Draft online platform (Fact Sheet)
1. Habitat type
code & name
AA.H1B Baltic photic muddy sediment characterized by submerged rooted plants
Photo of habitat type
 Please upload 1 or 2 photos of the habitat type
 Photo description (describe habitat and location of the photo):
No photograph currently available for this habitat.
Habitat definition
A description of the habitat’s distribution, characteristic native biota, abiotic features, key ecological
processes and interactions.
Subheaders are:
 Description
 Characteristic species
 European Vegetation Checklist alliances (only for terrestrial types)
 Indicators of quality
1
Description
Baltic bottoms in the photic zone with at least 90 % coverage of muddy sediment. The
sediment must contain at least 20 % of mud, silt or clay (grain size less than 63 µm). Submerged
rooted plants, including plants with rhizoids (i.e. Charales) cover at least 10 % of the seabed
and more than other perennial attached erect groups. Substrate is muddy sediment. Salinity
range: all; Exposure range: low.
Eight sub-biotopes with different dominant (>50% of the biovolume) macrophyte taxa can be
identified. The sub-biotopes differ in their distribution along gradients in salinity, depth and
wave exposure. The sub-biotope AA.H1B5 ’Baltic photic muddy sediment dominated by spiny
naiad (Najas marina)’ has a restricted distribution at 0-1 m depth in extremely sheltered areas
at low salinity (<4 psu). The sub-biotope AA.H1B8 ’Baltic photic muddy sediment dominated by
spikerush (Eleocharis spp.)’ is also found in shallow (0-2 m depth) and sheltered areas with low
salinity (<5 psu).
The sub-biotope AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed
(Potamogeton perfoliatus and/or Stuckenia pectinata)’ is found between 0.2-4 m depth in
sheltered sites with up to 6 psu. The sub-biotope AA.H1B3 ‘Baltic photic muddy sediment
dominated by watermilfoil (Myriophyllum spicatum and/or Myriophyllum sibiricum)’ has a
similar distribution but a more narrow depth range (0.2-2 m). AA.H1B6 ’Baltic photic muddy
sediment dominated by Ranunculus spp.’ is also found up to 6 psu but is restricted to
extremely sheltered sites.
The sub-biotope AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’ is found in a
wider range of salinity (2-15), depth (0.2-7 m) and wave exposure (low to moderate). Which
species dominate depend partly on the salinity range, the kind of sediment but also on the
growth season. The sub-biotope AA.H1B2 ’Baltic photic muddy sediment dominated by
Zannichellia spp. and/or Ruppia spp. and/or Zostera noltii’ is found at 0-4 m depth throughout
the salinity gradient of the Baltic Sea and in low to moderate exposure.
The subbiotope AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass
(Zostera marina)’ differs most strongly from the other sub-biotopes in distribution, occuring
mainly at moderate to high exposure and in salinities of 5 psu or higher. The sub-biotope is
typically found deeper than the other sub-biotopes (1-6 m) and often marks the lower depth
limit distribution of soft bottom vegetation. The sub-biotope is absent from areas with low
salinity in the Gulf of Finland and Gulf of Bothnia.
Characteristic species
Stuckenia pectinata, Potamogeton perfoliatus, Zostera marina, Ruppia maritima, Zanichellia
palustris, Myriophyllum spicatum, Najas marina, Chara tomentosa, Ranunculus peltatus subsp.
baudotii, Eleocharis sp.
Indicators of quality
-
Classification
Please indicate equivalent classification types as relevant, including:
2









