China's coastal-wetland change analysis based on high-resolution remote sensing

2020 ◽  
Vol 71 (9) ◽  
pp. 1161
Author(s):  
Yin Gao ◽  
Lijuan Cui ◽  
Jianjun Liu ◽  
Wei Li ◽  
Yinru Lei
Keyword(s):  
High Resolution ◽  
Salt Marshes ◽  
Coastal Wetlands ◽  
Large Scale ◽  
Coastal Wetland ◽  
Complex Structure ◽  
Hangzhou Bay ◽  
Bohai Bay ◽  
Change Analysis ◽  
High Productivity

Coastal wetlands not only have abundant biodiversity and high productivity, but they also play an irreplaceable and important role in regional ecosystems. Because of the complex structure and dynamic characteristics of coastal wetlands, it is difficult to observe the spatial changes of coastal wetlands on a large scale and improve data reliability. In this study, a spatially constrained manual-interpretation method based on nationwide high-resolution images in 2017 was adopted to extract China’s coastal wetland distribution, and, then, the second national wetland-survey data from 2011 were used as a baseline for change analysis. The results showed that under the influence of natural conditions and human activities, China’s coastal wetlands have decreased in distribution in the past 6 years. The situation of coastal wetland reclamation is critical, and the hotspot regions are mainly distributed in Bohai Bay, middle of Jiangsu province and Hangzhou Bay. Farming reclamation is another factor that occupies coastal wetlands in China, and main occupied wetlands are mudflats, shallow sea, tidal flats, intertidal salt marshes and estuarine waters. Tide is the main factor affecting extraction of wetlands, the spatially constrained method had a positive effect on wetland detection, and has potential to improve automatic algorithms of complex coastal wetlands.

scholarly journals Coastal wetlands in Lianyungang, Jiangsu Province, China: probably the most important site globally for the Asian Dowitcher (Limnodromus semipalmatus)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ziyou Yang ◽  
Jing Li ◽  
Yongxiang Han ◽  
Chris J. Hassell ◽  
Kar-Sin Katherine Leung ◽  
...  
Keyword(s):  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Migratory Bird ◽  
Jiangsu Province ◽  
Bohai Bay ◽  
High Concentration ◽  
Human Disturbances ◽  
Stopover Site ◽  
Stochastic Events ◽  
Global Population

Abstract Background Despite an increasing number of surveys and a growing interest in birdwatching, the population and distribution of Asian Dowitcher (Limnodromus semipalmatus), a species endemic to the East Asian–Australasian and Central Asian Flyways, remains poorly understood, and published information about the species is largely outdated. In boreal spring 2019, over 22,432 Asian Dowitchers were recorded in a coastal wetland at Lianyungang, Jiangsu Province, China, constituting 97.5% of its estimated global population. Methods In 2019 and 2020, we conducted field surveys at Lianyungang to determine the numbers of Asian Dowitchers using the area during both southward and northward migrations. We also assessed the distribution and abundance of Asian Dowitchers elsewhere along the China coast by searching literature and consulting expert opinion. Results The coastal wetlands of Lianyungang are the most important stopover site for Asian Dowitchers during both northward and southward migrations; they supported over 90% of the estimated global population during northward migration in two consecutive years (May 2019 and 2020). This area also supported at least 15.83% and 28.42% (or 30.74% and 53.51% using modelled estimates) of the global population during southward migration in 2019 and 2020 respectively. Coastal wetlands in the west and north of Bohai Bay also have been important stopover sites for the species since the 1990s. Although comprehensive, long-term monitoring data are lacking, available evidence suggests that the population of the species may have declined. Conclusions The high concentration of Asian Dowitchers at Lianyungang during migration means the species is highly susceptible to human disturbances and natural stochastic events. The coastal wetlands of Lianyungang should be protected and potentially qualify for inclusion in China’s forthcoming nomination for World Heritage listing of Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China (Phase II) in 2023. Additional research is needed to understand Asian Dowitchers’ distribution and ecology, as well as why such a high proportion of their population rely on the Lianyungang coast.

scholarly journals Large-scale predictions of salt-marsh carbon stock based on simple observations of plant community and soil type

2019 ◽  
Vol 16 (2) ◽  
pp. 425-436 ◽  
Author(s):  
Hilary Ford ◽  
Angus Garbutt ◽  
Mollie Duggan-Edwards ◽  
Jordi F. Pagès ◽  
Rachel Harvey ◽  
...  
Keyword(s):  
Plant Community ◽  
Salt Marshes ◽  
Soil Type ◽  
Carbon Stock ◽  
Large Scale ◽  
Coastal Wetland ◽  
Blue Carbon ◽  
Wetland Ecosystems ◽  
Soc Stock ◽  
Carbon Store

