We elevate the undervalued role of wetland protective services for mitigating disastrous consequences of unprecedented weather-related events for human communities. Scientific evidence increasingly reveals that wetlands play critical hydrologic roles in landscapes, helping to mitigate flood, drought, and, in some cases, fire risks. However, wetland protective services have not received sufficient policy action. We propose national wetland commissions, modeled after the concept of lake and river commissions, as one way to strategically link wetland protection to other societal objectives, including human disaster risk planning, infrastructure investments, and climate adaptation strategies. We offer an example applicable to the United States, describing an institutional design for a National Interagency Wetland Commission. We suggest it could be patterned after existing federal commissions statutorily created by Congress with delegated administrative and regulatory authority and designated independent agency status within the executive branch. It is time for bold and innovative policy action to incorporate wetland protective services into societies’ defenses against extreme weather events.
Habitat Type: CST
Coastal ecosystem
Oyster reefs have the potential as eco-engineers to improve coastal protection. A field experiment was undertaken to assess the benefit of oyster breakwater reefs to mitigate shoreline erosion in a monsoon-dominated subtropical system. Three breakwater reefs with recruited oysters were deployed on an eroding intertidal mudflat at Kutubdia Island, the southeast Bangladesh coast. Data were collected on wave dissipation by the reef structures, changes in shoreline profile, erosion-accretion patterns, and lateral saltmarsh movement and related growth. This was done over four seasons, including the rainy monsoon period. The observed wave heights in the study area ranged 0.1–0.5 m. The reefs were able to dissipate wave energy and act as breakwaters for tidal water levels between 0.5–1.0 m. Waves were totally blocked by the vertical relief of the reefs at water levels <0.5 m. On the lee side of the reefs, there was accretion of 29 cm clayey sediments with erosion reduction of 54% as compared to control sites. The changes caused by the deployed reefs also facilitated seaward expansion of the salt marsh. This study showed that breakwater oyster reefs can reduce erosion, trap suspended sediment, and support seaward saltmarsh expansion demonstrating the potential as a nature-based solution for protecting the subtropical coastlines.
‘Ocean Cities’ of the Pacific are where urban landscapes and seascapes meet, where built and natural environments interface, and where human behaviour and urban development have profound impacts on both terrestrial and marine ecosystems. Ocean Cities are at the forefront of climate change consequences, urbanisation challenges, and other development pressures. This article discusses the potential for nature-based solutions (NbS), including those focused on ecosystem services, in Pacific Small Island Developing States (SIDS) as a response to climate change, population growth, and urbanisation. Attention is directed to identifying the benefits of NbS and case-studies from Pacific SIDS, and if not available regionally, further afield. The article provides focus on possible barriers to implementation of NbS in a Pacific SIDS context and potential policy responses to these. Conclusions are threefold: (i) addressing interlinked ecological, climate, and human wellbeing issues in an integrated, ocean-focused and climate-responsive manner is vital for sustainable development in island systems; (ii) NbS can provide significant human wellbeing and biodiversity benefits in this context; and (iii) Pacific Ocean Cities, with a significant body of relevant traditional knowledge and emerging NbS experience, can inform global understanding of how to address converging urbanisation and climate change issues in Ocean Cities.
