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1.
Wang X  Yu J  Zhou D  Dong H  Li Y  Lin Q  Guan B  Wang Y 《Environmental management》2012,49(2):325-333
In this study, we compared ecological characteristics of wetland vegetation in a series of restoration projects that were carried out in the wetlands of Yellow River Delta. The investigated characteristics include plant composition structure, species diversity and community similarity in three kinds of Phragmites australis wetlands, i.e. restored P. australis wetlands (R1, R2, R3 and R4: restored in 2002, 2005, 2007 and 2009, respectively), natural P. australis wetland (N) and degraded P. australis wetland (D) to assess the process of wetlands restoration. The coverage of the R1 was 99%, which was similar to natural wetland. Among all studied wetlands, the highest and lowest stem density was observed in R1 and R2, respectively, Plant height and stem diameter show the same trend as N > R2 > R1 > R3 > D > R4. Species diversity of restored P. australis wetlands became closed to natural wetland. Both species richness and Shannon–Wiener index had similar tendency: increased first and then decreased with restored time. The highest species richness and species diversity were observed in R2, while the lowest values of those parameters were found in natural P. australis wetland. Similarity indexes between restored wetlands and natural wetland increased with the restoration time, but they were still less than 50%. The results indicate that the vegetation of P. australis wetlands has experienced a great improvement after several years’ restoration, and it is feasible to restored degraded P. australis wetlands by pouring fresh water into those wetlands in the Yellow River Delta. However, it is notable that costal degraded P. australis wetland in this region may take years to decades to reach the status of natural wetland.  相似文献   

2.
/ Investigation of a delta marsh restoration project proposed forthe Don River in Toronto, Ontario, underlines several concerns aboutconstructed wetland projects designed for water quality improvement andaquatic habitat enhancement. The Don is a highly urbanized river that hasundergone significant physiographic modifications and continually receives acomplex mixture of conventional, metallic, and organic contaminants frommultiple point and nonpoint sources. Rather than providing permanent removalof urban contaminants, wetland processes offer a limited capacity fortemporary storage of contaminant inputs, and potential reactions may actuallyproduce more toxic and/or bioavailable forms of some chemicals. Theseprocesses tend to result in the concentration of watershed contaminants inwetland vegetation and sediments. As the restored marsh would be availablefor spawning and feeding by aquatic fauna, the potential exists for chemicalbioconcentration and biomagnification through the aquatic community.Accordingly, wetland systems are not suited to the dual purposes of waterquality improvement and aquatic habitat enhancement. Upstream controls,including source reduction of contaminant inputs, are recommended asessential components of all constructed wetland projects.KEY WORDS: Constructed wetlands; Water quality; Ecological restoration;Don River  相似文献   

3.
Traditionally, wetland management strategies have focused on single familiar objectives, such as improving water quality, strengthening biodiversity, and providing flood control. Despite the relevant amount of studies focused on wetland creation or restoration with these and other objectives, still little is known on how to integrate objectives of wetland creation or restoration at different landscape scales. We have reviewed the literature to this aim, and based on the existing current knowledge, we propose a four step approach to take decisions in wetland creation or restoration planning. First, based on local needs and limitations we should elucidate what the wetland is needed for. Second, the scale at which wetland should be created or restored must be defined. Third, conflicts and compatibilities between creation or restoration objectives must then be carefully studied. Fourth, a creation or restoration strategy must be defined. The strategy can be either creating different unipurpose wetlands or multipurpose wetlands, or combinations of them at different landscape scales. In any case, in unipurpose wetland projects we recommend to pursue additional secondary objectives. Following these guidelines, restored and created wetlands would have more ecological functions, similar to natural wetlands, especially if spatial distribution in the landscape is considered. Restored and created wetlands could then provide an array of integrated environmental services adapted to local ecological and social needs.  相似文献   

