Ecosystem Services

Based on the well-known food chains from kelp, via fauna and several trophic levels
of fish, these areas should theoretically give rise to a substantial annual production of fish,
and in fact an estimated 1–2 million tons of cod are assumed to be dependent on the Norwegian
kelp forest, according to models by the Institute of Marine Research (Moy and
Steen 2014). Also, commercial fisheries are ranked as the second largest marine economic
activity in the Baltic Sea Region (HELCOM 2014, Hasler et al. 2016). The three most
important species is cod, Baltic herring (Clupea harengus) and sprat (Sprattus sprattus),
which constitute 95% of the landings, but in addition about 20 other species are caught
more locally (Hasler et al. 2016). Values that include both provisioning (food) and cultural
(recreational fishing) ecosystem services have been estimated for the cod stock (Eggert
and Olsson 2009, Carlsson et al. 2010), Baltic salmon (Kulmala et al. 2012), and fisheries
and fish stocks in general (Lewis et al. 2013, Kosenius and Ollikainen 2015).
However, the number of people in the fishery sector continues to decrease, particularly
in the small-scale fishery, and also the average age of a commercial fisherman is
continuously increasing (Naturvårdsverket 2008). Despite a relatively small scale, the
processing industry creates jobs in sparsely populated areas while maintaining cultural
heritages in coastal communities and is therefore of local importance. For an overview
of marine food production and its added values for the Baltic countries, see Naturvårdsverket
(2008), and for Norway, see Meld. St. 37 (2012–2013), Meld. St. 8 (2005–
2006) and Meld. St. 10 (2010–2011).
3.5 Regulating services
3.5.1 Maintenance of resilience
A commonly used definition of ecological resilience is the extent to which ecosystems
can absorb recurrent natural and human perturbations and continue to regenerate
without slowly degrading or unexpectedly shifting to alternate states (Holling 1973).
This service is essential for maintained ecosystem function (Naturvårdsverket 2008).
Kelp forests are remarkably resilient to natural disturbances such as wave impacts,
storm surges, and other extreme oceanographic events (Dayton 2003, Steneck et al.
2002) and this service is essential for the safeguarding of ecosystem functions. The resilience
of the kelp ecosystem depends among others on the biodiversity which contributes
to increase the robustness, stability and the ability of the ecosystem to recover.
If a species is disturbed, another can take over its function in response to the disturbance.
If an ecosystem’s resilience is weakened, for instance by over-fishing or eutroph-
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