Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sin...Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tree layer. Our results demonstrate that these forested wetlands were generally carbon sinks in the Xiaoxing’anling, and there was obvious spatial variation in carbon storage of ecosystems along the moisture gradient.展开更多
Combined with anti-waterlogging ditches, irrigation with treated paper mill effluent （TPME） and plowing were applied in this study to investigate the effects of remediation of degraded coastal sa- line-alkaline wetl...Combined with anti-waterlogging ditches, irrigation with treated paper mill effluent （TPME） and plowing were applied in this study to investigate the effects of remediation of degraded coastal sa- line-alkaline wetlands. Three treatments were employed, viz., control （CK）, irrigated with 10 cm depth of TPME （I）, and plowing to 20 cm deep before irrigating 10 cm depth ofTPME （IP）. Results show that both I-treatment and IP-treatment could improve soil structure by decreasing bulk density by 5% and 8%. Irrigation with TPME containing low salinity stimulated salts leaching instead of accumulating. With anti-waterlogging ditches, salts were drained out of soil. Irrigation with 10 cm depth of TPME lowered total soluble salts in soil and sodium adsorption ration by 33% and 8%, respective!y, but there was no significant difference compared with CK, indicating that this irrigation rate was not heavy enough to remarkably reduce so!l salinity and sodicity, Thus, in-i： gation rate should be enhanced in order to reach better effects of desalinization and desodication. Irrigation with TPME significantly increased soil organic matter, alkali-hydrolyzable nitrogen and available phosphorus due to the abundant organic matter in TPME. Plowing increased soil air circulation, so as to enhance mineralization of organic matter and lead to the loss of organic matter; however, plowing significantly improvedsoil alkali-hydrolyzable nitrogen and available phosphorus. Improvements of physicochemical properties in I-treatment and IP-treatment both boosted soil microbial population and activity. Microbial biomass carbon increased significantly by 327% （I-treatment） and 451% （IP-treatment）, while soil respiration increased significantly by 316% （I-treatment） and 386% （IP-treatment）. Urease and dehydrogenase activities in both I-treatment and IP-treatment were significantly higher than that in CK. Phosphatase in IP-treatment was significantly higher than that in CK. Compared to I-treatment, IP-treatment improved all of the soil properties except for soil organic matter. The key to remediation of degraded sa- line-alkaline wetlands is to decrease soil salinity and sodicity; thus, irri- gation plus plowing could be an ideal method of soil remediation.展开更多
This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate.Microbial carbon metabolism diversity was assessed using community-le...This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate.Microbial carbon metabolism diversity was assessed using community-level physiological profiles(CLPP)with 31 different carbon substrates.CLPP indicated that significant interactions occur during carbon substrate metabolism of the microorganisms.Furthermore,the different types of vegetation present in the wetland ecosystem combined with the seasonal effects to influence microbial carbon metabolism and enzymatic activity.The most significant differences occurred to carbohydrates,carboxylic acids,and amino acids.The Mantel test confirmed positive correlations between soil enzymatic activities and microbial carbon metabolism.Soil microorganisms in Betula ovalifolia and Carex schmidtii wetlands used carbon substrates more efficiently in summer than those in other forested wetlands during other periods.Enzymatic activities also showed a similar trend as microbial carbon metabolism.The results demonstrate that microbial carbon metabolism patterns can be used as biological indicators in wetland ecological alterations due to vegetation type or to seasonal factors.展开更多
We investigated the spatial distribution （horizontal and vertical concentrations） of copper （Cu）, lead （Pb）, zinc （Zn）, and cadmium （Cd） in five wetland types （mudflat, aquaculture wetland, water area, farm...We investigated the spatial distribution （horizontal and vertical concentrations） of copper （Cu）, lead （Pb）, zinc （Zn）, and cadmium （Cd） in five wetland types （mudflat, aquaculture wetland, water area, farmland wetland and mangrove） from three areas （Ningde, Fuding, and Xiapu）, China. Cu concentrations in five wetland types descended in the order： farm wetland, mudflat, aquaculture, water area and mangrove. Pb concentrations decreased in the order： aquaculture, mangrove, farm wetland, mudflat, and water area. Zn content decreased in the order： farm wetland, water area, aquaculture, mudflat and mangrove, and Cd content decreased as follows： mangrove, aquacul- ture, water area, rnudflat, and farm wetland. Comparison of the concentrations of the same heavy metals in different areas showed that the highest Cu （63.75 mg kg-1） and Zn （152.32mgkg-1） concentrations occurred in Ningdecoastal wetlands; Pb （110.58 mg kg-1） and Cd （2.81 mg kg-1） contents were highest in Fuding wetlands, and the average contents of all heavy metals were very low in Xiapu wetlands. Examination of the vertical distribution showed that the Cu content was high in all mudflat layers; Pb and Cd concentrations were highest in aquaculture and mangrove wetlands, respectively, and Zn content was highest in farm wetlands. The spatial distribution of Cu and Zn contents for different areas decreased as follows： Ningde 〉 Fuding 〉 Xiapu, for Pb and Cd were most concentrated in Fuding coastal wetlands. Concentrations of Zn and Cu were highly correlated, while Zn and Cu were not significantly correlated with Pb.展开更多
