Value Of Coastal Wetlands Research Articles

Suspected coastal reclamation areas detection by spatiotemporal fusion of landsat TM and Sentinel-1A: A case study of Fuzhou, Fujian, China

Increasing coastal reclamation activities have been undertaken to alleviate the shortage of land resources, posing significant challenges to the coordination of coastal reclamation, economic development and environmental protection. Over the past few decades, coastal reclamation has occurred extensively in the coastal region of China, especially the east coast, while the value of coastal wetlands and ecosystems has only been well understood and appreciated in the last decade. More recently, there is an important new trend to restore parts of reclaimed land to coastal wetlands for environmental protection purposes, which requires reliable reclamation detection results as a foundation for policy. This study aimed to propose a reclamation detection framework based on the spatiotemporal fusion of Landsat TM and Sentinel-1A. To utilize the complementary information of optical and SAR images, the proposed framework models the common and proprietary information of both types of data separately in a sparse manner. Then, with more reliable and detailed information, reclamation areas can be distinguished by band math and threshold segmentation using the spatiotemporal fusion of Landsat TM and Sentinel-1A images. Finally, taking Fuzhou in eastern China as an example, we provided a detailed analysis of coastal reclamation. The results confirmed that the proposed algorithm was effective for rapidly detecting suspected locations of coastal reclamation and showed great potential for monitoring the changes occurring in the coastal zone.

Coastal marshes provide valuable protection for coastal communities from storm-induced wave, flood, and structural loss in a changing climate

Wetlands such as tidal marshes and mangroves are known to buffer coastal communities from wave, flood, and structural loss during storms. Coastal communities and resource managers seek to understand the ecosystem service value of coastal wetlands for reducing storm-induced flood loss in a changing climate. A recent modeling study found that a tall and dense Phragmites-dominated Piermont Marsh reduced the flood loss in the Village of Piermont, New York, U.S.A. during Superstorm Sandy and the 1% annual chance flood and wave event by 8% and 11%, respectively. Here we used the same modeling approach to examine the marsh’s buffering capacity in a changing climate (from 2020 to 2100), considering a potential marsh restoration plan (from 2020 to 2025) and potential marsh loss due to sea-level rise. Results showed that from 2020 to 2100, the 1% annual chance flood, wave, and structural loss would increase due to sea-level rise, storms, and marsh loss. However, the marsh will buffer ~ 11–12% of structural loss until 2050. Under the extreme SLR scenario of 2.89 m and a low accretion rate, Piermont Marsh is expected to lose its buffering capacity by 2080–2100 but will retain some buffering capacity with a high accretion rate of 10 mm/year and marsh growth. The marsh’s buffering capacity will remain during extra-tropical storms during winter and spring unless the wind has a significant northerly component. Lessons learned from this study can be used by coastal communities and marsh managers to develop coastal resiliency and marsh restoration plan.

연안습지의 가치에 대한 지역주민 인식 조사

연안습지의 가치에 대한 지역주민 인식 조사

Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010

The reclamation of coastal land for agricultural, industrial, and urban land use—a common worldwide practice—has occurred extensively in the coastal region of China. In recent decades, all coastal provinces and metropolises in China have experienced severe coastal reclamation related to land scarcity caused by rapid economic growth and urbanization. However, the value of coastal wetlands and ecosystems has not been well understood and appreciated until recent development of advantageous methods of restoring reclaimed land to coastal wetlands in many developed countries. The overall objective of this study is to provide detailed spatial and temporal distributions of coastal reclamation; analyze drivers such as coastal economy, population growth, and urbanization; and understand the relationships among the drivers and land reclamation. We used long-term Landsat image time series from 1985 to 2010 in 5-year intervals, in combination with remotely sensed image interpretation and spatial analysis, to map the reclamation status and changes across the coastal region of China. The Landsat images time-series analysis was also conducted to evaluate the effects of the economy, population, and urbanization drivers on coastal reclamation. The analysis results indicated that 754,697 ha of coastal wetlands have been reclaimed across all coastal provinces and metropolises from 1985 to 2010, and the trend increased sharply after 2005. High-intensity coastal reclamation was mainly driven by the booming economy, especially after 2000, associated with urbanization and industrial development in China's coastal region; this was closely correlated with the gross domestic product (GDP) per capita. The continuous large-scale coastal reclamation of its coastal region now means China is facing a great challenge, including the enormous loss of vegetated coastal wetlands, negative environmental effects, and potential disaster risks related to coastal flooding under future change climate conditions. Long-term ecosystem-based coastal protection and management are critical to support sustainable coastal ecosystems in China in the future.

Nitrogen pools in a mangrove – saltmarsh system

It is only in comparatively recent times that the value of coastal wetlands has become recognised. In Australia, there is a scant knowledge of how these ecosystems function and hence the best way that they can be managed and utilized. This is in contrast to the wealth of information for estuaries in North America (e.g. Pomeroy and Wiegert, 1981), where studies have emphasised the importance of estuarine ecosystems in the production of organic matter for detritus based food webs (Odum and de la Cruz, 1967; Lugo and Snedaker, 1974; Haines, 1979a). they have also stressed the fact that each estuarine system has a unique set of physical and biological characteristics (Haines, 1979a). Few of these characteristics have been investigated for temperate Australian estuaries and there is a paucity of information about the nutrient flux and pools in wetland communities. Accordingly, a preliminary sampling of the nitrogen pools and other environmental characteristics was undertaken over a six month period in the Towra Point wetland.