Watershed and forest management for landslide risk reduction

Landslide hazard can be influenced by natural resource management and rural development related activities, such as forest management, road construction, agricultural practices and river management. Vegetation cover and its utilizations may play a role in mitigating the risk of landsliding. Moreover and above all, it does play a role in mitigating the processes leading to increased landslide hazard, such as gully erosion. Thus, forest management and development are of particular concern. But all people living in mountain areas rely on the soil stability for their livelihoods, and their livelihoods may influence this soil stability. Therefore all related activities have to be done on an appropriate way in order to promote soil and slope stability. To identify best adapted practices in a particular area, to organize spatially the different land uses and to promote the implementation of the identified best practices, the ideal scale is the watershed. It allows addressing upstream-downstream linking issues, such as landslides, and provides a framework for sound land use planning. However, it is not always possible to implement actions exactly with the watershed boundaries. From the lack of knowledge regarding the scientific evidence of the role of forests against landslides to the institutional challenge of implementing watershed scaled policies, many progresses have to be done regarding this issue. But the already existing scientific knowledge, the integrated projects which are already implemented and the results which are obtained are encouraging. Above all, they show that fundamental research, socio-economic levers and institutional development have to be carried out and developed in a sound way, towards a better understanding of all the natural and man-made processes and a better management of all natural resources, in particular water and soil of the mountain areas.

Climate change impacts on a large-scale erosion coast of Hai Hau district, Vietnam and the adaptation

Among the effects of global warming, sea level rise (SLR) and severe typhoons pose the greatest threat to the stability of human settlements along coastlines. Therefore, counter measures must be developed to mitigate the influences of strong typhoons and persistent SLR for coastal protection. This study assesses climate change impacts on coastal erosion, especially in two projected SLR scenarios of RCP2.6 and RCP8.5. The results show that SLR and severe typhoons lead to the increase of coastal erosion, beach lowering and scour. Moreover, as in projected SLR scenarios, average waves in high tide can cause severe soil erosion at inner slopes and lead to dyke failure by 2060. The paper highlights the need for additional countermeasures to protect the coast of Hai Hau district against SLR and severe typhoons. Among the alternatives available for countering these threats, applying soil stabilization and soil improvement combined with geosynthetics are promising strategies for coastal structures. Hybrid structures can be used with earth reinforcement and soil improvement. Additionally, the paper emphasizes the importance of multiple protective adaptations, including geosynthetics and ecological engineering measures against climate change-induced severe erosion on the coast of Hai Hau district.

Valuing ecosystems as an economic part of climate-compatible development infrastructure in coastal zones of Kenya and Sri Lanka

Even though ‘green’ options for addressing the impacts of climate change have gained in currency over recent years, they are yet to be fully mainstreamed into development policy and practice. One important reason is the lack of economic evidence as to why investing in ecosystems offers a cost-effective, equitable and sustainable means of securing climate adaptation, disaster risk reduction and other development co-benefits. This chapter presents a conceptual framework for integrating ecosystem values into climate-compatible development planning. Case studies from coastal areas of Kenya and Sri Lanka illustrate how such an approach can be applied in practice to make the economic and business case for ecosystem-based measures. It is argued that, rather than posing ‘grey’ and ‘green’ options as being necessarily in opposition to each other or as mutually incompatible, from an economic perspective both should be seen as being part and parcel of the same basic infrastructure that is required to deliver essential development services in the face of climate change

Defining New Pathways for Ecosystem-Based Disaster Risk Reduction and Adaptation in the Post-2015 Sustainable Development Agenda

This chapter seeks to articulate future directions in the field of Eco-DRR/CCA, in the context of the new post-2015 sustainable development agenda. It synthesises the experiences featured in this book and highlights the key challenges and opportunities in advancing Eco-DRR/CCA approaches. Four main themes are discussed: demonstrating the economic evidence of Eco-DRR/CCA; decision-making tools for Eco-DRR/CCA; innovative institutional arrangements and policies for mainstreaming Eco-DRR/CCA; and research gaps. The major global policy agreements in 2015 are examined for their relevance in promoting Eco-DRR/CCA implementation in countries. Finally, the authors reflect on a new agenda for Eco-DRR/CCA and outline some of the key elements required to significantly advance and scale-up Eco DRR/CCA implementation globally.

