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The predictions for coastal change under the scenario of global sea-level rise offer impending disaster for the variety of coastal morphologies, their associated habitats, and the accompanying infrastructure. However, the predictions tend to ignore the role of sediment budget in the maintenance of coastal morphology and the dynamics of sediment transfers in the beach-dune sand-sharing system. Accepting that shoreline displacement may be an outcome of sea-level rise and a negative sediment budget, conditions are presented that could lead to a positive or equilibrium sediment budget in the coastal foredune and the retention of the foredune system even as it is being displaced. Accommodation space is a key requirement for the continued functioning of the foredune morphologies during periods of sea-level rise.  相似文献   

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Surficial sediment samples were wet digested (HNO3‐HCI‐HF) and analysed by atomic absorption spectroscopy. The background values in the area, and the Pollution Index Load in the sampling points were calculated. Metal inputs of continental origin are specially important in Deva, Oria and Urola river mouths.  相似文献   

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Effective and efficient information dissemination is crucial for a successful management of coasts and beaches. Almost all coastal management activities use Internet portals to provide electronic accessibility of data and information. In this respect, we have analyzed web tracking data and costs to investigate the effectiveness and efficiency of two coastal management web portals. Indicators for the visiting quality, the volume and characteristics of the information flow and the associated costs were combined. The results show that mainly professional users were attracted by the two investigated online coastal management information offers. Furthermore, the coastal management contents were mainly relevant on regional scale. The results indicate that it is not enough to provide various information, instead it further needs also efforts to disseminate this information to a broader public. Specific preparation and presentation of information for the target groups would lead to an active dissemination process. The investigation of the costs shows that an increasing efficiency of information dissemination via the Internet goes together with the long term use of the information infrastructure. Therefore large coastal management web portals need runtimes of several years. The applied method combined and simplified actual used web analytic methods to allow valuable insights into the information dissemination of coastal management web portals. In this way the method can be used to help coastal decision makers or other practitioners to screen their web presence in the background of information supply and demand for all visitor groups they want to reach.  相似文献   

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The European Water Framework Directive (WFD) establishes a well differentiated typology of water bodies on the basis of scientific and biological criteria. For coastal waters, such criteria have long been established, while for transitional waters they are still under discussion. One of the difficulties when applying the WFD to coastal lagoons is to include them in only one of these categories, and while there is no doubt about the nature of estuaries as transitional waters, there is some controversy concerning lagoons. To what extent, reference conditions may be similar for estuaries and lagoons, or whether features common to all coastal lagoons are more important for differentiating them from other water bodies than the fact that there is (or is not) any fresh water influence, is something that remains unclear and is discussed in this work. Coastal lagoons and estuaries form part of a continuum between continental and marine aquatic ecosystems. Shelter, strong boundaries or gradients with adjacent ecosystems, anomalies in salinity regarding freshwater or marine ecosystems, shallowness, etc. all contribute to the high biological productivity of estuaries and lagoons and determine common ecological guilds in the species inhabiting them. On the other hand, fresh water influence, the spatial organization of gradients and environmental variability (longitudinal one-dimensional gradients in estuaries versus complex patterns and three-dimensional heterogeneity in lagoons) constitute the main differences, since these factors affect both the species composition and the dominance of certain ecological guilds and, probably, the system’s complexity and homeostatic capability. In the context of the WFD, coastal lagoons and estuaries are closer to each other than they are to continental or marine waters, and, on the basis of the shared features, they could be intercalibrated and managed together. However, coastal lagoons cannot be considered transitional waters according to the present definition. To assume that fresh water influence is an inherent characteristic to these ecosystems could lead to important changes in the ecological organization and functioning of coastal lagoons where natural fresh water input is low or null. In our opinion, the present day definition of transitional waters should be changed substituting the criterion of fresh water influence by another based on common features, such as relative isolation and anomalies in salinity in water bodies with marine influence. Otherwise, coastal lagoons should be considered a particularly characteristic type of water mass for establishing reference conditions of ecological status.  相似文献   

