Delavenne, J., Metcalfe, K., Smith, R. J., Vaz, S., Martin, C. S., Dupuis, L., Coppin, F., and Carpentier, A. 2012. Systematic conservation planning in the eastern English Channel: comparing the Marxan and Zonation decision-support tools. – ICES Journal of Marine Science, 69: 75–83. The systematic conservation approach is now commonly used for the design of efficient marine protected area (MPA) networks, and identifying these priority areas often involves using specific conservation-planning software. Several such software programmes have been developed in recent years, each differing in the underlying algorithms used. Here, an investigation is made into whether the choice of software influences the location of priority areas by comparing outputs from Marxan and Zonation, two widely used conservation-planning, decision-support tools. Using biological and socio-economic data from the eastern English Channel, outputs are compared and it is shown that the two software packages identified similar sets of priority areas, although the relatively wide distribution of habitat types and species considered offered much flexibility. Moreover, the similarity increased with increasing spatial constraint, especially when using real-world cost data, suggesting that the choice of cost metric has a greater influence on conservation-planning analyses than the choice of software. However, Marxan generally produced more efficient results and Zonation produced results with greater connectivity, so the most appropriate software package will depend on the overall goals of the MPA planning process.

International audienceAimThe species–area relationship (SAR) is increasingly being used to set conservation targets for habitat types when designing protected area networks. This approach is transparent and scientifically defensible, but there has been little research on how it is affected by data quality and quantity.LocationEnglish Channel.MethodsWe used a macrobenthic dataset containing 1314 sampling points and assigned each point to its associated habitat type. We then used the SAR-based approach and tested whether this was influenced by changes in (i) the number of sampling points used to generate estimates of total species richness for each habitat type; (ii) the nonparametric estimator used to calculate species richness; and (iii) the level of habitat classification employed. We then compared our results with targets from a similar national-level study that is currently being used to identify Marine Conservation Zones in the UK.ResultsWe found that targets were affected by all of the tested factors. Sample size had the greatest impact, with specific habitat targets increasing by up to 45% when sample size increased from 50 to 300. We also found that results based on the Bootstrap estimator of species richness, which is the most widely used for setting targets, were more influenced by sample size than the other tested estimators. Finally, we found that targets were higher when using broader habitat classification levels or a larger study region. However, this could also be a sample size effect because these larger habitat areas generally contained more sampling points.Main conclusionsHabitat targets based on the SAR can be strongly influenced by sample size, choice of richness estimator and the level of habitat classification. Whilst setting habitat targets using best-available data should play a key role in conservation planning, further research is needed to develop methods that better account for sampling effort

-The eastern English Channel, the narrow channel of water separating northern France and southeast England is an area of intense human use of the array of resources concentrated into its relative small area. The vulnerability of living resources and their habitats brought together French and British maritime experts within a common project (called CHARM): to create an atlas of marine resource habitats in the eastern English Channel so as to provide planners and decision-makers with the necessary information to help managing the use of its living and non-living resources. This multidisciplinary and richly illustrated atlas provides abundant information on the legal framework and physical environment; benthic invertebrates, fish and their habitats; fishing activities; and a first attempt at developing a trophic network model (using ECOPATH software) and a marine conservation planning exercise (using MARXAN software, at a spatial resolution of 25 km 2 ). Although most of the data used were collected elsewhere, some were collected especially for the project. Similarly, most of the analyses performed on the data where entirely original for this geographical area. The CHARM atlas has significantly improved the knowledge about the eastern Channel while contributing to the recognition that such holistic or multidisciplinary approaches to exploited marine systems are necessary to efficiently and durably manage their resources use. Key words: Eastern English ChannelRésumé -La Manche orientale, ce bras de mer qui sépare l'Angleterre de la France, est une zone très riche d'un point de vue écologique et soumise à une forte utilisation anthropique d'une gamme de ressources concentrées sur une superficie relativement faible. La fragilité des ressources marines vivantes et leurs habitats a rassemblé des experts maritimes français et britanniques autour d'un projet commun (nommé CHARM) dans le but de réaliser un atlas des habitats des ressources marines de la Manche orientale. Cet atlas contient les informations nécessaires aux planificateurs et décideurs pour une meilleure gestion des ressources marines, vivantes ou non. Dans ce document pluridisciplinaire, richement illustré, on peut trouver des informations sur le cadre juridique et l'environnement, les invertébrés benthiques, les poissons et leurs habitats ; les activités de pêche ; et également sur le développement d'un modèle de réseau trophique a Corresponding author: andre.carpentier@ifremer.frArticle published by EDP Sciences 500 C.S. Martin et al.: Aquat. Living Resour. 22, 499-508 (2009) (utilisant le logiciel ECOPATH) et un premier exercice de planification spatiale de la conservation (utilisant le logiciel MARXAN, à une résolution spatiale de 25 km 2 ). Bien que la plupart des données aient été collectées en dehors du projet, certaines l'ont été spécialement pour le projet. De même, la plupart des analyses faites sur ces données sont entièrement inédites pour cette zone géographique. L'atlas CHARM contribue de façon significative à une meilleure connaiss...

The delineation of essential fish habitats is necessary to identify, design and prioritize efficient marine protected area (MPA) networks with fishery objectives, capable, in addition to other possible objectives and functions of MPAs, of sustaining the renewal of marine living resources. Both the methods available to map essential fish habitats and the usefulness of these maps are discussed in this paper. Highlights ► The delineation of fish habitats is needed to identify MPAs with fishery objectives. This paper reviews: ► The quantitative methods to map fish habitats and identify key sites for fishery resources. ► The usefulness of maps to measure the importance of habitats to sustain resources. ► The relevance of fish habitat maps to design MPA networks.

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