This paper introduces the state of waterlands in China and discribes the applications of Remote Sensing （RS）, Geographical Information System （G1S） and Global Positioning System （GPS） in wetland research, includ...This paper introduces the state of waterlands in China and discribes the applications of Remote Sensing （RS）, Geographical Information System （G1S） and Global Positioning System （GPS） in wetland research, including land-coverclassification and change detection, wetland evolutionary processes, landscape-change analyses, channel migration, flood and wetlands resource monitoring and spatial quantitative analyses/modeling, ecosystem service evaluation, ecological processes and risk assessments, disease control, water quality monitoring/modeling, pollution monitoring/modeling, wetlands hydrology, wetland information systems and WebGIS. The limitations and needs for optimal use of these technologies are discussed, such as the limited advanced technical knowledge and skills, low awareness and capacity, unclear link between GIS output and policy making, lack of supporting policies and standards, lack of a wetlands geo-information networklimite, and the use of these techniques in wetland research. It is suggested that for realising true applications of RS, GIS and GPS technologies, the availability, accessibility, reliability, homogeneity, and continuity of wetlands-related geo-information enabling environment, policies and standards, and funding are needed.展开更多
This review describes the characteristics and hot spots of wetland research, including biodiversity protection of wetland, management and restoration of wetland, function and process of wetland, and the theories, meth...This review describes the characteristics and hot spots of wetland research, including biodiversity protection of wetland, management and restoration of wetland, function and process of wetland, and the theories, methods and scales of landscape ecology. Moreover, some deficits of landscape ecology theory and method were discussed, and the application of landscape ecology to research on wetlands was reviewed specially, involving in the application of landscape structure principle, landscape pattern, and scale and hierarchy theory. In conclusion, landscape ecology plays an enlightening and guiding function on the comprehensive research of wetlands at multi-scales.展开更多
We selected four kinds of land use types from Caohai wetlands of Guizhou plateau（a total number of 32 soil profiles） to study the distribution characteristics of organic carbon content in soil. With different ways o...We selected four kinds of land use types from Caohai wetlands of Guizhou plateau（a total number of 32 soil profiles） to study the distribution characteristics of organic carbon content in soil. With different ways of land use, the organic carbon content of soil profiles and organic carbon density show the tendency of decreasing firstly and then increasing from top to bottom. With the increase of depth, the vertical difference becomes smaller first and then starts increasing. Land reclamation reduces the soil organic carbon content and density, changing its distribution structure in topsoil. The average content of organic carbon in Caohai wetlands are as follows： lake bed silt [ marsh wetland [ farmland [ woodland, the average organic carbon content of lake bed silt, marsh wetland,farmland and woodland are 16.40, 2.94, 1.81 and 1.08 %,respectively. Land reclamation reduces the organic carbon content of soil, therefore the conversion of cultivated lands to wetlands and the increase of forest coverage will help to fix the organic carbon in soil and increase its reserves.展开更多
Human communities from the Okavango Delta benefit from the services and goods provided by the wetland ecosystem through its riparian vegetation. These include food and timber products used for the construction of shel...Human communities from the Okavango Delta benefit from the services and goods provided by the wetland ecosystem through its riparian vegetation. These include food and timber products used for the construction of shelter and canoes. Despite the importance of riparian tree species in the Delta, their regeneration structure is currently unknown. For riparian trees to be managed sustainably, information on the current regeneration status of the trees under different land uses is needed. The Moremi game reserve (protected area) and Seronga (communal area) were selected for this study on the regeneration of riparian tree species of Croton megalobotrys Müll. Arg, Philenoptera violacea (Klotzsch) Schrire, Senegalia nigrescens (Acacia nigrescens) Oliv and Diospyros mespiliformis Hochst. ex A. Dc. The height of each individual tree was estimated in randomly selected 30 plots (15 from each site) of 20 × 50 m for assignment to five regeneration classes: 0-0.5, 0.5-1, 1-2, 2-4 and >4 m. Linear regression was used to infer regeneration status of each species. An independent-sample Student’s t test was used to determine any significance differences in seedling density/ha and sapling density/ha between different sites at p < 0.05. Diospyros mespiliformis populations had an unstable regeneration structure in both sites, while P. violacea regeneration was stable regardless of land-use type. Croton megalobotrys and S. nigrescens had an unstable regeneration pattern in Seronga, while in Moremi it was stable; thus, the regeneration structure of C. megalobotrys and S. nigrescens is affected by land-use. This result implies that intervention is needed to conserve the two species in Seronga where the current land-use appears to be incompatible with regeneration; D. mespiliformis also needs to be conserved in both Moremi and Seronga.展开更多
The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. Th...The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.展开更多
