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    Spatial, socio-economic, and ecological implicationsof incorporating minimum size constraints in marineprotected area network designKristian Metcalfe, Gregory Vaughan, Sandrine Vaz, and Robert J. Smith Durrell Institute of Conservation and Ecology (DICE), School of Anthropology and Conservation, University of Kent, Canterbury,Kent, CT2 7NR, United KingdomGeospatial Services, 2/35 Arthur Road, Holloway, London, United KingdomInstitut Francais de Recherche pour lxploitation de la Mer (Ifremer), UMR MARBEC, Av. Jean Monnet, B.P.171, 34200 Sete, FranceCentre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall,TR10 9FE, UK, and Environment and Sustainability Institute, University of Exeter, Penryn Campus, Cornwall, TR10 9FE, UnitedKingdom

    Abstract: Marine protected areas (MPAs) are the cornerstone of most marine conservation strategies, butthe effectiveness of each one partly depends on its size and distance to other MPAs in a network. Despite this,current recommendations on ideal MPA size and spacing vary widely, and data are lacking on how theseconstraints might influence the overall spatial characteristics, socio-economic impacts, and connectivity ofthe resultant MPA networks. To address this problem, we tested the impact of applying different MPA sizeconstraints in English waters. We used the Marxan spatial prioritization software to identify a network ofMPAs that met conservation feature targets, whilst minimizing impacts on fisheries; modified the Marxanoutputs with the MinPatch software to ensure each MPA met a minimum size; and used existing data onthe dispersal distances of a range of species found in English waters to investigate the likely impacts of suchspatial constraints on the regions biodiversity. Increasing MPA size had little effect on total network area orthe location of priority areas, but as MPA size increased, fishing opportunity cost to stakeholders increased. Inaddition, as MPA size increased, the number of closely connected sets of MPAs in networks and the averagedistance between neighboring MPAs decreased, which consequently increased the proportion of the planningregion that was isolated from all MPAs. These results suggest networks containing large MPAs would bemore viable for the majority of the regions species that have small dispersal distances, but dispersal betweenMPA sets and spill-over of individuals into unprotected areas would be reduced. These findings highlight theimportance of testing the impact of applying different MPA size constraints because there are clear trade-offsthat result from the interaction of size, number, and distribution of MPAs in a network.

    Keywords: connectivity, Marxan, MinPatch, spatial conservation prioritization, spill-over and export, systematicconservation planning, viability

    Implicaciones Espaciales, Socio-Economicas y Ecologicas de la Incorporacion de Limitantes de Tamano Mnimo alDiseno de Redes de Areas Marinas Protegidas

    Resumen: Las areas marinas protegidas (AMPs) son el pilar de la mayora de las estrategias de conservacionmarina, pero la efectividad de cada una depende en parte de su tamano y de la distancia a otras AMPs enla red. A pesar de esto, las recomendaciones actuales para el tamano ideal de una AMP y el espaciado entreellas vara ampliamente, y la informacion carece de datos sobre como estas limitantes influyen en general alas caractersticas espaciales, los impactos socio-economicos y la conectividad de la red de AMPs resultante.Para atender este problema, evaluamos el impacto de la aplicacion de diferentes limitantes del tamano dela AMP en aguas inglesas. Utilizamos el software de priorizacion espacial Marxan para identificar una redde AMPs que cumpliera con los objetivos distintivos de la conservacion, a la vez que minimizara el impactode las pesqueras. Despues modificamos los resultados del Marxan con el software MinPatch para asegurar

    Address correspondence to R.J. Smith, email submitted March 21, 2014; revised manuscript accepted March 31, 2015.

    1615Conservation Biology, Volume 29, No. 6, 16151625C 2015 Society for Conservation BiologyDOI: 10.1111/cobi.12571

