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... Yet, to date, the existing risk assessment approaches, by large, have not included coastal natural systems (Garner et al., 2017;Lin et al., 2012;Saha, 2015) that shield communities from natural hazards (Arkema et al., 2013;Sajjad et al., 2018). Similar to the methods exclusive of community disaster resilience discussed in Section 1.2, these simplified risk assessment approaches could influence the spatial patterns of risk, affect the decision-making regarding prioritization to take measures, and mislead the adaptation investments for risk mitigation and resilience enhancement. ...
... The NWI database do not provide data on seagrass due to certain limitations such as aerial imagery constraints. Hence, due to the unavailability of the nation-wide data on seagrass, following Arkema et al. (2013), data on seagrass are gathered using a state-by-state data piecing approach. All the sources for data acquisition on seagrass are same as Arkema et al. (2013). ...
... Hence, due to the unavailability of the nation-wide data on seagrass, following Arkema et al. (2013), data on seagrass are gathered using a state-by-state data piecing approach. All the sources for data acquisition on seagrass are same as Arkema et al. (2013). (2008) and Cutter et al., (2003) for more details about SoVI. ...
Thesis
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Risk-informed planning and management are integral to the sustainability of hazard-prone areas at all spatial scales. In connection to this, the current thesis advances the in-practice traditional risk frameworks for inclusiveness, reliability, and future vigilance in the wake of natural hazards and climate change via fostering inter-disciplinary approaches, recommends the integration of natural systems in risk assessment process for co-benefits, proposes aligning risk and sustainability frameworks for multi-objective planning and management, and explains how geospatial information models/technology could assist in risk management (profiling, decision-making, policy development, and resource allocation). The thesis consists of four main parts: (I) risk assessment perspectives, (II) influence of natural systems on risk level and its distribution, (III) aligning risk and sustainability frameworks, and (IV) integrating spatial models for effective risk management. Each part addresses a specific objective of this study. These include risk perspectives, realizing natural habitats role in risk frameworks, aligning risk management and sustainability intentions, and integrating geospatial technology to inform risk management for effective planning (decision-making and resource allocation). Among all the natural hazards, tropical cyclones and coastal storms are chosen for this study due to their significant impacts. Part I comprehensively details different risk assessment perspectives using hurricane flood risk along the United States Atlantic and Gulf coasts as a case study—under current and future scenarios. Most of the high-risk hotspots are found in the Gulf coast region, particularly along the west coast of Florida. While the resultant risk is sensitive to the consideration of evaluation factors (i.e., hazard, vulnerability, and resilience), two out of three risk evaluation approaches indicate New York City as a risk hotspot under the future climate. Additionally, a machine-learning algorithm-based approach to map the spatially distinct groups shows that the counties in the highest risk group (15% of total counties, including New York City) in the future lack specifically in the community capital and the social components of community resilience. In Part II, a coupled human-nature system-based framework is used to provide evidence on the influence of coastal natural habitats (CNHs) on coastal storm-risk level and spatial distribution. To do so, a spatially relative risk index for each coastal county along the U.S. Atlantic coast is computed incorporating several bio-geo-physical variables (e.g., geomorphology, natural habitats, coastal relief, and historical data on sea level trends, wind, and wave) and data on socio-ecological systems. The index is calculated under two CNH scenarios (i.e., without- and with-habitat) and is further used for mapping the at-risk population. The without-habitat scenario is found to overestimate the population in the highest risk category by 10 % and the number of counties by as much as 40 % as compared to the with-habitat scenario—mostly in the Gulf region. Also, the without-habitat scenario miscalculates the spatial distribution of the risk. While the results highlight the role of CNHs in influencing the risk level and its distribution, the findings support the emphasis by conservationists on policies relevant to the protection and restoration of coastal natural systems owing to their multiple services. In Part III, a risk-resilience-sustainability nexus-based approach is proposed to align risk and sustainability frameworks. In contrast to traditional approaches, the framework employs an integrative approach and simultaneously provides useful input for resilience management in parallel to achieving certain Sustainable Development Goals (SDGs). The proposed framework is applied for risk assessment (represented by a Typhoon Risk Index—TRI) of coastal counties in Mainland China. A large spatial heterogeneity in typhoon risk is found with an increase in the risk from north to south in the study area. Further, the overall performance of coastal provinces in Mainland China is higher to achieve SDGs 3 and 15 followed by 13 and 8. The study shows that while Guangdong Province in southern China is in the highest risk category, its achievement status for SDG-13 (climate actions, strengthening resilience) is the lowest relative to other provinces. In Part IV, a geographic-information-system-based framework integrating spatial distributional models is proposed to evaluate the spatial heterogeneities of risk, its spatial patterns, and statistically significant hotspots of the highest risk. Further, the level of contribution of each risk parameter (i.e., hazard, vulnerability, and community resilience) towards overall risk is evaluated. It is found that among 70% exposed counties, ~ 30% are in the highest risk category (value ≥ 3rd quartile). The areas under the highest risk harbour > 50 million people (~43%)—more than 7 million non-adults (0–14 years, ~42%), and approximately 2.5 million elderly people (above 65 years, ~31%). The Pearl-River-Delta region of Guangdong Province in southern China is identified as the hotspot of the highest typhoon risk, followed by Fujian and Zhejiang provinces—95% confidence.
... Coastal dunes also provide habitats for a rich fauna (Maun, 2009) and other essential ecosystem services such as protection against storms (Arkema et al., 2013;Van der Biest et al., 2017). Nevertheless, they are currently listed among the most endangered ecosystems worldwide (Defeo et al., 2009) and at the European level, with most habitats recently classified as 'threatened' in the Mediterranean (Janssen et al., 2016). ...
... dune formation and stabilization). It thus follows that, beyond altering how habitats appear, changes in the abundance/occurrence of such key species would substantially impact the ecological functioning of the dune system and the provision of its associated services (Arkema et al., 2013;Van der Biest et al., 2017). ...
... Because well-conserved shifting dunes not only provide shelter for fixed dune communities but also guarantee high-valued ecosystem services (e.g. coastal protection), their degradation is likely to have cascading effects on the entire coastal dune ecosystem and on the wide range of services it provides (Arkema et al., 2013;Van der Biest et al., 2017). Finally, though fixed dunes underwent relatively small diversity changes, the considerable decline of Crucianella maritima, endangered and with a highly fragmented distribution (Acosta et al., 2006) represents an early warning of habitat disruption (Del Vecchio et al., 2016) in a particularly rare and threatened habitat type (Acosta et al., 2007;Janssen et al., 2016;Prisco et al., 2020). ...
Article
Assessing temporal changes in plant communities is a core aim of temporal ecology and a shared priority of global conservation agendas which is particularly urgent in threatened ecosystems. Mediterranean coastal dunes harbour some of the most threatened habitats in Europe. Yet, surprisingly, studies capturing the recent temporal dynamics of biodiversity in these systems by accounting for multiple diversity facets and different aspects of community structure are missing. Here, using data from a resurveying study, we provide a first comprehensive, habitat‐based, multi‐faceted assessment of recent (10–15 years) temporal changes in threatened Mediterranean coastal dunes. To this aim, we quantified taxonomic and functional changes in plant communities using indices capturing multiple biodiversity features, and we explored trends at both the community level and the species level. We compared observed biodiversity changes across habitats (to look for evidence of generalized biodiversity loss) and across facets (to infer the potential loss of unique functions), and tested their significance using a null model. Overall, we predicted large compositional shifts and biodiversity loss beyond expectations in many communities, although with differences among habitat types. Our results reveal severe shifts in the taxonomic profile of the communities, mostly driven by a non‐random species loss, and little temporal overlap in functional space, implying large changes in both community structure and ecological strategies of the investigated habitats. This, together with the disappearance of c. 23% of historical plots and with substantial losses in focal species, suggests that intense degradation processes are occurring in coastal dune habitats, particularly on the upper beach and on shifting dunes. Synthesis. This study provides the first evidence of large, often non‐random, taxonomic and functional changes occurring in Mediterranean coastal dune plant communities in a surprisingly short time‐span. Along with furthering our knowledge of the recent dynamics affecting these endangered ecosystems, our results also pinpoint the types of habitats that are most at risk, helping to direct future conservation efforts and management. Future research should now be directed at more precisely testing potential drivers of these changes. This study provides the first evidence of large, often non‐random, taxonomic and functional changes occurring in Mediterranean coastal dune plant communities in a surprisingly short time‐span. Along with furthering our knowledge of the recent dynamics affecting these endangered ecosystems, our results also pinpoint the types of habitats that are most at risk, helping to direct future conservation efforts and management.
... Rapid population growth and urban expansion are squeezing coastal ecosystems against a rising sea, limiting their ability to provide the lifesustaining services upon which human health and well-being depend. Accounting for these services leads to better-informed climate adaptation (Verburg et al., 2012;Arkema et al., 2013;Munang et al., 2013;Lavorel et al., 2015) and land-use planning decisions White et al., 2012;Arkema et al., 2015). Ecosystem service (ES) assessments allow these services to be incorporated into policy and management decisions (Carpenter et al., 2009;Costanza et al., 2017;Daily et al., 2009;MEA, 2005;Ruckelshaus et al., 2015;TEEB, 2010). ...
... We used the Coastal Protection Model to quantify the protective services (e.g., erosion control and flood mitigation) provided by natural habitats in the nearshore environment. We assigned protective values for the different nearshore habitats present on Johns Island based on existing literature (Arkema et al., 2013) and applied these to land cover datasets from the National Wetlands Inventory (USFWS, 2020) and the South Carolina Department of Natural Resources (SCDNR, 2015). The coastal protection model generates a habitat role index, which measures the rank difference between the exposure of the shoreline with natural habitat present and the exposure of the shoreline without that habitat. ...
... The highest agricultural yields were located in the south and southeast parts of the island (Fig. 5B). Total coastal exposure for Johns Island ranged from 1.6 (moderately-exposed) to 3.8 (highly-exposed; (Arkema et al., 2013). The habitat role index, which quantifies the overall protective role of the nearshore environment against damages from storms and wind, ranged in value from 0.3 to 0.8. ...
Article
Sea level rise and urbanization exert complex synergistic pressures on the provision of ecosystem services (ES) in coastal regions. Anticipating when and where both biophysical and cultural ES will be affected by these two types of coastal environmental change is critical for sustainable land-use planning and management. Biophysical (provisioning and regulating) services can be mapped using secondary data. We demonstrate an approach to mapping cultural ES by engaging stakeholders in iterative participatory mapping of personally and communally valuable cultural ES. We identify hotspots where highly valued cultural ES and high values for biophysical ES co-occur and generate spatially-explicit projections of sea level rise and urban expansion through 2060 to quantify impacts of the ‘coastal squeeze’ on ES. We study Johns Island, South Carolina, USA as an example of a vulnerable community in a low-lying region experiencing both rising water levels and a rapid influx of new residents and development. Our projections of environmental change through 2060 indicate that on Johns Island, cultural ES face disproportionately greater risk of decline than biophysical ES, with almost three quarters of the island’s cultural ES affected. We find that hotspots for cultural ES, such as community heritage sites and scenic vistas of oak-lined roads and marshes, rarely co-occur (only 3% area) with biophysical ES such as high values of carbon sequestration and agricultural production. This confirms the importance of engaging with local stakeholders to map cultural ES and puts them on a more level playing field with biophysical ES in decision-making contexts. Projected declines and limited overlap between biophysical and cultural ES highlight the need for tighter coordination between conservation and community planning, and for including locally valued cultural ES in assessments of threats posed by the ‘coastal squeeze’ of sea level rise and urban expansion.
... These areas have been experiencing a wide range of stressors from both climate change and human activities (Gabler et al., 2017;IPCC, 2014;Sekovskia et al., 2012), which threaten human lives and properties. Coastal habitats play an important role in mitigating the impacts of natural hazards and provide a broad range of collateral benefits to human well-being (e. g., foodstuffs and habitat provision, wastewater treatment, recreational opportunities) (Arkema et al., 2013). However, global sea level rise and coastal flooding are expected to increase significantly by mid-century (Hansen et al., 2016), while rapid urbanization with intensive human activities may accelerate the degradation of coastal ecosystems (Sekovskia et al., 2012). ...
... A variety of methods have been used to assess coastal vulnerability by incorporating different factors that indicate different dimensions (Arkema et al., 2013;Bevacqua et al., 2018;Hinkel and Klein, 2009). Inclusion of different factors into an assessment framework relies largely upon data availability and the context of different studies. ...
... Modeling spatial vulnerability at a fine scale based on an integration of representative factors is helpful in identifying the most vulnerable areas for prioritized interventions. Ecosystem service models like the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) show the impacts of changes in ecosystems and associated services at different spatial scales, and have been widely used to understand the biophysical vulnerability of coastlines globally (Arkema et al., 2013;Hopper and Meixler, 2016;Onat et al., 2018;Sajjad et al., 2018). To date, few models integrate ecological, physical and socioeconomic factors into synthetical vulnerability assessments of coastal areas. ...