The concept and establishment of Ecological Networks (EN) have been seen as a solution towards nature conservation strategies targeting biodiversity and ecological connectivity. Within this, the EN assumed a holistic view of land-use planning and biodiversity conservation as the core of the wider Green Infrastructure (GI) framework. The EN is considered a spatial concept recognized as a system of landscape structures or ecosystems, and a strategically connected fundamental infrastructure of abiotic and biotic systems, underlying the provision of multiple functions valuable to society. This concept moves beyond traditional approaches of “nature protection and preservation”, (re)focusing on the ecosystemic approach and the “continuum naturale”, emphasising the quality or potentiality of physical components, allowing the articulation with the nature conservation and at-risk areas. Portugal has long had legislation in place meant to protect the natural resources. Although the environmental policies are sectoral and unarticulated, and the environmental data is dispersed and absent. In addition, this study shows that the existing protected areas in Portugal, namely Natura 2000 and classified protected areas, are insufficient to ensure landscape ecological balance and avoid fragmentation. The main goal is to develop a methodology to map a National Ecological Network (NEN) for mainland Portugal, establish the theoretical framework of the EN/GI, by identifying and mapping the most valuable and sensitive areas that guarantee the ecosystem functioning through a multi-level ecological evaluation criteria that integrate the physical and biological systems. The Portuguese NEN map, with a 25 m spatial resolution, integrates in a single tool the Portuguese environmental policies more effectively, in order to facilitate its understanding and application into planning. Regarding the EN mapping method, it was used a GIS-based model made up of a sequence of analyses and evaluations that are driven by a GIS supported assessment of several indices/models used for each EN component. These NEN components were studied individually and collectively and the results, hierarchized in two levels, show that most of the ecological components do not overlap. The NEN1 has high biodiversity and ecological value, which means they are more vulnerable to anthropogenic activity. NEN1 covers a total of 67 % of the mainland, yet as of 2018, only 25 % is protected in nature conservation areas. Priority of action must be given to NEN1 in order to avoid/decrease landscape fragmentation, environmental risks, and natural disaster prevention. This paper contributes to the understanding of the NEN importance as an ecologically based tool towards a more sustainable landscape planning, and the basis of the development plans at national, regional and local levels in an integrated manner, instead of a compilation of disassociated often-contradictory planning tools. The benefits of a Portuguese NEN into a GI development and part of a (broader) nature base solutions by increasing the ecosystems quality and become less dependent on economic and social activities, helping in the restoration of degraded ecosystems and environmental risk prevention. Moreover, it represents the first attempt to map Portuguese EN, and addresses the lack of mapping and the inconsistent EN criteria. It is available online at http://epic-webgis-portugal.isa.ulisboa.pt.
Tropical beaches provide coastal flood protection, income from tourism, and habitat for flagship species. They urgently need protection from erosion, which is being exacerbated by changing climate and coastal development. Traditional coastal engineering solutions are expensive, provide unstable temporary solutions, and often disrupt natural sediment transport. Instead, natural foreshore stabilization and nourishment may provide a sustainable and resilient long-term solution. Field flume and ecosystem process measurements, along with data from the literature, show that sediment stabilization by seagrass in combination with sediment-producing calcifying algae in the foreshore form an effective mechanism for maintaining tropical beaches worldwide. The long-term efficacy of this type of nature-based beach management is shown at a large scale by comparing vegetated and unvegetated coastal profiles. We argue that preserving and restoring vegetated beach foreshore ecosystems offers a viable, self-sustaining alternative to traditional engineering solutions, increasing the resilience of coastal areas to climate change.
Urban nature has the potential to improve air and water quality, mitigate flooding, enhance physical and mental health, and promote social and cultural well-being. However, the value of urban ecosystem services remains highly uncertain, especially across the diverse social, ecological and technological contexts represented in cities around the world. We review and synthesize research on the contextual factors that moderate the value and equitable distribution of ten of the most commonly cited urban ecosystem services. Our work helps to identify strategies to more efficiently, effectively and equitably implement nature-based solutions.
Much of the United States’ critical infrastructure is either aging or requires significant repair, leaving U.S. communities and the economy vulnerable. Outdated and dilapidated infrastructure places coastal communities, in particular, at risk from the increasingly frequent and intense coastal storm events and rising sea levels. Therefore, investments in coastal infrastructure are urgently needed to ensure community safety and prosperity; however, these investments should not jeopardize the ecosystems and natural resources that underlie economic wealth and human well-being. Over the past 50 years, efforts have been made to integrate built infrastructure with natural landscape features, often termed “green” infrastructure, in order to sustain and restore valuable ecosystem functions and services. For example, significant advances have been made in implementing green infrastructure approaches for stormwater management, wastewater treatment, and drinking water conservation and delivery. However, the implementation of natural and nature-based infrastructure (NNBI) aimed at flood prevention and coastal erosion protection is lagging. There is an opportunity now, as the U.S. government reacts to the recent, unprecedented flooding and hurricane damage and considers greater infrastructure investments, to incorporate NNBI into coastal infrastructure projects. Doing so will increase resilience and provide critical services to local communities in a cost-effective manner and thereby help to sustain a growing economy.