EUNIS type
Annex 1 type of the Habitats Directive
IUCN Habitats Classification Scheme
Emerald type
Marine Strategy Framework Directive type
EUSeaMap type
European Forest Type
MAES type (level 2)
Other types...
Annex 1 relationships
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped by
HELCOM.
MAES relationships
Marine - Marine inlets and transitional waters
Marine - Coastal
MSFD relationships
Littoral sediment
Shallow sublittoral mud
EUSeaMap relationships
Shallow muds
IUCN ecosystem relationships
9.6 Subtidal Muddy
9.9 Seagrass
Other relationships
Correspondence to EUNIS (2004) depending on subhabitat:
A5.54 Angiosperm communities in reduced salinity
A5.542 Association with [Potamogeton pectinatus]
A5.543 Vegetation of brackish waters dominated by [Ranunculus baudotii]
A5.5343 [Ruppia maritima] in reduced salinity infralittoral muddy sand
A5.545 [Zostera] beds in reduced salinity infralittoral sediments
Level 5 of the HELCOM HUB classification (2013). This habitat has eight sub-habitats on HUB
level 6;
AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed (Potamogeton perfoliatus
and/or Stuckenia pectinata)’
AA.H1B2 ’Baltic photic muddy sediment dominated by Zannichellia spp. and/or Ruppia spp.
and/or Zostera noltii’
3
AA.H1B3 ‘Baltic photic muddy sediment dominated by watermilfoil (Myriophyllum spicatum
and/or Myriophyllum sibiricum)’
AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’
AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’
AA.H1B6 ’Baltic photic muddy sediment dominated by Ranunculus spp.’
AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’
AA.H1B8 ’Baltic photic muddy sediment dominated by spikerush (Eleocharis spp.)’

Does the habitat type present an outstanding example of typical characteristics of one or more
biogeographic regions?
Please tick () one box only:
(A habitat represents an outstanding example of typical characteristics of one or more
biogeographical regions, if it is especially characteristic of one or more biogeographic regions, in
terms of area, species composition, structure or functioning).
YES :
NO:
UNKNOWN:

 If Yes – please indicate the regions
For terrestrial types:
Alpine
Atlantic
Black Sea
Boreal
Continental
Macaronesia
Mediterranean
Pannonian
Steppic
For marine types:
Marine Atlantic
Marine Baltic
Marine Black Sea
Marine Macaronesia
Marine Mediterranean

Justification:
The biotope is common on photic muddy sediment in the entire Baltic Sea. Most of the
subbiotopes have a very typical and characteristic species composition for the Baltic
Sea with a dominance of species with freshwater origin.
4
2. Geographic occurrence and trends
Distribution map (in 10x10 km grids) of the habitat type in Europe (provided by Alterra/ NatureBureau)

For both terrestrial and marine types, please tick () the countries in which the habitat type is
present based on the territorial data sheets (please select “Present” or “Presence Uncertain” as
relevant)
EU 28
Austria
Belgium
Bulgaria
Croatia
Czech Republic
Cyprus
Denmark
Estonia
Finland
Finland mainland
Åland Islands
France
France mainland
Corsica
Germany
Greece
Greece (mainland and other islands)
Crete
East Aegean islands
Hungary
Ireland
Italy
Italy mainland
Sardinia
Sicily
Latvia
Lithuania
Luxembourg
Malta
Netherlands
Poland
Portugal
Portugal (mainland)
Azores
Madeira
Savage Islands
Romania
Slovakia
Slovenia
Spain (mainland)
Spain
Balearic Islands
Canary Islands
Sweden
United
Great Britain
5
Kingdom
Northern Ireland
Gibraltar
EU 28+
Albania
Andorra
Bosnia and Herzegovina
Faroe Islands
Guernsey
Iceland
Isle of Man
Jersey
Kaliningrad
Kosovo
Liechtenstein
Former Yugoslavian Republic of Macedonia (FYROM)
Monaco
Montenegro
Norway (mainland)
Norway
Svalbard
Jan Mayen
San Marino
Serbia
Switzerland
Vatican City

For marine habitats, please tick () the MSFD region and subregion in which the habitat type
occurs (please select “Present” or “Presence Uncertain” as relevant):
Mediterranean Sea
Black Sea
North-East Atlantic
Baltic Sea
Adriatic Sea
Aegian-Levantine Sea
Ionian Sea and the Central Mediterranean Sea
Western Mediterranean Sea
Black Sea
Sea of Marmara
Bay of Biscay and the Iberian Coast
Celtic Seas
Kattegat
Greater North Sea
Macaronesia
Baltic Proper 
Belt Sea 
Gulf of Bothnia 
Gulf of Finland 
Gulf of Riga 
The Sound 
6

Is the list of countries/seas selected above in correspondence with the provided map?
Please tick () the box confirming that a consistency check has been done:

