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Soil pore water salinity is widely accepted to be the primary influencing factor determining coastal vegetation succession. This study investigated an ecological wetland restoration process on the Nanhui coast, Shanghai, during which seasonal changes in vegetation density, soil salinity, and coastal elevation were recorded in detail. These variables interacted with each other and showed coincident distributions. The whole restoration process was categorized into four periods according to vegetation community dynamics. Regression analysis revealed that elevation, not soil pore water salinity, was the most critical factor influencing the spatial pattern of vegetation survival, expansion, and extinction on the Nanhui coast. From a long-term perspective, the local vegetation extinction pattern may have an irreparable influence on salt marsh succession, especially in environments with intricate hydrological and sedimentary conditions such as the Nanhui coastline. Without intact vegetation communities, deficiencies in coastal ecosystem resilience may cause vegetation extinction under the influence of a strong hydrological environment. The area between vegetation communities and bare tidal flats, the “vulnerable zone”, was a critical area determining the ultimate success of coastal vegetation restoration.

Watershed and catchment area-based water quality management are important methods for comprehensive management of rivers and lakes. The impacts of land use/land cover (LULC) on river water quality vary with spatial scales, such as watersheds, catchments, and riparian zones. Achieving an effective spatial scale relationship between LULC and water quality, determining priority management areas, and reaching sustainable development of large estuarine deltas remain problematic. In this study, buffering analysis on the water quality data of the Yangtze River Estuary from 2009 to 2018 was conducted based on LULC, and the priority management areas of the basin were identified. Also, we infer that future river restoration or management efforts should focus on priority management area construction of a 1500 m riparian zone and a 150 km reach zone. Conclusively, establishing a priority management area within the effective buffer zone is key to watershed water quality management.

We studied various soil characteristics associated with Scirpus mariqueter growth and spatial heterogeneity in the Shanghai Nanhui Dongtan wetlands. In September and October 2015, 12 soil characteristics (soil organic carbon, total phosphorus, total nitrogen, nitrate, nitrite, ammonia, orthophosphate, pH, moisture content, particle size, salinity, and tidal elevation) were analyzed from 101 soil samples. The key factors affecting S. mariqueter spatial distribution were determined using canonical correspondence analysis and curve-fitting analysis. Results showed that vegetation indices of height, cover, density, and biomass were positively correlated (P

Exploring how suitable habitat and population size of Red-crowned crane Grus japonensis respond to long-term coastal reclamation plays an important role in species conservation and in related coastal management. Here, we combined field data for suitable habitats and wintering population size of G. japonensis with GIS-based information to elucidate the influence of long-term coastal reclamation on this species and related conservation efforts. During 1975–2013, the intensity and spatial extent of coastal reclamation exhibited a temporal change, increasing dramatically in 1975–2000 and lessening considerably in 2000–2013. Under the pressure of long-term coastal reclamation, the decline of suitable habitat of G. japonensis was affected by increasing levels of human disturbance and decreasing availability of natural habitat. Moreover, the wintering population size of G. japonensis exhibited a decreasing trend during 1975–2013 as a result of the decreasing availability of fish ponds, bare tidal flats, and increasing spatial extent of residential areas and P. australis habitat, which were indirectly affected by long-term reclamation. Our results highlight the importance of considering the long-term effects of coastal reclamation on both populations and suitable habitat of G. japonensis, which should be considered in future plans for coastal management and conservation.

We examined how various soil characteristics are associated with Scirpus mariqueter growth and spatial heterogeneity in Shanghai Nanhui Dongtan wetlands and addressed a major knowledge gap regarding the effects of reclamation on microbial communities in the soil. Biolog was used to examine soil carbon resources, diversity, abundance, and community structure of S. mariqueter soil microbes after a 72-h culture. Tidal elevation influenced soil microbes, which used carbon resources at higher rates, exhibited more community diversity and had greater species richness in areas with dense S. mariqueter cover than in bare tidal flats (P

Little is known about consequences of Spartina alterniflora invasion on soil sulfate-reducing bacteria (SRB). This study compared the abundance, diversity, and community structure of SRB in S. alterniflora and in native plant communities along a successional gradient (bare mudflat, young/mature S. alterniflora, Suaeda salsa, and Phragmites australis) in coastal salt marshes of Eastern China. Quantitative polymerase chain reaction of dissimilatory sulfite reductase (dsrB) gene was applied to assess SRB abundance, and the diversity and composition of SRB was analyzed by 454 pyrosequencing of partial dsrB gene. We found that S. alterniflora had a significantly higher abundance and diversity of SRB than native plant species. For all plant covers, Desulfobacteraceae was the largest soil SRB group, with a relative abundance of 33.6%, followed by Desulfobulbaceae (29.2%). S. alterniflora showed a higher relative abundance of Desulfobacteraceae (42.5%) than native species (29.5%) did. Notably, S. alterniflora invasion decreased the relative abundance of a SRB branch clustering with the thermophilic Thermodesulfovibrio yellowstonii. In conclusion, S. alterniflora invasion of the eastern coast of China has greatly increased the abundance and diversity of SRB communities and altered their structure. This might further influence carbon mineralization and inhibit the production of methane in China’s coastal marshes.