Article
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Climate change and human activities exert a wide range of stressors on urban coastal areas. Synthetical assessment of coastal vulnerability is crucial for effective interventions and long-term planning. However, there have been few studies based on integrative analyses of ecological and physical characteristics and socioeconomic conditions in urban coastal areas. This study developed a holistic framework for assessing coastal vulnerability from three dimensions - biophysical exposure, sensitivity and adaptive capacity - and applied it to the coast of Bohai Economic Rim, an extensive and important development zone in China. A composite vulnerability index (CVI) was developed for every 1 km² segment of the total 5627 km coastline and the areas that most prone to coastal hazards were identified by mapping the distribution patterns of the CVIs in the present and under future climate change scenarios. The CVIs show a spatial heterogeneity, with higher values concentrated along the southwestern and northeastern coasts and lower values concentrated along the southern coasts. Currently, 20% of the coastlines with approximately 350,000 people are highly vulnerable to coastal hazards. With sea-level rises under the future scenarios of the year 2100, more coastlines will be highly vulnerable, and the amount of highly-threatened population was estimated to increase by 13–24%. Among the coastal cities, Dongying was categorized as having the highest vulnerability, mainly due to poor transportation and medical services and low GDP per capita, which contribute to low adaptive capacity. Our results can benefit decision-makers by highlighting prioritized areas and identifying the most important determinants of priority, facilitating location-specific interventions for climate-change adaptation and sustainable coastal management.
... Coastal regions are home to a large and ever-growing segment of the world's human population with nearly 2.5 billion people (or ~ 40% of the world's population) living within 100 km of a coastline (Neumann et al., 2015). An estimated 400 million live along our planet's relatively low-lying coasts, which are extremely vulnerable to repeated storms, flooding (<5 m elevation from storm surge events), and associated effects (Arkema et al., 2013;Bukvic et al., 2020;McGranahan et al., 2007;United Nations, 2017). Extreme storm-related events (e.g. ...
... These static and unchanging hard structural approaches may provide immediate protection on small spatial and temporal scales, but their inability to adapt to changing conditions, or to self-maintain, limits their effectiveness over time (Morris et al., 2018;Morris et al., 2020;Sutton-Grier et al., 2015). Further, these hard structures have limited value in providing any significant long-term ecological or socio-economic services such as enhanced biodiversity, habitat expansion, or fisheries production (Arkema et al., 2013;Borsje et al., 2011;Costanza et al., 2008;Woodruff et al., 2018). ...
... Recognizing that traditional hardened structures may not be able to keep pace with SLR or address related climate changes (Morris et al., 2020), a number of efforts have focussed on developing more sustainable shoreline protection strategies that are resilient to climate change impacts while also being self-repairing. These efforts are based on growing evidence that natural coastal ecosystems can contribute significantly to cost-effective coastal protection strategies by reducing the impacts of erosion and flooding, while also lessening losses of commercial and recreational fisheries, related livelihoods, and cultural values within coastal communities (Arkema et al., 2013;McGranahan et al., 2007;Morris et al., 2018;Narayan et al., 2016;Nicholls and Cazenave, 2010;Reguero et al., 2018;Spalding et al., 2014;Temmerman et al., 2013;Woodruff et al., 2018). ...
Article
Coastal areas are especially vulnerable to habitat loss, sea-level rise, and other climate change effects. Oyster-dominated eco-engineered reefs have been promoted as integral components of engineered habitats enhancing coastal resilience through provision of numerous ecological, morphological, and socio-economic services. However, the assessed ‘success’ of these eco-engineered oyster reefs remains variable across projects and locations, with their general efficacy in promoting coastal resilience, along with related services, often mixed at best. Understanding factors influencing the success of these eco-engineered habitats as valuable coastal management tools could greatly inform related future efforts. Here, we review past studies incorporating reef-building oysters for coastal resilience and enhanced ecosystem services. Our aims are to better understand their utility and limitations, along with critical knowledge gaps to better advance future applicability. Success depends largely on site selection, informed by physical, chemical and biological factors, and adjacent habitats and bottom types. Better understanding of oyster metapopulation dynamics, tolerance and adaptation to changing conditions, and interactions with adjacent habitats will help to better identify suitable locations, and design more effective eco-engineered reefs. These eco-engineered reefs provide a useful tool to assist in developing coastal resilience in the face of climate change and sea level rise.
... Since there is no authoritative report or research related to future SLR of the Xiamen coastline, we assume that the sea level in Xiamen will follow the global trend published by the fifth report of the IPCC (2014). By referring to the method of Arkema et al. (2013), predicted outcomes of Xiamen City under future RCP 8.5, 6.0, 4.5 and 2.5 scenarios are the global mean SLR values for 2050 reported by the IPCC, multiplied by a scaling factor (the ratio of the historical local rate to the historical global rate). The average under four scenarios was used in this study. ...
... In a coastal area, protection, management and restoration of wetlands (e.g., mangrove stands, saltmarshes, dunes and beaches), parks, fields and any other natural system, as effective nature-based solutions, can provide critical ecosystem services for coastal flood adaptation: for example, reducing surface water run-off and storm waves, accommodating continuing SLR, and eliminating the opportunity for property loss and economic disruption (Zimmermann et al., 2016). Arkema et al. (2013) revealed that the number of people and the total value of property exposed to storm tides and SLR can be reduced by half if the existing coastal wetland area along the United States coastlines remains fully intact. An empirical study by Beck et al. (2018) showed that, without coral reefs, the annual anticipated global damage from coastal flooding would double. ...
Article
Coastal flood risk facing urban communities is increasing due to the compound impacts of sea level rise (SLR) and urban growth. Accurate information on future dynamic risk of coastal flooding and its physical and socio-economic drivers is essential for planning effective and targeted adaptation. However, the current scenarios regarding urban development are insufficient to predict the future dynamic spatial distribution of urban socio-economic and physical growth, hindering the exact and dynamic assessment of future coastal flood risk. Moreover, the relative contributions of SLR and urban development to the future dynamics of city-level coastal flood risk have not been examined. Therefore, here we developed a land use-based urban growth scenario for the temporally and spatially explicit simulation of future urban growth in terms of buildings, roads and electrical facilities, and combined it with a local temporally explicit SLR scenario, into a “hazard-exposure-vulnerability” model, for the purpose of dynamic risk assessment of coastal flooding on the urban built environment in Xiamen, China by 2050, and accordingly examined the relative contributions of SLR and urban growth. Our results demonstrated a good performance of the land use-based urban growth model. SLR and urban growth will increase future coastal flood risk (represented by the expected annual damage, EAD) in varying degrees, but their combination is projected to exacerbate future flood damages significantly, indicating that considering either SLR or urban growth in isolation will underestimate future coastal flood risk. Moreover, the relative contributions of SLR and urban growth are dynamic over time, depending on the rate of SLR and the stage of urbanization: for example, the change in coastal flood risk is mainly attributable to urban growth in the phase of rapid urbanization before 2033 in Xiamen, yet the contribution of urban growth then becomes less important compared to SLR, when urbanization slows down, while SLR reaches a threshold after accelerating growth. The approach and results of our study can be considered a decision support tool, to help decision makers assess future coastal flood risk and detect the relative importance of each driving force, in order to employ land use planning, nature-based solutions and engineering protection, to achieve sustainable and resilient coastal cities.
... I also found that of Okinawa's two dominant anthropogenic land use gradients, agriculture worsened typhoon impacts (though agricultural sites responded heterogeneously in space) whereas urbanisation did not (see also Olivier et al. 2020). These results underscore the potential for natural habitats to stabilise ecosystems and soundscapes in response to climate change and extreme events (Uhl & Kauffman 1990;Arkema et al. 2013;Nimmo et al. 2016;Raymond et al. 2020). Taken together, the interactions discussed in Chapters 3 and 5 highlight nature's foundational role in promoting biodiversity regulation (e.g., Gotelli et al. 2017), and in buffering ecological communities against disturbance (e.g., Nimmo et al. 2016;Rasher et al. 2020). ...
... Human land useanother key axis of global environmental change(Sanderson et al. 2002; Devictor et al. 2007;Newbold et al. 2015; Daskalova et al. 2020)-has the potential to moderate storm impacts(Adger et al. 2005). For example, anthropogenic land use intensification may exacerbate the negative impact of storms or fire on wildlife(Uhl & Kauffman 1990;Raymond et al. 2020), while natural habitats can buffer ecosystems against the effects of extreme weather events(Adger et al. 2005;Arkema et al. 2013;Barbier 2015;Nimmo et al. 2016). Despite the potential for these two key global change drivers to interact, few studies have to date investigated explicitly the impacts of extreme events across land use types at landscape scales.Ecological stability is the core framework for considering the impacts of disturbances across scales from populations to ecosystems(Hillebrand et al. 2018; Kéfi et al. 2019). ...
Thesis
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Through global environmental change, humans are modifying the planet at an unprecedented rate and scale, triggering the ongoing biodiversity and climate crises. Ecological stability and the consistency of nature’s contributions to people are fundamental to the continued sustainability of human societies. Stability is a complex and multidimensional concept including components such as variability in time and space and the resistance to and recovery from disturbances. Global change has the potential to destabilise ecosystems, but the form and strength of the relationship between different global change drivers and dimensions of stability remains understudied, precluding general or mechanistic understanding. Here, I combine theory, a field experiment, and observational data from a high-resolution acoustic monitoring network to reveal the potential for multiple global change drivers to erode multidimensional ecological stability. Critically, I also show how biodiversity and natural habitats can buffer the destabilising effects of global environmental change on ecosystems and soundscapes, providing vital insurance against disturbance. In an era characterised by unrelenting global change and intensifying disturbance regimes, my results provide a key step towards a generalisable understanding—and ultimately management—of the stability of ecosystems and their contributions to human wellbeing.
... 'no regrets') and avoids maladaptation (Colloff et al. 2020). Coastal protection perfectly illustrates these cumulative benefits derived from enhanced feedback of climate adaptation services: the pursuit of a development pathway that leads to avoided loss of ecosystem services, including coastal protection, is adaptive; but in turn, coastal protection has the perk of further reducing other consequences of climate change, such as promoting ecosystem-based disaster risk reductions against sea-level rise (Arkema et al. 2013, Roberts et al. 2017. By pursuing development pathways that enhance such adaptation services we ensure that their feedback of adaptation benefits are perpetuated (Jones et al. 2012). ...
... By pursuing development pathways that enhance such adaptation services we ensure that their feedback of adaptation benefits are perpetuated (Jones et al. 2012). Our review highlights that Nature-based Solutions were the only pathway that was able to reduce risks on coastal environments and increase coastal protection (Arkema et al. 2013, Temmerman et al. 2013. ...
Article
Climate action is urgently needed to limit climate change and substantially reduce risks to humans and nature. However, even with successful climate mitigation, we will not be exempt from losses in the flow of nature’s contributions to people. Thus, beyond mitigation, climate change adaptation is imperative for society to cope and avoid losing critical ecosystem services. To effectively adapt to climate change, we need to anticipate which ecosystem services are more at risk and which development pathways are more likely to secure their maintenance. Here, using a meta-analytical approach, we evaluate the adaptive potential of pursuing different development pathways to reduce negative impacts on ecosystem services. We work with three possible pathways: “Human Development”, a human-centred pathway focused on economic growth, “Reduced Footprint”, a middle-of-the-road pathway focused on decelerating business-as-usual trends, and “Nature-based Solutions”, a nature-centred pathway focused on sustainability. We found that the pursuit of all development pathways effectively reduced risks, although with clear trade-offs. Human Development and Reduced Footprint pathways reduced risks for most services but were only able to increase the provision of just a few. Although risks were reduced in such pathways, they were not able to revert negative impacts. In contrast, Nature-based Solutions were able to reduce risks for all services, while concomitantly greatly increasing the provision of most of them, even in high climatic change conditions. We reinforce that unchecked climate change severely depletes ecosystem services, but mitigation benefits were noteworthy. In addition to cutting climate change risks by half, mitigation also allowed the adaptive pathways to increase services to a greater magnitude, thus promoting adaptation efficiency. Although the best-choice development pathway to be pursued must consider stakeholders needs, we emphasise the exceptional adaptive potential of Nature-based Solutions, as it concomitantly counteracts climate change and enhances multiple services.
... The coasts have remained among the most productive and economically valuable habitats 38,39 because long-term coastal ecosystem resilience is powered by positive interactions like facilitation cascades and mutualisms that increase biodiversity, speed recovery, and drive multifunctionality across landscapes 24,[40][41][42][43] . As novel physical and biotic factors change coastal ecosystems and coastal human populations continue to rise, the conditions that threaten coastal protection from rising oceans are now relevant to millions of people 44 . ...
... Error bars represent standard error. Degradation of facilitation cascades, habitat cascades and mutualisms will have long-lasting effects on the resilience of important coastal ecosystems like marshes, mangroves, seagrasses, kelp forests, and coral reefs 60,61 , by lowering coastal defense in the areas that shield people and property from sea-level rise and storms 44 . Here, in an ecosystem under threat from climate extremes, the feral hog invasion lowers the survival of both primary and secondary foundation species (Fig. 2a, b) and alters community structure (Fig. 2c), to reduce long-term resilience and slows largescale recovery. ...
