When marine infrastructure becomes habitat
How biodiversity monitoring is helping Femern A/S understand the ecological potential of rock structures at the Fehmarnbelt tunnel
At Rødbyhavn, Denmark, rock armour for erosion and scour protection of the land reclamation were designed as part of the Fehmarnbelt tunnel project. Femern A/S is looking beyond their engineering function to understand how they may develop as marine habitat.
DHI supports this ambition by combining field surveys, environmental DNA (eDNA) and ecological modelling to track biodiversity and habitat succession over time. This integrated approach reveals which species are colonising the rockwork, how suitable the structures may be as habitat and how they could connect with the surrounding marine ecosystem. The insights give Femern A/S a stronger basis for understanding the environmental development and potential ecological role of its marine infrastructure.
Challenge
Land reclamation at Rødbyhavn uses dredged material from the project's tunnel trench, with breakwaters providing the protection needed to reclaim new areas safely. Beneath the water, the rockwork also creates hard surfaces that marine species can potentially colonise.
For Femern A/S, the challenge is understanding whether and how marine habitat becomes established on these new structures, particularly as suspended sediment from dredging can affect newly establishing communities. This requires looking beyond which species are present to understand how biodiversity develops across space and time. Ultimately, the monitoring will help determine whether the rockwork could partly compensate for habitat loss and provide additional capacity for marine biodiversity.
Client:
Femern A/S, part of Sund & Bælt Holding A/S
Location:
Denmark
Related SDG(s):
SDG 14: Conserve and sustainably use the oceans, seas and marine resources for sustainable development
Technology:
Solution
DHI’s integrated approach combines biological monitoring with ecological modelling to give Femern A/S a more complete picture of how marine life is developing on the rockwork. Field observations and eDNA are combined with DHI’s BioQ suite of biodiversity assessment and modelling applications to understand habitat succession from multiple perspectives.
Solution highlights:
Monitor marine vegetation: Biomass sampling and video transects track the development and coverage of important macroalgae communities
Assess biodiversity using eDNA: Environmental DNA provides insights into species communities across important taxonomic groups
Track habitat succession: DHI’s Biodiversity State Indicator shows how biodiversity develops across space and time
Evaluate the biodiversity footprint: Machine learning algorithms, coupled with habitat modelling, sets the eDNA findings into perspective to assess the regional biodiversity footprint that is fostered through the newly established habitats on the rockworks
Understand ecosystem connectivity: Connectivity modelling assesses the role of the rockwork in larval dispersal and retention and its connection to the wider marine ecosystem
Together, these methods provide a more holistic understanding of habitat succession within the context of regional ecosystem dynamics than traditional monitoring alone.
Results
Ongoing year-to-year monitoring is building a clearer picture of how marine life is colonising and developing on the newly established rockwork. For Femern A/S, this provides evidence to understand habitat succession and the potential ecological role of the new marine infrastructure, including how it may contribute to marine biodiversity.
Clearer evidence of habitat development: Femern A/S can follow how habitat and species communities develop over time
A broader view of net-positive biodiversity: Monitoring across a wide range of taxonomic groups, from macroalgae to vertebrates, provides a more complete picture of the communities establishing on the rockwork
Insight beyond the rockwork: Connectivity modelling extends the monitoring findings by estimating the broader biodiversity footprint of the newly established habitats
'Our collaboration with DHI combines biodiversity monitoring and ecological modelling to examine the rock structures beyond their engineering function. The findings help document habitat development and improve our understanding of their potential contribution to marine biodiversity over time.'
Lars Hansen, Project Manager
Sund & Bælt Holding A/S
About our client
Femern A/S is a 100% Danish company tasked with planning, building and operating the fixed link across the Fehmarnbelt between Denmark and Germany. The company has 160 employees working from offices in Copenhagen, Rødbyhavn, Hamburg, Burg and Puttgarden. Femern A/S is a subsidiary of the state-owned Sund & Bælt under the Danish Ministry of Transport.