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Portuguese coastal areas are of current major concern due to the continuous expansion of a strong urbanization, accentuated development of economic activities, resilient land use and general population growth. A particular attention has been given to the shoreline evolution, pointing out evidences of critical coastal sectors that are prone to suffer adverse consequences of climate changes direct impacts. Areas where climate change and sea-level rise effects will be stronger include, among others, coastal sectors associated to soft rocky or mobile substrate shores and/or low morphological shores with recognized marked erosion trend. Within this context, the knowledge of the geological setting is imperative as different lithologies have distinct resistance and behavior against marine erosion. The available digital geological Portuguese cartography at 1:25000 scale is not suitable to well characterize the geology within the context of small geographic areas or within the perspective of costal management. Hence, the National Laboratory of Energy and Geology (LNEG) developed a prototype to evaluate the potential of the integrated “geological and coastal hazard mapping” at a 1:3000 resolution scale. The combination of detailed geology and historical coastline displacement information, in a single map, constitute a new and valuable cartographic product to support coastal managers and general users of littoral regions. The application of the prototype to the entire Portuguese coastal areas will be carried out by LNEG and digital information will be available at LNEG GeoPortal (http://geoportal.lneg.pt/).  相似文献   

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Research on interactions among wave, current, and vegetation has received increasing attention. An explicit depth-averaged hydrodynamic model coupled with a wave spectral model (CMS-wave) was proposed in this study in order to simulate the wave and wave-induced current in coastal waters. The hydrodynamic model was based on the finite volume method while the intercell flux was computed by employing the Harten–Lax–van Leer approximate Riemann solver to investigate the dry-to-wet interface, and the drag force of vegetation was modeled as the sink terms in the momentum equations. The CMS-wave model was used to investigate the non-breaking and the breaking random waves propagation in vegetation fields. Afterwards, an empirical wave energy dissipation term with plant effect was derived to represent the resistance induced by aquatic vegetation in the wave-action balance equation. The established model was calibrated and validated with both the experimental and field data. The results showed that the wave height decreased significantly along the wave propagation direction in the presence of vegetations. The sensitivity analysis for the plant density, the wave height, and the water depth were performed by comparing the numerical results for the wave height attenuation. In addition, wave and wave-induced current through a finite patch of vegetation in the surf zone were investigated as well. The strong radiation stress gradient could be produced due to the variation of the energy dissipation by vegetation effect in the nearshore zone, which impacted the direction and amplitude of the longshore current. The calculated results showed that the coupling model had good performance in predicting wave propagation and the current over vegetated water regions.  相似文献   

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This paper includes the proposals made in the report “Basis for a National Strategy for Coastal Zone Management” prepared for the Portuguese Ministry of Environment, Territorial Planning and Regional Development. The final version of that report was presented in June 2006. This paper describes a theme framework followed by a discussion of concepts. Nine Primary Principles, eight Principal Objectives, and 37 Strategic Options for an Integrated Coastal Zone Management are then presented. These Strategic Options are set hierarchically according to their sequential priority, identifying the dominant types of Associated Measures. The analysis of these arrives at a set of Structural Measures, which interlink and aggregate various actions and propose a new method of integrated management for the coastal zone, which includes the “Legal Basis of Coastal Zone”; the Organization System; the Action Plan and Monitoring.  相似文献   

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The present study investigates into the link between people’s vulnerability in the face of coastal hazards and sustainable livelihoods. It focuses on the town of Borongan in the Philippines and draws on questionnaire-based surveys and focus group discussions. This research shows that local fishermen are often compelled to go out fishing despite pending typhoon or storm surge to sustain the daily needs of their family. Its also demonstrates that the capacity of these people to protect themselves from the threat is constrained by poor and fragile livelihoods. In the event of a crisis, the study argues that people resort to a range of adjustments on their daily life which is rooted in the strength and diversity of their livelihoods. To reduce people’s vulnerability and enhance capacities to face coastal hazards, the study fosters Community-Based Disaster Risk Reduction with special emphasis to sustainable livelihoods.  相似文献   

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This paper examines existing measures taken to protect the coastal zones of the Mediterranean Sea and assesses their success. A summary of the main pressures facing this region is given, followed by an analysis of the legislation covering coastal zone development in ten countries: Algeria, Croatia, Egypt, France, Israel, Italy, Malta, Spain, Tunisia and Turkey. The paper finds that not all of these States have legislation specifically covering coastal zones, but there is concern in all areas that existing legislation is not working. The costs and benefits of controlling coastal development are examined. Firstly, a literature review of valuation studies identifies a range of values placed on the developed and undeveloped coastline for both users and local property owners. These values were then used in a model to evaluate policy options to control development of a stretch of coastline. The model indicates that a stricter control regime of coastal development may provide significant benefits.
A. MarkandyaEmail:
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The Chennai coast, an integral part of the east coast of India, extends over ca. 35 km. Over the past 120 yr the coastline has witnessed both man-made and natural disturbances which led to the destruction of the beach front. The construction of Madras harbour in 1876, was the prime cause of the degradation of this very sensitive coastal region. Continued growth of Madras harbour has helped in the natural formation of the wide ‘Marina Beach’, south of the harbour. But the shoreline north of the harbour suffered the consequences of harbour development activities. The north shore receded by ca. 500 m over the past 120 yr and received attention from the authorities in the past few decades because of the growing awareness of the conservation value of the coast. This paper highlights the effects of Madras harbour development on the adjoining coast and on the shortterm mitigation measures planned and executed by the Government agencies to protect the fragile coastline. In spite of sincere efforts to protect the coastline, the destruction continues unabated due to various reasons. This paper analyses the facts and suggests a long-term solution to protect the coastline and to regain the past glory. Feasible and cost effective permanent measures are identified, construction methods suggested and the advantages that the community can derive from the longterm solutions are discussed.  相似文献   