Intensively used coastal zones often know a history of hard defense structures to prevent erosion and protect infrastructure against floods. The interruption of sand transport between sea, beach and dunes however causes a domination of late successional stages such as dune shrub. With the decline of young, dynamic vegetation types, a change occurs in the provision of ecosystem services. In spite of the growing awareness on the role of dune dynamics to support human well-being and biodiversity, redynamisation of dunes is rarely implemented in coastal zone management. It has been argued in research documents that this may be caused by a failure to make those benefits tangible and specific. This study aims to underpin the added value of dynamic versus fixed dunes. Five different ecosystem services in a case-study in Belgium were quantified based on (compound) indicators and expressed in monetary units. The value of a natural, dynamic dune system covering the entire gradient of dune succession and dominated by young successional stages was compared with the value of a fixed dune system dominated by late successional stages. The results indicate that a dynamic dune complex may create up to ∼50% higher economic benefits, and that the main benefits are on account of recreation and coastal safety maintenance. The results underpin the statement that we can only continue benefitting from the services dunes provide if we accept their mobile nature, but that redynamisation requires a site-specific feasibility analysis.
Future scenarios indicate that growing human encroachment on coasts, more frequent and stronger storms and sea level rise will result in worsening coastal squeeze. In consequence, human lives, property and infrastructure, as well as ecosystem services, will increasingly be threatened. It is therefore vital to find the means to maintain or increase the resilience and resistance of coastal zones. As an alternative to hard infrastructure, ecosystem-based coastal defense strategies have been recommended as better and more sustainable solutions. Thus, the goal of this study wasto understand the interaction of dune plants with waves, dunes and humans. We used a pantropical beach plant (Ipomoea pes-caprae) and performed 24 wave flume experiments with two beach-dune profiles, four densities of vegetation cover, and three storm regimes. We also tested tolerance to burial in seed germination and seedling growth and finally explored the impact of tourism on Ipomoea. Erosion regimes of collision and overwash were observed in the dune profiles with a berm, whereas swash and overwash regimes were observed when no berm was present. Plant cover prevented overwash and thereby erosion of the landward side of the dune. Positive responses in seeds and seedlings of Ipomoea to burial by sand enable this plant to act as a dune builder. In conditions with low tourism, Ipomoea seems to be more affected by seasonal and meteorological conditions than by trampling. These responses increase further the potential for coastal protection of Ipomoea and, thus, such an ecosystem-based protective structure can be self-sustainable.
Much of the United States’ critical infrastructure is either aging or requires significant repair, leaving U.S. communities and the economy vulnerable. Outdated and dilapidated infrastructure places coastal communities, in particular, at risk from the increasingly frequent and intense coastal storm events and rising sea levels. Therefore, investments in coastal infrastructure are urgently needed to ensure community safety and prosperity; however, these investments should not jeopardize the ecosystems and natural resources that underlie economic wealth and human well-being. Over the past 50 years, efforts have been made to integrate built infrastructure with natural landscape features, often termed “green” infrastructure, in order to sustain and restore valuable ecosystem functions and services. For example, significant advances have been made in implementing green infrastructure approaches for stormwater management, wastewater treatment, and drinking water conservation and delivery. However, the implementation of natural and nature-based infrastructure (NNBI) aimed at flood prevention and coastal erosion protection is lagging. There is an opportunity now, as the U.S. government reacts to the recent, unprecedented flooding and hurricane damage and considers greater infrastructure investments, to incorporate NNBI into coastal infrastructure projects. Doing so will increase resilience and provide critical services to local communities in a cost-effective manner and thereby help to sustain a growing economy.