4.
We studied the changes in wetland habitats and waterbird communities between the 1980s and the 2000s at Chongming Dongtan, a Ramsar site in the Yangtze River estuary, an ecologically important region. This region is an important stopover site for shorebirds along the East Asian–Australasian flyway and is extensively used by waterfowl. A net loss of 11% of the wetland area was estimated during study periods at Chongming Dongtan. The change was dependent on wetland types: while the area of artificial habitats such as paddy fields and aquacultural ponds more than doubled, more than 65% of natural habitats including sea bulrush (Scirpus mariqueter) and common reed (Phragmites australis) marshes were lost over the two decades. An exotic plant species introduced from North America, smooth cordgrass (Spartina alterniflora), occupied 30% of the vegetated intertidal zone by the 2000s. Although waterbird species richness did not change between the 1980s (110) and the 2000s (111), 13 species found in 1980s were replaced by 14 newly recorded species. Moreover, there were more species with declining trends (58) than with increasing trends (19). The population trends of species were affected by residential status and habitat types. Transients, wintering migrants, and habitat specialists were more likely to show declining trends compared to those breeding at Dongtan (including year-round and summer residents) and habitat generalists. Furthermore, species associated mainly with natural wetlands were more likely to decline than those associated mainly with artificial wetlands. These patterns suggest that the loss and change of wetland habitats at Chongming Dongtan adversely affected local population dynamics and might have contributed to the global decline of some waterbird species. Because Chongming Dongtan provides stopover and wintering habitats for many migratory waterbirds, protection and restoration of natural wetlands at Chongming Dongtan are urgently needed.  相似文献   

5.
Wetland protection and utilization sometimes appear to be in conflict, but promoting the wise use of wetlands can solve this problem. All countries face the challenge of sustainable development of wetlands to a greater or lesser extent, but the problem is especially urgent in developing countries, such as China, that want to accelerate their economic development without excessive environmental cost. Chinese wetlands contribute greatly to economic development, but improper use of these natural resources has endangered their existence. It is thus necessary to provide scientific guidance to managers and users of wetlands. In this paper, we analyze the present status of Chinese wetland protection and utilization, and discuss problems in six categories: a lack of public awareness of the need for wetland protection; insufficient funding for wetland protection and management; an imperfect legal system to protect wetlands; insufficient wetland research; lack of coordination among agencies and unclear responsibilities; and undeveloped technologies related to wetland use and protection. The wise use of Chinese wetlands will require improvements in four main areas: increased wetland utilization research, scientific management of wetland utilization, improved laws and regulations to protect wetlands, and wider dissemination of wetland knowledge. Based on these categories, we propose a framework for the optimization of wetland use by industry to provide guidance for China and other countries that cannot sacrifice economic benefits to protect their wetlands.  相似文献   

6.
Brown, Jeffrey S., Martha Sutula, Chris Stransky, John Rudolph, and Earl Byron, 2010. Sediment Contaminant Chemistry and Toxicity of Freshwater Urban Wetlands in Southern California. Journal of the American Water Resources Association (JAWRA) 46(2):367-384. DOI: 10.1111/j.1752-1688.2009.00407.x Abstract: Wetlands provide many critical functions in urban ecosystems, including habitat for wetland-dependent fauna and enhancement of water quality. Interest in restoring or creating wetlands to enhance these functions is increasing due to the scale and extent of wetland loss and water quality problems associated with urbanization. One of the most pressing questions associated with urban wetland restoration is the extent to which urban wetlands tend to concentrate contaminants, and if so, whether an associated risk to wildlife exists. The goal of this study was to better understand these potential risks, and the associated tradeoffs with using wetlands to treat urban runoff. Sediment toxicity, contaminant chemistry, and macroinvertebrate (MI) community metrics were measured in 21 southern California wetlands that receive urban runoff as their primary water source. MI organisms in 18 of the 21 urban wetlands examined were considered to be at risk due to sediment contaminant concentrations and toxicity. Most of the sites were either toxic to the amphipod Hyalella azteca, exceeded a sediment quality guideline, or both. Sediment chemistry and toxicity identification evaluation studies suggest that pyrethroid pesticides may have been responsible for much of the toxicity documented in this study. The mean Probable Effects Concentration quotient (an index of degree of sediment contamination) was found to negatively correlate with MI diversity in these wetlands suggesting that toxicity was affecting organisms at the base of the food chain in these wetlands.  相似文献   

