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Biodiversity conservation often focuses on threatened or rare species. While this structural asset of biodiversity is indeed important, the functional diversity aspect has to be considered as an even more important criterion for marine management and conservation. This paper explores the use of functionally important ecosystem engineers in North Sea management approaches.An overview of several North Sea ecosystem engineering species shows that ecosystem engineers such as bulldozing echinoderms and burrowing shrimps as well as bio-irrigating polychaetes are bound to receive more attention in the management of marine areas than they do now, given their important structuring aspect in associated fauna and implications for seafloor ecosystem functioning.The use of ecosystem engineers could contribute considerably to the concept of Ecosystem-Based Management in the marine realm. This is clearly illustrated in the present case study of the bio-irrigating polychaete Lanice conchilega. Since this species manifests both autogenic and allogenic ecosystem engineering properties, the management of human activities that affect common species such as L. conchilega reefs can enhance protection of the entire local ecosystem. In the North Sea, some commonly occurring ecosystem engineers and their engineered habitat can be protected under the European Habitats Directive and the EU Marine Strategy Framework Directive.

Fine-scale seabed mapping (Results showed that highest abundances of some ecosystem engineering species (e.g. the tubeworm Owenia fusiformis, and the razor clam Ensis directus) occur near bedload convergence zones resulting from a mutually evasive flood- and ebb-dominant channel system. Such zones are at the end of the channels, hence also finegrained sediments, food and larvae are trapped. The combination of the coarser-grained bedload with the deposition of fines is indeed the optimum for a lot of suspension and detritus feeders. Still, highest abundances occur at the fringes of such a system where stress levels are intermediate. Hypotheses were successfully tested along the Dutch coastal zone. Those insights are important to assess changes in seafloor integrity and hydrographic conditions, two descriptors to define Good Environmental Status within Europe’s Marine Strategy Framework Directive.

Marine Protected Areas (MPAs) are clearly defined geographic areas which are designated, regulated and/or managed to achieve specific conservation objectives. MPAs are an acknowledged tool for protecting marine biodiversity (marine species, habitats and ecological processes), contributing to an Ecosystem Approach. However, their establishment in Europe has lagged behind terrestrial equivalents and has taken place in an ‘ad hoc’ and largely un-coordinated way in response to political drivers. European MPAs have been established for a variety of purposes and protection categories and, like distribution globally, their coverage is both uneven and unrepresentative at multiple scales. Networks of MPAs contributing to ecosystem-based marine spatial management are perceived as an optimal way to safeguard biodiversity assets and the Natura 2000 network and networks promoted by the European Regional Seas Conventions have grown exponentially in recent years, making significant progress towards global targets. A broad array of science needs and priorities together with clear attainable and measurable objectives are necessary to establish ecologically coherent MPA networks. Assessing the connectivity of marine populations remains a challenge for most species and multidisciplinary studies combining oceanographic modeling, larval ecology and population genetics are needed. Knowledge on connectivity is even more essential for designing networks of MPAs. A general understanding of the effectiveness of MPA networks as a fisheries management and conservation tool will depend on a broader range of case studies that apply new methods (such as genetics) to quantify connectivity. Assessing a coherent network of MPAs ideally requires an EU-wide coherent network of monitoring stations, particularly for evaluating recovery processes inside MPAs and connectivity among MPAs. Drawing on literature and practical case studies the Working Group has highlighted science research needs in the areas of data collection; habitat classifications; baselines and monitoring; ecological coherence and connectivity and ecological processes. These are complemented by recognition of the need for further research and guidance for MPAs in the context of emerging issues; legal clarifications; stakeholder involvement; policy guidance informed by science and advantages of closer cooperation between scientific monitoring and surveillance and enforcement activities., JRC.H.1-Water Resources

The tube-building polychaete Lanice conchilega can form dense populations, often called reefs, which promote benthic community change and constitute feeding grounds for secondary consumers. The aim of this study was to quantify the role of the L. conchilega reef of the Bay of the Mont Saint-Michel (BMSM) for feeding waders, by combining macrobenthos data, bird counts and bird diet information. Wader densities in the reef were on average 46.6 times higher than in non-reef areas. According to faecal analyses, waders in the reef mainly selected the accompanying fauna and especially crustaceans. The attractiveness of the reef to feeding birds may be largely explained by the high abundance, richness and biomass of macrobenthic species in the reef compared with the rest of the BMSM.