Article
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Invasive consumers can cause extensive ecological damage to native communities but effects on ecosystem resilience are less understood. Here, we use drone surveys, manipulative experiments, and mathematical models to show how feral hogs reduce resilience in southeastern US salt marshes by dismantling an essential marsh cordgrass-ribbed mussel mutualism. Mussels usually double plant growth and enhance marsh resilience to extreme drought but, when hogs invade, switch from being essential for plant survival to a liability; hogs selectively forage in mussel-rich areas leading to a 50% reduction in plant biomass and slower post-drought recovery rate. Hogs increase habitat fragmentation across landscapes by maintaining large, disturbed areas through trampling of cordgrass during targeted mussel consumption. Experiments and climate-disturbance recovery models show trampling alone slows marsh recovery by 3x while focused mussel predation creates marshes that may never recover from large-scale disturbances without hog eradication. Our work highlights that an invasive consumer can reshape ecosystems not just via competition and predation, but by disrupting key, positive species interactions that underlie resilience to climatic disturbances.
... These forms of protection are not suitable for all coastal areas, but where applicable such an approach is generally more cost effective and environmentally sustainable (Airoldi et al., 2005;Arkema et al., 2013;Firth et al., 2016). ...
... Coastal natural habitats such as seagrass meadows (Potouroglou et al., 2017), salt marshes (Möller et al., 2014), coral reefs (Ferrario et al., 2014), and mangroves (Montgomery et al., 2018) are regarded as natural defences for the shoreline (Arkema et al., 2013). These habitats act as buffers to incoming large waves and currents especially during stormy seasons (Rupprecht et al., 2017). ...
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Seagrass meadows are known to buffer wave energy, reduce current velocities and hence can provide stability to the coasts. The presence of seagrass on the seabed modifies the dynamics of the benthic boundary layer and thus the sediment transport. The overall aim of this project is to address the limited knowledge on the interactions between seagrass, seabed and the counteracting sedimentary processes by investigating interactions between the intertidal seagrass Zostera noltii and the surrounding sediments. Specifically, I am investigating how this species affects the mean flow, the turbulence in the canopy, and the resulting sediment mobilisation. Zostera noltii shows a strong seasonality, therefore the intertidal area of Ryde, Isle of Wight was monitored monthly over two annual cycles to assess the effect of seasonal changes on sediment characteristics and bed morphology. Grain size trend analysis was carried out in order to investigate the sand transport pathways on the intertidal flat in the region of seagrass. Sediment transport patterns were defined using Grain Trend Analysis. The Ryde intertidal flat is composed mainly of fine, well sorted and positively skewed sand. The transport vectors suggest a westward transport on the west side of Ryde Pier and an on-offshore transport on the east side of Ryde Pier. Gradients in sediment texture and composition were related to the season and influenced by meadow distribution and density. This was attributed to the mechanical trapping of particles and enhanced deposition due to dampening of current and wave action in the meadows. Locations inhabited by seagrass showed less change in bed morphology compared to bare sand areas. The tidal flat was found to be stable or exhibited minor bed accretion (cms) along vegetated profiles. Laboratory experiments carried out in a recirculating and annular flume on Zostera noltii showed that turbulence and mean flow were reduced within the canopy indicating low sediment transport in the region of the seagrass. Seagrass increases deposition in summer by modifying the boundary layer through its above-ground biomass and resists erosion in winter by increasing cohesiveness of the bed through its below-ground biomass (roots and rhizomes). Despite the reduction in seagrass canopy influence on the hydrodynamic forcing, the persistent presence of below-ground biomass all year round reduces sediment transport hence providing stability to the bed.
... These maps can also be combined with maps of relative socioeconomic vulnerability. Not all coastal populations will be able to respond to climate disasters equally (Arkema et al., 2013). Mangroves that protect large numbers of low-income families could be identified in future analyses. ...
... Finally, maps of coastal property value or asset value can be analyzed to identify where mangroves protect major financial interests (Arkema et al., 2013). Frequently, the locations of highvalue properties and socially vulnerable populations are different, requiring discussion on how to adequately protect both. ...
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We modeled the coastal protection and blue carbon ecosystem services provided by the mangroves of the Paz River Basin (El Salvador and Guatemala) using InVEST Coastal Vulnerability and Coastal Blue Carbon Models, with the goal of supporting the Regional Coastal Biodiversity Project of the International Union for the Conservation of Nature, in determining potential priority mangrove areas for conservation and restoration. To quantify the relative coastal protection that mangroves provide, we combined maps of different aspects of vulnerability, including ecological, physical, and social data. We also estimated carbon stocks, net sequestration, and the economic value of carbon sequestration as a service in 2050 and 2100. We then developed a combined index of coastal protection and carbon sequestration services to highlight potential priority conservation and restoration areas for mangroves. We found that in Guatemala the coastal protection service was provided in greater quantity in the province of Moyuta, while in El Salvador this service was the highest in the provinces of San Francisco Menéndez, Jujutla and Acajutla, which also had the greatest total carbon stock. In the Paz River Basin, we estimate there are approximately 1,741 hectares of mangroves that provide the highest coastal protection and carbon sequestration services. Furthermore, we identified 318.9 hectares across both countries where mangroves could potentially be restored.
... Pulse perturbations, such as the El Niño-Southern Oscillation (ENSO; hereafter El Niño), when superimposed on SLR, tend to exacerbate erosion (Barnard et al. 2015). Yet sandy coastlines, particularly in regions with high population density and coastal development, have no capacity to respond naturally to SLR and the landward migration of the LAZ (Arkema et al. 2013;Bindoff et al. 2020). ...
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Approximately half of the world’s ice-free ocean coastline is composed of sandy beaches, which support a higher level of recreational use than any other ecosystem. However, the contribution of sandy beaches to societal welfare is under increasing risk from local and non-local pressures, including expanding human development and climate-related stressors. These pressures are impairing the capacity of beaches to meet recreational demand, provide food, protect livelihoods, and maintain biodiversity and water quality. This will increase the likelihood of social–ecological collapses and regime shifts, such that beaches will sustain neither the original ecosystem function nor the related services and societal goods and benefits that they provide. These social–ecological systems at the land–sea interface are subject to market forces, weak governance institutions, and societal indifference: most people want a beach, but few recognize it as an ecosystem at risk.
... This framework builds a bridge between environmental science, engineering, and economic valuation. It has been used in many contexts to assess the effectiveness of plans and strategies for coastal protection (Arkema et al. 2013;Sutton-Grier et al. 2018). For example, in one assessment, a team worked extensively with the government of Belize to model the services provided by corals, mangroves, and seagrasses (Arkema et al. 2015). ...
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Designers and engineers are developing proposals for physical projects to adapt coastal sites to future sea level rise related threats. This puts pressure on local and regional decision makers to develop strategic frameworks for prioritizing, permitting and funding such projects. However, no systematic evaluation tools exist for the full range of these innovative designs. We build on the literature to develop an evaluation framework that synthesizes two different approaches to categorize these proposals and provide insight for coastal managers and decision makers. We apply this framework to physical projects that address sea level rise in their design around the San Francisco Bay Area, a leading region in sea level rise adaptation. We find that these projects demonstrate a shift toward more habitat-focused strategies, which likely marks the beginning of a larger transformation of the coastal zone. According to our five-part evaluation tool, we also find that the projects’ scores have improved over time, indicating that state agency work may be helping communities implement more flexible adaptation initiatives. Despite these positive signs, we also find that none of the projects achieved high marks in all five of the evaluation criteria. This finding indicates that there is a critical need for improvement in physical planning for adaptation to higher sea levels and associated impacts. Most importantly, we find that an evaluation framework such as the one used here can provide critical insights into the likely risks and benefits of proposed adaptation projects and their long-term implications for coastal zones.
... Pulse perturbations, such as the El Niño-Southern Oscillation (ENSO; hereafter El Niño), when superimposed on SLR, tend to exacerbate erosion (Barnard et al. 2015). Yet sandy coastlines, particularly in regions with high population density and coastal development, have no capacity to respond naturally to SLR and the landward migration of the LAZ (Arkema et al. 2013;Bindoff et al. 2020). ...
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In a nutshell: 1. Sandy beach ecosystems make up half of the world’s ice-free ocean coastlines and function as social-ecological systems. 2. No other ecosystem on the planet carries such a high level of recreational use, which is increasing worldwide as demand for leisure time rises. 3. We illustrate a global trend in social-ecological shifts and collapses of sandy beaches in the face of local and distant pressures. 4. A lack of long-term policies and strategic planning reduces governance capacity, which must be participatory and resilient to environmental changes. 5. Everyone wants a beach, but few recognize it as an ecosystem at risk.
... Natural and anthropogenic forces, such as sea-level rise 1,2 , coastal development 3 , reduction of riverine sediment 4,5 , and subsidence and compaction of coastal sediments 6,7 , have caused extensive land loss, degradation, and fragmentation of coastal ecosystems, threatening the delivery of important ecosystem services 8 . For example, the average relative sea-level rise in the Mississippi River Delta (MRD) is 13 mm/yr 9 . ...
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Marsh vegetation, a definitive component of delta ecosystems, has a strong effect on sediment retention and land-building, controlling both how much sediment can be delivered to and how much is retained by the marsh. An understanding of how vegetation influences these processes would improve the restoration and management of marshes. We use a random displacement model to simulate sediment transport, deposition, and resuspension within a marsh. As vegetation density increases, velocity declines, which reduces sediment supply to the marsh, but also reduces resuspension, which enhances sediment retention within the marsh. The competing trends of supply and retention produce a nonlinear relationship between sedimentation and vegetation density, such that an intermediate density yields the maximum sedimentation. Two patterns of sedimentation spatial distribution emerge in the simulation, and the exponential distribution only occurs when resuspension is absent. With resuspension, sediment is delivered farther into the marsh and in a uniform distribution. The model was validated with field observations of sedimentation response to seasonal variation in vegetation density observed in a marsh within the Mississippi River Delta. Wetland vegetation is typically considered only in terms of enhancing sediment accretion and positively impacting land-building. Here, the authors show that the degree of enhancement has a strong dependence on vegetation density through the influence on sediment supply and retention.
... The development of risk-based valuations of ecosystem-based flood protection has been limited by the lack of high-resolution data on bathymetry, topography, ecosystems and economic assets and the difficulty in modelling complex hydrodynamic processes across large regions. For these reasons, previous studies do not model flooding directly 31,32 or rely on global-scale data and simplified physics-based modelling approaches 17,33 . Yet, recent technological and data advances now make it possible to quantify and directly assess flood losses and the benefits of coastal ecosystems for reducing them with unprecedented rigour and spatial definition. ...
Article
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Habitats, such as coral reefs, can mitigate increasing flood damages through coastal protection services. We provide a fine-scale, national valuation of the flood risk reduction benefits of coral habitats to people, property, economies and infrastructure. Across 3,100 km of US coastline, the top-most 1 m of coral reefs prevents the 100-yr flood from growing by 23% (113 km²), avoiding flooding to 53,800 (62%) people, US$2.7 billion (90%) damage to buildings and US$2.6 billion (49%) in indirect economic effects. We estimate the hazard risk reduction benefits of US coral reefs to exceed US$1.8 billion annually. Many highly developed coastlines in Florida and Hawaii receive annual benefits of over US$10 million km–1, whereas US reefs critically reduce flooding of vulnerable populations. This quantification of spatial risk reduction can help to prioritize joint actions in flood management and environmental conservation, opening new opportunities to support reef management with hazard mitigation funding.
... Anderson et al., 2011Anyamba and Tucker, 2005Anyamba and Tucker, 2012Arkema et al., 2013Avellaneda et al., 2017Barone et al., 2014Bates and De Roo, 2000Blankespoor et al., 2017Booty et al., 2009Bottero et al., 2017Bradford and Bell, 2017Casini et al., 2015Crétaux et al., 2011Dai et al., 2004Das et al., 2011Dean, 2001Eckart et al., 2012EEA, 2015European Commission, 2016Ewen et al., 2000Fensholt et al., 2006Figlus et al., 2014Fuchs, 2012Funk et al., 2015Gallina et al., 2016Gracia et al., 2018Gralher et al., 2012Griffith et al., 2014Hallermeier and Rhodes, 1989Hashim and Catherine, 2013Hettiarachchi et al., 2013Hoque et al., 2020IPCC, 2014Ismail et al., 2012Ji and Peters, 2003Jones et al., 2019Kabisch and Van Den Bosch, 2017Kabisch et al., 2017bKarnieli et al., 1996Karnieli et al., 2010Kathryn et al., 2017Kim et al., 2017Kobayashi et al., 2013Kong et al., 2017Krauss et al., 2009Liquete et al., 2013Lucas and Sample, 2015Ma et al., 2014Macro et al., 2019Manis et al., 2015Martín et al., 2020Mazda et al., 1997McIvor et al., 2016McKee et al., 1993Mittermeier et al., 2008Mohammad et al., 2018Nam et al., 2015Nanzad et al., 2019Narayan et al., 2016Nepf and Vivoni, 2000Nesshöver et al., 2017Palmer, 1965Peters et al., 2002Provenzano, 2019Quinn et al., 2013Ramezani et al., 2019Raymond et al., 2017bRomañach et al., 2014Sahani et al., 2019Santamouris et al., 2017Short et al., 2019Silva et al., 2016Sonneveld et al., 2018Spinoni et al., 2018Thomas et al., 2014Thompson et al., 2004Torres-Batlló et al., 2020Tucker et al., 1991Van Coppenolle and Temmerman, 2019Van Delden et al., 2007Vázquez and Feyen, 2007Veijalainen et al., 2019Vuik et al., 2019Wang et al., 2005Webb et al., 2018Yang et al., 2018bYi and Wen, 2016Zischg et al., 2018 ...