Abstract. Carbon stored in coastal wetland ecosystems is of global relevance to climate regulation. Broadscale inventories of this “blue” carbon store are currently lacking and labour intensive. Sampling 23 salt marshes in the United Kingdom, we developed a Saltmarsh Carbon Stock Predictor (SCSP) with the capacity to predict up to 44 % of spatial variation in surface soil organic carbon (SOC) stock (0–10 cm) from simple observations of plant community and soil type. Classification of soils into two types (sandy or not-sandy) explained 32 % of variation in SOC stock. Plant community type (five vegetation classes) explained 37 % of variation. Combined information on soil and plant community types explained 44 % of variation in SOC stock. GIS maps of surface SOC stock were produced for all salt marshes in Wales (∼4000 ha), using existing soil maps and governmental vegetation data and demonstrating the application of the SCSP for large-scale predictions of blue carbon stores and the use of plant community traits for predicting ecosystem services.

scholarly journals CHANGES IN LANDSCAPE PATTERN OF WETLAND AROUND HANGZHOU BAY

2018 ◽  
Vol IV-3 ◽  
pp. 153-159
Author(s):  
Wenpeng Lin ◽  
Yuan Li ◽  
Dan Xu ◽  
Ying Zeng
Keyword(s):  
Landscape Pattern ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Diversity Index ◽  
Scientific Basis ◽  
Paddy Fields ◽  
Hangzhou Bay ◽  
The Sustainable Development ◽  
Wetland Landscape ◽  
Ecological Resources

Hangzhou Bay is an important estuarial coastal wetland, which offers a large number of land and ecological resources. It plays a significant role in the sustainable development of resources, environment and economy. In this paper, based on the remote sensing images in 1996, 2005 and 2013, we extracted the coastal wetland data and analyzed the wetland landscape pattern of the Hangzhou Bay in the past 20 years. The results show that: (1) the area of coastal wetland is heading downwards in the recent decades. Paddy field and the coastal wetland diminish greatly. (2) the single dynamic degree of wetland of the Hangzhou Bay displays that paddy fields and coastal wetlands are shrinking, but lakes, reservoirs and ponds are constantly expanding. (3) the wetland landscape pattern index shows that total patch area of the coastal wetland and paddy fields have gradually diminished. The Shannon diversity index, the Shannon evenness index as well as the landscape separation index of the coastal wetlands in the Hangzhou Bay increase steadily. The landscape pattern in the study area has shown a trend of high fragmentation, dominance decreases, but some dominant landscape still exist in this region. (4) Urbanization and natural factors lead to the reduction of wetland area. Besides the pressure of population is a major threat to the wetland. The study will provide scientific basis for long-term planning for this region.

scholarly journals Coastal Wetland Shoreline Change Monitoring: A Comparison of Shorelines from High-Resolution WorldView Satellite Imagery, Aerial Imagery, and Field Surveys

2021 ◽  
Vol 13 (15) ◽  
pp. 3030
Author(s):  
Kathryn E. L. Smith ◽  
Joseph F. Terrano ◽  
Jonathan L. Pitchford ◽  
Michael J. Archer
Keyword(s):  
High Resolution ◽  
Satellite Imagery ◽  
Coastal Wetland ◽  
Shoreline Change ◽  
Gps Data ◽  
Change Analysis ◽  
High Resolution Satellite Imagery ◽  
Vulnerable Habitats ◽  
High Wave Energy ◽  
Change Monitoring

Shoreline change analysis is an important environmental monitoring tool for evaluating coastal exposure to erosion hazards, particularly for vulnerable habitats such as coastal wetlands where habitat loss is problematic world-wide. The increasing availability of high-resolution satellite imagery and emerging developments in analysis techniques support the implementation of these data into shoreline monitoring. Geospatial shoreline data created from a semi-automated methodology using WorldView (WV) satellite data between 2013 and 2020 were compared to contemporaneous field-surveyed Global Position System (GPS) data. WV-derived shorelines were found to have a mean difference of 2 ± 0.08 m of GPS data, but accuracy decreased at high-wave energy shorelines that were unvegetated, bordered by sandy beach or semi-submergent sand bars. Shoreline change rates calculated from WV imagery were comparable to those calculated from GPS surveys and geospatial data derived from aerial remote sensing but tended to overestimate shoreline erosion at highly erosive locations (greater than 2 m yr−1). High-resolution satellite imagery can increase the spatial scale-range of shoreline change monitoring, provide rapid response to estimate impacts of coastal erosion, and reduce cost of labor-intensive practices.

scholarly journals Large-scale predictions of saltmarsh carbon stock based on simple observations of plant community and soil type

2018 ◽  
Author(s):  
Hilary Ford ◽  
Angus Garbutt ◽  
Mollie Duggan-Edwards ◽  
Jordi F. Pagès ◽  
Rachel Harvey ◽  
...  
Keyword(s):  
Plant Community ◽  
Salt Marshes ◽  
Soil Type ◽  
Carbon Stock ◽  
Large Scale ◽  
Coastal Wetland ◽  
Blue Carbon ◽  
Wetland Ecosystems ◽  
Carbon Store ◽  
Carbon Stores