For EU 28 and EU 28+:
1. Using the distribution map, the Project Management Team will provide the value for Extent
of Occurrence (extent of a minimum convex polygon enclosing all occurrences) and for Area
of Occupancy (number of 10*10 km cells occupied by the habitat type).
2. Using the territorial data sheets (along with additional information if relevant), please
provide the estimated total area (actual area in km2 of the habitat), calculated by adding up
the area of the habitat type in each country/sea.
Extent of
Occurrence
(EOO)
Area of
Occupancy
(AOO)
Current
estimated Total
Area (km2)
Comments
EU 28
EU 28+

How much of the current distribution of the habitat type lies within the EU 28?
Please estimate in percentage the proportion of the habitat type that the EU28 hosts in relation to
the habitat type’s total worldwide distribution. For the marine types this is (by definition)
compared to the total area within EU28+.
95%
Trends in quantity
Using the territorial data and any other relevant information, please describe the historical, recent and
estimated future trends in quantity (extent, distribution).
Current: The biotope is common in most parts of the Baltic Sea. Most subbiotopes are
present across the Baltic Sea coastline but the subbiotope AA.H1B7 ’Baltic photic
muddy sediment dominated by common eelgrass (Zostera marina)’ is absent from
areas with low salinity in the Gulf of Finland and Gulf of Bothnia.
Recent: The subbiotope AA.H1B4 ’Baltic photic muddy sediment dominated by
Charales’ has declined by >25% during the last 50 years. The biotope has declined to
a varying extent in different Baltic Sea regions with the strongest decline in the Western
and Southern Baltic Sea. In some bays and lagoons conditions have changed so
intensively that the biotope has disappeared completely.
7
The subbiotope AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad
(Najas marina)’ has exhibited a strong decline in the highly eutrophicated areas of the
Southern Baltic Sea and it is even known to have disappeared. A comparison of the
current with the historical distribution status of Najas marina within the German Bodden
areas of Mecklenburg Western Pomerania (Southern Baltic Sea) resulted in a nearly
total loss of the biotope. There are no data to support similar declines in other Baltic
Sea areas but the biotope is largely restricted to lagoons which is an endangered
biotope complex.
The subbiotope AA.H1B7 ’Baltic photic muddy sediment dominated by common
eelgrass (Zostera marina)’ has declined >25% during the last 50 years. The biotope
has declined to varying extents in the different Baltic Sea regions, with the largest
decline recorded in the Southern Baltic Sea.
The remaining subbiotopes have declined less than 25% during the last 50 years.
Historical: No data available.
Future: No estimates available.

Average current trend in quantity (extent):
EU 28
EU 28+

Stable
Increasing
Decreasing
Unknown 
Stable
Increasing
Decreasing
Unknown 
Does the habitat type have a small natural range following regression?
Please tick () one box only:
(The habitat has a small natural range following regression if the EOO ≤ 50,000 km² and the habitat
has undergone an important decline during the last 50 years)
YES :
NO:
UNKNOWN:

Justification (please indicate whether the decline is ongoing or has stopped, and provide any additional
supporting information):
8

Does the habitat have a small natural range by reason of its intrinsically restricted area?
Please tick () one box only:
(A habitat has a small natural range by reason of its intrinsically restricted area if the underlying
factors for the occurrence of the habitat occupy a very limited area and range)
YES :
NO:
UNKNOWN:

Justification:
3. Habitat condition and trends
Please describe the current quality of the habitat type, historical trends in quality and estimated future
trends. Use and build on the information from the territorial data sheets and the quality indicators from
the description.
The quality of the biotope has declined during the past 50 years, at least in some areas,
but there are no consistent data to quantify the decline.

Average current trend in quality:
EU 28
EU 28+
Stable
Increasing
Decreasing
Unknown 
Stable
Increasing
Decreasing
Unknown 
4. Country/regional sea trends
9
Using the territorial data sheets please indicate at the country or regional sea levels if the trends in
quantity and quality are increasing, decreasing, stable or unknown.
Current area of Recent trend in
habitat (km2) quantity (last 50 yrs)
Baltic
Sea