This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to ...This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 mu g kg(-1), with the mean value of 284.61 mu g kg(-1). PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland (PAW, 419.87 +/- 73.61 mu g kg(-1)) > Carex lasiocarpa wetland (CLW, 304.18 +/- 56.47 mu g kg(-1)) > Deyeuxia angustifolia wetland (DAW, 129.78 +/- 18.24 mu g kg(-1)). Dimethyl phthalate (DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate (DEHP) were found in all sediments, DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 mu g kg(-1). DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also suggests that contamination in natural ecosystems should not be overlooked.展开更多
The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exi...The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exist on the Sanjiang Plain, and three of them have been listed as wetlands of international importance to water bird conservation by the Ramsar Convention Bureau. The wetlands of Sanjiang Plain are noteworthy for its rich biodiversity, but they continue to decline in area and deteriorate in quality currently. The main threats or constrains, immediate cause, root cause and required response are analyzed in this paper, and the four aspects opinion such as improvement of watershed management, enhancement of protection and restoration of habitats and biodiversity, alternative livelihoods of rural residents living in and near natural wetland reserve, and reinforcement of capacity building of natural reserves are brought forward as the effective measures for the Sanjiang Plain wetland protection.展开更多
Wetland is a new type of sedimentary facies proposed for the first time in this paper. It is a type of sedimentary environment, transitional between land facies and water (sea or lake) facies. In this paper, wetland i...Wetland is a new type of sedimentary facies proposed for the first time in this paper. It is a type of sedimentary environment, transitional between land facies and water (sea or lake) facies. In this paper, wetland is redefined as “a type of sedimentary environments whose ground surface is flat and wet throughout the year, which may be covered with very shallow water (less than 2 m deep), and is covered with lush plant growth”. Wetland is reclassified into two types, swamp wetland (swamp in brief) and wet plain wetland (wet plain in brief). Swamp deposits are coal, while wet plain deposits are dark colored mudstones or silty mudstones rich in plant fossils and carbon debris. The deposits of wet plain are different from those of lake and floodplain in the abundance of plant fossils, color, resistivity well logging curve, and other sedimentary characteristics. In boreholes, resistivity logging can be used to distinguish between wet plain mudstones and lake mudstones. Understanding the sedimentary characteristics of wet plain wetland can help to identify wet plain deposits which were formerly classified as floodplain or lake deposits. This will help to reconstruct the palaeogeography and to understand the history of basin and climate evolution accurately, and is especially important in evaluation of the hydrocarbon generating potential of a basin. With the Jurassic Sangonghe Formation of the Yanqi Basin as an example, the identification characteristics of wetland are described.展开更多
Yellow River delta （YRD） is one of the biggest deltas that there is a large area of wetland in the world. Thanks to soil （sands） sediment carried by the Yellow River, there was averagely the newly formed land 21.3...Yellow River delta （YRD） is one of the biggest deltas that there is a large area of wetland in the world. Thanks to soil （sands） sediment carried by the Yellow River, there was averagely the newly formed land 21.3 km^2 in YRD. During the development of petroleum industry and urban expansion, wetlands were degraded due to population growth, irrational land use, in addition to adverse natural eco-environment such as lower precipitation, higher soil evaporation and soil salinazation. The major ecological measures to restore degraded wetland concerned with ensuring water supply, especially establishing perfect irrigation works; protecting virgin plant communities and assisting them to regenerate by the way of site preparation, improving living surroundings; introducing salt-tolerant plants to increase vegetation species and plant coverage, thereby enhancing the capability of wetland to combat contamination and pollution through plant remediation, uptake, absorption, etc. Finally making a comprehensive land use plan, accordingly removing deleterious facilities.展开更多
Plant communities on sandbars were important, and restoration of degraded wetland were significant to biological conservation in the East Dongting Lake region. In this study, typical wetland community types on sandbar...Plant communities on sandbars were important, and restoration of degraded wetland were significant to biological conservation in the East Dongting Lake region. In this study, typical wetland community types on sandbars and their site elevation were surveyed to explore relationship between community distribution and site elevation. Results show that eight major communities in this region were wetland communities dominated by Juncus effusus, Carex brevicuspis, Polygonum hydropiper, Salix triandra, Oenanthe Javanica, Phalaris arundinacea, Miscanthus sacchariflorus and Phragmites communis respectively. These communities had obvious constructive species and companion species, while site elevation could affect community composition and their species diversity. On sandbars in the East Dongting Lake, vegetation was largely composed of hygrophytes companied with a few mesophytes. The higher the site elevation was, the nearer the site was to the water, and the lower community diversity became. Except soil humidity and site elevation, growth period of plants after inundation could also affect species richness in the communities.展开更多
