Multicriteria Analysis to Implement Actions Leading to Coastal Dune Restoration

Abstract

This chapter explores the variables that can influence the success of beach and dune restoration, utilizing Analytic Hierarchy Process (AHP) and the contributions of a multidisciplinary panel of recognized experts that includes ecologists, geomorphologists, anthropologists, and specialists in the restoration of coastal dunes. The criteria selected to represent the beach–dune system were chosen taking into consideration their influence on the success or failure of ecological restoration. Three levels were considered: criteria, subcriteria, and indicators. The first consists of four criteria (degree of degradation, factors that cause stress to the system, facilitators and elements that assist prioritization). The second level has ten subcriteria: morphological degradation and system fragmentation; degradation of vegetation; internal stress factors; external stress factors; abiotic factors that facilitate restoration; biotic factors that facilitate restoration; presence of species in any category of risk; proximity to protected areas; increased occurrence of floods; ecosystem services at risk). The third level consists of 38 indicators (e.g., evidence of damage by trampling of vegetation, visitor pressure, infrastructure affecting sediment dynamics, proximity of sources of propagules that can be used in restoration, among others). The relative importance of the elements of each level was calculated by the panel of experts. In a range from 0 to 1, the highest weighting (0.37) was assigned to the criterion “facilitators”. This term refers to the existence of biotic and abiotic elements necessary for restoration to take place. This criterion also includes 12 indicators (availability of pioneer plants; presence of tolerant native plant species; availability of space, orientation of the coast with respect to the waves; aeolian transport; sediment size; presence of nearby sediment sources; presence of infrastructure that alters wind dynamics, among others). The lowest weighting (0.15) was assigned to the criterion “elements that assist prioritization”. This criterion refers to those elements that are priorities for mankind that attract public attention as well as financial investment for the restoration of a given site and includes indicators such as proximity to protected areas, proximity to cultural sites and tourist areas, as well as measured ecosystem services such as the presence of human interests that are at risk of disappearing because of hurricanes or under rising sea, an abundance of hotels, and the occurrence of floods. Multi-criteria analysis is useful for making complex decisions, such as the choice of beaches and dunes for restoration. This is because it allows the problem to be addressed in an orderly manner, chooses the most representative criteria as well as assigning weighting. Furthermore, the use of this analysis allowed us to take a range of opinions into account through the contributions of a panel of experts. Inclusion of such a panel saves time while giving credibility to the decisions taken.KeywordsAnalytic Hierarchy ProcessSandy BeachCoastal DuneMulticriteria AnalysisBeach NourishmentThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.