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.
Resource management and conservation require the definition of planning units (PUs), i.e., the spatial domain where management decisions are applied. PUs are either pre-established in size and shape following management constraints or are data driven (DDPUs) by overlay of multidisciplinary data layers. The trade-offs between these two approaches have not been investigated previously for small tropical islands and their characteristics. Here, we use resource density, fishing pressure and susceptibility to mortality for a giant clam fishery in a small French Polynesia atoll to discuss the suitability and impact of the two approaches in conservation management. Aggregation to pre-established PU grids highly affected data even for PU as small as 2500 m², with higher loss of spatial information for density and fishing effort. By contrast, DDPU rendered well small scale patterns of interest but reduced redundancy. Our results stress the importance of considering the initial patterns of data in the definition of planning units, and we suggest a 3 steps process to identify adequate trade-offs between PU size, PU redundancy and data loss to properly draw practical recommendations for small islands.
Oceans, particularly coastal areas, are getting busier and within this increasingly human-dominated seascape, marine biodiversity continues to decline. Attempts to maintain and restore marine biodiversity are becoming more spatial, principally through the designation of marine protected areas (MPAs). MPAs compete for space with other uses, and the emergence of new industries, such as marine renewable energy generation, will increase competition for space. Decision makers require guidance on how to zone the ocean to conserve biodiversity, mitigate conflict and accommodate multiple uses. Here we used empirical data and freely available planning software to identified priority areas for multiple ocean zones, which incorporate goals for biodiversity conservation, two types of renewable energy, and three types of fishing. We developed an approached to evaluate trade-offs between industries and we investigated the impacts of co-locating some fishing activities within renewable energy sites. We observed non-linear trade-offs between industries. We also found that different subsectors within those industries experienced very different trade-off curves. Incorporating co-location resulted in significant reductions in cost to the fishing industry, including fisheries that were not co-located. Co-location also altered the optimal location of renewable energy zones with planning solutions. Our findings have broad implications for ocean zoning and marine spatial planning. In particular, they highlight the need to include industry subsectors when assessing trade-offs and they stress the importance of considering co-location opportunities from the outset. Our research reinforces the need for multi-industry ocean-zoning and demonstrates how it can be undertaken within the framework of strategic conservation planning.
Marine spatial management is an important step in regulating the sustainable use of marine resources and preserving habitats and species. The systematic conservation planning software “Marxan” was used to analyse the effect of different conservation objectives and targets on the design of a network of marine protected areas around two islands of the Azores archipelago, Northeast Atlantic. The analyses integrated spatial patterns of the abundance and reproductive potential of multispecies, the vulnerability of fish to fishing, habitat type, algae biotopes, and socio-economic costs and benefits (including fishing effort and recreational activities). Three scenarios focused on fisheries-related objectives (“fisheries scenarios”, FSs) and three on multiple-use and biodiversity conservation objectives (“biodiversity scenarios”, BSs), respectively. Three different protection targets were compared for each set, the existing, minimum, and maximum levels of protection, whereas conservation features were weighted according to their biologically/ecologically functioning. Results provided contrasting solutions for site selection and identified potential gaps in the existing design. The influence of the conservation objective on site selection was most evident when minimum target levels were applied. Otherwise, solutions for FSs and BSs were very similar and mostly shaped by the protection level. More important, BSs that considered opportunity cost and benefits achieved conservation targets more cost-efficiently. The presented systematic approach ensures that targets for habitats with high fish abundance, fecundity, and vulnerability are achieved efficiently. It should be of high applicability for adaptive management processes to improve the effectiveness of existing spatial management practices, in particular when fishing and leisure activities coexist, and suggest that decision-makers should account for multiple users’ costs and benefits when designing and implementing marine reserve networks.