Wetland restoration had been implemented for more than two decades in Sanjiang Plain,Northeast China.To assess the restoration effi ciency of wetland vegetation,we investigated plants composition of community,plant sp...Wetland restoration had been implemented for more than two decades in Sanjiang Plain,Northeast China.To assess the restoration effi ciency of wetland vegetation,we investigated plants composition of community,plant species diversity and aboveground biomass of restored sites in a chronosequence of restoration(1,2,3,6,8,11,15 and 25 years)in the Sanjiang Nature Reserve.As comparison,we also investigated the same factors in a cropland and a natural marsh adjacent to the restored sites.The results showed that wetland plant species can invade quickly after croplands were abandoned when there were suitable hydrology conditions.On the early stage of the restoration,weeds were main plant species in the restored sites.Wetland species appeared at the same time but diff ered from the dominant species from the adjacent natural marshes.Common native wetland species could dominance the community after 3-year restoration.Species richness and diversity increased on the early stage,and then decreased to the similar level of the natural marsh with the extension of restoration.Plant biomass could restore easier than the species composition and diversity.Our results indicated that plant species composition and diversity of abandoned reclaimed wetlands can restore gradually by natural succession in Sanjiang Plain.However,25-year restoration site had similarity index of only 56%with the natural marsh,which revealed that two decades are not enough for complete restoration of vegetation.展开更多
Experiments in monitoring the removal of organic material and nitrogen and determining the amounts of mi- croorganism at different sites in the subsurface flow constructed wetland in Sihong county were performed. The ...Experiments in monitoring the removal of organic material and nitrogen and determining the amounts of mi- croorganism at different sites in the subsurface flow constructed wetland in Sihong county were performed. The results show that the removal of CODCr agrees with the kinetic equation of a first order reaction. The removal of pollutants varies with different seasons. The removal rates of CODCr, NH3-N, TN in the spring are 15%–23% higher than those in the autumn. The amount of ammonifier is larger than that of denitrifying bacteria and the amount of denitrifying bacte- ria is larger than that of nitrosomonas. The amount of bacteria around the plant roots is larger than that on the surface of the packing medium. No apparent change is observed for the amount of denitrifying bacteria and nitrosomonas between spring and autumn.展开更多
On the earth surface,there is a me-dium latitudinal zone in which the evapo-ration per year is greater than the precipita-tion per year.in China,the northern tem-perate belt and cold temperate belt arc lo-cated in the...On the earth surface,there is a me-dium latitudinal zone in which the evapo-ration per year is greater than the precipita-tion per year.in China,the northern tem-perate belt and cold temperate belt arc lo-cated in the latitudal zone,the northcrnChina and northeast China are all展开更多
There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnusjaponica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, J...There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnusjaponica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, Japan. To clarify maintenance mechanisms, we studied the forest profile, water level, groundwater and precipitation chemistry, seedling establishment patterns in relation to microhabitats, and seed migration. The profile of groundwater level insufficiently explained the abrupt boundary formation, while the groundwater chemistry differed significantly between the two forests ; i.e., EC, Na^＋, K^＋, Mg^2＋, Ca^2＋ and Cl^- were higher in P. glehnii forest and pH was lower. Precipitation in P. glehnii forest contained richer Na＋, Ca^2＋ and Cl^-, indicating that the differences in surface-water chemistry were mostly derived from precipitation. Solar radiation was less than 2.2 MJ.m^-2.d^-1 on P. glehnii forest in late June, while that was patchily distributed in A.japonica forest with a range from 1.0 to 3.7 MJ＇m^-2＇d^-1. Moss cover on the soil surface, most of which were made of Sphagnum spp., was 60% in P. glehnii forest, but was 10% in A. japonica forest. Surface water chemistry represented by pH was considered to determine the development of Sphagnum moss. About 70% of P. glehnii seedlings 〈 1.3 m in height established on moss cover. Seed-sowing experiments suggested that seed germination and seedling survival for both species were significantly higher in P. glehnii forest. Therefore, the regeneration of P. glehnii in A. japonica forest was negligible, owing to the paucity of favorable microhabitats and low seedling establishment. A. japonica regenerated only by resprouting, and the seedlings were few in both forests. In addition, A. japonica seed migration into the P. glehnii forests was greatly restricted, and low solar radiation in the P. glehnii forest contributed to low seedling survival. Based on those results, we concluded that Picea glehnii and Alnusjaponica could develop distinct and selfish environments being unsuitable for the other species and inhibit natural afforestation of another species each other by excluding invasion.展开更多
基金This project was supported fi nancially by the National Key Research and Development Program of China(2016YFA0600803)the National Natural Science Foundation of China(31370461).
