This paper aims to inform forward-planning policies in the face of sea-level rise due to climate change, focusing on the choice of reducing the vulnerability of property at risk through managed retreat or protection behind seawalls. This adaptation is important not only to reduce the cost of future damage but also to maintain the beaches which are an attractive feature for tourism, of vital importance for coastal areas. Some 421 residents with main and secondary homes were surveyed in Hyères-les-palmiers in the Var department (Southeast France). The survey sought to compare the willingness of residents to contribute financially to building a seawall or to relocating sea-front property. Preferences depend both on common variables and variables specific to the proposed arrangement. They reveal common concerns focused on effectiveness and the determining factor of property ownership. The results also show some awareness of the long-term advantages of managed retreat, despite some opposition from older people, who are also more skeptical about the reality of the risk incurred.
Marine spatial planning (MSP) is an emerging responsibility of resource managers around the United States and elsewhere. A key proposed advantage of MSP is that it makes tradeoffs in resource use and sector (stakeholder group) values explicit, but doing so requires tools to assess tradeoffs. We extended tradeoff analyses from economics to simultaneously assess multiple ecosystem services and the values they provide to sectors using a robust, quantitative, and transparent framework. We used the framework to assess potential conflicts among offshore wind energy, commercial fishing, and whale-watching sectors in Massachusetts and identify and quantify the value from choosing optimal wind farm designs that minimize conflicts among these sectors. Most notably, we show that using MSP over conventional planning could prevent >$1 million dollars in losses to the incumbent fishery and whale-watching sectors and could generate >$10 billion in extra value to the energy sector. The value of MSP increased with the greater the number of sectors considered and the larger the area under management. Importantly, the framework can be applied even when sectors are not measured in dollars (e.g., conservation). Making tradeoffs explicit improves transparency in decision-making, helps avoid unnecessary conflicts attributable to perceived but weak tradeoffs, and focuses debate on finding the most efficient solutions to mitigate real tradeoffs and maximize sector values. Our analysis demonstrates the utility, feasibility, and value of MSP and provides timely support for the management transitions needed for society to address the challenges of an increasingly crowded ocean environment.
Conservation planners must reconcile trade-offs associated with using biodiversity data of differing qualities to make decisions. Coarse habitat classifications are commonly used as surrogates to design marine reserve networks when fine-scale biodiversity data are incomplete or unavailable. Although finely-classified habitat maps provide more detail, they may have more misclassification errors, a common problem when remotely-sensed imagery is used. Despite these issues, planners rarely consider the effects of errors when choosing data for spatially explicit conservation prioritizations. Here we evaluate trade-offs between accuracy and resolution of hierarchical coral reef habitat data (geomorphology and benthic substrate) derived from remote sensing, in spatial planning for Kubulau District, Fiji. For both, we use accuracy information describing the probability that a mapped habitat classification is correct to design marine reserve networks that achieve habitat conservation targets, and demonstrate inadequacies of using habitat maps without accuracy data. We show that using more detailed habitat information ensures better representation of biogenic habitats (i.e. coral and seagrass), but leads to larger and more costly reserves, because these data have more misclassification errors, and are also more expensive to obtain. Reduced impacts on fishers are possible using coarsely-classified data, which are also more cost-effective for planning reserves if we account for data collection costs, but using these data may under-represent reef habitats that are important for fisheries and biodiversity, due to the maps low thematic resolution. Finally, we show that explicitly accounting for accuracy information in decisions maximizes the chance of successful conservation outcomes by reducing the risk of missing conservation representation targets, particularly when using finely classified data.
This study investigated the effects of a community-led temperate marine reserve in Lamlash Bay, Firth of Clyde, Scotland, on commercially important populations of European lobster (Homarus gammarus), brown crab (Cancer pagurus), and velvet swimming crabs (Necora puber). Potting surveys conducted over 4 years revealed significantly higher catch per unit effort (cpue 109% greater), weight per unit effort (wpue 189% greater), and carapace length (10–15 mm greater) in lobsters within the reserve compared with control sites. However, likely due to low levels of recruitment and increased fishing effort outside the reserve, lobster catches decreased in all areas during the final 2 years. Nevertheless, catch rates remained higher within the reserve across all years, suggesting the reserve buffered these wider declines. Additionally, lobster cpue and wpue declined with increasing distance from the boundaries of the marine reserve, a trend which tag–recapture data suggested were due to spillover. Catches of berried lobster were also twice as high within the reserve than outside, and the mean potential reproductive output per female was 22.1% greater. It was originally thought that higher densities of lobster within the reserve might lead to greater levels of aggression and physical damage. However, damage levels were solely related to body size, as large lobsters >110 mm had sustained over 218% more damage than smaller individuals. Interestingly, catches of adult lobsters were inversely correlated with those of juvenile lobsters, brown crabs, and velvet crabs, which may be evidence of competitive displacement and/or predation. Our findings provide evidence that temperate marine reserves can deliver fisheries and conservation benefits, and highlight the importance of investigating multispecies interactions, as the recovery of some species can have knock-on effects on others.