The understanding of the role of nature conservation (NC) is used to illustrate how an integrated and sustainable approach to decision-making could be developed for planning and managing activities in the marine environment. The need for NC to be integrated in the marine spatial planning (MSP) decision-making process is highlighted in various initiatives around the world. However none of these initiatives describes a commonly applicable framework to achieve this goal. The plethora of interpretations regarding the meaning, role and position of NC in planning, makes such an attempt more complex. A good starting point in order to develop such a process is to answer the question: how NC can contribute to the achievement of sustainability in the context of MSP? In the present study the different ways that NC has been interpreted over time are explored and several definitions are analyzed, concluding that there is currently no common approach to NC in MSP initiatives. Therefore it is indicated that NC should be treated as a means to achieve good environmental status of the ecosystem, based on its spatial, economic and conflict resolution dimensions, characteristics that are common among all marine uses. Consequently, it is proposed that NC at sea should be put in a central position during the MSP processes. A schematic presentation of the concept is provided in this paper.

Ecosystem-based marine spatial management (EB-MSM) aims to supply a generic framework and a set of strategic tools for a sustainable marine and coastal development. Identifying and assessing the importance of the numerous distinct marine ecosystem units (hereafter biotopes) along with their related benefits and conservation issues is an essential first step to this end. Herein, 56 types of European seabed biotopes and their related goods, services, sensitivity issues, and conservation status (at European and international level) were compiled. Destructive fishing (particularly trawling) and marine pollution were recognized as the main threats to European seabed biotopes. Moreover, increased seawater turbidity, dredging and aggregate extraction, sediment disposal, coastal constructions, biological invasions, mining, shipping-related activities, tourism, hydrocarbon exploitation, and even some practices of scientific research, also exert substantial pressure. Although significant effort has been put into the protection of European seabeds through international agreements as well as European and national legislation, a finer scale of classification and assessment of marine biotopes is crucial in shaping priorities and management guidelines towards the sustainability of European marine resources.

This doctoral thesis bridges experimental research and policy issues in the marine environment. The focus is on the challenging relation between nature conservation and current fisheries practices. The study sites investigated consist largely of sedimentary sand banks and swales, situated in North-Western Europe. A particular biogenic habitat has been chosen to study both the ecological importance and the resilience towards the physical disturbance of beam-trawling. This habitat is Lanice conchilega reefs, which are distinct aggregations of tube dwelling polychaetes (bristle worms). The implications of these tube worm reefs for the benthic environment as well as for flatfish species are studied in depth and several experiments (in lab and field conditions) quantify the impact of beam trawl fisheries. The thesis finishes by integrating these results in legal policy options and discusses the process of MPA-implementation. The general discussion elaborates how this thesis may contribute to the application of an ecosystem approach to support marine management

The application of an ecosystem approach to management of the sea requires both integrated and strategic frameworks such as Integrated Coastal Zone Management (ICZM) and the use of marine spatial planning (MSP) to minimize spatial use conflicts and environmental degradation. Such an integrated management promotes sustainable development based on achieving a balance of environmental, social and economic objectives. Here we introduce a first draft of a generic framework which is developed in the EU FP7 project MESMA that gives guidance on how to assess the effectiveness of an existing management within a spatially defined area. More precisely, we define spatially managed areas as geographical entities where a marine planning framework is or will be used to manage multiple human activities in space and time while aiming to maintain ecosystem integrity. The framework consists of seven steps and comprises practical guidance on the selection of operational objectives and related criteria (step 1), the collation and integration of information (steps 2, 3 and 4), performance assessment (step 5), and feedback processes (steps 6 and 7). In the course of the MESMA project, this generic framework will be applied and tested in nine case studies, representing all European seas. Here we highlight the processes and practical tasks involved in each of the framework steps, reflect on the first attempts to implement this framework and identify the requirements for practical tools such as standardized methods to map human activities and assess their cumulative impacts.