文摘Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tree layer. Our results demonstrate that these forested wetlands were generally carbon sinks in the Xiaoxing’anling, and there was obvious spatial variation in carbon storage of ecosystems along the moisture gradient.
基金financially supported by the National Science & Technology supporting Program of China (NO. 2010BAC68B01 NO. 2011BAC02B01)+1 种基金the Science and Technology Planning Program of Shandong Province (NO. 2008GG10006024 NO. 2008GG3NS07005)
文摘Combined with anti-waterlogging ditches, irrigation with treated paper mill effluent （TPME） and plowing were applied in this study to investigate the effects of remediation of degraded coastal sa- line-alkaline wetlands. Three treatments were employed, viz., control （CK）, irrigated with 10 cm depth of TPME （I）, and plowing to 20 cm deep before irrigating 10 cm depth ofTPME （IP）. Results show that both I-treatment and IP-treatment could improve soil structure by decreasing bulk density by 5% and 8%. Irrigation with TPME containing low salinity stimulated salts leaching instead of accumulating. With anti-waterlogging ditches, salts were drained out of soil. Irrigation with 10 cm depth of TPME lowered total soluble salts in soil and sodium adsorption ration by 33% and 8%, respective!y, but there was no significant difference compared with CK, indicating that this irrigation rate was not heavy enough to remarkably reduce so!l salinity and sodicity, Thus, in-i： gation rate should be enhanced in order to reach better effects of desalinization and desodication. Irrigation with TPME significantly increased soil organic matter, alkali-hydrolyzable nitrogen and available phosphorus due to the abundant organic matter in TPME. Plowing increased soil air circulation, so as to enhance mineralization of organic matter and lead to the loss of organic matter; however, plowing significantly improvedsoil alkali-hydrolyzable nitrogen and available phosphorus. Improvements of physicochemical properties in I-treatment and IP-treatment both boosted soil microbial population and activity. Microbial biomass carbon increased significantly by 327% （I-treatment） and 451% （IP-treatment）, while soil respiration increased significantly by 316% （I-treatment） and 386% （IP-treatment）. Urease and dehydrogenase activities in both I-treatment and IP-treatment were significantly higher than that in CK. Phosphatase in IP-treatment was significantly higher than that in CK. Compared to I-treatment, IP-treatment improved all of the soil properties except for soil organic matter. The key to remediation of degraded sa- line-alkaline wetlands is to decrease soil salinity and sodicity; thus, irri- gation plus plowing could be an ideal method of soil remediation.
基金The work was supported by the National Natural Science Foundation of China(No.31500508)the Fundamental Research Funds for the Central Universities(No.2572020BD02)Natural Science Foundation of Heilongjiang Province(No.LH2020C041).
文摘This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate.Microbial carbon metabolism diversity was assessed using community-level physiological profiles(CLPP)with 31 different carbon substrates.CLPP indicated that significant interactions occur during carbon substrate metabolism of the microorganisms.Furthermore,the different types of vegetation present in the wetland ecosystem combined with the seasonal effects to influence microbial carbon metabolism and enzymatic activity.The most significant differences occurred to carbohydrates,carboxylic acids,and amino acids.The Mantel test confirmed positive correlations between soil enzymatic activities and microbial carbon metabolism.Soil microorganisms in Betula ovalifolia and Carex schmidtii wetlands used carbon substrates more efficiently in summer than those in other forested wetlands during other periods.Enzymatic activities also showed a similar trend as microbial carbon metabolism.The results demonstrate that microbial carbon metabolism patterns can be used as biological indicators in wetland ecological alterations due to vegetation type or to seasonal factors.
基金supported by the National Natural Science Foundation of China(Grant No.31370624)Key Financing Project of Fujian Provincial Department of Science and Technology(2009N0009)
文摘We investigated the spatial distribution （horizontal and vertical concentrations） of copper （Cu）, lead （Pb）, zinc （Zn）, and cadmium （Cd） in five wetland types （mudflat, aquaculture wetland, water area, farmland wetland and mangrove） from three areas （Ningde, Fuding, and Xiapu）, China. Cu concentrations in five wetland types descended in the order： farm wetland, mudflat, aquaculture, water area and mangrove. Pb concentrations decreased in the order： aquaculture, mangrove, farm wetland, mudflat, and water area. Zn content decreased in the order： farm wetland, water area, aquaculture, mudflat and mangrove, and Cd content decreased as follows： mangrove, aquacul- ture, water area, rnudflat, and farm wetland. Comparison of the concentrations of the same heavy metals in different areas showed that the highest Cu （63.75 mg kg-1） and Zn （152.32mgkg-1） concentrations occurred in Ningdecoastal wetlands; Pb （110.58 mg kg-1） and Cd （2.81 mg kg-1） contents were highest in Fuding wetlands, and the average contents of all heavy metals were very low in Xiapu wetlands. Examination of the vertical distribution showed that the Cu content was high in all mudflat layers; Pb and Cd concentrations were highest in aquaculture and mangrove wetlands, respectively, and Zn content was highest in farm wetlands. The spatial distribution of Cu and Zn contents for different areas decreased as follows： Ningde 〉 Fuding 〉 Xiapu, for Pb and Cd were most concentrated in Fuding coastal wetlands. Concentrations of Zn and Cu were highly correlated, while Zn and Cu were not significantly correlated with Pb.
