Ecosystem Services

fish stock sizes, are multifaceted, with some species losing and others actually gaining
from the effects of eutrophication (Bergström et al. 2013, Candolin et al. 2008).
Fishing, as an additional type of pressure, further complicates the picture by the
fact that it may indirectly lead to a decrease in the quality of the ecosystem by relaxing
the top-down control of filamentous nuisance algae maintained by predatory fish
(Eriksson et al. 2009, 2011, Östman et al. 2016). Nevertheless, these biotope complexes
(sensu HELCOM 2013b) are all red-listed as threatened due to adverse effects of eutrophication
and constructions.
Since human uses can adversely impact ecosystem processes and functions, there
is a need to find a long-term sustainable balance between the use and preservation of
these ecosystems and associated services for a continued human well-being.
6.3 Supporting services
6.3.1 Habitat and biodiversity
A multitude of ecosystem services are provided by shallow, wave sheltered bays and
inlets in the northern Baltic Sea. The most important ecosystem services include their
supporting role in biodiversity, providing habitat and food for various organisms. The
vegetation community in bays and inlets of the northern Baltic Sea maintains (for the
species-poor Baltic Sea) a relatively high biodiversity, with many species forming a
three dimensional habitat equivalent to underwater forests (like the kelp forests, Chapter
3) in which many other organisms thrive (Figure 22).
The rich vegetation community provides habitat and shelter from predators and
increases macroinvertebrate biodiversity, from a mixture of marine and freshwater species
with high total biomass in open inlets, to macrophyte and macroinvertebrate communities
with larger proportions of a few freshwater taxa with lower total biomass in
isolated bays (Hansen et al. 2008, 2012). Both seasonal variation in invertebrate biomass
and species composition have been shown to be related to Chara spp. biomass in
freshwaters (Van den Berg et al. 1997), and freshwater charophytes may also serve as
food for a number of organisms, such as herbivorous fish (Lake et al. 2002), snails (Baker
et al. 2010), water-fowl (Noordhuis et al. 2002, Schmieder et al. 2006, Matuszak et al.
2012, Rodrigo et al. 2013) and crayfish (Cirujano et al. 2004, Chucholl 2013).
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