Ecosystem-based approaches have proven effective and efficient in reducing disaster risks while ensuring continued benefits to people from ecosystem services. In this article, a new concept of Ecosystem-based Disaster Risk Reduction (Eco-DRR) for enhancing social-ecological resilience is proposed, based on analysis of several case studies. Field studies in developing countries such as Ghana and Myanmar have shown the benefits of Eco-DRR as implemented by local communities. These projects improve local livelihoods and social-ecological resilience. In Japan, after the massive damage from the 11 March 2011, Great East Japan earthquake and tsunami, ecosystem-based approaches were an important element of the national government’s DRR efforts. Analysis of these cases shows that Eco-DRR is a socially, economically and environmentally sustainable tool for DRR that creates new value for a region. It also shows the importance of multi-stakeholder participation in the process of promoting Eco-DRR. It is likely to become even more important in the future, as a means for addressing the increase in disasters resulting from climate and ecosystem change as well as demographic change. The contribution of Eco-DRR to maintaining and restoring ecosystems is particularly valuable for countries where there is reduced capacity for land management, as currently occurring in Japan due to rapid population decline and aging.
Traditionally, actions taken to reduce vulnerability to beach erosion have been based on protecting economic resources, recreational activities and human lives. Hard infrastructure for coastal protection has proven effective, but the side effects have been called into question, given that making the coastal system more rigid alters the natural dynamics, degrades environmental services and damages the landscape. Ecosystem based coastal defence strategies are now seen as a more environmentally friendly alternative which can maintain and even increase the resilience and resistance of coastal zones. This work aims to improve the understanding of the behaviour of nature-based coastal defences by analysing the morphodynamic response of a dune-beach system with vegetation to storms. Small scale tests were performed in which beach profiles with natural dune vegetation were exposed to high energy waves. Free surface elevation and velocity profiles were recorded during the tests and the profile evolution was measured at the end of each experiment. Erosion regimes of collision and overwash were observed in the dune profiles with a berm, whereas swash and overwash regimes were observed when no berm was present. Retarding erosion time seems to be the most relevant morphological effect of the dune vegetation, which gives a slight, but relevant, contribution to the resilience and resistance of the beach profile. In turn, the wave breaking point is displaced seawards and bed velocities close to the shoreline are lower when vegetation is present, both of which explain the protective role of vegetation on the beach profile. To develop a numerical tool capable of reproducing the morphological evolution of the beach profiles tested, the CSHORE model was calibrated and validated for the laboratory data finding good correlation.
A changing climate will inevitably impact on the natural environment, including agriculture. Anticipatory adaptation is necessary to minimise the negative impacts of climate change, to take advantage of opportunities, and to ensure that food and fibre production is maintained. More detailed information is required as to which adaptation measures will yield relatively greater social rates of return. Such information would help define an efficient adaptation agenda in the agricultural sector. This article identifies key adaptation strategies across England’s agricultural sector, and applies cost–benefit analysis to these to determine their net present values, highlighting where the greatest returns can be made, and the role for policy. The results span a wide range, with some soil management activities indicating a negative NPV of £122 million over the course of this century, to a positive NPV of £3,279 million in the case of some livestock adaptations to heat stress. Animal disease surveillance and peatland restoration also generated high NPVs of £1,850 million and £1,840 million, respectively. Adaptations addressing crop disease, water storage measures and managed coastal realignment generated more modest values ranging from £1 million to £61 million. Direct comparison of the numbers is misleading however as some refer to the national level while others are site‐specific. The analysis provides a basis for a discussion on priorities and planning for adaptation in the agricultural sector.