Shelter from the storm? Use and misuse of coastal vegetation bioshields for managing natural disasters

Vegetated coastal ecosystems provide goods and services to billions of people. In the aftermath of a series of recent natural disasters, including the Indian Ocean Tsunami, Hurricane Katrina and Cyclone Nargis, coastal vegetation has been widely promoted for the purpose of reducing the impact of large storm surges and tsunami. In this paper, we review the use of coastal vegetation as a “bioshield” against these extreme events. Our objective is to alter bioshield policy and reduce the long-term negative consequences for biodiversity and human capital. We begin with an overview of the scientific literature, in particular focusing on studies published since the Indian Ocean Tsunami in 2004 and discuss the science of wave attenuation by vegetation. We then explore case studies from the Indian subcontinent and evaluate the detrimental impacts bioshield plantations can have upon native ecosystems, drawing a distinction between coastal restoration and the introduction of exotic species in inappropriate locations. Finally, we place bioshield policies into a political context, and outline a new direction for coastal vegetation policy and research.

The effectiveness of coral reefs for coastal hazard risk reduction and adaptation

The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97%. Reef crests alone dissipate most of this energy (86%). There are 100 million or more people who may receive risk reduction benefits from reefs or bear hazard mitigation and adaptation costs if reefs are degraded. We show that coral reefs can provide comparable wave attenuation benefits to artificial defences such as breakwaters, and reef defences can be enhanced cost effectively. Reefs face growing threats yet there is opportunity to guide adaptation and hazard mitigation investments towards reef restoration to strengthen this first line of coastal defence.

The present and future role of coastal wetland vegetation in protecting shorelines: answering recent challenges to the paradigm

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.

Protective capacity of mangroves during tropical storms: A case study from ‘Wilma’ and ‘Gamma’ in Belize

Globally threatened mangrove forest habitat is often considered an important buffer protecting coastlines from wave and storm impacts and coastal erosion. However, there is little empirical data quantifying the protective effects of mangroves during storms, primarily because of the difficulty of predicting where and when a storm will intersect the shoreline, to facilitate data collection before and after storm events. In 2005, opportunistic results from an ongoing study quantifying differences between intact and cleared mangrove areas on Turneffe Atoll, Belize, provided such pre- and post-storm data from tropical storms ‘Wilma’ (later a Category 5 Hurricane) and ‘Gamma’. We compared differences in equipment retention rates of 3 types of experimental devices previously installed in adjacent intact and cleared mangrove areas. Retention rates were greater in intact mangrove areas, empirically demonstrating the protective capacity of mangroves during moderate magnitude storm events. The results support the assumption that removal of mangroves diminishes coastal protection not only during catastrophic storm events such as hurricanes or tsunamis, but also during less energetic but more frequent events, such as tropical storms. This highlights the importance of improved coastal zone management, as storm events may increase in frequency and intensity with changing climate, and coastal mangrove forest habitats continue to decline in size and number.

Shifting sands? Coastal protection by sand banks, beaches and dunes

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.

Ecosystem-Based Adaptation and Disaster Risk Reduction: Costs and Benefits of Participatory Ecosystem Services Scenarios for Sumava National Park, Czech Republic

The aim of the study was to analyse economic costs and benefits of stakeholder-defined adaptation scenarios for the Šumava National Park, the Czech Republic, and to evaluate their impact on the provision of ecosystem services, primarily focusing on ecosystem-based adaptation options which support disaster risk reduction in a broader region. The study utilised an array of approaches, including participatory scenario building, GIS modelling and economic evaluation. Based on a participatory input by local stakeholders, four adaptation scenarios were created, formulating various possibilities of future development in the area as well as potential vulnerabilities and adaptation needs. The scenarios subsequently served as the basis for biophysical modelling of the impacts of adaptation and disaster risk reduction measures on the provision of ecosystem services with the InVEST modelling suite, focusing on climate regulation, water quality and hydropower production. Finally, a cost-benefit analysis was conducted, quantifying management and investment costs of each adaptation scenario, and benefits originating from the provision of previously modelled regulating ecosystem services, together with a supplementary selection of provisioning services. This study serves as an example of combining stakeholder views, biophysical modelling and economic valuation in the cost-benefit analysis of ecosystem-based adaptation and disaster risk reduction, which provides the opportunity to find shared solutions for the adaptation of social-ecological systems to global change.

Greening Flood Protection—An Interactive Knowledge Arrangement Perspective

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.