No data
No data
Recent trends in
quality (last 50 yrs)
No data
Please upload all the territorial data sheets for this habitat type
5. Pressures and threats
Indicate in the look-up table below (provided by Doug Evans and based on Article 17/MSFD) the five
most significant threats affecting the habitat and whether these are of past, current or future
importance.
In the accompanying text field below, indicate the main causes of the threats affecting the habitat and
their scale of significance within the EU 28 and EU 28+. Use and build on the information from the
territorial data sheets and other available information.
Past and Current Threats (Habitat directive article 17):
Eutrophication (H01.05), Epidemics (wasting disease; K03.03), Fishing (bottom trawling
F02.02.01), Water traffic (D03, G01), Construction sand extraction C01.01, dredging J02.02.02,
dumping J02.11.01, dykes, embankments and artificial beaches J02.12), Ditching (J02.01),
Other threat factors (aquaculture F01)
Future Threats (Habitat directive article 17):
Eutrophication (H01.05), Fishing (bottom trawling F02.02.01), Epidemics (wasting disease;
K03.03), Ditching (J02.01), Water traffic (D03, G01), Construction (sand extraction C01.01,
dredging J02.02.02, dumping J02.11.01, J02.12, modification of hydrographic function J02.05,
dykes, embankments and artificial beaches J02.12), Other threat factors (aquaculture F01),
Climate change (M02), Oil spills (oil spills in the sea H03.01)
Observed declines of the spatial distribution of the subbiotopes AA.H1B4 ’Baltic photic muddy
sediment dominated by Charales’ and AA.H1B5 ’Baltic photic muddy sediment dominated by
spiny naiad (Najas marina)’ are mainly caused by increased eutrophication and connected
effects. Decreasing light penetration depth, massive growth of ephemeral algae and increased
siltation rates cause massive alterations in the biotopes of sheltered coastal areas. The
enclosed characteristic of bays and lagoons intensify the eutrophication impacts. Coastal
10
constructions (e.g. dredging for deepening of harbour access channels, ditching and
construction of leisure facilities) and increased tourism has led to a further degradation of the
biotope. The threat level is particularly high in the Western and Southern Baltic Sea. In the
future climate change (increasing exposure levels, temperatures) or increasing aquaculture in
bays may cause additional threats.
The main causes of the observed declines of the spatial distribution of the subbiotope AA.H1B7
’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’ are (1) the
“wasting disease” that caused about 90% of the North European stock to disappear in the 1930
and also affected the Zostera beds in Danish waters (Möller 2008) and (2) eutrophication of the
Baltic Sea that has resulted in significant decline of eelgrass meadows in mainly Danish,
German, Swedish and Polish coastal areas (Möller 2008). Eutrophication has decreased the
depth where Zostera dominated biotopes can receive enough light and may in addition cause a shift
from eelgrass meadows to communities dominated by fast-growing macro-algae. Climate
change is predicted to lower the salinity level in the northern parts of the Baltic Sea due to an
increase of precipitation, which may threaten Zostera marina in the northernmost areas where
it currently exists on the limits of its salinity tolerance (HELCOM 2013).
6.
Con
ser
vati
on
and
ma
nag
em
ent
Please describe the main (e.g. no more than 5) current approaches to conservation and management of
this habitat type, and outline what additional actions are needed.
All actions to reduce eutrophication of the Baltic Sea are important for the conservation of the declining
subbiotopes. For the subbiotopes that mainly occurs in bays with limited water exchange with the open
ocean (subbiotopes AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’ and AA.H1B5
’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’), combatting local sources of
eutrophication is essential. Conservation measures are also important, such as area protection and
restrictions on coastal constructions and dredging in shallow coastal lagoons and archipelago areas.
 Conservation and management needs
Please tick the main essential and realistic conservation and management actions needed for the habitat
type (following the description provided above). The actions should be selected only if they are relevant
to the conservation of the particular habitat being assessed (the classification below is derived from the
Habitats Directive Article 17 reporting)
Code
1
1.1
1.2
1.3
Measure
Examples
No measures
No measures needed for the conservation of the
habitat/species
Measures needed, but not implemented
No measure known/ impossible to carry out
specific measures
species migrations, habitat changes due to climate change,
glacier retreat, monitoring changes without intervention
11
2
Measures related to agriculture and
open habitats
2.0
2.1
Other agriculture‐related measures
Maintaining grasslands and other open habitats
2.2
Adapting crop production
3
Measures related to forests and
wooded habitats
3.0
3.1
Other forestry‐related measures
Restoring/improving forest habitats
3.2
Adapt forest management
4
Measures related to wetland,
freshwater and coastal habitats
4.0
4.1
4.2
Other wetland‐related measures
Restoring/improving water quality
Restoring/improving the hydrological regime
4.3
Managing water abstraction
4.4
Restoring coastal areas
5
Measures related to marine habitats
5.0
5.1
6
Other marine‐related measures
Restoring marine habitats
mowing, burning, grazing, removal/control of shrubs and
other woody plants
adapting input of nutrients and pesticides/herbicides;
adapting crop timing (advance/delay harvest dates)
replanting with autochthonous species, enable/
promote natural re‐growth, removing non‐natives
species, change single species and even‐aged stands
into multi‐species and uneven‐aged stands, burning/
maintaining a fire regime
adapting harvesting cycles, adapting techniques and
equipment
restoring alluvial situations,
reducing eutrophication
restoring river dynamics, removal of barriers and artificial
margins, managing water levels (e.g. in bogs and mires)
managing periods and/or quantity of water abstracted for
irrigation, energy production
stabilisation of dunes, re‐establishing dune dynamics,
removing coastal infrastructures
Restoration can be a viable mesure for the subbiotope
characterized by Zostera marina
Measures related to spatial planning
6.0
6.1
6.2
Other spatial measures
Establish protected areas/sites
Establishing wilderness areas/ allowing
succession
6.3
Legal protection of habitats and species
6.4
Manage landscape features
6.5
Adaptation/ abolition of military land use
no intervention after calamities, natural catastrophic
events, succession where no management is
necessary
legal habitat type protection (regardless where they
occur, also outside protected areas), strictly legally
protected species including their habitats
maintenance or creation of hedges, tree lines,
corridors
nature management on military training grounds,
abolition of military use
12
7
Measures related to hunting, taking and
fishing and species management
7.0
7.1
Other species management measures
Regulation/ Management of hunting and
taking
7.2
Regulation/ Management of fishery in limnic
systems
7.3
Regulation/ Management of fishery in marine
and brackish systems
Specific single species or species group
management measures
7.4
8
Measures related to urban areas,
industry, energy and transport
8.0
Other measures
8.1
8.2
Urban and industrial waste management
Specific management of traffic and energy
transport systems
8.3
Managing marine traffic
9
Measures related to special resource use
9.0
9.1
Other resource use measures
Regulating/Management exploitation of natural
resources on land
Regulating/Managing exploitation of natural
resources on sea
9.2

