To restore coastal marine areas, we need to work across multiple habitats simultaneously

August 2nd, 2023

Restoration of coastal marine habitats – often conducted under the umbrella of “nature-based solutions” – is one of the key actions underpinning global intergovernmental agreements, including the Paris Agreement and the 2021–2030 United Nations (UN) Decade of Restoration.

To achieve global biodiversity and restoration targets we need methods that accelerate and scale up restoration activities in size and impact. Part of the solution is cross-habitat facilitation – positive interactions that occur when processes generated in one habitat benefit another. These interactions involve physical, biological, and biogeochemical processes, such as wave energy dampening, competition reduction, and nutrient cycling.

To date, positive cross-habitat interactions, known as ‘facilitative interactions,’ underpin coastal ecosystem development, resilience, and expansion, but have received little attention in coastal marine restoration practice beyond small-scale studies.

We found that only six of 2,145 coastal marine restoration studies addressed restoration of multiple habitats concurrently, and just three explicitly aimed to harness cross-habitat facilitation. In contrast, terrestrial ecosystem restoration often employs multihabitat restoration approaches.

And yet, these interactions are incredibly important for habitat formation. Without cross-habitat facilitation via oyster and coral reefs that baffle waves, for example, saltmarshes, seagrasses, and mangroves cannot naturally develop in many locations. Biotic interactions, such as species migrations, can mediate long-distance cross-habitat facilitation. Cross-habitat facilitation can extend beyond coastal marine seascape interactions to interactions across marine–terrestrial borders. For example, nutrient exchange between land and sea can increase sand dune or reef productivity.