This doctoral thesis bridges experimental research and policy issues in the marine environment. The focus is on the challenging relation between nature conservation and current fisheries practices. The study sites investigated consist largely of sedimentary sand banks and swales, situated in North-Western Europe. A particular biogenic habitat has been chosen to study both the ecological importance and the resilience towards the physical disturbance of beam-trawling. This habitat is Lanice conchilega reefs, which are distinct aggregations of tube dwelling polychaetes (bristle worms). The implications of these tube worm reefs for the benthic environment as well as for flatfish species are studied in depth and several experiments (in lab and field conditions) quantify the impact of beam trawl fisheries. The thesis finishes by integrating these results in legal policy options and discusses the process of MPA-implementation. The general discussion elaborates how this thesis may contribute to the application of an ecosystem approach to support marine management

One way to generate detailed knowledge of the response to physical disturbance is quantifying the resistance of biogenically created emergent structures towards fisheries. The biogenic structures targeted in the present study are shaped by the ecosystem engineering polychaeteLanice conchilega. Direct mortality ofL. conchilega as a consequence of sustained physical disturbance at varying frequencies has been tested to quantify the resilience of this particular reef system. Research is based on a laboratory experiment in which four different disturbance regimes were applied (disturbance every other 12, 24 and 48 h and no fishing disturbance as a control). Survival proportions were measured over time and tested with a generalized linear mixed model (GLMM). Survival dropped ignificantly after 10 and 18 days (with a disturbance frequency of every 12 and 24 h, respectively). The results indicate that L.conchilega is relatively resistant to physical disturbance but that reef systems can potentially collapse under continuous high frequency disturbance. The results of this experiment are discussed in the light of beam trawl fisheries, a common physical disturbance in areas where knowledge of the general resilience.

Dynamics in the marine environment tend to be orders of magnitude higher than their terrestrial counterparts. The functioning of marine ecosystems depends on these high dynamics and takes therefore place at vast geographical scales. Furthermore, oceans and seas seem to be quite prone to be affected by global climate change. As marine ecosystems are threatened, conservation strategies are set out in international policy to face the large scale of the ecosystem. However, not only the scale is important to manage marine ecosystems, also ecosystem dynamics should have a prominent place in the strategies. Present chapter points out the danger of applying an (international) environmental law system in a rigid way, leading to a slow decision making process and the inflexibility of management programs. This rigid interpretation of international legislation is therefore expected to fail in its aim of implementing a sustainable use of the sea. The Belgian case is developed as an example, pointing out that international (EU) legislation is too rigidly interpreted and decelerates the implementation rate or may even provoke a reflex of doing as little as possible. During the policy process of MPA-designation, objection was given to the protection of particular tube worm reefs as the possibility exists that these reefs may develop towards other reef types when strong nature conservation measures are taken. Moreover, some parties feared a legal declassification because of doubts on how to interpret the definition on the reef habitat type, even though clear scientific evidence was available for the particular reef system occurring in the Belgian waters. The reluctance of protecting important reef structures is amongst others due to the fact that interpretation of nature conservation law is related to difficulties in adapting to natural developments that are not easy to predict or to model. So far, application of nature conservation law has been rather static. This is well illustrated in this chapter with the case study on the Belgian part of the North Sea. Arguments for the rigid interpretation were (1) the possibility of natural succession; (2) the fact that other definitions (not in Habitats Directive) should be taken into account; (3) the fact that a species is not listed as an example in the Interpretation Manual and (4) that there is a possible semantic misunderstanding of specific words. Nonetheless, in the case of the EU Habitats Directive, a more flexible approach is possible and needed. We therefore advocate a robust though flexible interpretation of environmental legislation in the marine environment, especially because a changing climate is altering the environment in an even more profound and more unpredictable way. We acknowledge this is a difficult exercise, as there is a risk of undermining the final goal of environmental legislation if increasing flexibility would be translated into looser protection.