Abstract. Carbon stored in coastal wetland ecosystems is of global relevance to climate regulation. Broad-scale inventories of this "blue" carbon store are currently lacking and labour intensive. Sampling 23 salt marshes in the United Kingdom, we developed a Saltmarsh Carbon Stock Predictor (SCSP) with the capacity to predict up to 44 % of spatial variation in soil organic carbon (SOC) from simple observations of plant community and soil type. Classification of soils into two types (sandy or not-sandy) explained 32 % of variation in SOC. Plant community type (5 vegetation classes) explained 37 % of variation. Combined information on soil and plant community types explained 44 % of variation in SOC. GIS maps of SOC were produced for all salt marshes in Wales (~ 4000 hectares), using existing soil maps and governmental vegetation data, demonstrating the application of the SCSP for large-scale predictions of blue carbon stores and the use of plant community traits for predicting ecosystem services.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
United States ◽  
Salt Marsh ◽  
Marine Fish ◽  
Salt Marshes ◽  
Coastal Wetlands ◽  
Life Histories ◽  
Coastal Wetland ◽  
Fish Habitat ◽  
Northeastern United States ◽  
Fishery Habitat

<em>Abstract</em> .—The importance of coastal wetlands to a large number of commercially important marine fish species for spawning, nursery, and foraging habitat is a commonly held belief. Few studies to substantiate this belief have been conducted in the northeastern United States. This paper examines in detail the life histories and habitat requirements of three species of fish commonly found in salt marshes in the northeastern United States. The results indicate that valuable commercial and recreational species of fish and their prey require coastal wetlands as habitat during their life cycles in New England. Coastal wetland restoration projects will increase the abundance of wetland habitat types required by commercial and recreational species of marine fish. The restoration of the salt marsh within the Galilee Bird Sanctuary in Narragansett, Rhode Island is used as case study. When enhancement of fishery habitat value is a goal of a restoration project, the project should incorporate certain design features. However, the designers of many salt-marsh restoration projects assume that reestablishment of salt-marsh vegetation will result in recolonization by other species of animals.

Modeling Wave Attenuation With Rigid Vegetation Plants

2014 ◽  
Author(s):  
Don Liu ◽  
Yonglai Zheng
Keyword(s):  
High Resolution ◽  
Flow Field ◽  
Coastal Wetlands ◽  
Large Scale ◽  
High Efficiency ◽  
Wave Attenuation ◽  
Direct Numerical Simulations ◽  
Regular Pattern ◽  
Rigid Vegetation ◽  
Cylinder Model

Virtual Cylinder Model (VCM) was used to simulate flows over vegetation plants (cylinders) in coastal wetlands. VCM is capable of characterizing the flow field with a few plants as well as numerous plants with high efficiency and accuracy. Numerical results of flow over cylinders at a regular pattern are compared with Direct Numerical Simulations and at irregular patterns are presented with varied resolutions. VCM provides decent accuracy and efficiency without high resolution in tiny mesh. Results demonstrate that it is suitable for large-scale simulation of vegetation resilience to protect coastal wetlands from waves.

Updating global coastal wetland areas presented in Davidson and Finlayson (2018)

2019 ◽  
Vol 70 (8) ◽  
pp. 1195 ◽  
Author(s):  
Nick C. Davidson ◽  
C. Max Finlayson
Keyword(s):  
Salt Marshes ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Tidal Flats ◽  
Seagrass Beds ◽  
Wetland Area

Global and regional areas and trends in area of unvegetated tidal flats, salt marshes, mangroves and seagrass beds are updated and corrected from those published in Davidson and Finlayson (2018). The global area of coastal wetlands is now estimated as a minimum of 1.42×106 km2, ~8.9–9.5% of an updated global wetland area of 15.0×106–16.0×106 km2.

Coastal Wetland Investigations by Airborne LiDAR: A Case Study in the Yellow River Delta, China

2011 ◽  
Vol 45 (5) ◽  
pp. 59-70 ◽  
Author(s):  
Qiong Ding ◽  
Wu Chen ◽  
Bruce Anthony King ◽  
Yongqi Chen ◽  
Yanxiong Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Yellow River ◽  
Yellow River Delta ◽  
River Delta ◽  
Airborne Lidar ◽  
Vegetation Coverage ◽  
The Yellow River ◽  
The Yellow River Delta

AbstractCoastal wetlands are considered the most biologically diverse of all ecosystems. Understanding their structures and functions is important for coastal environmental management and development. Airborne LiDAR (Light Detection and Ranging) has emerged as an effective tool for creating high-resolution digital surface models (DSM, highest elevation points) and digital terrain models (DTM, ground only points), which are vital geographic information sources for various applications in coastal areas, and investigating spatial patterns of vegetation in areas that are difficult to access. This paper investigates LiDAR’s capability for mapping marine wetlands, extracting vegetation and channel networks, and identifying intertidal zones. The Yellow River Delta, China, was selected as a study site to conduct experiments. With only a 4.5-h flight, an area of more than 670 km2 was surveyed with great detail. High-resolution DSMs and DTMs were generated, the vegetation coverage and heights were extracted using methods based on height and multi-return and the results were compared, and the water and tidal channels, which reflect the complete water transport system in the area, were mapped and measured. By combining LiDAR data and local tidal observations, the intertidal zone, which is a significant part of coastal wetlands, is clearly identified.

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