Impacts of coastal reclamation on wetlands: Loss, resilience, and sustainable management

Abstract Coastal wetlands are some of the most valuable ecosystems on Earth because they provide many ecological services for coastal security. However, these wetlands are seriously threatened by accelerated climate change and intensive anthropogenic activities. To understand the impacts of land reclamation on landscape change of coastal wetlands and the long-term effects of disturbances of coastal wetlands on their sustainable management, we used time-series Landsat imagery with an object-oriented classification and Digital Shoreline Analysis System to map wetland changes within a reclaimed area in the Pudong District (PD), in Shanghai, China. Our analysis indicated that from 1989 to 2013, 19,793.4 ha of coastal wetlands have been changed to inland wetlands enclosed by a seawall and dike since 1989, thereby cutting off the exchange of sediment and water flux between the wetlands and the coastal ocean. Subsequently, under the increasing threats of anthropogenic activities, the wetland ecosystem collapsed sharply, in a transformation chain of inland wetland (fresh swamp), artificial wetland (agriculture and aquaculture wetland), and non-wetland (urban land). Under this explosive utilization following coastal reclamation, only 8.9% of natural wetlands remain in the reclaimed area, which has experienced an average annual wetland loss rate of 3.8% over the past 24 years. More than 80% of the wetlands have been developed for agricultural, industrial, and urban land uses, leading to an enormous loss of associated ecological services—benefits arising from the ecological functions provided by wetland ecosystems, thereby undermining the coastal protection these wetlands provided. Nevertheless, considerable regeneration of wetlands occurred because of their inherent resilience. This paper addresses the importance of maintaining a balance between economic growth and coastal ecological protection for sustainable management. It proposes a strategy for how ecosystem-based land planning and ecological engineering should be applied to ensure the effective and sustainable management of living shorelines so that the benefits of healthy ecological functions accrue to coastal ecosystems.

[1]  R. O'Neill,et al.  The value of the world's ecosystem services and natural capital , 1997, Nature.

[2]  Y. Hayashi,et al.  Application of an integrated system dynamics and cellular automata model for urban growth assessment: A case study of Shanghai, China , 2009 .

[3]  Carrie V. Kappel,et al.  Coastal Ecosystem-Based Management with Nonlinear Ecological Functions and Values , 2008, Science.

[4]  B. Li,et al.  Monitoring rapid vegetation succession in estuarine wetland using time series MODIS-based indicators: An application in the Yangtze River Delta area , 2009 .

[5]  Z. Dai,et al.  Detection of the Three Gorges Dam influence on the Changjiang (Yangtze River) submerged delta , 2014, Scientific Reports.

[6]  M. Kirwan,et al.  Tidal wetland stability in the face of human impacts and sea-level rise , 2013, Nature.

[7]  Wu Wenting,et al.  The trends of coastal reclamation in China in the past three decades , 2016 .

[8]  Hanqiu Xu.  Extraction of Urban Built-up Land Features from Landsat Imagery Using a Thematicoriented Index Combination Technique , 2007 .

[9]  N. Nakagoshi,et al.  The impact of urban planning on land use and land cover in Pudong of Shanghai, China. , 2003, Journal of environmental sciences.

[10]  Carrie V. Kappel,et al.  Understanding and Managing Human Threats to the Coastal Marine Environment , 2009, Annals of the New York Academy of Sciences.

[11]  P. Kareiva,et al.  Coastal habitats shield people and property from sea-level rise and storms , 2013 .

[12]  Jing Li,et al.  A Review of Wetland Remote Sensing , 2017, Sensors.

[13]  Li Xing,et al.  Shanghai Urban Wetland Extraction and Classification with Remote Sensed Imageries Based on A Decision Tree Model , 2009 .

[14]  Helen Briassoulis,et al.  The Socio-ecological Fit of Human Responses to Environmental Degradation: An Integrated Assessment Methodology , 2015, Environmental Management.

