BSEP116B Biodiversity in the Baltic Sea - Helcom

4.3.2 Conclusions
Long-term data on the population development
of bird species in the Baltic Sea show
that a more or less stable status quo never has
existed. Dynamic changes in terms of the range
and size of populations are characteristic. Some
of the observed long-term changes can clearly
be attributed to persecution or impacts on the
reproductive success caused by hazardous substances.
Other anthropogenic factors, such as
loss of habitats, introduction of non-native predatory
mammals, oil spills and by-catch in fishing
gear, may also affect bird populations. On the
other hand, human land-use management may
promote certain species: high nutrient inflows
from the catchment area have resulted in an
increased biomass production in the Baltic and
improved the feeding conditions for some species
(e.g., cormorant). Last but not least even fishery
practices may have advantageous effects for
birds: the good status of auks is, at least partly,
attributed to the growth of the sprat stocks
owing to overfishing of cod.
However, not all population developments of bird
species in the Baltic Sea can be solely attributed
to anthropogenic factors. The decline of dunlin
and ruff, the fluctuations of wintering populations
of Steller’s eider, and the range expansion into
the Baltic of sandwich tern, herring gull (Larus
argentatus) and barnacle goose are examples of
population developments that are obviously not,
or at least not primarily, driven by human activities.
Global factors such as climate change or
environmental changes in breeding areas outside
the Baltic Sea certainly also exert a strong impact
on the range and population size of bird species.
White-tailed eagle (Haliaeetus albicilla)
4.3.3 Recommendations
Conservation measures should focus on those
species that are negatively affected by anthropogenic
factors such as habitat loss, deliberate or
incidental killing, or hazardous substances.
In order to reach a ’favourable conservation
status of Baltic Sea biodiversity‘, the protection
of important bird habitats, including breeding,
resting and wintering sites, is necessary.
The establishment of an ecologically coherent
network of Baltic Sea Protected Areas (BSPA),
Natura 2000 areas and Emerald sites in the Baltic
Sea by 2010 is an important step towards the
protection of these sites.
Strategic approaches to the conservation of birds
in the Baltic Sea need to acknowledge the dynamics
of their populations with respect to range and
size. They should focus on anthropogenic factors
that are known to have adverse impacts on bird
populations or that are considered as potential
threats. It must be recognized that the decline of
some species (e.g., dunlin, ruff in the southern and
western Baltic) must be attributed to reasons other
than direct anthropogenic impacts such as habitat
destruction or contamination. It will probably
not be possible to reverse the negative population
trend of these species by nature conservation
measures.
Restoration and adequate management of
degraded areas, especially coastal meadows and
wetlands, are also important measures to improve
habitat conditions for birds.
The BSAP target “By 2012 spatial/temporal and
permanent closures of fisheries of sufficient size/
duration are established throughout the Baltic
Sea area” should consider the serious impact of
the gillnet fishery in wintering areas of seabirds;
seasonal closures of gillnet fisheries in areas
with high seabird concentrations are required to
achieve the target “by-catch rates of water birds
close to zero by 2015”.
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