Around 0 AD, the Rhine-Meuse estuary in the southwest of the Netherlands was a typical coastal plain estuary. Drainage of peatland and land subsidence behind the dunes later caused the sea to penetrate into the land. Most of the peat was eroded, and by 1000 AD the so-called Delta area had turned into a landscape of large estuaries and intertidal zones. Rotterdam developed from a small fishing village on the banks of the tidal river “Nieuwe Maas” from the 14th century onwards into the largest seaport of Europe in 2013. The Rotterdam harbour area situated in the northern part of the Delta area includes the former Europoort harbour, and is nowadays known as Rijnmond. The hydrology of the area is controlled by the drainage regime of the sluices in the Haringvliet barrier that was constructed as part of the “Delta Works” project to protect the southwest of the Netherlands against storm surges. The sluices are opened at slack tide to discharge river water to the sea and are always closed at flood tide. As a baseline study for environmental and ecological reconstruction and development, we describe in detail the loss of intertidal soft sediment ecotopes due to land reclamation, harbour development and river training works (straightening of the navigational channel) in the tidal rivers, and the expansion of hard substrate ecotopes (quay walls, groynes, training walls, riprap, concrete, stones etc.) in the Rijnmond area in the 19th and 20th centuries. Within 135 years, more than 99% of the original 4775 ha of characteristic pristine soft sediment estuarine ecotopes have disappeared. In the same period, 338 ha of hard intertidal substrate zone was constructed. Such trends can also be observed in harbour areas elsewhere, and have ecological and environmental consequences for estuarine areas in particular. Restoration of soft substrate estuarine ecotopes can be achieved by opening the Haringvliet Sluices at both ebb and flood tide, which would restore large-scale estuarine dynamics to the northern part of the Rhine-Meuse estuarine system. This will have a highly favourable effect on many ecosystem services. The Dutch division of the Word Wild Life Fund has launched a new proposal for a safer and more attractive South-West Delta area. It comprises the reopening of the sea inlets such as the Haringvliet by removing the barriers, and building climateproof dikes in combination with natural wetlands. In case of storm surges, the hinterland could be protected with a new generation of barriers that do not hamper the free transport of sediment, tides and animals. Based on 30 ecosystem services or subservices, it was calculated that opening the Haringvliet inlet would lead to an increase in Total Economic Value (TEV) of at least 500 million Euro per year. The costs of removing old barriers and the construction of new ones was not included in the calculations.
Riverine input is essential for the sustainability of the estuaries, wetlands, and swamps into which they flow. An existing coastal ecosystem model was used with forested wetland and fish habitat indicators to evaluate current environmental conditions as well as future restoration projects via 50-year simulations of riverine flow with sea level rise and subsidence. The objective of this study was to utilize the Integrated Compartment Model developed for the Louisiana Coastal Protection and Restoration Authority’s 2017 Coastal Master Plan to understand how alternations of riverine flow from existing rivers and future restoration projects may influence the spatial and temporal distribution of wetland habitats and suitability of fish habitats. The model was applied to the Lake Maurepas ecosystem where the Amite River flows into the lake and supports vital fisheries for surrounding communities, as well as a unique and valuable recreational resource. Additionally, the Amite River nourishes the marshes and swamps around Lake Maurepas that are essential for storm surge protection for the broader region. Modeling results suggest that the major contributing factor to the freshwater conditions to the Lake Maurepas area is the challenge of relative sea level rise − the combination of rising seas and subsidence. Fresh forested areas comprised of bald cypress (Taxodium distichum) and tupelo gum (Nyssa aquatica) in Maurepas Swamp decrease significantly under all future climate and relative sea level rise simulations except when future restoration projects are utilized. An estimated ∼1000 km2 of fresh forested wetland could be maintained over a 50-year period when considering certain restoration projects that increase freshwater flow and under climate change-related rainfall patterns, sea level rise and subsidence. However, modeled results indicate that more than 100% of the current riverine flows into the Maurepas Swamp region are still not sufficient to fully counteract the impacts of the assumed future sea level rise scenario and maintain the current forested wetlands surrounding Lake Maurepas. The higher salinities and more estuarine open water areas provide additional habitat in the future that will likely be more suitable for spotted seatrout (Cynoscion nebulosus), and adult bay anchovy (Anchoa mitchilli) than largemouth bass (Micropterus salmoides). Modeled future conditions of this ecosystem can inform restoration agencies and organizations by helping to prioritize and plan for future decades by incorporating critical factors such as sea level rise, subsidence and precipitation patterns, including the possible need to plan and prepare for changes in the fish communities and consider how that might influence the well-being of local communities.