7.
Poverty, hunger and demand for agricultural land have driven local communities to overexploit forest resources throughout Ethiopia. Forests surrounding the township of Humbo were largely destroyed by the late 1960s. In 2004, World Vision Australia and World Vision Ethiopia identified forestry-based carbon sequestration as a potential means to stimulate community development while engaging in environmental restoration. After two years of consultation, planning and negotiations, the Humbo Community-based Natural Regeneration Project began implementation—the Ethiopian organization’s first carbon sequestration initiative. The Humbo Project assists communities affected by environmental degradation including loss of biodiversity, soil erosion and flooding with an opportunity to benefit from carbon markets while reducing poverty and restoring the local agroecosystem. Involving the regeneration of 2,728 ha of degraded native forests, it brings social, economic and ecological benefits—facilitating adaptation to a changing climate and generating temporary certified emissions reductions (tCERs) under the Clean Development Mechanism. A key feature of the project has been facilitating communities to embrace new techniques and take responsibility for large-scale environmental change, most importantly involving Farmer Managed Natural Regeneration (FMNR). This technique is low-cost, replicable, and provides direct benefits within a short time. Communities were able to harvest fodder and firewood within a year of project initiation and wild fruits and other non-timber forest products within three years. Farmers are using agroforestry for both environmental restoration and income generation. Establishment of user rights and local cooperatives has generated community ownership and enthusiasm for this project—empowering the community to more sustainably manage their communal lands.  相似文献   

8.
Sanjiang National Nature Reserve (NNR) is a state-owned natural wetland in China that has suffered severe degradation due to cultivation and wetland reclamation by farmers. As a consequence, the conversion of cultivated land to wetlands (CCW) was proposed by the government of Heilongjiang province and the United Nations Development Programme/Global Environment Facility (UNDP/GEF) project team in 2007. We suggest that voluntary participation in the CCW could be an important tool for accomplishing the integrated objectives of wetland conservation and local development. The purpose of this study was to examine the main factors that influence farmers’ willingness to participate in the CCW through a field investigation and a questionnaire. Based on the data from our questionnaire, which provided an effective sample of 310 households in 11 villages, the influencing factors of farmers’ willingness to participate were analyzed through binary logistic regression analyses. It was concluded that age, education, the amount of cultivated land, geographical location, and the perceived benefits and risks were important factors for participation. Furthermore, suggestions for improving the wetland compensation system and providing alternative livelihoods are proposed to strengthen participation.  相似文献   

9.
The US Army Corps of Engineers often requires wetland creation or restoration as compensation for wetlands damaged during development. These wetlands are typically monitored postconstruction to determine the level of compliance with respect to site-specific performance standards. However, defining appropriate goals and measuring success of restorations has proven difficult. We reviewed monitoring information for 76 wetlands constructed between 1992 and 2002 to summarize the performance criteria used to measure progress, assess compliance with those criteria, and, finally, to evaluate the appropriateness of those criteria. Goals were overwhelmingly focused on plant communities. Attributes used to assess the quality of restored plant communities, including percent native species and the Floristic Quality Index, increased over time but were apparently unrelated to the number of species planted. Compliance frequencies varied depending on site goals; sites often failed to comply with criteria related to survival of planted vegetation or requirements that dominant plant species should not be exotic or weedy, whereas criteria related to the establishment of cover by vegetation or by wetland-dependent plants were often met. Judgment of a site’s success or failure was largely a function of the goals set for the site. Some performance criteria were too lenient to be of value in distinguishing failed from successful sites, whereas other criteria were unachievable without more intensive site management. More appropriate goals could be devised for restored wetlands by basing performance standards on past performance of similar restorations, identifying consistent temporal trends in attributes of restored sites, and using natural wetlands as references.  相似文献   