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Nature-based solutions (NBS) for hydro-meteorological risks (HMRs) reduction and management are becoming increasingly popular, but challenges such as the lack of well-recognised standard methodologies to evaluate their performance and upscale their implementation remain. We systematically evaluate the current state-of-the-art on the models and tools that are utilised for the optimum allocation, design and efficiency evaluation of NBS for five HMRs (flooding, droughts, heatwaves, landslides, and storm surges and coastal erosion). We found that methods to assess the complex issue of NBS efficiency and cost-benefits analysis are still in the development stage and they have only been implemented through the methodologies developed for other purposes such as fluid dynamics models in micro and catchment scale contexts. Of the reviewed numerical models and tools MIKE-SHE, SWMM (for floods), ParFlow-TREES, ACRU, SIMGRO (for droughts), WRF, ENVI-met (for heatwaves), FUNWAVE-TVD, BROOK90 (for landslides), TELEMAC and ADCIRC (for storm surges) are more flexible to evaluate the performance and effectiveness of specific NBS such as wetlands, ponds, trees, parks, grass, green roof/walls, tree roots, vegetations, coral reefs, mangroves, sea grasses, oyster reefs, sea salt marshes, sandy beaches and dunes. We conclude that the models and tools that are capable of assessing the multiple benefits, particularly the performance and cost-effectiveness of NBS for HMR reduction and management are not readily available. Thus, our synthesis of modelling methods can facilitate their selection that can maximise opportunities and refute the current political hesitation of NBS deployment compared with grey solutions for HMR management but also for the provision of a wide range of social and economic co-benefits. However, there is still a need for bespoke modelling tools that can holistically assess the various components of NBS from an HMR reduction and management perspective. Such tools can facilitate impact assessment modelling under different NBS scenarios to build a solid evidence base for upscaling and replicating the implementation of NBS.
... Other indirect evidence comes from regional-, continental-, and global-scale assessments, based on modeling approaches assessing factors such as surface areas, population numbers, and economic assets sheltered by tidal wetlands (e.g., Arkema et al. 2013, Menendez et al. 2020, Van Coppenolle et al. 2018, van Zelst et al. 2021. Although model assessments on such large scales are inevitably approximate, they indicate that storm protection benefits from wetlands might be widespread. ...
Article
Tidal marshes and mangroves are increasingly valued for nature-based mitigation of coastal storm impacts, such as flooding and shoreline erosion hazards, which are growing due to global change. As this review highlights, however, hazard mitigation by tidal wetlands is limited to certain conditions, and not all hazards are equally reduced. Tidal wetlands are effective in attenuating short-period storm-induced waves, but long-period storm surges, which elevate sea levels up to several meters for up to more than a day, are attenuated less effectively, or in some cases not at all, depending on storm conditions, wetland properties, and larger-scale coastal landscape geometry. Wetlands often limit erosion, but storm damage to vegetation (especially mangrove trees) can be substantial, and recovery may take several years. Longer-term wetland persistence can be compromised when combined with other stressors, such as climate change and human disturbances. Due to these uncertainties, nature-based coastal defense projects need to adopt adaptive management strategies. Expected final online publication date for the Annual Review of Marine Science, Volume 15 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... Estuarine alluvial islands have unique ecosystem characteristics due to the impact of nature and human activities [1][2][3]. Intense land-sea interactions [4,5] include morphological changes to islands, and are dominated by sedimentation and supplemented by erosion [3,[6][7][8][9][10], seawater intrusion and soil salinization [2,11], sea level rise [4,12,13], and coastal erosion [14]. Interference caused by complex human activities [15], such as urban and rural construction, land reclamation, farmland expansion, coastal engineering, and aquaculture, have jointly caused spatiotemporal changes in the surface characteristics of estuarine alluvial islands [9,[16][17][18][19]. ...
Article
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Net Primary Productivity (NPP) can effectively reflect the characteristics and strength of the response to external disturbances on estuarine alluvial island ecosystems, which can provide evidence for regulating human development and utilization activities and improving blue carbon capacity. However, there are a few studies on NPP of estuarine alluvial islands. We established a model based on a Carnegie–Ames–Stanford Approach (CASA) to estimate NPP on Chongming Island, a typical estuarine alluvial island, by considering the actual ecological characteristics of the island. The NPP of different land-cover types and protected areas in different years and seasons were estimated using Remote Sensing and Geographic Information System as the main tools. Correlations between NPP and Remote Sensing-based spatially heterogeneous factors were then conducted. In the last 30 years, the mean NPP of Chongming Island initially increased and then slowly decreased, while total NPP gradually increased. In 2016–2017, Chongming Island total NPP was 422.32 Gg C·a−1, and mean NPP was 287.84 g C·m−2·a−1, showing significant seasonal differences. NPP showed obvious spatial differentiation in both land-cover and protected area types, resulting from joint influences of natural and human activities. Chongming Island vegetation growth status and cover were the main factors that positively affected NPP. Soil surface humidity increased NPP, while soil salinity, surface temperature, and surface aridity were important NPP limiting factors.
... Reefs function as foundation habitats supporting aquatic food webs, and potentially provide numerous other ecosystem services, such as nutrient regulation, storage, and wave attenuation (Coen et al., 2007;Grabowski et al., 2012). These services likely benefit adjacent habitats, such as salt marsh, by mitigating erosion and stabilizing shorelines (Arkema et al., 2013;Piazza et al., 2005;Scyphers et al., 2011). For these reasons, restoration of reefs for ecosystem-based management is growing in practice (Currin et al., 2010;Frederick et al., 2016). ...
Article
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Self-organization is a process of establishing and reinforcing local structures through feedbacks between internal population dynamics and external factors. In reef-building systems, substrate is collectively engineered by individuals that also occupy it and compete for space. Reefs are constrained spatially by the physical environment, and by mortality, which reduces production but exposes substrate for recruits. Reef self-organization therefore depends on efficient balancing of production and occupancy of substrate. To examine this, we develop a three-dimensional individual-based model (IBM) of oyster reef mechanics. Shell substrate is grown by individuals as valves, accumulates at the reef level, and degrades following mortality. Single restoration events and subsequent dynamics are simulated for a case study in South Carolina (USA). Variability in model processes is included on recruitment, spatial environmental constraints, and predation, over multiple independent runs and five predator community scenarios. The main goal for this study is to summarize trends in dynamics that are robust across this uncertainty, and from these generate new hypotheses and predictions for future studies. Simulation results demonstrate three phases following restoration: initial transient dynamics with considerable shell loss, followed by growth and saturation of the live population, and then saturation of settlement habitat several years later. Over half of simulations recoup initial shell losses as populations grow, while others continue in decline. The balance between population density, substrate supporting the reef, and exposed surfaces for settlement is mediated by overall population size and size structure, presence of predators, and relative amounts of live individuals and intact dead shells. The efficiency of settlement substrate production improves through time as population size structure becomes more complex, and the population of dead valves accumulates.
... The coastline is an interface between sea and land [1]. Coastal habitats shield the hinterland from marine hazards [2][3][4]. Sandy coasts are constantly evolving [5] under the Figure 1. A typical western French sandy coast profile. ...
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Due to the coastal morphodynamic being impacted by climate change there is a need for systematic and large-scale monitoring. The monitoring of sandy dunes in Pays-de-la-Loire (France) requires a simultaneous mapping of (i) its morphology, allowing to assess the sedimentary stocks and (ii) its low vegetation cover, which constitutes a significant proxy of the dune dynamics. The synchronization of hyperspectral imaging (HSI) with full-waveform (FWF) LiDAR is possible with an airborne platform. For a more intimate combination, we aligned the 1064 nm laser beam of a bi-spectral Titan FWF LiDAR with 401 bands and the 15 cm range resolution on the Hyspex VNIR camera with 160 bands and a 4.2 nm spectral resolution, making both types of data follow the same emergence angle. A ray tracing procedure permits to associate the data while keeping the acquisition angles. Stacking multiple shifted FWFs, which are linked to the same pixel, enables reaching a 5 cm range resolution grid. The objectives are (i) to improve the accuracy of the digital terrain models (DTM) obtained from an FWF analysis by calibrating it on dGPS field measurements and correcting it from local deviations induced by vegetation and (ii) in combination with airborne reflectances obtained with PARGE and ATCOR-4 corrections, to implement a supervised hierarchic classification of the main foredune vegetation proxies independently of the acquisition year and the physiological state. The normalization of the FWF LiDAR range to a dry sand reference waveform and the centering on their top canopy echoes allows to isolate Ammophilia arenaria from other vegetation types using two FWF indices, without confusion with slope effects. Fourteen HSI reflectance indices and 19 HSI Spectral Angle Mapping (SAM) indices based on 2017 spectral field measurements performed with the same Hyspex VNIR camera were stacked with both FWF indices into a single co-image for each acquisition year. A simple straightforward hierarchical classification of all 35 pre-classified co-image bands was successfully applied along 20 km, out of the 250 km of coastline acquired from 2017 to 2019, prefiguring its systematic application to the whole 250 km every year.
... Plants have been observed to directly increase the erosion threshold of bed sediments and indirectly trap sediments by providing additional drag force (Leonard and Luther, 1995;Temmerman et al., 2005;Chen et al., 2016), which mediates flow patterns and consequently enhances local sediment deposition (Neumeier and Amos, 2006;Horstman et al., 2015). The enhancement of sediment deposition by coastal wetland vegetation has received more extensive attention in recent decades, in part due to the predicted impacts of accelerated sea-level rise and the C storage ability in this type of particular environment (van der Wal and Pye, 2004;Cahoon et al., 2006;Nellemann et al., 2009;Arkema et al., 2013;Woodroffe et al., 2016;Rovai et al., 2018). ...
Chapter
Mangroves and tidal saltmarshes are known for their considerable capacity to store carbon (C). Mangrove-saltmarsh ecotones have high dynamics in C cycling based on some evidence of mangroves encroaching into saltmarshes. The mangrove encroachment may also increase the surface elevation, enhance C storage and further change the ecosystem services. In China, an exotic Spartina alterniflora (cordgrass) introduced from the East Coast of the United States has been extensively invading mangrove wetlands. During this situation, the carbon dynamics and associated sedimentary processes within the mangrove wetlands under cordgrass invasion are largely unknown. In this chapter, we discuss the biochemical and eco-geomorphological feedbacks related to surface sediment carbon and discuss the biological factors affecting sediment carbon flux, vegetation-sediment interaction and the consequent sedimentary processes. We assess the change in carbon stocks after cordgrass invaded mangroves in the Yunxiao Estuary and present a conceptual model of carbon dynamics and the evaluation of regional carbon storage in typical mangrove-Spartina ecotones. The invasion of cordgrass can increase the sediment deposition and enhance the surface elevation on the edges of mangrove-Spartina ecotones, which has a positive feedback on their further expansion to the mudflat. Thus, cordgrass invasion in the mangroves in China would enhance sediment C stocks in the mangrove wetlands. However, the long-term studies of the C dynamics in mangrove-Spartina ecotones still require truly interdisciplinary approaches of biology, biochemistry and eco-geomorphology.
... The potential for natural infrastructure to protect coasts by slowing erosion and reducing storm surge and flooding can be considerable in many settings, particularly in areas subject to high relative rates of sea level rise and vulnerability to storms (Arkema et al. 2013, Sutton-Grier et al. 2015, Narayan et al. 2016. Natural features that can attenuate waves (e.g., marshes) are being created to protect shorelines in many estuaries and coasts, and this practice has grown substantially over the past 20 yr (Sutton-Grier et al. 2015). ...
Article
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Coastal communities increasingly invest in natural and nature‐based features (e.g., living shorelines) as a strategy to protect shorelines and enhance coastal resilience. Tidal marshes are a common component of these strategies because of their capacity to reduce wave energy and storm surge impacts. Performance metrics of restoration success for living shorelines tend to focus on how the physical structure of the created marsh enhances shoreline protection via proper elevation and marsh plant presence. These metrics do not fully evaluate the level of marsh ecosystem development. In particular, the presence of key marsh bivalve species can indicate the capability of the marsh to provide non‐protective services of value, such as water quality improvement and habitat provision. We observed an unexpected low to no abundance of the filter‐feeding ribbed mussel, Geukensia demissa, in living shoreline marshes throughout Chesapeake Bay. In salt marsh ecosystems along the Atlantic Coast of the United States, ribbed mussels improve water quality, enhance nutrient removal, stabilize the marsh, and facilitate long‐term sustainability of the habitat. Through comparative field surveys and experiments within a chronosequence of 13 living shorelines spanning 2–16 years since construction, we examined three factors we hypothesized may influence recruitment of ribbed mussels to living shoreline marshes: (1) larval access to suitable marsh habitat, (2) sediment quality of low marsh (i.e., potential mussel habitat), and (3) availability of high‐quality refuge habitat. Our findings suggest that at most sites larval mussels are able to access and settle on living shoreline created marshes behind rock sill structures, but that most recruits are likely not surviving. Sediment organic matter (OM) and plant density were correlated with mussel abundance, and sediment OM increased with marsh age, suggesting that living shoreline design (e.g., sand fill, planting grids) and lags in ecosystem development (sediment properties) are reducing the survival of the young recruits. We offer potential modifications to living shoreline design and implementation practices that may facilitate self‐sustaining ribbed mussel populations in these restored habitats.
