Ecosystem services assessment and compensation costs for installing seaweed farms
Introduction
The European Union (EU) Integrated Maritime Policy promotes the sustainable development of new blue growth activities [1], such as marine renewable energy, raw material extraction, leisure activities, and aquaculture including seaweed farming. Currently there are several on-going projects related to seaweed farming, for instance, the EnAlgae project (www.enalgae.eu) seeking to reduce reliance on fossil fuels by developing algal biofuel technologies, and the MARIBE project (www.maribe.eu) aiming to identify and develop business models for blue growth activities, including seaweed farming. Despite reports of several positive effects associated with seaweed farming worldwide [2], [3], [4], failures in or lack of knowledge exchange between the aquaculture industry, policymakers, local population, and people who depend on aquaculture, may jeopardize the ‘Blue growth’, which includes seaweed farming [5]. Additionally, it has also been reported that negative impacts of seaweed on ecosystems have not yet been fully investigated [6]. Altogether, these factors may contribute to the lack of social acceptance of this activity not only in France but also in other countries.
In France, seaweed farming activities started in the 1970–1980s, for instance, with the culture of Undaria pinnatifida, an introduced species native to Asia. Currently, there are ongoing projects such as IDEALG (www.idealg.ueb.eu) developing this sector by using local species (e.g. L. saccharina). Since 2008 this activity has gained new interest as a response to the crisis faced by oyster farmers due to the high mortality of oysters. The installation of seaweed farms along the French Atlantic coasts is now perceived as a source of complementary income to these farmers and gives new use to the existing oyster farms. However, not all of the available concessions are suitable for the cultivation of seaweed using subsurface long-lines, which should take place in deep waters rather than on the shore. Additionally, new projects of mussels or seaweed farms in deep waters are facing social resistance from local populations who fear negative impacts on ecosystems, fisheries activities and tourism, related to the degradation of seascape/seawater quality and increasing restrictions on recreational uses. Although the French administration has authorized new concessions, they have not been implemented due to the opposition of residents or associations.
To facilitate the development of these new activities, the European Commission urges countries to implement Marine Spatial Planning (MSP), which includes a consultation phase to identify the use of each marine zone. EU countries are also required to draw up a maritime spatial plan no later than 31 March 2021 [7]. However, considering the opposition faced by seaweed farming projects in France and other countries, it is necessary to go beyond simple spatial planning and to develop new concepts, methods, and tools to facilitate discussion and negotiation between the actors of the system.
The “ecosystem services” concept seems interesting to use for facilitating discussion at a territory scale (see for example the Natural Capital Project1). Marine ecosystems are complex and changing systems that provide multiple services to humans [8]. However, there is a recognized biodiversity crisis in marine environments, particularly in coastal zones where a diverse set of human activities and drivers are concentrated [9] and interact [10]. Services provided by marine systems have diminished while human exploitation patterns have been increasing [11]. One way of addressing this global problem is through ecosystem-based management (EBM) approaches, which propose managing seas and oceans by maintaining ecosystems structure, redundancies, and resilience to environmental changes [12]. EBM includes local political aspects and management actions at different spatial scales of application [13]. Despite the recognition of the interest in this approach at a global scale through the Millennium Ecosystem Assessment [8], [14], successful examples of local EBM approaches are relatively rare [15]. EBM failures have different explanations, for instance, conflicts between users who expect or envision different benefits from ecosystems (e.g. commercial fishing versus conservation interests) or lack of institutions for effective governance [16], [17], [18], as well as level of transaction costs to overcome implementing this method [19]. Differences in terminology and knowledge among different groups of interests [20], [21], [22] coupled with the complexity and specificities of marine and coastal systems [23] make consultation in EBM a rough task. The use of the ecosystem services framework can help to improve the implementation of EBM approaches by providing a common set of facts and a common currency to better understand trade-offs between alternative development projects [15], [24].
In addition to the concept of ecosystem services, it also seems important to adopt multi-criteria methods for describing interactions between human uses and ecological dynamics (and not an aggregated monetary valuation). Indeed, the marine socio-ecosystem is characterized by multiple systems of values with multiple sustainability criteria which makes its governance a global challenge [25], [26]. Thus, considering simultaneously the analysis of variables and values characterized by limited comparability is a task that can be assessed only using a multi-criteria analysis [27], [28].
Three main dimensions associated with the location of implementation of seaweed farms were identified. First, seaweed farms face operational constraints, such as optimal depth, but also a minimal distance from the coast, which is directly associated to their visual impact. Second, marine ecosystems are subject to multiple uses, and locating farms where uses are already numerous increases the potential level of conflict among users. Third, the implementation of a new farm must be associated with an environmental impact assessment that can raise stakeholders’ opposition but also lead to a mitigation procedure (avoiding, reducing, and compensating).
Adopting a multi-criteria analysis based on ecosystem services assessment requires innovative tools to provide useful information that can help the emergence of a general agreement. Two different tools were applied: i) the first tool is called InVEST (Integrated Valuation of Ecosystem Services and Trade-offs), which relies on ecological information to map, quantify, and value the distribution of ecosystem services across a landscape (or a seascape) [14], [29], [30]; and, (ii) the HEA (Habitat Equivalency Analysis), which has been used by the US administration in the case of accidental impacts on marine ecosystems and habitats to determine the size of a compensatory measure based on a biophysical ecosystem services unit criterion [31], [32].
The goal of this paper is to provide biophysical and socioeconomic indicators describing the constraints for seaweed farm deployment and the impacts generated on ecosystem services in order to assist decision-makers through an illustrative case study. The selected indicators include biophysical constraints (especially the depth), distance to the coast, impacts on ecosystem services (provisioning and cultural), potential conflicts with other uses, and compensation costs. The objective is not to find the “best possible location” but to illustrate the efficiency of an integrative assessment tool for decision-makers. The approach could also contribute to the design of regional plans for the development of marine aquaculture activities (e.g. the development of the regional development schema of marine aquaculture as part of the fisheries and agriculture modernization law [33]).
Section snippets
Study area
The Normand-Breton Gulf (GNB), located in the western part of the English Channel includes several habitats depending on complex currents and the presence of islands, archipelagos and rocky reefs [34] (Fig. 1). The Normandy and Brittany coasts are heterogeneous areas more developed and densely populated around the main urban centers of Ille-et-Vilaine and Côtes d’Armor, although less than along other French coasts such as the Mediterranean coasts [35]. There are 267 municipalities within a
Results
A mask with the suitable biophysical characteristics (i.e., depth, distance to coastline, habitat, within the 12 nautical miles, and visual impact) delimiting the suitable area for the seaweed farm was created. Subsequently, the InVEST Overlap Analysis tool was used to calculate the number of human activities existing in a grid of 1 km spatial resolution (Fig. 5). The maximum number of overlapping activities is five and lowest is one.
Fig. 6 depicts using a 1 km spatial resolution cell, the
Discussion and conclusions
An EBM approach was proposed to provide quantitative biophysical, ecological and socioeconomic indicators to help marine planners decide on where to create seaweed farms in the GNB. The aim was to provide an approach that supports decision making enabling an informed discussion between administration and local stakeholders during the installation of new aquaculture projects. Being the best in three out of seven indicators, farm A could be seen as the “best” location. However, criteria may have
Acknowledgements
This work benefited from the support of the French government through the National Research Agency with regard to an investment expenditure program, IDEALG (ANR-10-BTBR-04).
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