regulation of hunting (periods, species), collection
permits for plants, berries etc., regulation of game
density
regulation of amount, fish species & catching
methods allowed, removal of certain fish species,
control of measures for enhancing fish production,
maintenance of traditional fish pond systems
adapting fishing techniques and equipment
Management of coastal constructions (e.g. dredging
for deepening of harbour access channels, ditching
and construction of leisure facilities)
measures to reduce collision, maintenance of semi
natural roadsides, protection of birds on high voltage
systems, regulations to manage traffic density
Prohibition of anchoring
management of quarries with amphibians,
wind exploitation
managing oil, gas, gravel/sand, wind exploitation on
sea
Conservation status
Please indicate the overall conservation status in the relevant biogeographical regions of all related
Annex 1-types according to the Habitats Directive. For marine types, please also indicate the OSPAR
or Helcom status if relevant.
13
The habitat has eight subhabitats which according to HELCOM Red List Assessment 2013 are given the
following threat categories:
AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed (Potamogeton perfoliatus and/or
Stuckenia pectinata)’: LC (A1)
AA.H1B2 ’Baltic photic muddy sediment dominated by Zannichellia spp. and/or Ruppia spp. and/or
Zostera noltii’: LC (A1)
AA.H1B3 Baltic photic muddy sediment dominated by watermilfoil (Myriophyllum spicatum and/or
Myriophyllum sibiricum)’: LC (A1)
AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’: NT (A1)
AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’: NT (A1)
AA.H1B6 ’Baltic photic muddy sediment dominated by Ranunculus spp.’: LC (A1)
AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’: NT (A1)
AA.H1B8 ’Baltic photic muddy sediment dominated by spikerush (Eleocharis spp.)’: LC (A1)