To demonstrate how ecosystem service tradeoff models might help decision makers predict the effects of proposed management approaches, SeaPlan collaborated with research teams from New England and the West Coast in 2009 to conduct a two and a half year pilot study analyzing multi-use issues in Northern Massachusetts Bay. The area includes active maritime commerce, two provisional wind energy areas and well-studied, protected waters in the Stellwagen Bank National Marine Sanctuary. The two research teams applied different modeling approaches intended to support resource managers during decision making processes. One team led by researchers from the National Center for Ecological Analysis and Synthesis (NCEAS) used the concept of efficiency frontiers from the field of economics to examine how siting an offshore wind farm would affect the ecological and economic aspects of commercial fishing and whale watching. The other team led by researchers from Boston University and University of Vermont used a complex platform called Multiscale Integrated Model of Ecosystem Services (MIMES) to simulate the interplay between commercial fishing, whale watching, offshore wind energy and conservation. To make the technical results understandable to a broad audience, researchers created a user-friendly interface called the Marine Integrated Decision Analysis System (MIDAS). The Northern Massachusetts Bay pilot study demonstrated that ecosystem service tradeoff models can improve understanding of complex interactions within human-marine ecosystems and help visualize likely outcomes resulting from management actions taken across multiple sectors. The research suggests such tools can point to options that are more comprehensive and cost-effective when compared to typical sector-by-sector ocean management.
Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean coral reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater coral recovery rate for a given harvest rate. However, maintaining resilient coral reefs even until 2030 requires the addition of harvest limitations (<10% of virgin fishable biomass) to cope with a changing climate and induced coral disturbances, even in reefs that are relatively healthy today. Managing parrotfish is not a panacea for protecting coral reefs but can play a role in sustaining the health of reefs and high-quality habitat for reef fisheries.
This paper investigates the ecological, social and institutional dimensions of the synergies and trade-offs between seagrasses and human activities operating in the Natura 2000 protected site of San Simón Bay (Galicia, NW Spain). By means of a multidisciplinary approach that brings together the development of a biological inventory combined with participatory mapping processes we get key spatial and contextual understanding regarding how, where and why marine users interact with seagrasses and how seagrasses are considered in policy making. The results highlight the fisheries' reliance on seagrass meadows and the controversial links with shellfisheries. The study also reveals unresolved conflicts among those management plans that promote the protection of natural values and those responsible for the exploitation of marine resources. We conclude that the adoption of pre-planning bottom-up participatory processes is crucial for the design of realistic strategies where both seagrasses and human activities were considered as a couple system.
In order to perform a science-based evaluation of ecosystem service tradeoffs, research is needed on the impacts to ecosystem services from multiple human activities and their associated stressors (‘impact-pathways’). Whereas research frameworks and models abound, the evidence-base detailing these pathways for trade-off evaluation has not been well characterized. Toward this end, we review the evidence for impact-pathways using estuaries as a case study, focusing on seagrass and shellfish. Keyword searches of peer-reviewed literature revealed 2379 studies for a broad suite of impact-pathways, but closer inspection demonstrated that the vast majority of these made connections only rhetorically, and only 4.6% (based on a subset of 250 studies) actually evaluated impacts of stressors on ecosystem services. Furthermore, none of the reviewed studies tested pathways based on metrics of ecosystem services value that are most relevant to beneficiaries. Multi-activity tradeoff evaluation and management will require a concerted effort to structure ecosystem-based research around impact-pathways.
The use of management strategy evaluation (MSE) techniques to inform strategic decision-making is now standard in fisheries management. The technical aspects of MSE, including how to design operating models that represent the managed system and how to simulate future use of management strategies, are well understood and can be readily applied, especially for single-species fisheries. However, MSE evaluations seldom identify strategies that will satisfy all the objectives of decision-makers simultaneously, i.e. each strategy will achieve a different trade-off among the objectives. This study illustrates the basis for identifying management objectives and representing them mathematically using performance measures, as well as how trade-offs among management objectives have been displayed to various audiences who provide input into decision-making. Approaches and experiences are illustrated using case studies. Examples highlight the wide variety of objectives that can be considered using MSE, but that traditional single-species considerations continue to dominate the information provided to decision-makers. The desirability and consequences of having minimum acceptable standards of performance for management strategies, as well as difficulties assigning plausibility ranks to alternative states of nature, are found to be among the major challenges to effective provision of strategic advice on trade-offs among management strategies.
lthough the literature surrounding the development of decision support tools (DSTs) has rapidly expanded in recent years, their use in marine spatial planning (MSP) processes remains limited. Tradeoff analysis is considered essential to the MSP process by most implementation guides, but the use of DSTs to conduct tradeoff analysis is rare. Here I identify the barriers to widespread use of DSTs for tradeoff analysis. To inform this objective, I conduct an independent assessment of three DSTs that have been used in MSP in order to identify the strengths and weaknesses of each. Based on this analysis, I identify weaknesses that may contribute to infrequent use in tradeoff analysis and MSP development. Ultimately, three major barriers are detected: 1) significant data requirements impede institutional capacity to use DSTs; 2) lack of sufficient documentation and information available to practitioners; and 3) outputs that can be difficult to interpret for stakeholders and decision-makers. Because of the barriers identified, practitioners may benefit from using simpler tools as part of a broader stakeholder process.