The superior effect of nature-based solutions in land management for enhancing ecosystem services

The rehabilitation and restoration of land is a key strategy to recover services -goods and resources- ecosystems offer to the humankind. This paper reviews key examples to understand the superior effect of nature-based solutions to enhance the sustainability of catchment systems by promoting desirable soil and landscape functions. The use of concepts such as connectivity and the theory of system thinking framework allowed to review coastal and river management as a guide to evaluate other strategies to achieve sustainability. In land management, NBSs are not mainstream management. Through a set of case studies: organic farming in Spain; rewilding in Slovenia; land restoration in Iceland, sediment trapping in Ethiopia and wetland construction in Sweden, we show the potential of nature-based solutions (NBSs) as a cost-effective long term solution for hydrological risks and land degradation. NBSs can be divided into two main groups of strategies: soil solutions and landscape solutions. Soil solutions aim to enhance the soil health and soil functions through which local ecosystem services will be maintained or restored. Landscape solutions mainly focus on the concept of connectivity. Making the landscape less connected, facilitating less rainfall to be transformed into runoff and therefore reducing flood risk, increasing soil moisture and reducing droughts and soil erosion we can achieve the sustainability. The enhanced ecosystem services directly feed into the realization of the Sustainable Development Goals of the United Nations.

Ecological and Economic Analysis of Watershed Protection in Eastern Madagascar

Watershed protection is one of the many goods and services provided by the world’s fast disappearing tropical forests. Among the variety of watershed protection benefits, flood damage alleviation is crucial, particularly in upland watersheds. This study is a rare attempt to estimate flooding alleviation benefits, resulting from the protection of upland forests in Eastern Madagascar. A three stage model is used to examine the relationship between the economic concept of value and the bio-physical dimensions of the protected area. This approach combines techniques from remote sensing, soil and hydrologic sciences and economics. In stage one, the relationship between changes in land use practices and the extent of flooding in immediate downstream is established by using remotely sensed and hydrologic-runoff data. Stage two relates the impact of increased flooding to crop production by comparing the hydrologic data with the agronomic flood damage reports for the same time period. In stage three, a productivity analysis approach is adopted to evaluate flood damage in terms of lost producer surplus. The presence of the Mantadia National Park, in eastern Madagascar, is designed to prevent land conversions and changes in hydrologic patterns, thereby alleviating flood damage. This averted flood damage is a measure of the watershed protection benefits to society. Given that natural systems are subject to considerable stochastic shocks, sensitivity analysis is used to examine the uncertainty associated with the key random variables. The results of this analysis should help policy makers assess trade-offs between the costs and benefits of protecting tropical rainforest.

Key lessons for incorporating natural infrastructure into regional climate adaptation planning

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.

Understanding stakeholder preferences for flood adaptation alternatives with natural capital implications

Inland flood risks are defined by a range of environmental and social factors, including land use and floodplain management. Shifting patterns of storm intensity and precipitation, attributed to climate change, are exacerbating flood risk in regions across North America. Strategies for adapting to growing flood risks and climate change must account for a community’s specific vulnerabilities, and its local economic, environmental, and social conditions. Through a stakeholder-engaged methodology, we designed an interactive decision exercise to enable stakeholders to evaluate alternatives for addressing specific community flood vulnerabilities. We used a multicriteria framework to understand what drives stakeholder preferences for flood mitigation and adaptation alternatives, including ecosystem-based projects. Results indicated strong preferences for some ecosystem-based projects that utilize natural capital, generated a useful discussion on the role of individual values in driving decisions and a critique of local environmental and hazard planning procedure, and uncovered support for a river management alternative that had previously been considered socially infeasible. We conclude that a multicriteria decision framework may help ensure that the multiple benefit qualities of natural capital projects are considered by decision makers. Application of a utility function can demonstrate the role of individual decision-maker values in decision outcomes and help illustrate why one alternative may be a better choice than another. Although designing an efficient and accurate multicriteria exercise is quite challenging and often data intensive, we imagine that this method is applicable elsewhere. It may be especially suitable to group decisions that involve varying levels of expertise and competing values, as is often the case in planning for the ecological and human impacts of climate change.

Flood mitigation benefit of wetland soil – A case study in Momoge National Nature Reserve in China

Wetlands have many important functions. To a wide range of wildlife species, they offer critically important habitats. They also act to mitigate flooding, regulate micro and macro climate changes, degrade pollutants and control erosion etc. Wetland benefits are these functions, which provide direct, indirect, and non-use values to humans. In this study, field soil data are used to calculate the flood mitigation benefits of wetland soils within the Momoge National Nature Reserve, Jilin Province, the People’s Republic of China. Calculations are based upon environmental economic assessment methods and GIS techniques. The estimated flood mitigation capacity of wetland soils within the Momoge Reserve was 7.15 × 104 m3/hm2/yr. This translated into an economic benefit of 5700 $/hm2/yr due to flood mitigation. Spatial differences in the flood mitigation ability of soils were observed across the Momoge wetlands. Benefits associated with flood mitigation were highest within the middle reaches of the Momoge wetlands and least in the East. This quantitative analysis of flood mitigation benefit, with its investigation of wetland soils, will be a useful reference both for the assessment of wetland values in the local region and also for the greater understanding wetland function and value assessment methods.