10.
Wetlands in the Rainwater Basin in Nebraska are vulnerable to sediment accumulation from the surrounding watershed. Sediment accumulation has a negative impact on wetland quality by decreasing the depth and volume of water stored, and the plant community species composition and density growing in the wetland. The objective of this study was to determine the amount of sediment that has accumulated in five selected wetlands in the Rainwater Basin in Nebraska. Soil cores were taken at five or six locations along transects across each wetland. This study used the fly ash, which is generated by coal‐burning locomotives that were present generally in the late 1800s and early 1900s, as a marker to quantify the sediment deposition rates. The cores were divided into 5 cm sections and the soils were analyzed using a fly ash extraction and identification technique. Results indicate that the average depth of sediment ranged from 23.00 to 38.00 cm. The annual average depth of sediment accumulation ranged from 0.18 cm/yr to 0.29 cm/yr. The annual sediment accumulation rate from both wind erosion and water erosion in these five sampling wetlands was between 1.946 and 3.225 kg/m2/yr. The results of this research can be used to develop restoration plans for wetlands. The fly ash testing technology can also be applied to other areas with the railroads across the United States.  相似文献   

11.
Over one hundred wetland specialists and Earth Observation experts from around the world gathered at the European Space Agency's 'GlobWetland Symposium: Looking at wetlands from space' in Frascati, Italy, from 19 to 20 October, 2006. The aim of the Symposium was to stimulate discussion between the two communities by reviewing the latest developments in Earth Observation (EO) for the inventory, assessment and monitoring of wetlands and identify key scientific, technical and policy-relevant challenges for the future. The results provide an overview of the key areas of current research in the use of EO for mapping and managing wetlands, while also pointing out gaps that could hinder global inventory, assessment and monitoring of wetlands. This paper provides a summary of the main outputs with a focus on the role of EO technologies in supporting the implementation of the Ramsar Convention on Wetlands. The summary contains a qualitative analysis of the state of the art and considers possible directions and priorities for future research, development and application of EO-based technologies in wetland management. In this context we: 1) highlight those applications where EO technologies are ready for wider uptake by wetland managers, and provide suggestions for supporting such uptake; 2) indicate where EO technologies and applications currently in the research and development stages could potentially be useful in wetland management; and 3) provide recommendations for new research and development of EO technologies, that can be utilized to address aspects of wetland management not covered by the range of current EO applications.  相似文献   

12.
The effects of permitting decisions made under Section 404 of the Clean Water Act for which compensatory mitigation was required were examined. Information was compiled on permits issued in Oregon (January 1977–January 1987) and Washington (1980–1986). Data on the type of project permitted, wetland impacted, and mitigation project were collected and analyzed. The records of the Portland and Seattle District Offices of the US Army Corps of Engineers and of Environmental Protection Agency Region X were the primary sources of information. The 58 permits issued during the years of concern in Oregon document impacts to 82 wetlands and the creation of 80. The total area of wetland impacted was 74 ha while 42 ha were created, resulting in a net loss of 32 ha or 43%. The 35 permits issued in Washington document impacts to 72 wetlands and the creation of 52. The total area of wetland impacted was 61 ha while 45 ha were created, resulting in a net loss of 16 ha or 26%. In both states, the number of permits requiring compensation increased with time. The area of the impacted and created wetlands tended to be ≤0.40 ha. Permitted activity occurred primarily west of the Cascade Mountains and in the vicinity of urban centers. Estuarine and palustrine wetlands were impacted and created most frequently. The wetland types created most often were not always the same as those impacted; therefore, local gains and losses of certain types occurred. In both states the greatest net loss in area was in freshwater marshes. This study illustrates how Section 404 permit data might be used in managing a regional wetland resource. However, because the data readily available were either incomplete or of poor quality, the process of gathering information was very labor intensive. Since similar analyses would be useful to resource managers and scientists from other areas, development of an up-to-date standardized data base is recommended.  相似文献   

13.
Coastal communities along the United States coast often experience significant economic damage resulting from the impacts of tropical storms and hurricanes. Research suggests that certain factors that affect economic damages are increasing the vulnerability of coastal communities. Population growth, which increases vulnerability by placing valuable lives and assets in the path of storms, is expected to increase. Climate change has the potential to cause more frequent and intense storms, and coastal wetland loss is contributing to the vulnerability of coastal populations. Wetlands conservation and restoration is often advocated for as a means of reducing the impacts of coastal storms. The relationship between wetlands and storm surge energy is understood relatively well in physical terms, but very little economic analysis has been conducted to estimate the degree to which wetlands reduce economic impacts. Using factor analysis, the relationships among coastal populations, wetlands, storm intensity, and economic damage are explored. The factor analysis suggests that wetland presence is associated with a reduction in economic damages from coastal storms. Factor score analysis suggests that the proportion of damage explained by wetland presence is smaller for more intense storms. These results are consistent with those found in the physical science literature and have potentially large consequences for how wetlands are used in risk reduction.  相似文献   