基金This project was supported by National Natural Science Foundation of China （No. 30270275） Acknowledgement We thank State Forest Administration and the Chinese Academy of Sciences with its many research institutes for providing the information required for this paper. Also, a sincere thank to Bai Yajun for her patience and endless support in discussions and email correspondence.
文摘This paper introduces the state of waterlands in China and discribes the applications of Remote Sensing （RS）, Geographical Information System （G1S） and Global Positioning System （GPS） in wetland research, including land-coverclassification and change detection, wetland evolutionary processes, landscape-change analyses, channel migration, flood and wetlands resource monitoring and spatial quantitative analyses/modeling, ecosystem service evaluation, ecological processes and risk assessments, disease control, water quality monitoring/modeling, pollution monitoring/modeling, wetlands hydrology, wetland information systems and WebGIS. The limitations and needs for optimal use of these technologies are discussed, such as the limited advanced technical knowledge and skills, low awareness and capacity, unclear link between GIS output and policy making, lack of supporting policies and standards, lack of a wetlands geo-information networklimite, and the use of these techniques in wetland research. It is suggested that for realising true applications of RS, GIS and GPS technologies, the availability, accessibility, reliability, homogeneity, and continuity of wetlands-related geo-information enabling environment, policies and standards, and funding are needed.
基金This research was supported by Major Natural Sci-ence of Fujian province (No: 2001F007)
文摘This review describes the characteristics and hot spots of wetland research, including biodiversity protection of wetland, management and restoration of wetland, function and process of wetland, and the theories, methods and scales of landscape ecology. Moreover, some deficits of landscape ecology theory and method were discussed, and the application of landscape ecology to research on wetlands was reviewed specially, involving in the application of landscape structure principle, landscape pattern, and scale and hierarchy theory. In conclusion, landscape ecology plays an enlightening and guiding function on the comprehensive research of wetlands at multi-scales.
基金supported by Project of Guizhou Special Funds for High-level Personnel (Grant Number TZJF-2011-44)Program for New Century Excellent Talents in University (NCET-12-0659)Project of Guizhou Governor Capital Fund (Guizhou province designed cooperative [2012]71)
文摘We selected four kinds of land use types from Caohai wetlands of Guizhou plateau（a total number of 32 soil profiles） to study the distribution characteristics of organic carbon content in soil. With different ways of land use, the organic carbon content of soil profiles and organic carbon density show the tendency of decreasing firstly and then increasing from top to bottom. With the increase of depth, the vertical difference becomes smaller first and then starts increasing. Land reclamation reduces the soil organic carbon content and density, changing its distribution structure in topsoil. The average content of organic carbon in Caohai wetlands are as follows： lake bed silt [ marsh wetland [ farmland [ woodland, the average organic carbon content of lake bed silt, marsh wetland,farmland and woodland are 16.40, 2.94, 1.81 and 1.08 %,respectively. Land reclamation reduces the organic carbon content of soil, therefore the conversion of cultivated lands to wetlands and the increase of forest coverage will help to fix the organic carbon in soil and increase its reserves.
基金supported by German Federal Ministry for Education and Research
文摘Human communities from the Okavango Delta benefit from the services and goods provided by the wetland ecosystem through its riparian vegetation. These include food and timber products used for the construction of shelter and canoes. Despite the importance of riparian tree species in the Delta, their regeneration structure is currently unknown. For riparian trees to be managed sustainably, information on the current regeneration status of the trees under different land uses is needed. The Moremi game reserve (protected area) and Seronga (communal area) were selected for this study on the regeneration of riparian tree species of Croton megalobotrys Müll. Arg, Philenoptera violacea (Klotzsch) Schrire, Senegalia nigrescens (Acacia nigrescens) Oliv and Diospyros mespiliformis Hochst. ex A. Dc. The height of each individual tree was estimated in randomly selected 30 plots (15 from each site) of 20 × 50 m for assignment to five regeneration classes: 0-0.5, 0.5-1, 1-2, 2-4 and >4 m. Linear regression was used to infer regeneration status of each species. An independent-sample Student’s t test was used to determine any significance differences in seedling density/ha and sapling density/ha between different sites at p < 0.05. Diospyros mespiliformis populations had an unstable regeneration structure in both sites, while P. violacea regeneration was stable regardless of land-use type. Croton megalobotrys and S. nigrescens had an unstable regeneration pattern in Seronga, while in Moremi it was stable; thus, the regeneration structure of C. megalobotrys and S. nigrescens is affected by land-use. This result implies that intervention is needed to conserve the two species in Seronga where the current land-use appears to be incompatible with regeneration; D. mespiliformis also needs to be conserved in both Moremi and Seronga.
