The MARINEFF project has identified the following opportunities for increasing biodiversity in coastal infrastructure:
Coastal infrastructure, such as sea defences (breakwaters, sea walls etc) and boat moorings, present both challenges and opportunities to coastal marine species. Coastal infrastructure built in soft sediment environments can offer an increase in biodiversity by acting as ‘islands’ for marine species that prefer harder substrate to colonise. These ‘islands’ have the capacity to extend the ranges and dispersal of marine species and promote the exchange of genetic diversity by linking up geographically separated populations. However, the usefulness of this benefit is limited by the size of the available habitat and the distance from similar populations that can colonise the coastal infrastructure. It can also provide habitats for fish, which are attracted to structures that occur in soft sediment environments as they present opportunities for shelter, feeding and as nursery habitat for juveniles.
Coastal infrastructure is predominantly finished with smooth, flat surfaces that do not incorporate cracks and crevices to retain water or produce shaded areas. Therefore, they have lower species diversity than natural shores. Eco-engineering aims to disrupt the homogenous surface of coastal defence structures by imitating natural rocky shore habitat, providing habitat complexity and opportunities for colonisation of marine species. This allows more species to survive the periodic exposure to air at low tide and reduces the risk of desiccation and death. When the tide returns, these same cracks and crevices provide refuge from predators and wave energy. Greater habitat complexity also increases surface area, enhancing the island effect.
Funding is another issue with incorporating eco-engineering into coastal infrastructure. Often eco-engineering is not incorporated within coastal engineering budgets as funding is not available for it. Eco-engineering needs to be marketed to practitioners in a way that highlights the benefits such as community engagement and bioprotection capabilities. For example, the colonisation of barnacles on concrete can reduce the impacts of weathering and erosion.