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The high conservational value of the lichen-rich vegetation and landscape of the marine foreland Ørkenen on the isle of Anholt is treated from a Danish as well as a European perspective. The sensitivity of the lichen-rich vegetation to physical disturbance is emphasized. The impact of invasive species such asPinus mugo as well as the effect of atmospheric deposition of nutrients on the heaths at Anholt is described. Considerations related to the development of a management plan for Ørkenen are presented.  相似文献   

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In Italy, the incapability of the State to implement a national strategy for the sustainable development of coastal areas lead the regional authorities to adopt integrated coastal zone management plans. These initiatives are often relevant, correcting the defiency of the national legislation, but do not assure the implementation of a coherent littoral policy. Thereby, it is to be hoped that the recent developments in international law—and particularly the Mediterranean protocol on integrated coastal zone management recently adopted—will compel the Italian State to make a positive commitment to coastal protection.  相似文献   

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Launch of the Integrated Maritime Policy for the European Union in 2007 served as important factor that stimulates consolidation of coastal and marine information to support policy implementation. Policy’s action plan provides approaches for maritime governance, research and planning relevant to information. In particular, roadmap for maritime spatial planning stimulates development of coastal and marine GIS. Article reviews the current general status of coastal and marine systems and puts them in the context of the policy actions. Main focus is on formation of geospatial information platform for integrated assessment and ecosystem-based management of coastal and marine areas. Recent developments in data, indicator and information systems are summarized in European perspective: better characterization of maritime space and marine ecosystems, development of GMES Marine Core service and related in situ data collection; data harmonisation, interoperability and access, promoted by Shared Environmental Information System principles.  相似文献   

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The marine foreland called Ørkenen (=the desert) at Anholt is covered by lichen-richEmpetrum nigrum-Corynephorus canescens heath vegetation on beach ridg e systems formed during the elevation of land after the Weichsel ice age andStereocaulon saxatile-richAmmophila arenaria-Corynephorus canescens vegetation on semi-fixed aeolic dunes. The development of the vegetation at Ørkenen is the result of various kinds of human exploitation, with its maximum in the 16th and 17th century. After the cessation of human use, a slow succession towards closed vegetation with mainlyEmpetrum nigrum andCorynephorus canescens began. The present heath ecosystem, developed on sandy substrate with very little organic matter and a small nutrient supply, is a high priority habitat in Europe.  相似文献   

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The polychaete Pectinaria koreni exhibits a complex life cycle characterized by non-overlapping generations and widespread larval dispersal. To explore how “local” metapopulation genetic structure varies spatially and temporally during population turnover, we combined observations on demography, larval dispersal through hydrodynamic modelling and population genetics of successive age cohorts in the Baie de Seine (eastern English Channel, France). Mature adults (March), newly settled (July) and later-stage juveniles (September) were sampled in 2003 on the edge and in the main demes of the metapopulation. Demes displayed an asynchronous dynamics due to variations in habitat quality affecting reproductive timing (e.g. three distinct spawning events observed) and in local larval supply linked to temporal fluctuations of hydrodynamism. Two-source populations were identified among dense areas with the greatest larval retention and self-recruitment rates: one with a single recruitment event, stable temporal genetic variation and a strong spatial genetic re-homogenization during turnover, and the other with two recruitment events and significant allele frequency changes over time. Sink habitats displayed single recruitment event and experienced strong inter-generational (juveniles vs adults) genetic changes due to genetic drift associated with strong winter mortalities. Altogether, results suggested that adult spawning asynchrony and sweepstakes reproductive success, together with genetic drift, played a greater role than hydrodynamics itself in determining effective recruitment rates at some sites and generating genetic patchiness.  相似文献   

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