Although seed dispersal is a key process determining the regeneration and spread of invasive plant populations, few studies have explicitly addressed the link between dispersal vector behavior and seedling recruitment to gain insight into the invasion process within an urban garden context. We evaluated the role of bird vectors in the dispersal of pokeweed (Phytolacca americana), a North American herb that is invasive in urban gardens in China. Fruiting P. americana attracted both generalist and specialist bird species that fed on and dispersed its seeds. The generalist species Pycnonotus sinensis and Urocissa erythrorhyncha were the most frequent dispersers. Seedling numbers of P. americana were strongly associated with the perching behavior of frugivorous birds. If newly recruited bird species use seedling-safe perching sites, the P. americana will regenerate faster, which would enhance its invasive potential. Based on our observations, we conclude that the 2 main bird vectors, P. sinensis and U. erythrorhyncha, provide potential effective dispersal agents for P. americana. Our results highlight the role of native birds in seed dispersal of invasive plants in urban gardens.

This study aimed to develop a practical approach to identify the priority areas with ecological significance along highly human disturbed coastal areas. Field surveys were used to assess and complement to the results of the remote sensing (RS)-based analysis. The RS-based biodiversity hotspot (BH) identification process was accomplished in three steps. The lands with native vegetation cover, including the national natural reserve lands, were first selected as the baseline BHs (BBHs). Then, after assigning resistance coefficients to each land use, the least accumulative cost (LAC) of the BBHs was calculated by distance analysis, while the normalized differential vegetation index (NDVI) from the Landsat Thematic Mapper was reclassified into 20 grades based on the Euclidean distance to the main anthropogenic sources. Finally, the RS-based BH identification was realized through the logistic calculation of LAC less than a series of thresholds and NDVI more than 10. While the field survey-based BH identification was through the logistic calculation between HM potential ecological risks of low to moderate and BHs acquired by NDVI-based integrated assessments. The results proved that RS-based analysis could be an important surrogate for necessary field surveys to manage BHs along coasts.

An approach of identifying priority spatial patterns in response to different ecological risk levels associated with heavy metals (HM) is proposed. First, ecological hotspots (EH) are delineated by integrating NDVI-based assessment with the impact assessment of anthropogenic impact sources. Second, the HM potential ecological risks index (PERI) is calculated and spatially interpolated. Finally, the EH with different PERI values are identified through logic calculation. Study results show that 45.2% of the study region has low HM risks, 53.2% with moderate HM risks, and only 1.6% with high HM risks. In addition, the percentage of EH with low HM risks is 6.5%; the percentage with moderate HM risks is 5.4%; and the percentage with high HM risks is 0.4%. The EH with low and moderate HM ecological risks are proposed to be the regions in priority for management. This approach is potentially useful to HM ecological risk assessment and HM contamination management around the world.

IntroductionChina feeds 22 % of the world’s population, yet commandsonly 9 % of the arable land, necessitating an intensive ap-proach to agricultural production. Food production more thandoubled in China from 239.96 million tons in 1970 to 530.82million tons in 2009. Among other factors, application ofnitrogenfertilizershascontributedtothisremarkableincrease.There is pervasive nitrogen fertilizer over-application inChina.Forexample,theaveragenitrogenfertilizerapplicationrate for rice production is 180 kg per hectare, about 75 %higher than the world average (Peng et al. 2009). Nitrogenfertilizerthatisnotabsorbedbycropscontributessignificantlyto nutrient enrichment in waters, causing negative impacts onenvironmental quality, ecosystem services, and biodiversity(Glibert et al. 2006; Howarth 2008). These problems in theLakeTairegionareamongthemostintenseintheworld.LakeTai is increasingly eutrophied and has suffered from episodesofcyanobacterialblooms.In2007,aseverealgaebloominthelake left 4.43 million people without safe drinking water innearby Wuxi City (Yang et al. 2008).Much research has been conducted to mitigate the seriouswater pollution problems associated with inappropriate fer-tilizer application (Hite et al. 2002; Ladha et al. 2005; Cui etal. 2010). Nevertheless, most of the existing research hasbeen devoted to the measures for reducing environmentaldegradation, and little has focused on understanding farm-ers’ perceptions towards these measures (Adrian et al. 2005;Han and Zhao 2009). Across China, there is a paucity ofreliable information on how farmers make decisions on theamount and timing of fertilizer application, their perceptionstowards the potential adverse environmental impacts offertilizers, and their attitudes towards best managementpractices (BMPs) (Cui et al. 2010).In order to facilitate the development offeasible and cost-effective programs to mitigate the serious situation of Nfertilizer over-application, face-to-face surveys were con-ducted in 15 villages within 5 km west of Lake Tai. Thesurvey results provide insight into the local farmers’ currentfertilizing practices as well as their perceptions towardsfertilizer use and implementation of BMPs.Study Area and MethodsWhile accounting for 0.4 % of its land area and 2.9 % of itspopulation, the Lake Tai basin generates more than 14 % ofChina’s Gross Domestic Product (GDP) (Zhang et al. 2007).Rapid economic development in the basin has led to the lossof cropland to urbanization, although agriculture is still thelargest land use category (Zhang and Liu 2011). Overall, theLake Tai basin is a region of intense economic developmentand industrial modernization. Yet, the agricultural sectormaintains elements of traditionalism that intersect withmodernization in unique and sometimes unfortunate ways.The 5 km riparian region west of Lake Tai has been offi-ciallydesignatedasthecategoryIcriticalzone.Fifteenvillageswith large acreage of cropland were randomly selected in thecritical zone. A random sample of farmers in the villages wereinterviewed with a pre-constructed questionnaire designed togain insights into the farmers’ fertilizer application behaviors,their decision-making process, and their perceptions of theenvironmental impacts of fertilizer use (Fig. 1).

Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% costal wetlands) because of the wetland reclamation during China's long history of civilization, and the population pressure and the misguided policies over the last 50 years. Recently, with an improved understanding that healthy wetland ecosystems play a vital role in her sustainable economic development, China started major efforts in wetland conservation, as signified by the policy to return reclaimed croplands to wetlands, the funding of billions of dollars to restore degraded wetlands, and the national plan to place 90% of natural wetlands under protection by 2030. This paper describes the current status of the natural wetlands in China, reviews past problems, and discusses current efforts and future challenges in protecting China's natural wetlands.

The contribution of forest generalists and specialists to the dispersal pattern of tree species is not well understood. Specialists are considered low-quality dispersers because their dispersal distance is often short. However, disregard for seed deposition site may result in underestimation of the dispersal quality of specialists. The present study estimated the contribution of generalist and specialist species to the dispersal patterns of the endangered Chinese yew (Taxus chinensis) in a subtropical patchy forest in Southeast China. A relatively diverse assemblage of frugivorous birds visited T. chinensis source trees and specialist Hypsipetes leucocephalus and generalist Urocissa erythrorhyncha were by far the highest-quantity dispersers. Considering dispersal effectiveness, the quantity aspect of effectiveness differed between the specialist assemblage and generalist assemblage; the contribution of specialists to the quantity part of effectiveness was significantly higher than that of generalists despite the relatively low diversity of specialists. After foraging, both specialist H. leucocephalus and generalist U. erythrorhyncha significantly contributed to the number of seedlings and their contributions to seedling recruitment did not differ with regard to quality. Our results highlight the ability of T. chinensis to recruit an effective disperser assemblage in patchy habitats, thus increasing its persistence in this disturbed habitat.

Face-to-face interviews (n = 553) were conducted in five counties in East-Central China to study farmers’ fertilizer application behaviors, decision-making processes, attitudes towards adopting better fertilizer application technologies, and environmental consciousness. The survey results revealed widespread fertilizer misapplication and highly variable application behaviors in the study regions. The lack of scientific knowledge on fertilizers and the absence of guidance from agricultural extension services have forced the farmers to rely on personal judgment and advice from fertilizer dealers and friends to make decisions in fertilizer application. Overall, farmers have been idiosyncratic in fertilizer application with limited adoption of better fertilizer application technologies. There are great potentials for reducing pollutant load from agricultural runoff through promoting scientific fertilizer application in the regions. However, farmers’ diverse preferences over agricultural extension programs necessitate an integrated approach emphasizing farmer involvement throughout the development of such programs for promoting better fertilizer application practices.

An understanding of trace metal pollution due to reclamation activities around Yancheng National Nature Reserve is important for the utilisation and management of the reserve and surrounding coastal and marine areas. In the present study, we evaluated the current state of Cu, Cd, Pb and Zn pollution (total concentrations and ecological risk), their potential hazard (availability index and desorption rate) and soil properties (cation exchange capacity, iron and manganese oxide content, soil organic matter, salinity and pH) in different land use types around this nature reserve. Although the current state of trace metal pollution was not severe, the potential hazards of these trace metals should not be ignored, especially for Cd because of its significantly higher availability index values in farmlands and aquaculture ponds than in natural habitats (by 33 and 32% of the total amount of Cd respectively). Thus, strict monitoring and environmentally responsible land reclamation management practices should be considered for these coastal areas.

China is a country poor in water resources, with an annual 2800 km3 of freshwater storage and 2300 m3 of water availability per capita. Both the water shortage and low use efficiency make modern China thirsty. Furthermore, the loss of glaciers and wetlands in the western plateau that feed the major rivers of China as their headwaters will exacerbate this thirst in the future. Although groundwater might be tapped as a resource, most regions already use their aquifers excessively. China needs to focus on its urgent water-shortage problems to safeguard its booming economy and to contribute more to world development.