Louisiana is in the midst of a land loss crisis that has claimed more than 4800 km(2) since the 1930s. Unless aggressive, large-scale action is taken, Louisiana could lose an additional 4500 km(2) in the next 50 years, resulting in a projected increase in annual damages from hurricane storm surge flooding of more than $23 billion. Louisiana’s 2012 Coastal Master Plan is a long-term plan with clear economic, social, and environmental benefits, such as decreasing potential damages from storm surge by $5.3 billion to $18 billion. Implementation of projects in the master plan should result in no net loss of land after 20 years and an annual net gain of land after 30 years. To develop the plan, the Coastal Protection and Restoration Authority (CPRA) utilized a state-of-the-art systems approach to coastal planning and a science-based decision-making process that resulted in a funding- and resource-constrained plan that makes the greatest progress toward achieving a sustainable coast. A series of integrated, coastwide predictive models were developed to provide data for a new planning tool used to identify the suite of projects that would make the greatest progress toward meeting the master plan objectives while considering uncertainties in future environmental conditions. Recognizing that the success of the plan hinges on stakeholder support, as well as science, the CPRA also implemented a comprehensive outreach plan to obtain input and feedback from key stakeholders and the public. The resulting plan recommends a specific list of restoration and protection projects and has achieved widespread support.
Since the Indian Ocean tsunami on 26 December 2004, there have been continuous efforts to upgrade the (tsunami) early warning systems as well as their accessibility in local and regional places in South and Southeast Asia. Meanwhile, the protection offered by coastal vegetation like mangroves to the people, property and physical landscape was also recognized and prioritized by both public and private authorities at various governance levels. As more than 90% of the Sri Lankan coastline is vulnerable to water-related impacts and existing bioshields like mangroves are potentially able to protect less than one-third of it, if at all they are in good condition, an attempt was made to build knowledge on the other potential natural barriers along the coast. In this context, a ca. 2 km belt of the entire coast was digitized, classified and assessed for vulnerability in relation to the existing land-use/cover. First, a visually interpreted land-use/cover map comprising 16 classes was developed using Google Earth imagery (Landsat-5, 2003). Second, based on the Global Digital Elevation Model data from the ASTER satellite, the land-use/cover map was further re-classified for elevation demarcation into waterless, run-up and flooded areas. And finally, both vulnerable and less vulnerable areas were identified by taking into account the average wave heights that the 2004 tsunami reached in the country (North: 5.5 m, South: 7 m, East: 5 m and West: 3.75 m). Among the selected areas studied, Jaffna and Kaluvanchikudy-Komari are found to be vulnerable and, Trincomalee, Yala and Puttalam are less vulnerable. While vulnerability was largely associated with the conditions devoid of natural barriers, the less vulnerable areas had mangroves, Casuarina, dense vegetation and/or sand dunes as land cover, all of which might prove effective against ocean surges. However, these land cover types should never be considered as providing full protection against the type of threats that can be expected. As the present study provides only base-line information on island-wide vulnerability of areas to water-related impacts, further investigation and validation along similar research lines are needed to establish a blueprint for future preparedness.
Results of recent investigations suggest that climate change tends to accelerate geodisasters. Therefore, adaptation to climate change has rapidly become and urgent issue. In comparison to those examining water disasters, few studies have examined climate change-induced geodisasters. This study aims to focus on climate change-induced geodisasters in various countries of the Asia-Pacific region, especially in Japan and Vietnam. Sea level rise is accounted for about 2 mm/1 on average in the region. This amount is much larger in some places due to groundwater extraction. Moreover, we should prepare for the worst case in which climate-induced severe rainfall, wave attacks, storm surges and a great earthquake might take place simultaneously or almost simultaneously with each other in the coastal zone, although this worst case might be very rare. As a possible compound geohazard caused by climate change, we propose solutions with emphasizes on using geosynthetics and ecological engineering measures.
Given the unfortunate, frequent occurrence of droughts, practical actions are ever more critical to ensure achieving food security in this region [Africa]. Understanding what has previously worked can provide a guiding vision as we proactively address the current crisis. Food security and human security are inextricably linked, and innovative initiatives are needed to create opportunities to face continental challenges regarding future food security requirements. Sustainable food security strategies must thus, among others, develop new opportunities, increase productivity in agriculture, and assist in the development of domestic markets that can withstand international economic volatility. Investment in EbA is one of the most important keys to job creation opportunities that simultaneously contribute to poverty eradication and to sustainable long-term food security. Such investments will improve the competitiveness of domestic production, increase farmers’ profits, and make food more affordable for the poor. Creative strategies supported by dynamic leadership and management are the only way that Africa will be able to achieve the envisaged food-secure society in which its population does not experience fear of want. With proper planning, transparent resource management, innovative food security policies, and integrative agriculture inputs and outputs, it is not too late to turn the Africa’s food crisis to the benefit of local communities.