14.
Wetland protection and restoration strategies that are designed to promote hydrologic resilience do not incorporate the location of wetlands relative to the main stream network. This is primarily attributed to the lack of knowledge on the effects of wetland location on wetland hydrologic function (e.g., flood and drought mitigation). Here, we combined a watershed‐scale, surface–subsurface, fully distributed, physically based hydrologic model with historical, existing, and lost (drained) wetland maps in the Nose Creek watershed in the Prairie Pothole Region of North America to (1) estimate the hydrologic functions of lost wetlands and (2) estimate the hydrologic functions of wetlands located at different distances from the main stream network. Modeling results showed wetland loss altered streamflow, decreasing baseflow and increasing stream peakflow during the period of the precipitation events that led to major flooding in the watershed and downstream cities. In addition, we found that wetlands closer to the main stream network played a disproportionately important role in attenuating peakflow, while wetland location was not important for regulating baseflow. The findings of this study provide information for watershed managers that can help to prioritize wetland restoration efforts for flood or drought risk mitigation.  相似文献   

15.
The main goal of the present study was to develop an ecological integrity index for littoral wetland management and conservation in semiarid Mediterranean areas that have been highly impacted by agriculture, including the selection of pressure and state indicators at landscape and wetlands scales that reflect the status, condition, and trends of wetlands ecosystems. We used a causality framework based on the relationship between pressure of anthropogenic activities and the ecological state of wetlands and their catchments, integrating environmental, biologic, economic, and social issues. From the application of 51 indicators in 7 littoral wetlands in the southeastern Iberian Peninsula, we selected 12 indicators (5 at catchment scale and 7 at wetland scale) to constitute the ecological integrity index proposed. The potential nitrogen export per area at catchment scale and the potential relative nitrogen export from the area surrounding the wetlands were the best pressure single predictors of state indicators with a causal relationship with environmental meaning. Wetlands in catchments with more agriculture had less ecological integrity than those in less impacted areas. A wide riparian zone in some wetlands acts as a buffer area, diminishing the effects of intensive agriculture. The index of ecological integrity developed here has a number of essential characteristics that make it a useful tool for ecosystem managers and decision-makers. The index can be used to (1) assess and control ecological integrity, (2) diagnose probable causes of ecological impairment, (3) establish criteria for protecting and restoring wetland ecosystems, and (4) integrate catchment management. Published online  相似文献   

16.
Irrigated agriculture throughout western North America faces increasing pressure to transfer water to nonagricultural uses, including instream flows for fish and wildlife management. In an important case, increased instream flows are needed in Nebraskas Platte River for recovery of threatened and endangered fish and wildlife species. Irrigated agriculture in the Laramie Basin of southeast Wyoming is a potential water source for the effort to enhance instream flow. However, flood irrigation of hayfields in the Laramie Basin has created many wetlands, both ephemeral and permanent, over the last century. Attempting to increase Platte River instream flows by purchasing water rights or improving irrigation efficiency in the Laramie Basin would transform irrigated agriculture, causing a substantial fraction of the Laramie Basins wetlands to be lost. A creative solution is needed to prevent the sacrifice of one ecosystem on behalf of another. A rotating short-term water-leasing program is proposed. The program allows Laramie Basin producers to contribute to instream flows while continuing to support local wetlands. Permanent wetland desiccation is prevented and regional environmental water needs are met without impairing local ecological resources. Budget analysis is used to provide an initial cost estimate for acquiring water from agriculture through the short-term leasing program. The proposed approach is more expensive than traditional programs but allows contribution to instream flows without major wetland loss. Short-term leasing is a more efficient approach if benefits from wetlands exceed the difference in cost between the short-term lease program and programs that do not conserve wetlands.  相似文献   