When severely damaged, does the habitat retain the capacity to recover its typical character and
functionality? Estimate the time taken for such recovery (1) naturally and (2) through intervention.
Please fill in the matrix below.
Justification (please also describe the specific resources and actions required to recover the habitat,
if possible):
The subbiotope AA.H1B7 ’Baltic photic muddy sediment dominated by common
eelgrass (Zostera marina)’ can be slow to recover after strong decline (>20 yrs) and
intervention may speed up the recovery. For the other subbiotopes natural recovery can
probably occur within 10 years. (According to expert opinion by S.Wikström, 2014).
Time
(years)
None
Low
Effort required
Medium
High
10 yrs
20 yrs
50+ yrs
200+ years
7. Synopsis
Please synthesize the relevant information obtained from the territorial data sheets and other sources in
order to facilitate the assessment process.
Input data:
-
HELCOM Questionnaire raw data
-
Expert opinion
-
Subsequent expert discussions in the HELCOM Red List of Biotopes assessment
-
HELCOM Biotope information sheets for biotopes AA.H1B4 ’Baltic photic muddy
14
sediment dominated by Charales’, AA.H1B5 ’Baltic photic muddy sediment dominated
by spiny naiad (Najas marina)’ and AA.H1B7 ’Baltic photic muddy sediment dominated
by common eelgrass (Zostera marina)’
8. Red List assessment
Criterion A: Reduction in quantity
Please indicate in the table below the percentage of decline obtained after applying Criterion A, as far as
data are available. Explain the percentage and provide any supporting evidence, including the map base
or other source(s) used to estimate change in distribution. If A2b was applied, please also give the
beginning and end (in years) of the 50-year period over which the decline was measured. Please cite
data sets and other sources of information used; if the primary data has not been published, please
provide a copy for archive to support future re-assessments.
Criterion A
EU 28
EU 28+
A1
>25%
>25%
A2a
NoData
NoData
A2b
NoData
NoData
A3
NoData
NoData
The values above were calculated based on collected data, expert judgement and expert
discussions.
The assessment is only made on the subbiotopes AA.H1B4 ’Baltic photic muddy sediment
dominated by Charales’, AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad
(Najas marina)’ and AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass
(Zostera marina)’ that have the highest threat category.
For the remaining subbiotopes the estimated decline was <20% during the past 50 years (A1).
Criterion B: Restricted geographic distribution
Please indicate in the table below the values obtained after applying Criterion B, as far as data are
available. Explain the values and provide any supporting evidence. If B1a or B2a is used, please indicate
which subcriteria (i, ii and/or iii) this is based on. If B1b or B2b is used, please explain the threatening
processes and their effects. If B3 is used, please give the most serious plausible threat and justify how it
will cause the habitat to become Critically Endangered or Collapsed, including the time frame in which
this could occur. Please cite data sets and other sources of information used; if the primary data has not
been published, please provide a copy for archive to support future re-assessments.
Criterion
B1
B2
B3
15
B
EU 28
EU 28+
EOO
NoData
NoData
a
NoData
NoData
b
NoData
NoData
c
NoData
NoData
AOO
NoData
NoData
a
NoData
NoData
b
NoData
NoData
c
NoData
NoData
NoData
NoData
Criteria C and D: Reduction in abiotic and/or biotic quality
Please indicate in the table below the percentage of change in abiotic and/or biotic quality. Please
report them together (criterion C/D), but if possible, also report abiotic (criterion C) and biotic (criterion
D) percentages separately.
Please explain the resulting values obtained, and provide any supporting evidence. Whenever possible,
please identify the abiotic environmental and/or biotic ecological factor(s) and data sources used to
assess reduction in quality. If criteria C/D2, C2 or D2 are used, please define the 50-year time period
over which the reduction was measured. Please cite data sets and other sources of information used; if
the primary data has not been published, please provide a copy for archive to support future reassessments.
C/D1
Criteria C/D
EU 28
EU 28+
Criterion C
EU 28
EU 28+
Criterion D
EU 28
EU 28+
Extent
affected (%)
No data
available
No data
available
Relative
severity
No data
available
No data
available
C1
Relative
Extent
severity
affected (%)
(%)
No data
No data
available
available
No data
No data
available
available
D1
Relative
Extent
severity
affected (%)
(%)
No data
No data
available
available
No data
No data
available
available
C/D2
Extent
Relative
affected
severity
(%)
No data
No data
available
available
No data
No data
available
available
C2
Extent
Relative
affected
severity
(%)
(%)
No data
No data
available
available
No data
No data
available
available
D2
Extent
Relative
affected
severity
(%)
(%)
No data
No data
available
available
No data
No data
available
available
C/D3
Extent
affected
(%)
No data
available
No data
available
Extent
affected
(%)
No data
available
No data
available
Extent
affected
(%)
No data
available
No data
available
Relative
severity
No data
available
No data
available
C3
Relative
severity
(%)
No data
available
No data
available
D3
Relative
severity
(%)
No data
available
No data
available
16
Criterion E: Quantitative analysis to evaluate risk of habitat collapse
Describe the method/model used to estimate risks of habitat collapse. Please explain the resulting
values obtained, specify the basis and provide any supporting evidence. Please cite data sets and other
sources of information used; if the primary data has not been published, please provide a copy for
archive to support future re-assessments.
Criterion E
EU 28
EU 28+
E
No data
available
No data
available
No quantitative analysis has been carried out for this habitat.
Overall assessment “Balance sheet” for EU 28 and EU 28+ 1
Please complete the table below, indicating the Red List Category that the habitat type qualifies for,
after assessing the habitat types against all criteria for which data is available. If any criteria were not
applied, the habitat type should be considered Data Deficient (DD) under those criteria.
Category
EU
28
EU
28+
A1
NT
NT
A2a
DD
DD
A2b
DD
DD
A3
DD
DD

