BSEP116B Biodiversity in the Baltic Sea - Helcom

Implications for the Baltic Sea Action Plan
HELCOM has acknowledged the need for the
mapping of important marine species and habitats
in the Baltic Sea. The BSAP states that the goal
is, by 2013, to identify and map the distribution
of a number of habitat-forming species, including
bladder wrack (Fucus vesiculosus), eelgrass
(Zostera marina) and blue mussel (Mytilus trossulus).
This work has already been initiated and the
experiences to date suggest that spatial modelling
is a promising tool, even though a large effort is
still needed to provide better input data for the
models.
In order to achieve the goal of the BSAP by 2013, it
may be necessary in some cases to produce a first
generation of somewhat coarser maps if the input
maps are not of sufficient quality or detail. During
the production of these maps, the shortcomings
in the input data should be analysed and efforts
to improve the data sets should be suggested. A
second generation of maps with higher quality and
detail may be produced when the input data sets
have been improved.
3.2.3 Conclusions
The conservation status of several habitat-forming
species (e.g., bladder wrack, stoneworts and eelgrass)
in the Baltic Sea as a whole is unfavourable.
Declines in species abundances as well as distribution
area have been recorded recently. The most
problematic areas seem to be the southernmost
Chara sp., Archipelago Sea, Finland
areas of the Baltic Sea. In contrast, coastal areas of
the northern Baltic Proper show recent improvements
and here the natural distribution of several
functionally and structurally important species has
almost been achieved.
The use of spatial modelling in marine applications
has increased rapidly in recent years and is now a key
tool in mapping the marine environment. Modelling
will be used not only to map the current state, but
also the changes in the distribution of species and
habitats in response to environmental changes. To be
able to use the full potential of this tool, much effort
must also be put into collating existing data and
collecting new data on species and environmental
parameters covering the Baltic Sea.
3.2.4 Recommendations
The number of habitat-forming species in the Baltic
Sea is relatively low and, in case of decline or disappearance,
there are no other species that can fully
replace their function in the ecosystem. In order to
achieve the targets set by the BSAP and to reach
a favourable conservation status of all habitatforming
species, the most important human pressures
that should be mitigated are eutrophication
caused by anthropogenic nutrient enrichment, and
physical damage and fragmentation of the coastal
zone caused by numerous human activities. To
follow up progress towards the targets of the BSAP,
it is crucial to establish effective monitoring as well
as a system of regular assessment of the status of
habitat-forming species.
It is recommended that effort be put into the production
of high-quality maps of structuring environmental
factors. This includes environmental factors
that are important at the local scale (bathymetry,
wave exposure, surface sediment, etc.), but also
additional factors that are known to influence the
species distributions on the regional scale, including
salinity and climatic factors.
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There is also a need for additional geographically
representative field data on species, providing good
coverage of all existing environments. Many data can
likely be assembled from existing data sets collected
by national inventory and monitoring programmes. If
the data abundance is low in certain habitat types or
regions, there will also be a need for more data collection
based on identified data deficiencies.