative relationship of the four types of water in this region. Results show that the water cycle in the study area is influenced by human activities intensely and presents characteristics of duality of nature and society, which finally affect the transformation among the four types of water. In 2003-2010, the surface water, the soil water and the groundwater in the study area had net replenishments, which increased the available amount of local water resources. The study region needs water supplement from area outside to support the annual average rainfall of 3977 million m3 in the study period. Finally, on the basis of quantitative analysis, several suggestions about the management and utilization of the local water resources are given. The study on the relationship of the region “four-water” transformation can provide basic technical supports for the local water resources evaluation, planning and management.

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    Study on the Performance ofWater Users Association and Its Influencing Factors: An Empirical Study of 3949 WUAs in Jiangxi Province
    ZHOU Li-ping, WENG Zhen-lin, DENG Qun-zhao
    2015, 30 (9):  1582-1593.  doi: 10.11849/zrzyxb.2015.09.014
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    In recent years, the number of water users association (WUA) showed explosive growth, but research on its operational performance and its influencing factors are not comprehensive and in-depth. Using data of 3949 WUAs in 11 cities of Jiangxi Province, this paper empirically studied the operational performance of WUAs and their affecting factors. Studies have shown that registration, the number of participated farmers, the boundaries of organization, the way the leaders are generated, the ownership certificates of the irrigation project, the condition of irrigation facilities, and the scale of the irrigation district all have significant positive impact on the performance of WUAs. But rented or borrowed office space, the number of WUA staff, the origin of WUA, and the status of the principal leaders of WUA have significant negative impact. To run the WUA well, the government should pay attention to the registration of WUA, improve the way of generating main leaders of the association, control the scale of WUA staff, and reform the property rights of small irrigation facilities.

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    Comprehensive Discussion
    Advances in the Research on Methane Emissions of Coastal Saline Wetlands in China
    XU Xin-wanghao, ZHAO Yi-fei, ZOU Xin-qing, TANG De-hao, LIU Da-wei
    2015, 30 (9):  1594-1605.  doi: 10.11849/zrzyxb.2015.09.015
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    Methane is mainly produced by methanogenesis under anaerobic conditions, oxidized by methanotrophic bacteria under aerobic environment, and transported to atmosphere by diffusion, ebullition and aerenchyma of plants. Coastal saline wetlands store large proportion of carbon compared to the other ecosystems, and become a significant source of atmosphere CH4 due to the anaerobic environment. Coastal wetlands are characterized by high temporal and spatial variations of methane emission due to topographic feature, vegetation cover and astronomic tidal fluctuation, resulting in the difficulty in the field sampling of greenhouse gas, especially methane flux which is sensitive to global climate change. Consequently, it’s urgent to comprehensively investigate and review the methane emission in the coastal wetlands in order to accurately evaluate the contribution of coastal wetlands to global warming. The mechanism, spatial-temporal variations and controlling environment factors of CH4 emissions were summarized in this paper. We may safely draw the conclusion that the mean CH4 emissions from Minjiang River estuary were higher than those from Yangtze River estuary and Jiangsu coastal saline wetland. The average CH4 fluxes in spring, summer, autumn and winter were -0.0109, -0.0174, -0.0141 and -0.0089 mg CH4?m-2?h-1, indicating that the coastal marsh in Yellow River estuary acted as CH4 sink. In addition, significant differences existed among different tidal flats in Mangrove in South China. The effect of tidal fluctuation on CH4 emission presented to be a trend of “M”. When the tide rises, the CH4 fluxes firstly increase, and then begin to decrease with the increasing of tidal water. Later when the tide ebbs, the CH4 emit to the atmosphere obviously increase due to high abundant of produced CH4 in the spring tide. When the tide falls below the surface soil, CH4 is easily oxidized and so its flux decreased. However, there existed some problems we need to solve: 1) lacking of the standard system of the research method; 2) lacking of the research on the effect of microorganism and microbial enzymes on the CH4 emission; 3) strengthening the studies of effects of flood and ebb on the CH4 emission. Finally, we proposed the principles and methods of sampling when chamber was used to collect the gas sampling, which uses different sampling frequency, and samples at different site layouts according to the research objects and the variations of vegetation, soil, and hydrology in the coastal wetlands.

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