WP6 Cost-benefit analysis

Cost-benefit analysis of ecosystem services provided by eelgrass restoration.

The hypothesis that benefits of widespread and healthy eelgrass meadows outweigh the costs
of restoration and protection actions will be examined by balancing the estimated costs of
protection of existing eelgrass habitats and restoration of new eelgrass habitats against the
gains derived from ecosystem services provided by these habitats.

The cost estimates of protection and restoration of eelgrass habitats will be based on
project data (WP 1, WP 2, WP 4 and WP 5) combined with restoration literature where costs for
seeding 1 ha of bottom with eelgrass (Zostera marina) is reported to range from $6,674 to
$165,699, depending on seeding density and dispersal method used (Busch et al. 2010). The
large range in cost estimates is due to differences in use of e.g. equipment, labor and
transport (Paling et al. 2009).

The focus for the benefit assessment will be on the ecosystem services that eelgrass
delivers in terms of e.g. CO2 sequestration, nutrient filtering and coastal protection. The
benefits of these services will primarily rely on data from WP 4 and WP 5, as well as the
literature. Threshold effects and uncertainties will be taken into consideration at any time.
Benefits of the ecosystem services will be estimated from shadow prices (alternative costs) of
achieving similar services by reduction in nutrient discharge from agriculture and waste water
treatment, reduced CO2 emissions from transport and heating, and artificial coastal protection.
Shadow prices on CO2 sequestration will be used for sensitivity analyses of eelgrass benefits,
and the shadow prices of agricultural nutrient reduction actions is estimated using costeffectiveness
models, including retention and spatial data developed for Odense Fjord (Hasler
et al. 2012).
This cost-benefit approach will ensure and test the economic balance and validity
of eelgrass restoration efforts. The tests will primarily utilize data from WP 4 and WP 5 to
ensure consistency in the analyses of restoration methods, effects, costs and benefits.

An important final product of the socio-economic research is guidelines for environmental
managers and decision makers, expressing the balance between area-specific costs and
benefits of full-scale restorations in various types of locations.