基金the National "11th Five Year" Plan of Science and technology (2006BAD26B06,2006BAD03A1205) Ecological Restore Project of Water Resources Ministry of China (2006-2008)
文摘The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.
基金supported by the National Natural Science Foundation of China(No.31470543)
文摘This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 mu g kg(-1), with the mean value of 284.61 mu g kg(-1). PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland (PAW, 419.87 +/- 73.61 mu g kg(-1)) > Carex lasiocarpa wetland (CLW, 304.18 +/- 56.47 mu g kg(-1)) > Deyeuxia angustifolia wetland (DAW, 129.78 +/- 18.24 mu g kg(-1)). Dimethyl phthalate (DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate (DEHP) were found in all sediments, DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 mu g kg(-1). DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also suggests that contamination in natural ecosystems should not be overlooked.
文摘The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exist on the Sanjiang Plain, and three of them have been listed as wetlands of international importance to water bird conservation by the Ramsar Convention Bureau. The wetlands of Sanjiang Plain are noteworthy for its rich biodiversity, but they continue to decline in area and deteriorate in quality currently. The main threats or constrains, immediate cause, root cause and required response are analyzed in this paper, and the four aspects opinion such as improvement of watershed management, enhancement of protection and restoration of habitats and biodiversity, alternative livelihoods of rural residents living in and near natural wetland reserve, and reinforcement of capacity building of natural reserves are brought forward as the effective measures for the Sanjiang Plain wetland protection.
基金supported by the "973" National Major Fundamental Research & Development Project "Reservoir-forming mechanism and distribution law of oil and gas in superimposed basins of China" (2006C13202300)
文摘Wetland is a new type of sedimentary facies proposed for the first time in this paper. It is a type of sedimentary environment, transitional between land facies and water (sea or lake) facies. In this paper, wetland is redefined as “a type of sedimentary environments whose ground surface is flat and wet throughout the year, which may be covered with very shallow water (less than 2 m deep), and is covered with lush plant growth”. Wetland is reclassified into two types, swamp wetland (swamp in brief) and wet plain wetland (wet plain in brief). Swamp deposits are coal, while wet plain deposits are dark colored mudstones or silty mudstones rich in plant fossils and carbon debris. The deposits of wet plain are different from those of lake and floodplain in the abundance of plant fossils, color, resistivity well logging curve, and other sedimentary characteristics. In boreholes, resistivity logging can be used to distinguish between wet plain mudstones and lake mudstones. Understanding the sedimentary characteristics of wet plain wetland can help to identify wet plain deposits which were formerly classified as floodplain or lake deposits. This will help to reconstruct the palaeogeography and to understand the history of basin and climate evolution accurately, and is especially important in evaluation of the hydrocarbon generating potential of a basin. With the Jurassic Sangonghe Formation of the Yanqi Basin as an example, the identification characteristics of wetland are described.
基金Supported by the National Tenth Five-year Key Scientific & Technological Project (Grant No. 2004BA516A13)Shandong Provincial Key Scientific & Technological Project of Plant Community Restoration in Yellow River Delta Region
文摘Yellow River delta （YRD） is one of the biggest deltas that there is a large area of wetland in the world. Thanks to soil （sands） sediment carried by the Yellow River, there was averagely the newly formed land 21.3 km^2 in YRD. During the development of petroleum industry and urban expansion, wetlands were degraded due to population growth, irrational land use, in addition to adverse natural eco-environment such as lower precipitation, higher soil evaporation and soil salinazation. The major ecological measures to restore degraded wetland concerned with ensuring water supply, especially establishing perfect irrigation works; protecting virgin plant communities and assisting them to regenerate by the way of site preparation, improving living surroundings; introducing salt-tolerant plants to increase vegetation species and plant coverage, thereby enhancing the capability of wetland to combat contamination and pollution through plant remediation, uptake, absorption, etc. Finally making a comprehensive land use plan, accordingly removing deleterious facilities.