Climate change is increasing the threat of erosion and flooding along coastlines globally. Engineering solutions (e.g. seawalls and breakwaters) in response to protecting coastal communities and associated infrastructure are increasingly becoming economically and ecologically unsustainable. This has led to recommendations to create or restore natural habitats, such as sand dunes, saltmarsh, mangroves, seagrass and kelp beds, and coral and shellfish reefs, to provide coastal protection in place of (or to complement) artificial structures. Coastal managers are frequently faced with the problem of an eroding coastline, which requires a decision on what mitigation options are most appropriate to implement. A barrier to uptake of nature-based coastal defence is stringent evaluation of the effectiveness in comparison to artificial protection structures. Here, we assess the current evidence for the efficacy of nature-based versus artificial coastal protection and discuss future research needs. Future projects should evaluate habitats created or restored for coastal defence for cost-effectiveness in comparison to an artificial structure under the same environmental conditions. Cost-benefit analyses should take into consideration all ecosystem services provided by nature-based or artificial structures in addition to coastal protection. Interdisciplinary research among scientists, coastal managers and engineers are required to facilitate the experimental trials needed to test the value of these shoreline protection schemes, in order to support their use as alternatives to artificial structures. This research needs to happen now as our rapidly changing climate requires new and innovative solutions to reduce the vulnerability of coastal communities to an increasingly uncertain future.
Ecosystem-based approaches (EBAs) to managing anthropogenic pressures on ecosystems, adapting to changes in ecosystem states (indicators of ecosystem health), and mitigating the impacts of state changes on ecosystem services are needed for sustainable development. EBAs are informed by integrated ecosystem assessments (IEAs) that must be compiled and updated frequently for EBAs to be effective. Frequently updated IEAs depend on the sustained provision of data and information on pressures, state changes, and impacts of state changes on services. Nowhere is this truer than in the coastal zone, where people and ecosystem services are concentrated and where anthropogenic pressures converge. This study identifies the essential indicator variables required for the sustained provision of frequently updated IEAs, and offers an approach to establishing a global network of coastal observations within the framework of the Global Ocean Observing System. The need for and challenges of capacity-building are highlighted, and examples are given of current programmes that could contribute to the implementation of a coastal ocean observing system of systems on a global scale. This illustrates the need for new approaches to ocean governance that can achieve coordinated integration of existing programmes and technologies as a first step towards this goal.
Sea-level rise, potential changes in the intensity and frequency of storms, and consequent shoreline erosion and flooding will have increasing impacts on the economy and culture of coastal regions. A growing body of evidence suggests that coastal ecosystems—natural infrastructure—can play an important role in reducing the vulnerability of people and property to these impacts. To effectively inform climate adaptation planning, experts often struggle to develop relevant local and regional information at a scale that is appropriate for decision-making. In addition, institutional capacity and resource constraints often limit planners’ ability to incorporate innovative, scientifically based approaches into planning. In this paper, we detail our collaborative process in two coastal California counties to account for the role of natural infrastructure in climate adaptation planning. We used an interdisciplinary team of scientists, economists, engineers, and law and policy experts and planners, and an iterative engagement process to (1) identify natural infrastructure that is geographically relevant to local jurisdictional planning units, (2) refine data and models to reflect regional processes, and (3) develop metrics likely to resonate within the local decision contexts. Using an open source decision-support tool, we demonstrated that protecting existing natural infrastructure—including coastal dunes and wetlands—could reduce the vulnerability of water resource-related structures, coastal populations, and farmland most exposed to coastal flooding and erosion. This information formed part of the rationale for priority climate adaptation projects the county governments are now pursuing. Our collaborative and iterative approach, as well as replicable use of an open source decision-support tool, facilitated inclusion of relevant natural infrastructure information into regional climate adaptation planning processes and products. This approach can be applied in diverse coastal climate adaptation planning contexts to locate and characterize the degree to which specific natural habitats can reduce vulnerability to sea-level rise and storms.