... In tandem with the direct protection of coastlines, mangroves and salt marshes can mitigate coastal erosion and reduce the vulnerability of people and property (Arkema et al. 2013). Under normal conditions, mangroves and salt marshes stabilise sediments through a number of mechanisms. ...
Chapter
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Ecosystem services are now strongly applied to mangrove forests, though they are not a new way of viewing mangrove-people interactions; the benefits provided by such habitats, and the negative interactions (ecosystem disservices) between mangroves and people have guided perceptions of mangroves for centuries. This study quantified the ecosystem services and disservices of mangroves as written by colonial explorers from 1823–1883 through a literature survey of 96 expedition reports and studies. Ecosystem disservices were most commonly discussed (60%), with settlers considering mangroves as reservoirs of diseases such as malaria, with wide-ranging implications, such as the global drainage of wetlands in the 19th–20th centuries. Multiple ecosystem services were discussed, especially provisioning services for export, representing colonial views of new lands as ripe for economic use. Interestingly, regulating services of mangroves such as erosion control and sediment accretion that are a focus of much contemporary research were recognized as early as 1865. This study shows that the ecosystem service paradigm has a long history in mangroves. We should not underestimate mangrove ecosystem disservices, and how contemporary perceptions of mangroves may be influenced by such historical viewpoints. Archival materials provide a rich resource to study human-environment interactions, and how they change through time. Open access: https://www.mdpi.com/1999-4907/7/9/183/htm
... When managing coastal hazards, it is important to consider engineering and socio-economic factors (Arkema et al., 2017). In Australia coastal communities are often dominated by older people (Gurran, 2008;MacKenzie, 2020) who can be more vulnerable to coastal hazards, because they are slower to respond and recover from extreme weather events, such as flooding (Arkema et al., 2013;MacKenzie, 2020). We found that coastal landowners were more likely to use mangroves for recreational activities such as fishing, bird watching and walking, than other respondents. ...
Article
Coastal flooding and erosion cause significant social and economic impacts, globally. There is a growing interest in using natural habitats such as mangroves to defend coastlines. The protective services of mangroves, however, have not been assessed in the same rigorous engineering and socio-economic terms as rock revetments, and therefore are often overlooked by coastal managers. We used field measurements, a social science survey and economic valuation to compare the coastal protection services of mangroves and rock revetments, at five locations across Victoria, Australia. The results showed, in sheltered locations, both mangroves and rock revetments attenuated waves, however, the wave attenuation (per metre) of rock revetments was greater than mangroves, at two of the five locations. Only a small proportion of the survey respondents had observed flooding or erosion in their suburb but most agreed that mangroves provide important coastal protection benefits. Coastal landowners visited areas with mangroves more often than the public but were less likely to worry about the links between climate change and coastal erosion and flooding, or to agree that the coast was well protected with existing artificial coastal infrastructure, than other respondents. There were much higher up-front costs associated with building rock revetments, than planting mangroves, but rock revetments required less land than mangroves. Mangroves covered a larger area and averted more damages than rock revetments. Coastal managers and policy makers will have more success in advocating for nature-based solutions for coastal protection, if they are implemented in locations where they are eco-engineering and socio-economically acceptable options for climate change adaptation.
... For example, in a rigorous analysis, Storlazzi et al. [41] determined that the annual value of flood risk reduction provided by coral reefs in the U.S. is more than 18,000 lives and US$1.8 billion (2010 dollars). Narayan et al. [42] estimated that coastal wetlands averted more than US$625 million in flood damages from Hurricane Sandy across the northeastern U.S. Arkema et al. [43] calculated that the number of vulnerable people and value of residential property in the U.S. that are most exposed to hazards (including storm wind/wave exposure and inundation) could be reduced by 50% if existing coastal habitats are preserved. Moudrak and Feltmate [1], Moudrak et al. [26], Circé et al. [44], Horizon Advisors [45], Sherren et al. [46], and the Municipal Natural Assets Initiative [47], [48] present numerous examples of economic analyses that quantitatively illustrate the benefits of NbS and natural assets in Canada: ...
Article
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Canadian communities and infrastructure are vulnerable to coastal and riverine flood hazards. The risks associated with coastal and river flooding are escalating as a result of development in river floodplains and coastal zones, and the effects of climate change on flood and erosion hazards. There is growing interest in the potential for Nature-based Solutions (NbS) to play a role in managing these risks, owing in part to Canada’s co-leadership of the Nature-based Solutions Action Track of the Global Commission on Adaptation. Despite this increasing interest in NbS for coastal and riverine flood and erosion risk management, they remain relatively underutilized in Canada. Standards and guidelines can contribute to mainstreaming NbS by clarifying the underlying concepts and principles, raising awareness, and educating practitioners, potential project proponents, and the public. This review and synthesis of published literature and interviews with stakeholders and experts was conducted to: • Assess how NbS can be used to manage flood and erosion risks in coastal and riverine environments in Canada; and • Determine needs and opportunities for standards to support deployment of NbS to reduce coastal and riverine flooding and erosion risks. NbS for coastal and riverine flood and erosion risk management are strategies or measures that depend on, or mimic, natural system processes to provide flood and erosion risk management function, while delivering a suite of environmental and other societal co-benefits. NbS embrace the principles of “whole system” analysis, adaptive management, multi-disciplinary teams, innovation, and long-term planning for uncertainty. They can be deployed through sustainable planning and regulatory frameworks that recognize the value of natural assets and infrastructure in supporting risk management objectives (e.g., Integrated Water Resources Management and Integrated Coastal Zone Management), and/or the targeted deployment of nature-based features to provide specific flood and erosion risk management functions. Nature-based features can deliver flood and erosion risk management benefits in a variety of ways, for example: • In coastal regions – beaches/dunes, reefs, and wetlands provide buffers against wave action, storm surges, and erosion; • In river watersheds – wetlands, reconnected floodplain areas, and restored river channels enhance groundwater infiltration, reduce or delay runoff, and attenuate peak flood flows and water levels; and • In estuaries – marsh and wetland systems can be preserved, expanded, or restored to provide additional hydraulic storage and attenuate waves. NbS span a continuum of human intervention from green (least intervention) to grey (traditional hard infrastructure); from simply conserving or protecting existing natural systems (e.g., floodplain preservation), to enhancing or restoring natural processes (e.g., beach nourishment), to hybrid or grey-green solutions that integrate hard engineering or structural measures with more natural features (e.g., buried revetments), to “greening” traditional infrastructure (e.g., by incorporating features to enhance ecological value or provide habitat). Although there are Canadian examples of NbS for flood and erosion risk management that date back to the 1970s, they remain relatively underutilized today. Key barriers to broader uptake include challenges in predicting performance of NbS in distinct and varied Canadian regional settings, a paucity of data demonstrating the performance and track record of NbS, a shortage of highly qualified professionals, stakeholder perceptions that NbS are more uncertain or less effective than (hard engineering) alternatives, project funding models that disincentivize NbS, undervaluation of the co-benefits of NbS in conventional economic analyses and financing models, a lack of authoritative technical guidance, and complex governance and regulatory environments. The growth in research and interest surrounding NbS has led to the proliferation of numerous reports and guidance documents relevant to the implementation of NbS for coastal and riverine flood and erosion risk management. With a few exceptions, the majority of guidance is relatively high-level, and lacks either the technical detail or region specific contexts needed to support effective design and implementation of NbS for coastal and riverine flood and erosion risk management across Canada. Collectively, however, available and emerging guidance provides a sound foundational basis for working towards implementation of best practices through future Canadian national standards and design guides. The benefits of national standardization and guidance would include mainstreaming of NbS principles, education of stakeholders and potential proponents on factors affecting the performance of NbS, and increased investor confidence in NbS projects. In particular, monitoring and evaluation protocols for NbS, and frameworks supporting evaluation and deployment of NbS represent potential short-term opportunities for standardization to facilitate wider adoption. Knowledge and research gaps to be addressed to enable the development of Canadian guides and standards for NbS in coastal zones and river watersheds include: • Evidence of NbS performance across distinct and varied Canadian coastal and river settings, particularly northern environments, where NbS are relatively untested; • Improvement and validation of predictive tools; • Potential adverse impacts of NbS; and • An improved understanding of the comparative performance of non-structural (i.e., planning-based), conventional, and nature-based (including hybrid) flood and erosion risk management solutions in achieving multiple benefits.
... Rapid and largescale reclamation activities presently carried out in China's coastal areas have far exceeded the carrying capacity of the natural environment [25,38,54]. The seaward expansion of artificial coastlines weakens sediment dynamics and hydrodynamics, decreases the biodiversity and intertidal waterbird habitats, and reduce ecosystem services, leading to a reduction in the overall benefit of coastal reclamation [10,25,[50][51][52][53][54]. The ecological service values of coastal wetlands in China will be CNY 20 million/km 2 each year, and port reclamation has directly decreased the ecological service value of occupied coastal wetlands [55]. ...
Article
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Coastal land reclamation (CLR), particularly port reclamation, is a common approach to alleviating land shortages. However, the spatial extent, percentages, and processes of these newly reclaimed ports are largely unknown. The Bohai Sea is the most concentrated area of port reclamation worldwide. Thus, this study addresses the changes in the different coastline types and port reclamation process in the area. The reclamation area of the 13 ports in the Bohai Sea in 2002–2018 was 2,300 km ² , which decreased the area of the sea by 3%. The natural coastline length in Tianjin decreased by 47.5 km, whereas the artificial coastline length increased by 46.6 km. Based on the port boundary, however, only 26.3% of the reclaimed areas have been used for port construction, which concentrates in the Tianjin and Tangshan ports. The ratio of built-up area within the ports is only 32.5%, and approximately 48.3% of the reclaimed areas have no construction projects. The port land reclamation in the Bohai Sea has been undergoing periods of acceleration, peak, deceleration, and stagnation since 2002. Hence, future port reclamation should not be totally prohibited, and fine management should be conducted based on the optimization of the reclaimed port area. The innovation of this research is its analysis of the port internal land use pattern, the percentage of built-up area in the ports, and the sustainability of port reclamation policies. The findings have vital implications for scientifically regulating the spatial pattern and exploring the utility of port reclamation.
... As flood risk is expected to increase in the future as a result of rising extreme sea levels and socioeconomic developments, there is a need to increase coastal resilience accompanied with a strong demand for coastal flood protection measures 17,18 . The role that coastal vegetation can play in reducing coastal flood risk has been quantified in several local, regional, national and global studies 5,[19][20][21][22] . Only few global studies have been based on process-based wave modelling, and those that have taken this approach focused on mangroves only 23 . ...
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Exposure to coastal flooding is increasing due to growing population and economic activity. These developments go hand-in-hand with a loss and deterioration of ecosystems. Ironically, these ecosystems can play a buffering role in reducing flood hazard. The ability of ecosystems to contribute to reducing coastal flooding has been emphasized in multiple studies. However, the role of ecosystems in hybrid coastal protection (i.e. a combination of ecosystems and levees) has been poorly quantified at a global scale. Here, we evaluate the use of coastal vegetation, mangroves, and marshes fronting levees to reduce global coastal protection costs, by accounting for wave-vegetation interaction.The research is carried out by combining earth observation data and hydrodynamic modelling. We show that incooperating vegetation in hybrid coastal protection results in more sustainable and financially attractive coastal protection strategies. If vegetated foreshore levee systems were established along populated coastlines susceptible to flooding, the required levee crest height could be considerably reduced. This would result in a reduction of 320 (range: 107-961) billion USD 2005 Power Purchasing Parity (PPP) in investments, of which 67.5 (range: 22.5- 202) billion USD 2005 PPP in urban areas for a 1 in 100-year flood protection level.
... All of these types of nature-based solutions can support coastal resilience and risk reduction by using natural processes and landforms to provide protection for both ecosystems and the built environment 10,11 . They can provide not only protection from sea-level rise and storms [12][13][14] , but also climate change mitigation through carbon sequestration, opportunities for recreation, habitat for key species, and other benefits [15][16][17][18][19][20] . These benefits-ecosystem services or nature's contributions to people-help connect healthy, functioning ecosystems to human wellbeing 21,22 . ...