[15]  Xing Li,et al.  Evolution of the Jiuduansha wetland and the impact of navigation works in the Yangtze Estuary, China , 2016 .

[16]  Chris J. Kennedy,et al.  The value of estuarine and coastal ecosystem services , 2011 .

[17]  M. Snoussi,et al.  Vulnerability assessment of the impact of sea-level rise and flooding on the Moroccan coast: the case of the Mediterranean eastern zone. , 2008 .

[18]  J. Milliman,et al.  50,000 dams later: Erosion of the Yangtze River and its delta , 2011 .

[19]  P. V. Sundareshwar,et al.  RESPONSES OF COASTAL WETLANDS TO RISING SEA LEVEL , 2002 .

[20]  G. Daily,et al.  The Ecosystem Services Framework and Natural Capital Conservation , 2008 .

[21]  S. Temmerman,et al.  Limits on the adaptability of coastal marshes to rising sea level , 2010 .

[22]  F. J. Jiménez-Cárceles,et al.  Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities , 2007 .

[23]  E. Granek,et al.  Information Needs Assessment for Coastal and Marine Management and Policy: Ecosystem Services Under Changing Climatic, Land Use, and Demographic Conditions , 2015, Environmental Management.

[24]  A. Ayanlade,et al.  Assessing wetland degradation and loss of ecosystem services in the Niger Delta, Nigeria , 2016 .

[25]  Bo Tian,et al.  Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010 , 2016 .

[26]  Tsai-Ming Lee,et al.  Applying remote sensing techniques to monitor shifting wetland vegetation: a case study of Danshui River estuary mangrove communities, Taiwan. , 2009 .

[27]  Stacy L. Ozesmi,et al.  Satellite remote sensing of wetlands , 2002, Wetlands Ecology and Management.

[28]  D. Donato,et al.  Estimating Global “Blue Carbon” Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems , 2012, PloS one.

[29]  K. Schuyt.  Economic consequences of wetland degradation for local populations in Africa , 2005 .

[30]  Carlos M. Duarte,et al.  A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2 , 2011 .

[31]  R. Nicholls,et al.  Future flood losses in major coastal cities , 2013 .

[32]  L. Cui,et al.  Integrated Approach Based on a Regional Habitat Succession Model to Assess Wetland Landscape Ecological Degradation , 2015, Wetlands.

[33]  Demin Zhou,et al.  Mapping wetland changes in China between 1978 and 2008 , 2012 .

[34]  S. Temmerman,et al.  Ecosystem-based coastal defence in the face of global change , 2013, Nature.

[35]  B. Anderson,et al.  The rising tide: assessing the risks of climate change and human settlements in low elevation coastal zones , 2007 .

[36]  Ronald M. Thom,et al.  Detecting wetland changes in Shanghai, China using FORMOSAT and Landsat TM imagery , 2015 .

[37]  Bregje K. van Wesenbeeck,et al.  Coastal adaptation with ecological engineering , 2013 .

[38]  K. Zainal,et al.  The cumulative impacts of reclamation and dredging on the marine ecology and land-use in the Kingdom of Bahrain. , 2012, Marine pollution bulletin.

[39]  Zoltán Vekerdy,et al.  Spatial analysis of the impact of shrimp culture on the coastal wetlands on the Northern coast of Sinaloa, Mexico , 2011 .

[40]  W. Kuang,et al.  Mapping Water Vulnerability of the Yangtze River Basin: 1994–2013 , 2016, Environmental Management.

[41]  A. Cazenave,et al.  Sea-Level Rise and Its Impact on Coastal Zones , 2010, Science.

[42]  Alex W. Peimer,et al.  National-Level Wetland Policy Specificity and Goals Vary According to Political and Economic Indicators , 2016, Environmental Management.

[43]  D. Cahoon,et al.  A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise , 2013 .

[44]  C. Lemckert,et al.  Impact of urbanization on coastal wetland structure and function , 2006 .