From grey to green: efficacy of eco-engineering solutions for nature-based coastal defence

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.

The role of ecosystem services in climate change adaptation and disaster risk reduction

This paper analyzes the vicious spiral between climate change impacts, ecosystem degradation and increased risk of climate-related disasters; secondly, it defines the central role of ecosystem management in climate change adaptation and disaster risk reduction and their multifaceted linkages; and thirdly, it assesses the challenges for enhanced ecosystem management for climate change adaptation and disaster risk reduction. Given the increasing importance of ecosystem services and management in adapting and responding to climate change impacts and associated disaster risks, the paper concludes that political commitment at the highest level is urgently needed if ecosystem management is to have the adequate weight it deserves in the post-2012 climate change agreement. It is further recommended that adequate financial, technological and knowledge resources be allocated for integrating ecosystem management in the climate change and disaster risk reduction portfolios, including within national policy-setting, capacity building, planning and practices, particularly in developing countries vulnerable to climate change impacts and increased risks of climate-related disasters

The Value of Coastal Wetlands for Flood Damage Reduction in the Northeastern USA

As exposure to coastal hazards increases there is growing interest in nature-based solutions for risk reduction. This study uses high-resolution flood and loss models to quantify the impacts of coastal wetlands in the northeastern USA on (i) regional flood damages by Hurricane Sandy and (ii) local annual flood losses in Barnegat Bay in Ocean County, New Jersey. Using an extensive database of property exposure, the regional study shows that wetlands avoided $625 Million in direct flood damages during Hurricane Sandy. The local study combines these models with a database of synthetic storms in Ocean County and estimates a 16% average reduction in annual flood losses by salt marshes with higher reductions at lower elevations. Together, the studies quantify the risk reduction ecosystem services of marsh wetlands. Measuring these benefits in collaboration with the risk modelling industry is crucial for assessing risk accurately and, where appropriate, aligning conservation and risk reduction goals.

Natural hazards in a changing world: A case for ecosystem-based management

Communities worldwide are increasingly affected by natural hazards such as floods, droughts, wildfires and storm-waves. However, the causes of these increases remain underexplored, often attributed to climate changes or changes in the patterns of human exposure. This paper aims to quantify the effect of climate change, as well as land cover change, on a suite of natural hazards. Changes to four natural hazards (floods, droughts, wildfires and storm-waves) were investigated through scenario-based models using land cover and climate change drivers as inputs. Findings showed that human-induced land cover changes are likely to increase natural hazards, in some cases quite substantially. Of the drivers explored, the uncontrolled spread of invasive alien trees was estimated to halve the monthly flows experienced during extremely dry periods, and also to double fire intensities. Changes to plantation forestry management shifted the 1:100 year flood event to a 1:80 year return period in the most extreme scenario. Severe 1:100 year storm-waves were estimated to occur on an annual basis with only modest human-induced coastal hardening, predominantly from removal of coastal foredunes and infrastructure development. This study suggests that through appropriate land use management (e.g. clearing invasive alien trees, re-vegetating clear-felled forests, and restoring coastal foredunes), it would be possible to reduce the impacts of natural hazards to a large degree. It also highlights the value of intact and well-managed landscapes and their role in reducing the probabilities and impacts of extreme climate events.

The role of seagrasses in coastal protection in a changing climate

The contribution of seagrasses to coastal protection is examined through the review of the most relevant existing knowledge. Seagrasses are the largest submerged aquatic vegetation ecosystem protected in Europe and it is worth examining their contribution to coastal protection. The review performed highlights incident energy flux, density, standing biomass and plant stiffness as the main physical and biological factors influencing the efficiency of the protection provided by seagrasses. The main conclusion achieved is that seagrass meadows cannot protect shorelines in every location and/or scenario. The optimal conditions for enhancing the protection supplied might be achieved in shallow waters and low wave energy environments, with high interaction surface, at the vertical and horizontal dimension, between water flow and seagrasses. Likewise, the most favorable protection might be provided by large, long living and slow growing seagrass species, with biomass being largely independent of seasonal fluctuations and with the maximum standing biomass reached under the highest hydrodynamic forcings. It is shown that seawater warming, increasing storms and sea level rise, together with the increasing population and anthropogenic threats in the coastal area may lead to rates of change too fast to allow seagrasses to adapt and keep their coastal defense service. Finally, to amend the decline of seagrasses and consequent coastal protection loss, different artificial and natural adaptation measures are provided.