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Globally, rising seas threaten massive numbers of people and significant infrastructure. Adaptation strategies increasingly incorporate nature-based solutions. New science can illuminate where these solutions are appropriate in urban environments and what benefits they provide to people. Together with stakeholders in San Mateo County, California, USA, we co-developed nature-based solutions to support adaptation planning. We created six guiding principles to shape planning, summarized vulnerability to sea-level rise and opportunities for nature-based solutions, created three adaptation scenarios, and compared multiple benefits provided by each scenario. Adaptation scenarios that included investments in nature-based solutions deliver up to eight times the benefits of a traditionally engineered baseline as well as additional habitat for key species. The magnitude and distribution of benefits varied at subregional scales along the coastline. Our results demonstrate practical tools and engagement approaches to assessing the multiple benefits of nature-based solutions in an urban estuary that can be replicated in other regions.
... Salt marsh vegetation are halophytic herbs, grasses and shrubs that grow in the low energy zone of intertidal areas; forming the interface between marine and terrestrial ecosystems. Salt marsh vegetation provides ecosystem services to coastal population including fishery support, storm surge protection, nutrient cycling, shoreline protection, water purification, carbon sequestration, sea level rise adaptation, recreational and cultural benefits (Siikamäki et al., 2012;Arkema et al., 2013;Hansen and Reiss, 2015;Banerjee et al., 2017;NOAA, 2017). In addition, salt marsh vegetation is also used as a proxy of soil topography to estimate ground elevation (Silvestri et al., 2003) and indicator for physical or chemical degradation in wetland ecosystem (Dennison et al., 1993). ...
Article
Salt marshes are coastal wetlands dominated by the grasslands and they are one among the most productive coastal ecosystems which provide several benefits and multiple ecosystem services. Their spatial distribution is at risk due to wide range of human activities and sea level rise. Remote sensing technique can be applied to assess their spatial coverage in quick time. Field spectrometry, an accessory tool of remote sensing, measures the reflectance using spectroradiometer to acquire continuous spectrum from a target. Developing spectral catalogue for salt marsh vegetation is essential to discriminate the vegetation into species level. In the present study, species canopy spectral signatures for seven salt marsh species were measured using spectroradiometer. Several post-processing steps were conducted for noise removal and the spectral catalogue was developed. In addition, Landuse/Landcover (LULC) spectral signatures for salt marsh vegetation were acquired from Multispectral data ofSentinel-2B satellite in near real-time using field ground truth coordinates. The species canopy and LULC spectral signatures were applied in the MSI data to perform species level classification of salt marsh vegetation. The results were significant, and indicated an overall accuracy of 65.8 %, and 73.55 % for species canopy and LULC spectral signatures respectively. The spectral outcome of this study can be utilized directly for rapid classification and to assess the change in the dynamics of salt marsh ecosystems for the areas with low accessibility. Further the mapping results can be used as baseline information for change detection analysis which would support coastal resources management, and help in strengthening the regulatory framework for protection and conservation purposes.
... It is evident that the majority of existing research has focused on the impact of geometrical shapes, size of estuaries, characteristics of incident waves, depth and topographical changes to the harbors on oscillation, whereas relatively few studies have concentrated on the impact of coastal vegetation. Coastal wetlands including mangroves, seagrasses, saltmarshes and so on, are considered as effective buffers to incident wave (Arkema et al., 2013;Möller et al., 2014;Suzuki et al., 2019). The upstanding coastal vegetation have significant ability to weaken incident wave energy (Anderson et al.), resulting in the reduction of energy load on dikes and stabilization of seabed (Callaghan et al., 2010;Shi et al., 2012). ...
Article
Harbor oscillation can cause damage to wharves, ships and coastal buildings. Vegetation zones can alter the wave field within harbors, and are therefore an effective, environmentally-friendly and cost-effective approach to reducing the harm of the harbor oscillation. However, few studies have focused on the influence of vegetation on harbor oscillation. This study used a new time-domain model, Simulating WAves till SHore (SWASH), to explore the relationship between harbor oscillation and different vegetation variables. The influence of configuration, width of vegetation zones, and height, diameter, density of plants were explored. The results showed that the positioning of vegetation zones along the four boundaries of a harbor minimized wave height. Increasing the width of the vegetation zones and height, diameter and density of plants resulted in a reduction in wave height and alteration of the modes of oscillation. The different vegetation variables had different impacts on harbor oscillation. This study can guide in the plants selection and vegetation zones distribution to effectively minimize the damage caused by harbor oscillation.
... A flora do manguezal, principalmente a feição arbórea, é o que define a paisagem do ecossistema, participando direta ou indiretamente dos processos ecológicos que ocorrem no manguezal. Dentre os serviços ecossistêmicos prestados pelos manguezais podemos citar alguns bem conhecidos, tais como proteção da costa (erosão costeira e tempestades), regulação climática, fonte de alimentos e ecoturismo (Arkema et al., 2013;Donato et al., 2011). Da mesma forma que em outros ecossistemas costeiros, os manguezais e sua biodiversidade estão sendo degradados por diferentes ameaças antropogênicas (Polidoro et al., 2010), no Brasil principalmente por: aquicultura, agricultura, exploração de madeira, indústria pesqueira, urbanização e mudanças climáticas (ICMBio, 2018a). ...
... On the other hand, from the correlation analysis based on every line i, the R matrix element data suggest different results. It can be concluded that when the cloud model is applied for comprehensive evaluation, the above results that we obtained using the linear regression analysis method of correlation between the Ex j value and each single u i index and the results of ω i weight distribution calculation, which obviously is a more practical and objective method, are inconsistent (Arkema et al., 2013). ...
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Global climate change-induced sea-level rise and storm wave intensification, along with the large population densities and high-intensity human development activities in coastal areas, have caused serious burden and damage to China’s coasts, led to the rapid growth of artificial shorelines development, and formed a “new Great Wall” of reinforced concrete against the laws of nature. After the last ice age, transgression formed the different features of China’s coast. Depending on the types of geological and landform features, coasts are divided into 36 evaluation units, and 10 indicators are selected from natural aspects (including tectonics, geomorphology, sediment, and storms) and aspects of social economy (population, GDP, Gross Domestic Product), and cloud model theory is used to build a coastal erosion vulnerability evaluation index system in China. The results show that high grade (V), high-middle grade (IV), middle grade (III), low-middle grade (II), and low grade (I) coastal erosion vulnerability degrees account for 5.56, 13.89, 41.67, 33.33, and 5.56% of the Chinese coastlines, respectively. The coastal erosion vulnerability of the subsidence zone is significantly higher than that of the uplift zone. Reverse cloud model and analytic hierarchy process calculation show that the main factors that control coastal erosion vulnerability since the transgression after the last ice age are geological structure, topography and lithological features, and in recent years, the decrease in sea sediment loads and increase in reclamation engineering. Mainland China must live with the basic situation of coastal erosion, and this study shows that the index system and method of cloud modeling are suitable for the evaluation of the coastal erosion vulnerability of the Chinese mainland. This study provides a scientific basis for the adaptive management of coastal erosion, coastal disaster assessment and the overall planning of land and sea.
... Validation of NCP is particularly difficult given there are no direct measurements for many NCP with assessment reliant on remotely sensed proxies. We utilize the best available global modeling approaches and data, most of which have been validated in at least some locations 16,20,[30][31][32][33][34][35][36][37] . As availability of global models for many of these NCP increases, future work should move toward ensemble modeling approaches, which have been shown to increase accuracy and reduce uncertainty compared to individual model outputs. ...
Preprint
Sustaining the organisms, ecosystems, and processes that underpin human well-being is necessary to achieve sustainable development. Here we identify critical natural assets, natural and semi-natural ecosystems that provide 90% of the total current magnitude of 14 types of nature’s contributions to people (NCP). Critical natural assets for maintaining local-scale NCP (12 of the 14 NCP mapped) comprise 30% of total global land area and 24% of national territorial waters, while 44% of land area is required for maintaining all NCP (including those that accrue at the global scale, carbon storage and moisture recycling). At least 87% of the world’s population lives in the areas benefiting from critical natural assets for local-scale NCP, while only 16% lives on the lands containing these assets. Critical natural assets also overlap substantially with areas important for biodiversity (covering area requirements for 73% of birds and 66% of mammals) and cultural diversity (representing 96% of global Indigenous and non-migrant languages). Many of the NCP mapped here are left out of international agreements focused on conserving species or mitigating climate change, yet this analysis shows that explicitly prioritizing critical natural assets for NCP could simultaneously advance development, climate, and conservation goals. Crafting policy and investment strategies that protect critical natural assets is essential for sustaining human well-being and securing Earth’s life support systems.
Chapter
Islands in estuaries, major river deltas, and open-coast environments reduce the severity of hazards, including erosion and flooding from wind-driven waves and extreme water levels, on the nearby habitats and shorelines. Islands may also provide critical ecosystem function for threatened and endangered species and migratory birds while providing access to recreational opportunities and navigation co-benefits. This chapter (Chapter 11) of the International Guidelines on Natural and Nature-Based Features (NNBF) for Flood Risk Management focusses on islands as NNBFs that support coastal resilience. Three types of islands are discussed—barrier islands, deltaic islands (including spits), and in-bay or in-lake islands. These islands may be new construction or, as in most cases, the restoration of island remnants. The degradation and loss of islands through combined processes such as sea-level rise, subsidence, and inadequate sediment input (e.g., upstream impoundments, navigation channels, evolving natural processes) are reducing the coastal resilience benefits of these features.
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Estuaries and coasts (hereafter, coasts) host some of the most biologically productive ecosystems on Earth (Mann 1982), where a diversity of geomorphological processes create coastal landforms that range from wave dominated hard rock cliff s, shore platforms, and sandy beaches to more vegetated tide dominated landforms such as saltmarshes and mangrove forests. These habitats provide a wide range of critical ecosystem services (hereafter, ES) and natural habitat value for society for food, recreation, and for resilience against the damaging eff ects of fl oods and storms on urban communities (Barbier et al. 2011). However, there is a notable lack of coverage of coasts in urban ecology discourse, which is surprising given the high levels of population growth and urbanization at the coast (Neumann et al. 2015). This chapter: 1. Outlines the spectrum of key coastal landforms and the social/ ecological benefi ts they provide. 2. Identifi es how nature-based analogues of these natural systems can be used in place of, or in concert with, traditional 'gray', hard engineering solutions in urban coastal settings. 3. Discusses the challenges and opportunities inherent in using natural and/ or nature-based habitats to improve ecological and resilience outcomes in urban coastal settings.
Article
The Perdido Key beach mouse (Peromyscus polionotus trissyllepsis), Choctawhatchee beach mouse (P. p. allophrys), and St. Andrew beach mouse (P. p. peninsularis) are 3 federally endangered subspecies that inhabit coastal dunes of Alabama and Florida, USA. Conservation opportunities for these subspecies are limited and costly. Consequently, well‐targeted efforts are required to achieve their downlisting criteria. To aid the development of targeted management scenarios that are designed to achieve downlisting criteria, we developed a Bayesian network model that uses habitat characteristics to predict the probability of beach mouse presence at a 30‐m resolution across a portion of the Florida Panhandle. We then designed alternative management scenarios for a variety of habitat conditions for coastal dunes. Finally, we estimated how much area is needed to achieve the established downlisting criterion (i.e., habitat objective) and the amount of effort needed to achieve the habitat objective (i.e., management efficiency). The results suggest that after 7 years of post‐storm recolonization, habitat objectives were met for Perdido Key (within its Florida critical habitat) and Choctawhatchee beach mice. The St. Andrew beach mouse required 5.14 km2 of additional critical habitat to be protected and occupied. The St. Andrew beach mouse habitat objective might be achieved by first restoring protected critical habitat to good dune conditions and then protecting or restoring the unprotected critical habitat with the highest predicted probability of beach mouse presence. This scenario provided a 28% increase in management efficiency compared to a scenario that randomly protected or restored undeveloped unprotected critical habitat. In total, when coupled with established downlisting criteria, these quantitative and spatial decision support tools could provide insight into how much habitat is available, how much more is needed, and targeted conservation or restoration efforts that might efficiently achieve habitat objectives. © 2020 The Wildlife Society. This study aids coastal habitat managers by providing quantitative, spatially explicit decision support tools that estimate how much beach mouse habitat is available and how much more is needed to achieve established downlisting criteria related to habitat. These results could also guide selection of specific management actions, where those actions might be taken, and over how much critical habitat they must be applied.
Article
Jamaica, like most Small Island Developing States, is at high risk from coastal hazards due to its exposure to tropical storms, high levels of coastal development, vulnerable coastal communities and the predicted impacts of climate change. Environmental degradation has been linked to increased vulnerability to disasters. Nature‐based solutions, although not formally present in the literature, are being implemented at various scales in Jamaica. This paper presents an overview of three marine and coastal nature‐based solutions being used in Jamaica ‐ protected area management (Special Fishery Conservation Areas), mangrove restoration and coral restoration ‐ presenting an overview of current applications in Jamaica, and argues that these conservation projects traditionally focussed on biodiversity have co‐benefits as nature‐based solutions for disaster resilience. The paper closes with several future research objectives to further the use of NbS for disaster resilience in Jamaica.