基金supported by the National Key Technology R&D Program (2006BAD03A15)
文摘Plant communities on sandbars were important, and restoration of degraded wetland were significant to biological conservation in the East Dongting Lake region. In this study, typical wetland community types on sandbars and their site elevation were surveyed to explore relationship between community distribution and site elevation. Results show that eight major communities in this region were wetland communities dominated by Juncus effusus, Carex brevicuspis, Polygonum hydropiper, Salix triandra, Oenanthe Javanica, Phalaris arundinacea, Miscanthus sacchariflorus and Phragmites communis respectively. These communities had obvious constructive species and companion species, while site elevation could affect community composition and their species diversity. On sandbars in the East Dongting Lake, vegetation was largely composed of hygrophytes companied with a few mesophytes. The higher the site elevation was, the nearer the site was to the water, and the lower community diversity became. Except soil humidity and site elevation, growth period of plants after inundation could also affect species richness in the communities.
基金the National Natural Science Foundation of China(31870443)the Fundamental Research Funds for the Central Universities(2572016CA03)the Heilongjiang Postdoctoral Funds(LBH-Z16014).
文摘Wetland restoration had been implemented for more than two decades in Sanjiang Plain,Northeast China.To assess the restoration effi ciency of wetland vegetation,we investigated plants composition of community,plant species diversity and aboveground biomass of restored sites in a chronosequence of restoration(1,2,3,6,8,11,15 and 25 years)in the Sanjiang Nature Reserve.As comparison,we also investigated the same factors in a cropland and a natural marsh adjacent to the restored sites.The results showed that wetland plant species can invade quickly after croplands were abandoned when there were suitable hydrology conditions.On the early stage of the restoration,weeds were main plant species in the restored sites.Wetland species appeared at the same time but diff ered from the dominant species from the adjacent natural marshes.Common native wetland species could dominance the community after 3-year restoration.Species richness and diversity increased on the early stage,and then decreased to the similar level of the natural marsh with the extension of restoration.Plant biomass could restore easier than the species composition and diversity.Our results indicated that plant species composition and diversity of abandoned reclaimed wetlands can restore gradually by natural succession in Sanjiang Plain.However,25-year restoration site had similarity index of only 56%with the natural marsh,which revealed that two decades are not enough for complete restoration of vegetation.
文摘Experiments in monitoring the removal of organic material and nitrogen and determining the amounts of mi- croorganism at different sites in the subsurface flow constructed wetland in Sihong county were performed. The results show that the removal of CODCr agrees with the kinetic equation of a first order reaction. The removal of pollutants varies with different seasons. The removal rates of CODCr, NH3-N, TN in the spring are 15%–23% higher than those in the autumn. The amount of ammonifier is larger than that of denitrifying bacteria and the amount of denitrifying bacte- ria is larger than that of nitrosomonas. The amount of bacteria around the plant roots is larger than that on the surface of the packing medium. No apparent change is observed for the amount of denitrifying bacteria and nitrosomonas between spring and autumn.
文摘On the earth surface,there is a me-dium latitudinal zone in which the evapo-ration per year is greater than the precipita-tion per year.in China,the northern tem-perate belt and cold temperate belt arc lo-cated in the latitudal zone,the northcrnChina and northeast China are all
文摘There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnusjaponica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, Japan. To clarify maintenance mechanisms, we studied the forest profile, water level, groundwater and precipitation chemistry, seedling establishment patterns in relation to microhabitats, and seed migration. The profile of groundwater level insufficiently explained the abrupt boundary formation, while the groundwater chemistry differed significantly between the two forests ; i.e., EC, Na^＋, K^＋, Mg^2＋, Ca^2＋ and Cl^- were higher in P. glehnii forest and pH was lower. Precipitation in P. glehnii forest contained richer Na＋, Ca^2＋ and Cl^-, indicating that the differences in surface-water chemistry were mostly derived from precipitation. Solar radiation was less than 2.2 MJ.m^-2.d^-1 on P. glehnii forest in late June, while that was patchily distributed in A.japonica forest with a range from 1.0 to 3.7 MJ＇m^-2＇d^-1. Moss cover on the soil surface, most of which were made of Sphagnum spp., was 60% in P. glehnii forest, but was 10% in A. japonica forest. Surface water chemistry represented by pH was considered to determine the development of Sphagnum moss. About 70% of P. glehnii seedlings 〈 1.3 m in height established on moss cover. Seed-sowing experiments suggested that seed germination and seedling survival for both species were significantly higher in P. glehnii forest. Therefore, the regeneration of P. glehnii in A. japonica forest was negligible, owing to the paucity of favorable microhabitats and low seedling establishment. A. japonica regenerated only by resprouting, and the seedlings were few in both forests. In addition, A. japonica seed migration into the P. glehnii forests was greatly restricted, and low solar radiation in the P. glehnii forest contributed to low seedling survival. Based on those results, we concluded that Picea glehnii and Alnusjaponica could develop distinct and selfish environments being unsuitable for the other species and inhibit natural afforestation of another species each other by excluding invasion.
