Coasts and Estuaries

The Future

Eric Wolanski, John W. Day, Michael Elliott, Ramachandran Ramesh, Eric Wolanski, John W. Day, Mike Elliott, Ramachandran Ramesh

• Editore: Elsevier
• Anno: 2019
• ISBN:
  9780128140048
• Argomento: Physical Sciences
• Categoria: Oceanography

Coasts and Estuaries: The Future provides valuable information on how we can protect and maintain natural ecological structures while also allowing estuaries to deliver services that produce societal goods and benefits. These issues are addressed through chapters detailing case studies from estuaries and coastal waters worldwide, presenting a full range of natural variability and human pressures. Following this, a series of chapters written by scientific leaders worldwide synthesizes the problems and offers solutions for specific issues graded within the framework of the socio-economic-environmental mosaic. These include fisheries, climate change, coastal megacities, evolving human-nature interactions, remediation measures, and integrated coastal management.

The problems faced by half of the world living near coasts are truly a worldwide challenge as well as an opportunity for scientists to study commonalities and differences and provide solutions. This book is centered around the proposed DAPSI(W)R(M) framework, where drivers of basic human needs requires activities that each produce pressures. The pressures are mechanisms of state change on the natural system and Impacts on societal welfare (including well-being). These problems then require responses, which are the solutions relating to governance, socio-economic and cultural measures (Scharin et al 2016).

• Covers estuaries and coastal seas worldwide, integrating their commonality, differences and solutions for sustainability
• Includes global case studies from leading worldwide contributors, with accompanying boxes highlighting a synopsis about a particular estuary and coastal sea, making all information easy to find
• Presents full color images to aid the reader in a better understanding of details of each case study
• Provides a multi-disciplinary approach, linking biology, physics, climate and social sciences

Chapter 1

A Synthesis: What Is the Future for Coasts, Estuaries, Deltas and Other Transitional Habitats in 2050 and Beyond?

Michael Elliott^⁎; John W. Day^†; Ramesh Ramachandran^‡; Eric Wolanski^{§ *} Institute of Estuarine and Coastal Studies, University of Hull, Hull, United Kingdom
^† Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA, United States
^‡ National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Government of India, Anna University Campus, Chennai, India
^§ TropWATER and College of Marine & Environmental Sciences, James Cook University and Australian Institute of Marine Science, Townsville, QLD, Australia

Abstract

We synthesized the results of many case studies from experts worldwide on the state of the environment, sustainability, and the likely future of estuaries, lagoons, semienclosed seas, and coastal ecosystems. There is a high natural variability in these ecosystems and in their responses to historical human pressures within their catchments, the river, and the estuary, and the potential for sustainability depends on many variables including population growth, the culture, historical changes, and the involvement of the communities. The problems faced by half of the global population living near coasts are truly worldwide challenges and they give us the opportunity to study commonalities and differences and to provide solutions. Fundamental to addressing these challenges is an understanding of the biophysical constraints especially along the catchment-river-estuary ecosystem continuum. We emphasize that there is a need to better manage all these areas to ensure that we can maintain natural ecological structure and functioning while also allowing these systems to deliver services that produce societal goods and benefits, both now and in the future. By investigating the problems, we can offer solutions for specific issues graded within the framework of the socioeconomic and environmental mosaic. These challenges include fisheries, climate change, growing resource scarcity, coastal megacities, a growing population and an increaisng urbanisation and industrialisation of the coast, evolving human-nature interactions, remediation measures, and the willingness to adopt governance at the catchment scale. In these case studies, the DAPSI(W)R(M) problem-solving framework usefully allows us to assess risks and potentials for an effective response which have to be based on the use of good science. To be effective, this framework must be accompanied by the so-called 10-tenets of sustainable management, which include the ecological, economic, technological, societal, administrative, legislative, political, ethical/moral, cultural, and communication aspects. Stakeholder involvement therefore becomes central to successful management of the coasts and estuaries in accommodating changes over the coming century.

Keywords

Human population; Urban development; Degradation; Sustainability; Restoration; Recovery; Use of science; Catchment-river-estuary ecosystem

1 Introduction

Estuaries, deltas, coastal lagoons, and fjords are transitional waters and contain ecosystems between riverine and coastal marine ecosystems. They are sites of important connectivity and intense gradients that make them among the world’s most productive ecosystems. The coastal and transitional areas considered here are only a small fraction of the marine and brackish areas worldwide (~ 5%) but produce approximately half of the global fish catch per year (Palomares and Pauly, 2019). Although up to half of this catch is from small-scale fisheries (artisanal, subsistence, and recreational), it gains less attention worldwide than the larger-scale and open ocean industrial fisheries. At the same time, they develop ecological communities with an important diversity and complex mechanisms of self-regulation (Pérez-Ruzafa et al., 2019) and they provide significant ecosystem services and societal goods and benefits (Van den Belt and Costanza, 2011; Wolanski and Elliott, 2015). These and associated coastal ecosystems, including the open coast, enclosed and semi-enclosed seas, and special systems such as polar and coral environments, will be subject to change in the coming decades, and those changes will have to be either managed or accommodated by society.