In flood protection, the dominant paradigm of ‘building hard structures’ is being challenged by approaches that integrate ecosystem dynamics and are ‘nature-based’. Knowledge development and policy ambitions on greening flood protection (GFP) are rapidly growing, but a deficit remains in actual full-scale implementation. Knowledge is a key barrier for implementation. To analyse conditions for the implementation of GFP, a knowledge-arrangement perspective is developed. The knowledge-arrangement perspective is applied on a case study of successful implementation of GFP in the Netherlands, the pilot Sand Engine Delfland, a large-scale (21.5 Mm3) sand nourishmentproject. This project confirms that an integrated knowledge arrangement enables GFP as it allows for multifunctionality. Effectiveness of the integrated arrangement in this project is explained by its ‘flexible’ nature providing ample design space. This was possible because core values in flood protection and nature were not part of the integrated arrangement. More generally the case study demonstrates the difficulties of implementing GFP in existing mainstream flood protection routines. These are not (yet) geared to incorporate uncertainty, dynamics and multifunctionality, characteristics associated with GFP. The Sand Engine project can be regarded as a ‘field laboratory’ of physical and institutional learning and an innovation for mainstream flood protection.
In a closely integrated system, (sub-) littoral sandy sediments, sandy beaches, and sand dunes offer natural coastal protection for a host of environmentally and economically important areas and activities inland. Flooding and coastal erosion pose a serious threat to these environments, a situation likely to be exacerbated by factors associated with climate change. Despite their importance, these sandy ‘soft’ defences have been lost from many European coasts through the proliferation of coastal development and associated hard-engineering and face further losses due to sea-level rise, subsidence, storm surge events, and coastal squeeze. As part of the EU-funded THESEUS project we investigated the critical drivers that determine the persistence and maintenance of sandy coastal habitats around Europe’s coastline, taking particular interest in their close link with the biological communities that inhabit them. The successful management of sandy beaches to restore and sustain sand budgets (e.g. via nourishment), depends on the kind of mitigation undertaken, local beach characteristics, and on the source of ‘borrowed’ sediment. We found that inter-tidal invertebrates were good indicators of changes linked to different mitigation options. For sand dunes, field observations and manipulative experiments investigated different approaches to create new dune systems, in addition to measures employed to improve dune stabilisation. THESEUS provides a ‘toolbox’ of management strategies to aid the management, restoration, and creation of sandy habitats along our coastlines, but we note that future management must consider the connectivity of sub-littoral and supra-littoral sandy habitats in order to use this natural shoreline defence more effectively.
For more than a century, coastal wetlands have been recognized for their ability to stabilize shorelines and protect coastal communities. However, this paradigm has recently been called into question by small-scale experimental evidence. Here, we conduct a literature review and a small meta-analysis of wave attenuation data, and we find overwhelming evidence in support of established theory. Our review suggests that mangrove and salt marsh vegetation afford context-dependent protection from erosion, storm surge, and potentially small tsunami waves. In bio-physical models, field tests, and natural experiments, the presence of wetlands reduces wave heights, property damage, and human deaths. Meta-analysis of wave attenuation by vegetated and unvegetated wetland sites highlights the critical role of vegetation in attenuating waves. Although we find coastal wetland vegetation to be an effective shoreline buffer, wetlands cannot protect shorelines in all locations or scenarios; indeed large-scale regional erosion, river meandering, and large tsunami waves and storm surges can overwhelm the attenuation effect of vegetation. However, due to a nonlinear relationship between wave attenuation and wetland size, even small wetlands afford substantial protection from waves. Combining man-made structures with wetlands in ways that mimic nature is likely to increase coastal protection. Oyster domes, for example, can be used in combination with natural wetlands to protect shorelines and restore critical fishery habitat. Finally, coastal wetland vegetation modifies shorelines in ways (e.g. peat accretion) that increase shoreline integrity over long timescales and thus provides a lasting coastal adaptation measure that can protect shorelines against accelerated sea level rise and more frequent storm inundation. We conclude that the shoreline protection paradigm still stands, but that gaps remain in our knowledge about the mechanistic and context-dependent aspects of shoreline protection.