17.
The U.S. Clean Water Act requires compensatory mitigation for wetland and stream damage through restoration of damaged aquatic ecosystems. We evaluate the North Carolina’s Ecosystem Enhancement Program (EEP), a state agency responsible for compensatory mitigation. We compare communities gaining and losing aquatic resources during mitigation, finding new types of socioeconomic disparities that contradict previous studies of mitigation program behavior. We find average distances between impact and mitigation sites for streams (43.53 km) and wetlands (50.3 km) to be larger in North Carolina than in off-site mitigation programs in other regions previously studied. We also find that aquatic resources in the State are lost from urbanized areas that are more affluent, white, and highly educated, and mitigated at sites in rural areas that are less affluent, less well educated, and have a higher percentage of minorities. We also analyze the relationship between urban growth indicators and EEP accumulation of compensation sites. Growth indicators and long-term population projections are uncorrelated with both projected transportation impacts and advance mitigation acquired by the EEP, suggesting that growth considerations can be more effectively incorporated into the EEP’s planning process. We explore the possibility that spatial mismatches could develop between watersheds that are rapidly growing and those that are gaining mitigation. We make recommendations for ways that regulators incorporate growth indicators into the mitigation planning process.  相似文献   

18.
Since wetland construction projects are becoming more commonplace, meaningful follow-up studies are needed to evaluate how these systems change over time. To that end, the objective of our study was to examine the temporal changes in plant community composition and water chemistry in two constructed wetlands. We investigated two wetland sites that were constructed in 2003 in northern Otsego County, NY, a county that is largely dominated by agriculture. Site 1 was previously an active cow pasture and site 2 was previously a wet meadow surrounded by agricultural fields. No active plant introduction was made during the construction; however, both sites were located in areas with many remnant wetlands and were connected to through-flowing streams. In 2004 (Year 1) and 2010 (Year 7), the plant community composition and nitrogen retention were assessed. We found that both sites experienced site-wide declines in plant species richness, including the loss of upland and facultative upland species and the unanticipated loss of facultative wetland and some obligate species. We propose that high water levels, which, at their maximum depth were >1.5 m deeper than in Year 1, maintained by landowners in the years after the initial survey, may have been responsible for the unexpected loss of wetland species. We also found that site 1 exhibited considerable nitrogen retention in both Year 1 and Year 7; however, N concentrations were low at site 2 in both years.  相似文献   

19.
The overall objective of the Ramsar Convention, signed in 1971, is the conservation and wise use of wetlands by national action and international cooperation as a means to achieving sustainable development. This complex and challenging task requires national, local and international bodies involved in the implementation of the convention to rely on suitable geo-information to better understand wetland areas, complete national inventories, perform monitoring activities, carry out assessments and put in practice suitable management plans based on updated and reliable information. In the last years, Earth Observation (EO) technology has been revealed as a key tool and unique information source to support the environmental community in different application domains, including wetlands' conservation and management. In this context, the European Space Agency (ESA) in collaboration with the Ramsar Secretariat launched in 2003 the "GlobWetland" project in order to demonstrate the current capabilities of Earth Observation technology to support inventorying, monitoring, and assessment of wetland ecosystems. This paper collects the main results and findings of the "GlobWetland" project, providing an overview of the current capabilities and limits of EO technology as a tool to support the implementation of the Ramsar Convention. The project was carried out in collaboration with several regional, national and local conservation authorities and wetland managers, involving 50 different wetlands across 21 countries on four continents. This large range of users provided an excellent test bed to assess the potential of this technology to be applied in different technical, economic and social conditions.  相似文献   

20.
The prior identification of local people’s preferences for conservation-development projects will help gear nature-conservation strategies toward the needs of different groups of local people. This will help policy-makers in designing a more acceptable and effective conservation strategy. This article reports a study of local perceptions of a community forestry project that aims to help improve the design as well as local acceptance of the project. The data originated from personal interviews conducted in communities around Okwangwo Division of the Cross River National Park in southeast Nigeria and were analysed using ordered logit and binary logit models. The results showed that >50% of the respondents were satisfied with the community forestry project. The respondents’ perceptions were mainly influenced by education, age, gender, and willingness to contribute money to tourism as well as the contributions of cocoa, banana, and afang (Gnetum africanum) to the respondents’ income. The results from this study have important implications for nature conservation in Nigeria and potentially other conservation contexts across the developing world.  相似文献   

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