  • 1616 Marine Protected Area Size

    que cada AMP cumpliera con un tamano mnimo. Finalmente utilizamos datos existentes de las distanciasde dispersion de una gama de especies que se hallan en aguas inglesas para investigar los impactos probablesde dichas limitantes espaciales sobre la biodiversidad de la region. El incremento del tamano de la AMPtuvo un efecto mnimo sobre el total del area de la red o la ubicacion de areas prioritarias, pero conformeincremento el tamano de la AMP, el costo de la oportunidad de pesca para los accionistas incremento. Ademas,conforme incremento el tamano de la AMP, el numero de conjuntos de AMPs cercanamente conectados enlas redes y la distancia promedio entre las AMPs colindantes disminuyo, lo que en consecuencia incrementola proporcion de la region de planeacion que se aislo de todas las AMPs. Estos resultados sugieren que lasredes que contienen AMPs grandes seran mas viables para la mayora de las especies de la region que tienendistancias de dispersion reducidas, pero la dispersion entre conjuntos de AMPs y el derrame de individuoshacia areas sin proteccion se vera reducida. Estos hallazgos resaltan la importancia de evaluar el impactode la aplicacion de las diferentes limitantes de tamano de las AMPs ya que hay compensaciones evidentes queresultan de la interaccion del tamano, el numero y la distribucion de las AMPs en una red.

    Palabras Clave: conectividad, derrame y exportacion, Marxan, MinPatch, planeacion sistematica de la conser-vacion, priorizacion de la conservacion espacial, viabilidad


    Marine protected areas (MPAs) can produce a widerange of ecological, economic, and social benefits,making them a cornerstone of most marine conservationstrategies (Klein et al. 2013). However, these benefitscan only accrue if MPA networks are well designed, soscientists have identified 6 ecological goals that shouldunderpin the design process: representation, replication,adequacy, viability, connectivity, and protection (Airameet al. 2003; Roberts et al. 2003; Edgar et al. 2014). Acommonly used approach to help achieve these goals in-volves identifying important conservation features (e.g.,species and habitat types), setting quantitative targetsfor how much of each feature should be conserved, andthen using conservation planning software to identifywhere new MPAs should be located to meet these targets(Moilanen et al. 2009). This approach is termed spatialconservation prioritization and addresses several stageswithin a systematic conservation planning framework byexplicitly accounting for MPA network representation,replication, and adequacy. These factors are accountedfor because the approach seeks to represent a range ofhabitats; includes replicates of each habitat, and identifiesa sufficient amount of each habitat for protection toadequately conserve a range of associated species,communities, and physical characteristics (Moilanenet al. 2009).

    Marine conservation planning, however, needs tomove beyond simply representing biodiversity features,so there is increasing emphasis on incorporating targetsrelated to viability, connectivity, and protection withinthe planning process (Magris et al. 2014). Whilst the de-velopment of new conservation planning software nowbetter accounts for protection by letting users set targetsfor the amount of each feature allocated to different man-agement zones (Watts et al. 2009; Metcalfe et al. 2015),viability and connectivity targets are still rarely accountedfor in MPA network design (Magris et al. 2014). This isparticularly problematic because MPAs need to be large

    enough to encompass the typical movements of speciesand support viable populations that are self-sustainingthroughout natural cycles of variation (Airame et al. 2003;Roberts et al. 2003) and be spaced close enough to main-tain connectivity between individual MPAs, a processlargely driven by dispersal of propagules and movementof adults (Palumbi 2003).

    This is why design criteria such as the minimum sizeof and maximum spacing between MPAs are increasinglybeing adopted (Table 1). Such size and spacing targets aretypically developed to account for viability and connec-tivity goals by considering the movement and dispersalcharacteristics of a broad range of target species. Forexample, the minimum size of an MPA can be basedon the maximum home range of target species, andthe maximum spacing between MPAs can be based onthe dispersal requirements that would benefit the widestrange of species (Moffitt et al. 2010; Green et al. 2014).However, developing these targets is inherently difficultbecause marine organisms vary greatly in their movementability (Palumbi 2003; Shanks et al. 2003) and most MPAplanning initiatives lack dispersal data for species in thearea. Therefore, whilst studies of home ranges, tagging,and dispersal characteristics would ideally be used toinform size and spacing targets, practitioners often relyon previously developed rules of thumb.

    Nevertheless, incorporating these size and spacingtargets into spatial prioritization analyses has untilrecently been restricted by the functionality of theavailable software. In particular, software such as Marxanand Zonation (Ball et al. 2009; Moilanen et al. 2009)allows users to influence only whether MPA networksare clumped or fragmented and not to set minimum sizeconstraints. This has had two negative effects. First, ithas been impossible to account for minimum MPA sizein spatial prioritization analyses, so planners typicallyhave to modify software outputs post hoc. Whilst suchmodifications are not unusual to meet stakeholderrequirements (Pressey et al. 2013), large changes areli