Within coastal nurseries, the distribution of juvenile flatfish may depend on small-scale habitat variability. The present study investigates the relation between the distribution of two juvenile flatfish species (Pleuronectes platessa and Limanda limanda) with two sessile tube dwelling polychaetes that create specific habitats at high densities. Their modulating effects make them classify as ecosystem engineers. Lanice conchilega and Owenia fusiformis, both frequently occurring in the coastal zones of the North Sea are the studied ecosystem engineers. These two benthic tube worm systems are investigated for their function as ‘essential juvenile habitat’ (EJH) in two geographical areas (the Belgian part of North Sea and the Dutch part of the Wadden Sea). General responses were identified by comparing relative differences between ecosystem engineered habitats and adjacent bare sand (i.e. non ecosystem engineered) habitats. Results show that both flatfish species select for the ecosystem engineered habitat. This behaviour was further investigated using stomach content analyses. For P. platessa occurring in L. conchilega habitat, this selection was explained as feeding behaviour. For the habitats created by O. fusiformis, no such a relation was found. For L. limanda higher densities within the ecosystem engineered habitats cannot be explained by feeding advantage but by the use of this habitat as a shelter. Therefore, higher flatfish densities could be explained by an antipredation behaviour. Lanice conchilega aggregations may be more important as feeding area for juvenile flatfish species in comparison with O. fusiformis aggregations. The indirect impacts of bottom trawling on benthic tube worm aggregations by reducing the suitability of the areas for juvenile flatfishes are discussed. We conclude that the emergent structures in the flatfish nursery area play an important role in the ecology of the juvenile flatfishes as feeding ground and/or as refuge from predation. These small-scale aspects of nursery grounds can be considered as EJH and merit attention in habitat suitability models as well as in marine conservation.

Concepts as ‘integrative’ and ‘ecosystem approach’ are often mentioned as key concepts to manage renewable marine resources sustainably. The existing amount of information on how to manage marine ecosystems in a sustainable way, however, is often perceived as insufficient. Combining the aim of putting a halt to ecosystem deterioration with an efficient and sustainable fishery seems to be a major challenge. In areas where the use of bottom gear is common, both overexploitation and the direct damage to bottom life prove to be concerns that need to be addressed urgently. This chapter presents a strategy to gather scientific information to support ecosystem management, taking into account the complexity of the system. The Belgian part of the North Sea (BPNS) was used as a model to apply this strategy. The strategy focuses on small-scale, short-term studies on a limited set of organisms in order to provide ready-to-use scientific information on a short term basis. Organisms investigated are chosen because of their horizontal and vertical links with other (groups of) organisms and because of their (direct or indirect) economic value. For the application in the BPNS, the bio-engineering polychaete Lanice conchilega (Sandmason) has been used. As it enabled specific research to quantify both the importance for commercial fish species as well as the impact of beam trawl fisheries on the benthic environment, this reef builder was proven to be a good proxy for the quality of the benthic environment. The strategy of using small scale, short term studies on a limited number of species makes it possible to study a well defined area in a cost-efficient way; the information gathered in the case of L. conchilega is an example of ready-to-use information for the marine renewable resource management of the soft-bottom area of concern, taking the ecosystem approach into account.

1.The decision to designate, implement and manage marine protected areas (MPAs) is often made ad hoc without clear guiding procedures. This study evaluates the process of establishment and management of MPAs in temperate soft-bottom marine areas, including identification of objectives, site selection, designation, implementation, ecological effectiveness and socio-economic impacts. 2. For the first time, literature about marine conservation strategies in soft-bottom temperate areas is brought together in one systems approach, which is visualized in a flow chart including three phases: setting policy objectives, making decisions and evaluating the eventual effects of the MPA. Policy objectives are generally easy to identify and in most cases national policy objectives are driven by international and regional legal obligations. The decision making process is the most complex phase, as the acceptance of MPAs has to be balanced against the human activities that take place in the area. 3. The relation between fisheries and MPA-management appears to be most challenging in soft-bottom temperate marine areas because of conflicting interests and institutional differences. Activities limited in space and not relying directly on ecosystem functions (e.g. offshore energy production and aggregate extraction) are generally easier to manage than fisheries. 4. The conceptual mapping exercise presented here serves as a basis for a systems approach for MPAs and has been tested for the Belgian coastal environment. In the Belgian MPA-process, the application of the systems approach proves to be useful in providing insight into the complex interactions of various authorities with scattered jurisdictions. 5. The unified and simplified representation of the various aspects is (1) a useful communication tool for policy makers and managers to inform other sectors and the public at large and (2) a valuable support during the MPA-process that considerably enhances the prospects for success.