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Sea-level rise (SLR) is projected to increase dramatically with profound effects on tidal marshes, yet uncertainty stemming from underlying climate change scenarios, model specifications, and temporal scale is a major hurdle to conservation planning. We compared likely effects of SLR for 2030 and 2050 under static inundation and dynamic response model predictions for the northeastern USA, where tidal marshes experience elevated rates of SLR compared to global averages. Static inundation and dynamic response models of SLR, which differ in how they incorporate uncertainty associated with local processes and biophysical feedbacks, have historically been applied at different scales, and generally differ in spatial and temporal predictions of marsh vulnerability. We used population estimates for five tidal marsh bird species of conservation concern to predict patterns of population change for each SLR model and examined how uncertainty affects planning decisions for these species. Static inundation and dynamic response models differed markedly in their predictions for 2030, yet both models predicted with reasonable certainty that only 10–15% of tidal marsh in northeastern USA is likely (> 66% chance; as defined by the IPCC) to remain by 2050. Most (85–90%) of the marsh is predicted to be as likely as not (33–66% chance) to disappear, representing high potential for the loss of habitat for > 85% of current populations of four of the five bird species. We propose a planning approach using guidelines established by the IPCC to categorize uncertainty associated with marsh loss due to SLR and apply it to prioritize key sites for preservation.
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The coastline is considered as the boundary between water and land. coasts are one of the most important environmental effects that directly affect human life. Rising sea levels due to global warming have made coastal cities among the areas under threat. Therefore, management and planning to prevent coastal erosion is one of the important issues that should be considered. In this research, we have studied the changes of shoreline using Sentinel-1 satellite images in Mazandaran province, the coast between the cities of Chalous and Tonekabon. For this purpose, two images on 15/01/2019 and 01/09/2021 have been used and the desired images have been taken from the Google Earth engine system. In the pre-processing step of the images, we corrected the height error of the study area and adjusted the speckle noise. The edge of the shore was discovered with the Otsu threshold in the images. Finally, Digital Shoreline analysis system (DSAS) was used to calculate the amount of sedimentation and erosion of the coast by EPR technique. In 87% of the coast of this region, we have witnessed coastal erosion. The average amount of erosion is about 7 meters per year.
Thesis
Seagrass is a marine flowering plant predominantly existing in inter- or subtidal nearshore areas. Seagrass can affect the rate and direction of sediment transport, contributing to coastal protection by reducing erosion, enhancing accretion or stabilising the position of the shoreline. Three primary mechanisms by which seagrass can affect the shoreline are; 1) wave attenuation, 2) sediment stabilisation, and 3) sediment accretion. Coastal protection is of increasing importance for coastal developments which are at a heightened risk of coastal flooding associated with storms and sea-level rise. However, it is not well understood how physical conditions and seagrass characteristics interact to affect these three mechanisms, and the potential for seagrass to provide coastal protection has not yet been quantified. This thesis aims to investigate how interactions between and variability within physical conditions and seagrass characteristics affect each of the three mechanisms; 1) wave attenuation, 2) sediment stabilisation, and 3) sediment accretion, and highlight the implications for coastal protection by seagrass. Research Objective 1: Develop an improved method for predicting seagrass-induced wave attenuation in different conditions. Seagrass induces drag in the water column, attenuating wave height and therefore reducing wave energy reaching the shoreline across a variety of different conditions. Currently, it is difficult to make comparisons between the results of existing seagrass-wave attenuation studies due to differences in how wave attenuation is measured and recorded. Consequently, the findings of existing studies cannot be used to predict wave attenuation in different locations or different vegetation and wave conditions. To address this issue, in this study, each observation of wave attenuation was converted into the unifying drag coefficient (CD), allowing the existing results to be compared to each other. A simple wave model using the mean CD calculated across 11 published studies, demonstrated that wave attenuation increases with meadow length, canopy height, shoot width and shoot density. Increases in these seagrass characteristics also increased the depth in which waves can be attenuated. The findings in this study can be used in two ways to predict wave attenuation from seagrass: 1) in process-based wave models, and 2) qualitative assessments. Where seagrass is represented by a constant drag coefficient in process-based wave models, this work proposes mean CD = 0.7 as the best value representing the effect of seagrass on wave attenuation. A conceptual diagram is introduced, to generalise the effects of specific seagrass and wave characteristics on wave attenuation in qualitative assessments. Research Objective 2: Investigate how below-ground biomass architecture and cliff height affects the lateral erosion rate of Enhalus acoroides cliffs exposed to wave energy. Seagrass can reduce rates of erosion by stabilising the sediment through their below-ground biomass structure. To test this effect, seagrass cores were transplanted from Xincun Bay (Hainan Province, China) into a wave flume at Hainan Tropical Ocean University (Sanya), where the stabilising effect of seagrass in cliffs exposed to wave energy was measured. This is the first study to explore the effect of; 1) seagrass with non-branching and non-dense root-mat-forming below-ground biomass structure on erosion rates, 2) cliff height on erosion rates, and 3) investigate seagrass cliff erosion in coarse sand. The results suggest that seagrass species which do not form dense root-mats may have a limited ability to reduce erosion compared to other seagrass species. High rates of cliff erosion were measured compared to previous students, and this is attributed at least in part to the large sediment grain size in this study. This work highlights the challenges of quantifying ecosystem functions in the real world with laboratory experiments. Research Objective 3: Determine the physical conditions in which seagrass is likely to protect the coast by identifying shoreline response to seagrass under different ecological and physical conditions. Shoreline response to hard infrastructure is well documented. However, the effect of green infrastructure alternatives, such as seagrasses on shorelines, is not well understood. This work identifies similarities and differences between; 1) the functions of conventional submerged structures and seagrasses, 2) response of coastal morphodynamics to conventional submerged structures and seagrass. These insights are used to synthesise the impact of seagrass on coastal processes and hence shoreline morphodynamics to determine where, and the degree to which seagrass may provide coastal protection. This research bridges the gap between the ecological data from marine ecology and insights into processes from coastal engineering, to make qualitative predictions about the potential of seagrass for coastal protection in different contexts. This PhD contributes to the emerging field of 'ecological engineering' by integrating the disciplines of coastal engineering (coastal morphodynamics, sediment transport, linear wave theory) and marine ecology (seagrass ecology, marine conservation, ecosystem services) to synthesise existing data and provide new information on the potential contribution of seagrass for shoreline protection.
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Forecasting biogeomorphological conditions for barrier islands is critical for informing sea‐level rise (SLR) planning, including management of coastal development and ecosystems. We combined five probabilistic models to predict SLR‐driven changes and their implications on Fire Island, New York, by 2050. We predicted barrier island biogeomorphological conditions, dynamic landcover response, piping plover (Charadrius melodus) habitat availability, and probability of storm overwash under three scenarios of shoreline change (SLC) and compared results to observed 2014/2015 conditions. Scenarios assumed increasing rates of mean SLC from 0 to 4.71 m erosion per year. We observed uncertainty in several morphological predictions (e.g., beach width, dune height), suggesting decreasing confidence that Fire Island will evolve in response to SLR as it has in the past. Where most likely conditions could be determined, models predicted that Fire Island would become flatter, narrower, and more overwash‐prone with increasing rates of SLC. Beach ecosystems were predicted to respond dynamically to SLR and migrate with the shoreline, while marshes lost the most area of any landcover type compared to 2014/2015 conditions. Such morphological changes may lead to increased flooding or breaching with coastal storms. However—although modest declines in piping plover habitat were observed with SLC—the dynamic response of beaches, flatter topography, and increased likelihood of overwash suggest storms could promote suitable conditions for nesting piping plovers above what our geomorphology models predict. Therefore, Fire Island may offer a conservation opportunity for coastal species that rely on early successional beach environments if natural overwash processes are encouraged.
Article
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Ecosystem establishment under adverse geophysical conditions is often studied within the “windows of opportunity” framework, identifying disturbance-free periods (e.g., calm wave climate) where species can overcome establishment thresholds. However, the role of biogeophysical interactions in this framework is less well understood. The establishment of saltmarsh vegetation on tidal flats, for example, is limited by abiotic factors such as hydrodynamics, sediment stability and drainage. On tidal flats, raised sediment ridges colonized by algal mats (Vaucheria sp.) appear to accomodate high densities of plant seedlings. Such ridges were previously found to have higher sediment strength than substratum without algae. Here, we investigate whether these measurements can be explained by geophysical factors only, or that biological (Vaucheria-induced) processes influence tidal marsh establishment by forming stabilized bedforms. We performed two experiments under controlled mesocosm conditions, to test the hypotheses that i) Vaucheria grows better on elevated topographic relief, that ii) the binding force of their algal filaments increases sediment strength, and that iii) Vaucheria consequently creates elevated topographic relief that further facilitates algal growth. Our experimental results confirm the existence of this algal-induced biogeomorphic feedback cycle. These findings imply that benthic algae like Vaucheria may contribute significantly to tidal marsh formation by creating elevated and stabilized substratum. This suggests biogeophysical feedbacks can “widen” the windows of opportunity for further ecosystem establishment. Our results could be useful for the design of managed realignment projects aimed at restoring the unique ecosystem services of coastal wetlands, such as habitat biodiversity, carbon sequestration potential and nature-based flood defense.
Book
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Sri Lanka’s location, historic and geologic isolation from the continental landmass, topography and climate act to shape its biogeography and biodiversity, including conferring a remarkably high level of endemism, given its close proximity to the mainland. The island hosts several ‘point endemic1 species and even monotypic endemic genera. However this irreplaceable biodiversity is now under severe threat because of extensive anthropogenic landuse changes that began over two centuries ago, under colonial rule, and continues to this present date. Due to high levels of endemism, extensive loss and degradation of natural ecosystem, Sri Lanka has been identified as one of the 36 global biodiversity hotspots.
Chapter
Decision support systems (DSS) aim to provide evidence in a usable format for decision-makers, thereby improving the prospects for evidence-informed conservation policy and practice. These systems are usually software-based either in computer or app-form, but may exist in other formats such as on paper. Conservation decision-makers are typically faced with complex socio-environmental landscapes, competing stakeholder interests, and irreducible uncertainty. Consequently, conservation has been the focus for numerous decision support systems, which can help users to face the challenge of making trade-offs. Despite the many systems designed for conservation, there is not an accepted framework for how to develop systems that make an impact in practice. There is evidence, however, to suggest that some systems are failing to make an impact in practice. This chapter draws on lessons learned from conservation and related disciplines on how to design good decision support systems that are desirable to intended end users. To this end, we suggest a five-stage process for participatory user-centred design—(1) identifying the user, (2) proving system value, (3) assessing available infrastructure and focusing on ease of use, (4) adopting a good marketing plan, and (5) establishing a long-term legacy—a process which could be used by researchers and funders alike to ensure that systems will be used by their intended audiences. Above all, we need to change our own design behaviour to increase the relevance and usefulness of the systems we are building. Acknowledging the reality that decision support systems will be implemented in complex and potentially data-sparse environments, we also reflect on how decision support systems can help decision-makers to deal with uncertain information. This final element seeks to establish the value both of quantifying uncertainty and communicating it in accessible ways to decision-makers.
Article
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Natural infrastructure such as parks, forests, street trees, green roofs, and coastal vegetation is central to sustainable urban management. Despite recent progress, it remains challenging for urban decision-makers to incorporate the benefits of natural infrastructure into urban design and planning. Here, we present an approach to support the greening of cities by quantifying and mapping the diverse benefits of natural infrastructure for now and in the future. The approach relies on open-source tools, within the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) software, that compute biophysical and socio-economic metrics relevant to a variety of decisions in data-rich or data-scarce contexts. Through three case studies in China, France, and the United States, we show how spatially explicit information about the benefits of nature enhances urban management by improving economic valuation, prioritizing land use change, and promoting inclusive planning and stakeholder dialogue. We discuss limitations of the tools, including modeling uncertainties and a limited suite of output metrics, and propose research directions to mainstream natural infrastructure information in integrated urban management.
Article
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The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named ‘Command and (out of) Control’, focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called ‘Living and Connecting’, emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the ‘Living and Connecting’ scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society’s diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the United Nations Decade of Ocean Science. Graphic abstract
Technical Report
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Ecological restoration is a set of actions that are conducted to restore nature to a previous state after harmful human impacts. In coastal and marine environments, it may concern transplanting eelgrass shoots or coldwater corals, reconstructing coastal wetlands, or adding nutrient binding substances to counteract remaining eutrophication effects from earlier human activities. Restoration is an active measure, which aims at restoring ecosystems to historically pristine conditions and can be seen as the process to assist the recovery of an ecosystem that has been degraded, damaged or detroyed. The experience with ecological restoration in marine environments is, however, limited, and a rule of thumb is that it is less costly to prevent environmental damage in the coastal zone than to later restore environments. Another rule of thumb is that the activities and pressures originally causing the disturbance/loss should first be remedied in order for restoration measures to be effective. This report aims to provide a rather detailed overview of experiences with ecological restoration in coastal and marine environments, with a particular focus on Sweden. Hopefully, the report will be useful for managers and decision makers and constitute the basis for future restoration projects.