Coastal and transitional ecosystems have been, are being, and will continue to be adversely affected by global climate change in many ways. These changes include increasing temperatures and sea levels, either reduced, increased, or at least subject to more erratic rainfall and freshwater discharges, especially in temperate areas, and the likelihood of more frequent or more severe droughts and storms (Day and Rybczyk, 2019). The changes to biogeographical regimes are likely with the movement of organism distributions toward higher latitudes. Higher sea levels, perhaps up to 1.5 m higher in the next century, will both increase saline intrusion and water levels into transitional areas, thereby changing vegetation and foodweb structure and perhaps causing loss of wetlands that have been important in producing ecosystem services and delivering societal goods and benefits. Growing resource scarcity, especially of energy, will limit our ability to handle these evolving problems effectively (Day et al., 2016, 2018; Wiegman et al., 2017; Day and Rybczyk, 2019).

In addition to climate changes, coastal and transitional ecosystems are increasingly subject to other types of environmental degradation, not least from increased industrialization, urbanization (urban development), and agricultural and aquacultural expansion. There is an increasing occurrence of non-native species with more vectors and migration routes becoming available; for example, the loss of polar ice may open up migration routes. There is increasing habitat loss and fragmentation not the least of which is because of land use changes for perhaps short-term economic gain but with long-term environmental and societal consequences; for example, the loss of mangroves for shrimp ponds ultimately reduces the resilience of coasts to hazards and storm events (Elliott et al., 2015, 2016; Day and Rybczyk, 2019). Because of this, there is the need for a holistic approach which incorporates the catchment-river-estuary continuum of ecosystems as well as the adjacent coastal and marine areas.

This synthesis, which is based largely on the chapters in this volume, aims to show that an eventual reduction in land and water resources, and perhaps increases in energy use in restoration and alleviation schemes, have long-term consequences (Day and Rybczyk, 2019). The loss of these resources and the increase in arid areas, the reduction in deltas and wetlands, and the loss of resilience and resistance to natural hazards may all exceed biophysical limits. Therefore, using a set of case studies covering a large geographical area (Fig. 1), in this chapter we focus on the need for a holistic approach to create sustainable management of the coastal areas. We emphasise that there is the need for a good and appropriate use of the best-available science linked to that management. Such science will help to indicate the causes and consequences of the problems as well as the solutions to them.

Fig. 1 Location map of the main study sites discussed in the text.

2 Setting the Scene: The DAPSI(W)R(M) Framework

All environments are affected by change, both natural and anthropogenic. To determine the causes and consequences of change, there is an increasing need for risk assessment and risk management frameworks that center on the human uses and abuses of the environment. One such framework originated as the DPSIR approach, but it more recently has been refined into DAPSI(W)R(M) (Drivers, Activities, Pressures, State change, Impacts (on human Welfare), Responses (using management Measures), (Patricio et al., 2016; Elliott et al., 2017). This relates to the acceptance that society has basic demands, termed Drivers, from the environment, such as the need for food, for shelter, well-being, and security, which require current Activities in an area. These activities in turn create Pressures in an area, which are termed endogenic managed pressures (for example, the need to go fishing for food and to build sea defenses for shelter and security as the mechanisms of change; again, for example, fishing involves scraping nets over the bed whereas building sea defenses may influence hydrographic processes and sediment-scouring in an area). The pressures are the mechanisms of both State change on the natural system (the loss of biota or the interference with normal hydrographic processes) and Impacts (on human Welfare). For example, the latter may be a loss of fish for human food or the reduced resilience of an area to storm events that results in the loss of human assets and livelihoods. The State changes and the Impacts on human Welfare then require Responses, which are management Measures to prevent the adverse effects. Hence the Responses should operate on the Drivers, Activities and Pressures.

The Responses (including management Measures) can fall within what has been termed the 10-tenets: that for the management to be successful and sustainable, our actions have to be ecologically sustainable, technologically feasible, economically viable, socially desirable/tolerable, legally permissible, administratively achievable, politically expedient, ethically defensible (morally correct), culturally inclusive, and effectively communicable (Barnard and Elliott, 2015). It is emphasized that whereas only one of these relates to ecological well-being, the remainder are all society-based. As noted earlier, growing pressures arising from climate change, resource scarcity, environmental degradation, and growing population will challenge the ability to manage these problems effectively.

The Endogenic Managed Pressures emanate from inside an area in which management can address both the causes and the consequ...