Ecosystem engineers modify the physical environment and have profound effects on ecosystem functioning and on local biodiversity. Yet, in soft bottom marine environments, they have rarely been included in hydrodynamic studies or in management strategies. The lack of quantified stabilization potential and ecological impact are, respectively, the main reasons for not including ecosystem engineers. The present study evaluates the ecosystem engineering capacity of the tube dwelling polychaete Owenia fusiformis. The ecological implications of aggregations of this species are investigated using a long term dataset (1994- 2006). Results show that its presence has significant implications for species richness and species density. These aggregations are further investigated with different remote sensing tools. Owenia fusiformis is able to stabilize sand dunes that normally migrate 12 m a year. Specific biological characteristics explain the stabilizing effects in a highly dynamic environment. Our results confirm the need to pay attention to biota in sediment transport modelling. We conclude that O. fusiformis creates an important marine system which can be investigated with sensing techniques. These techniques can therefore be used to visualize hotspots of biodiversity, to quantify their biogeomorphological impacts and to underpin ecosystems based management in the marine environment.

Reefs of the tube-building polychaete Lanice conchilega are known to represent hotspots of biodiversity within inter- and subtidal soft sediments of the North Sea. However, because of their patchy distribution, point sampling does not appropriately map their subtidal spatial distribution. This study evaluated the feasibility to detect L. conchilega reefs by very-high resolution side-scan sonar imagery. A subtidal very-high resolution (410 kHz) side-scan survey, combined with grab sampling, revealed high densities of L. conchilega (up to 1979 ind. m- 2) to coincide with a higher reflectivity, patchy and grainy acoustic facies. From the side-scan sonar imagery, individual reefs were estimated to reach a maximum size of 15 m2. To ground truth the acoustic facies, the distribution of intertidal L. conchilega reefs was mapped at low tide and side-scan sonar imagery was recorded during the following high tide. Intertidal L. conchilega reefs had a patch size of 0.8 m2 up to 11.6 m2, elevated 7.5 to 11.5 cm above the surrounding seafloor and covered approximately 10% of the selected area. The very-high (445 kHz) resolution side-scan sonar imagery revealed a similar acoustic facies as in the subtidal. Lower-resolution (132 kHz) side-scan sonar imagery was less efficient to detect physically less developed L. conchilega reefs. We conclude that (1) there are no major technical restrictions to map L. conchilega reefs using side-scan sonar, (2) the developmental stage of L. conchilega reefs impacts the detectability of the reefs, and (3) very-high resolution side-scan sonar imagery is considered a necessity when mapping small-scale structures, such as L. conchilega reefs.

European legislation and policy contain obligations on the designation and management of Natura 2000 sites in the marine environment. In implementing these obligations ecological, legal and social challenges occur. As designation of marine sites is a relatively recent process, additional sites will have to be designated, based on the ecological criteria set forth in the Habitats Directive. For these sites ecological objectives and management and restoration measures have to be taken. The exact procedure for designating the sites and determining both the ecological goals and the management measures is left to the member countries. Each country will have its own legislation and procedures. The procedure to designate sites might involve public participation. This raises questions on how to organize public participation and on the impact of public participation (to what extent can public participation influence decision making in setting ecological goals and determining management measures?). The ecological, legal and social issues relating to the implementation of Natura 2000 in the marine environment will be discussed in a Belgian case study. A legal framework has been put forward for the designation and management of Belgian marine sites. After a lengthy and difficult process, several Natura 2000 sites were designated. The process for establishing conservation objectives and taking specific management measures is ongoing. Although several sites have been designated, additional designation seems necessary.

The project WAKO wants to give a first attempt to map the current knowledge and the knowledge gaps on the effects of trammel net and beam trawl fisheries for the Belgian part of the North Sea. The project focuses on three ecosystem components, i.e. benthic invertebrates, sea birds and marine mammals. The aim of this project consists of three phases: (1) compilation and analysis of existing, experimental data for the Belgian part of the North Sea on the effects of trammel net and beam trawl fisheries; (2) current knowledge on the impact of beam trawl and trammel/gill net fisheries, based on literature review and (3) evaluation of the direct effects of beam trawl and trammel/gill net fisheries on three ecosystem components, knowledge gaps and investigation of an appropriate methodology to evaluate the environmental impact of fishing gears.WAKO indicates that direct, short-term effects of trammel net and beam trawl fisheries are clearly directed to different ecosystem components. Similarities between analogous, scientific studies allow a first evaluation of the effects, but quantitative data (on both biological impact data and data related to fishing effort and distribution) are so far insufficient to allow the development of a decision support tool for environmental and fisheries management.