Book
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Coastal Erosion and Climate Change looks at the implications of future climate change, sea-level rise and erosion risks to global communities and infrastructure located at the coast. Latest projections reveal global sea level is rising and could add +2.5m to current levels by 2100; extreme weather and storms are also increasing. These changes are causing severe impacts at the coast including nuisance flooding, erosion and shoreline transgression. The impacts and losses are catastrophic and whilst coastal defences can protect assets for a short time they commit authorities and private owners to rising costs for maintenance, repairs and renewals. Strategic coastal planning, management and adaptation are key to mitigating future losses and ensuring that coastal development, communities and infrastructure are resilient and sustainable in the long-term. This 86-page illustrated non-technical guide summarises Jacobs’ domain expertise in coastal planning and management aimed at government authorities, communities, developers and stakeholders; aligned to Jacobs’ promise to create a more connected, sustainable world. The guide is illustrated with high-profile case studies and examples of the lessons learned and successful approaches to sustainable coastal planning, management and adaptation from Jacobs’ worldwide experience over the past three decades
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Estuaries and coasts (hereafter, coasts) host some of the most biologically productive ecosystems on Earth (Mann 1982 ), where a diversity of geomorphological processes create coastal landforms that range from wave dominated hard rock cliffs, shore platforms, and sandy beaches to more vegetated tide dominated landforms such as saltmarshes and mangrove forests. These habitats provide a wide range of critical ecosystem services (hereafter, ES) and natural habitat value for society for food, recreation, and for resilience against the damaging eff ects of fl oods and storms on urban communities (Barbier et al. 2011 ). However, there is a notable lack of coverage of coasts in urban ecology discourse, which is surprising given the high levels of population growth and urbanization at the coast (Neumann et al. 2015 ).
Technical Report
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A large and fast-growing part of the world’s population lives in low-lying coastal zones. To sustain economic activities and living in these areas a wide range of coastal defence measures has been constructed. These coastal defence measures reduce the risk to economic values and populations in coastal zones prone to flooding. Coastal defence measures can even help to enable living in areas that are below sea level, for example in parts of the Netherlands and New Orleans. Climate change, and more specifically sea level rise, poses a direct threat to these areas (Ericson et al., 2006; Nicholls et al., 2008). Sea level rise requires the coastal defence measures to be adapted to higher water levels and more intense hydraulic boundary conditions (such as waves and storm surges). The exposure of coastal zones and especially coastal cities to flooding was determined by Nicholls et al. (2008). However the risk of flooding and the costs of adaptation to sea level rise are greatly influenced by coastal defence measures. The study of Linham et al. (2010) builds upon Nicholls et al. (2008) to determine the risk and impact of flooding in port cities. This study is part of a global study on the costs of adaptation to the effects of climate change (Linham et al., 2010). It adds information from three specific case studies (the Netherland, New Orleans and Vietnam) to the global study. The case study areas are comparable by type of coast; all are low-lying deltaic coastal areas. This study investigates the unit cost estimates of coastal defence for the full range of hard and soft engineering measures, such as dikes/levees, sea walls, (beach) nourishments and other measures, for example storm surge barriers.
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Adapting to climate change is among the biggest challenges humanity faces in the next century. An overwhelming focus of adaptation strategies to reduce climate change-related hazards has been on hard-engineering structures such as sea walls, irrigation infrastructure and dams. Closer attention to a broader spectrum of adaptation options is urgently needed. In particular, ecosystem-based adaptation approaches provide flexible, cost-effective and broadly applicable alternatives for buffering the impacts of climate change, while overcoming many drawbacks of hard infrastructure. As such, they are a critical tool at adaptation planners' disposal for tackling the threats that climate change poses to peoples' lives and livelihoods.
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This article examines the vulnerability of US coastal counties to erosion by combining a socioeconomic vulnerability index with the US Geological Survey's physically based coastal vulnerability index. The end product is a county-based index of overall coastal place vulnerability. The results indicate that place vulnerability along the coast is highly differentiated and influenced by a range of social, economic, and physical indicators. Regionally, Gulf Coast vulnerability is more of a product of social characteristics rather than physical attributes. The opposite is true of Pacific and Atlantic coastal counties, where physical characteristics are more influential in determining erosion-hazard vulnerability. It is clear that overall vulnerability of coastal counties cannot be determined without the union of social, economic, built-environment, and physical characteristics. Yet the methods for combining these components are not widely used at present by coastal scientists and policy makers, rendering hazards assessments incomplete and mitigation plans untenable for many places.
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Future changes in wind-wave climate have broad implications for the operation and design of coastal, near- and off-shore industries and ecosystems, and may further exacerbate the anticipated vulnerabilities of coastal regions to projected sealevel rise1,2. However, wind waves have received little attention in global assessments of projected future climate change. We present results from the first community-derived multi-model ensemble of wave-climate projections. We find an agreed projected decrease in annual mean significantwave height (HS) over 25.8% of the global ocean area. The area of projected decrease is greater during boreal winter (January–March, mean; 38.5% of the global ocean area) than austral winter (July–September, mean; 8.4%). A projected increase in annual mean HS is found over 7.1% of the global ocean, predominantly in the Southern Ocean, which is greater during austral winter (July–September; 8.8%). Increased Southern Ocean wave activity influences a larger proportion of the global ocean as swell propagates northwards into the other ocean basins, observed as an increase in annual mean wave period (TM) over 30.2% of the global ocean and associated rotation of the annual mean wave direction (�M). The multi-model ensemble is too limited to systematically sample total uncertainty associated withwave-climate projections. However, variance of wave-climate projections associated with study methodology dominates other sources of uncertainty (for example, climate scenario and model uncertainties).
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Nearshore environments are nurseries for estuarine nekton and are preferentially sought out within an estuary. Habitat is the template on which population and community dynamics occur, and many linkages between habitat and nekton production are being altered by development. Thus, we are studying this linkage (function) while it is changing. We reviewed the literature on habitat alteration in nearshore environments, focusing on small-scale changes and their cumulative impacts. On a small scale, bulkheads and levees eliminate or significantly reduce access to intertidal marsh habitat, but these can accumulate to a larger area of impact, fragmenting habitat and reducing connectivity. Cumulative impacts are problematic because they are not immediately noted and build up over time to produce a more substantial impact. The creation of habitat patchiness (non-continuous segments) caused by development has received little attention but contributes to reduced environmental sustainability. Direct or indirect modification of landscapes influence access to nursery habitat for nekton and can reduce growth, increase mortality, and modify settlement and post-settlement habitat use patterns. Policymakers must make cumulative impacts an important item in their coastal management strategy, as there is growing evidence that created wetlands do not function like natural ones even after several decades.
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We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recog-nition of a physical–biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not been widely implemented in sandy beaches, could be a key tool for biodiversity conservation and should also facilitate spillover effects into adjacent beach habitats. Setback and zoning strategies need to be enforced through legislation, and all relevant stakeholders should be included in the design, implementation and institutionalisation of these initiatives. New perspectives for rational management of sandy beaches require paradigm shifts, by including not only basic ecosystem principles, but also incentives for effective governance and sharing of management roles between government and local stakeholders.
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A common assumption is that ecosystem services respond linearly to changes in habitat size. This assumption leads frequently to an "all or none" choice of either preserving coastal habitats or converting them to human use. However, our survey of wave attenuation data from field studies of mangroves, salt marshes, seagrass beds, nearshore coral reefs, and sand dunes reveals that these relationships are rarely linear. By incorporating nonlinear wave attenuation in estimating coastal protection values of mangroves in Thailand, we show that the optimal land use option may instead be the integration of development and conservation consistent with ecosystem-based management goals. This result suggests that reconciling competing demands on coastal habitats should not always result in stark preservation-versus-conversion choices.
Article
Aggregated demographic datasets are associated with analytical and cartographic problems due to the arbitrary nature of areal unit partitioning. This article describes a methodology for generating a surface-based representation of population that mitigates these problems. This methodology uses dasymetric mapping and incorporates areal weighting and empirical sampling techniques to assess the relationship between categorical ancillary data and population distribution. As a demonstration, a 100-meter-resolution population surface is generated from U.S. Census block group data for the southeast Pennsylvania region. Remote-sensing-derived urban land-cover data serve as ancillary data in the dasymetric mapping.
Article
Climate warming does not force sea-level rise (SLR) at the same rate everywhere. Rather, there are spatial variations of SLR superimposed on a global average rise. These variations are forced by dynamic processes, arising from circulation and variations in temperature and/or salinity, and by static equilibrium processes, arising from mass redistributions changing gravity and the Earth's rotation and shape. These sea-level variations form unique spatial patterns, yet there are very few observations verifying predicted patterns or fingerprints. Here, we present evidence of recently accelerated SLR in a unique 1,000-km-long hotspot on the highly populated North American Atlantic coast north of Cape Hatteras and show that it is consistent with a modelled fingerprint of dynamic SLR. Between 1950-1979 and 1980-2009, SLR rate increases in this northeast hotspot were ~ 3-4 times higher than the global average. Modelled dynamic plus steric SLR by 2100 at New York City ranges with Intergovernmental Panel on Climate Change scenario from 36 to 51cm (ref. ); lower emission scenarios project 24-36cm (ref. ). Extrapolations from data herein range from 20 to 29cm. SLR superimposed on storm surge, wave run-up and set-up will increase the vulnerability of coastal cities to flooding, and beaches and wetlands to deterioration.
Article
Sea level rise threatens to increase the impacts of future storms and hurricanes on coastal communities. However, many coastal hazard mitigation plans do not consider sea level rise when assessing storm surge risk. Here we apply a GIS-based approach to quantify potential changes in storm surge risk due to sea level rise on Long Island, New York. We demonstrate a method for combining hazard exposure and community vulnerability to spatially characterize risk for both present and future sea level conditions using commonly available national data sets. Our results show that sea level rise will likely increase risk in many coastal areas and will potentially create risk where it was not before. We find that even modest and probable sea level rise (.5 m by 2080) vastly increases the numbers of people (47% increase) and property loss (73% increase) impacted by storm surge. In addition, the resulting maps of hazard exposure and community vulnerability provide a clear and useful example of the visual representation of the spatial distribution of the components of risk that can be helpful for developing targeted hazard mitigation and climate change adaptation strategies. Our results suggest that coastal agencies tasked with managing storm surge risk must consider the effects of sea level rise if they are to ensure safe and sustainable coastal communities in the future.
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Manhattan flooding bolsters argument for a massive engineering project to protect New York.
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To develop improved estimates of (1) flooding due to storm surges, and (2) wetland losses due to accelerated sea-level rise, the work of Hoozemans et al. (1993) is extended to a dynamic analysis. It considers the effects of several simultaneously changing factors, including: (1) global sea-level rise and subsidence; (2) increasing coastal population; and (3) improving standards of flood defence (using GNP/capita as an “ability-to-pay” parameter). The global sea-level rise scenarios are derived from two General Circulation Model (GCM) experiments of the Hadley Centre: (1) the HadCM2 greenhouse gas only ensemble experiment and (2) the more recent HadCM3 greenhouse gas only experiment. In all cases there is a global rise in sea level of about 38 cm from 1990 to the 2080s. No other climate change is considered. Relative to an evolving reference scenario without sea-level rise, this analysis suggests that the number of people flooded by storm surge in a typical year will be more than five times higher due to sea-level rise by the 2080s. Many of these people will experience annual or more frequent flooding, suggesting that the increase in flood frequency will be more than nuisance level and some response (increased protection, migration, etc.) will be required. In absolute terms, the areas most vulnerable to flooding are the southern Mediterranean, Africa, and most particularly, South and South-east Asia where there is a concentration of low-lying populated deltas. However, the Caribbean, the Indian Ocean islands and the Pacific Ocean small islands may experience the largest relative increase in flood risk. By the 2080s, sea-level rise could cause the loss of up to 22% of the world's coastal wetlands. When combined with other losses due to direct human action, up to 70% of the world's coastal wetlands could be lost by the 2080s, although there is considerable uncertainty. Therefore, sea-level rise would reinforce other adverse trends of wetland loss. The largest losses due to sea-level rise will be around the Mediterranean and Baltic and to a lesser extent on the Atlantic coast of Central and North America and the smaller islands of the Caribbean. Collectively, these results show that a relatively small global rise in sea level could have significant adverse impacts if there is no adaptive response. Given the “commitment to sea-level rise” irrespective of any realistic future emissions policy, there is a need to start strategic planning of appropriate responses now. Given that coastal flooding and wetland loss are already important problems, such planning could have immediate benefits.
Restoration of the mississippi delta: Lessons from hurricanes katrina and rita
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The Impact of Climate Change upon Coastal Defense Structures (Department for Environment, Food and Rural Affairs
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Coastal vulnerability to sea-level rise: A preliminary database for the US Atlantic, Pacific and Gulf of Mexico Coasts
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Hammar-Klose, E. S. & Thieler, E. R. Coastal vulnerability to sea-level rise: A preliminary database for the US Atlantic, Pacific and Gulf of Mexico Coasts. (US Geological Survey Digital Data Series, Vol. 68, 2001).
InVEST 2.3.0 User's Guide (The Natural Capital Project
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Protecting New York City, Before Next Time
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User Manual and System Documentation of WAVEWATCH III version 3.14 Technical Note (US Department of Commerce, National Oceanographic and Atmospheric Administration
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