Conserving intertidal habitats: What is the potential of ecological engineering to mitigate impacts of coastal structures?

Globally, coastlines are under pressure as coastal human population growth and urbanization continues, while climatic change leads to stormier seas and rising tides. These trends create a strong and sustained demand for land reclamation and infrastructure protection in coastal areas, requiring engineered coastal defence structures such as sea walls. Here, we review the nature of ecological impacts of coastal structures on intertidal ecosystems, seek to understand the extent to which ecological engineering can mitigate these impacts, and evaluate the effectiveness of mitigation as a tool to contribute to conservation of intertidal habitats. By so doing, we identify critical knowledge gaps to inform future research. Coastal structures alter important physical, chemical and biological processes of intertidal habitats, and strongly impact community structure, inter-habitat linkages and ecosystem services while also driving habitat loss. Such impacts occur diffusely across localised sites but scale to significant regional and global levels. Recent advances in ecological engineering have focused on developing habitat complexity on coastal structures to increase biodiversity. ‘Soft’ engineering options maximise habitat complexity through inclusion of natural materials, species and processes, while simultaneously delivering engineering objectives such as coastal protection. Soft options additionally sustain multiple services, providing greater economic benefits for society, and resilience to climatic change. Currently however, a lack of inclusion and economic undervaluation of intertidal ecosystem services may undermine best practice in coastline management. Importantly, reviewed evidence shows mitigation and even restoration do not support intertidal communities or processes equivalent to pre-disturbance conditions. Crucially, an absence of comprehensive empirical baseline biodiversity data, or data comprising additional ecological parameters such as ecosystem functions and services, prohibits quantification of absolute and relative magnitudes of ecological impacts due to coastal structures or effectiveness of mitigation interventions. This knowledge deficit restricts evaluation of the potential of ecological engineering to contribute to conservation policies for intertidal habitats. To improve mitigation design and effectiveness, a greater focus on in-situresearch is needed, requiring stronger and timely collaboration between government agencies, construction partners and research scientists.

Lessons for climate change adaptation from better management of rivers

Autonomous adaptation in the water sector is assessed to derive lessons for more successful climate change adaptation from six empirical, consistently designed river management case studies based on projects of WWF. They show that when adaptation measures are considered in the context of common problems in water management, many practical ways of building resilience to climate change through mainstream programs are evident. The cases are mainly from developing countries—India, China, Mexico, Brazil, the lower Danube basin and Tanzania—where efforts to reduce environmental degradation and enhance livelihoods have directly helped to reduce vulnerability to natural hazards and climate change. The key lessons include: the benefits of concurrent measures for improving livelihoods and reducing physical vulnerability; the need to enhance and fund local institutions to mainstream adaptation programmes; and the value in implementing ‘no and low regrets’ measures despite uncertainties.

Nature-based solutions: lessons from around the world

This paper considers an emerging group of coastal management approaches which offer the potential to reduce coastal flood and erosion risks whilst also providing nature conservation, aesthetic and amenity benefits. These solutions mimic the characteristics of natural features, but are enhanced or created by man to provide specific services such as wave energy dissipation and erosion reduction. Such approaches can include beaches, dunes, saltmarshes, mangroves, sea grasses, coral and oyster reefs. The paper describes a number of innovative projects and the lessons learned in their development and implementation. These lessons include the planning, design and construction of projects, their development following implementation, the engagement of local communities and the cost effectiveness of solutions.

Ecosystem-Based Disaster Risk Reduction and Adaptation in Practice

This book is a compilation of recent developments in the field of ecosystem-based disaster risk reduction and climate change adaption (Eco-DRR/CCA) globally. It provides further evidence that ecosystem-based approaches make economic sense, and showcases how research has progressively filled knowledge gaps about translating this concept into practice. It presents a number of methods, and tools that illustrate how Eco-DRR/CCA has been applied for various ecosystems and hazard contexts around the world. It also discusses how innovative institutional arrangements and policies are shaping the field of Eco-DRR/CCA. The book is of relevance to scientists, practitioners, policy-makers and students in the field of ecosystem management for disaster risk reduction and climate change adaptation.