1
Category
EU
28
EU
28+
B1
DD
DD
B2
DD
B3
DD
Category
EU
28
EU
28+
C/D1
DD
DD
DD
C/D2
DD
DD
C/D3
DD
Category
EU
28
EU
28+
C1
DD
DD
DD
C2
DD
DD
C3
DD
Category
EU
28
EU
28+
D1
DD
DD
DD
D2
DD
DD
DD
D3
DD
DD
Category
E
EU
28
EU
28+
DD
DD
Overall Category &
Criteria
EU 28
NT
A1
Synthesis
Provide a summary of the reasons why the habitat type qualifies for the Category and Criteria
recorded above, justifying assessment decisions, limits of data quality, reliability of assessment,
etc.), using the information from above.
This table possibly will be filled automatically in the online platform
17
EU 28+
NT
A1
This habitat type has been listed as Near Threatened A1 based on the subbiotopes AA.H1B4
’Baltic photic muddy sediment dominated by Charales’, AA.H1B5 ’Baltic photic muddy sediment
dominated by spiny naiad (Najas marina)’ and AA.H1B7 ’Baltic photic muddy sediment
dominated by common eelgrass (Zostera marina)’ that have the highest threat category.
During the last 50 years the distribution of the three Near Threatened biotopes has declined
>25%. The biotopes have declined to varying extents in the different Baltic Sea regions with the
strongest decline in the Western and Southern Baltic Sea. In some bays and lagoons conditions
have changed so intensively that the biotopes have disappeared completely.
The other subbiotopes have been assigned threat category Least Concern based on A1
(HELCOM Red list assessment 2013). The assessment was based on collected data, expert
judgement and expert discussions.

Please indicate the confidence in the assessment; please tick () one box only:
Low
(mainly based on uncertain or indirect information, inferred and
suspected data values, and/or limited expert knowledge)
Medium
(evenly split between quantitative data/literature and uncertain
data sources and assured expert knowledge)
High
(mainly based on quantitative data sources and/or scientific
literature)


Sub-habitat types that may require further examination
Indicate and specify if any sub-types of the assessed habitat type may require further examination
due to their particular character or potentially threatened status. These may be subtypes in a
specific region, or thematic subtypes, having a certain specific species composition or structure.
AA.H1B1 ’Baltic photic muddy sediment dominated by pondweed (Potamogeton perfoliatus and/or
Stuckenia pectinata)’
AA.H1B2 ’Baltic photic muddy sediment dominated by Zannichellia spp. and/or Ruppia spp. and/or
Zostera noltii’
AA.H1B3 Baltic photic muddy sediment dominated by watermilfoil (Myriophyllum spicatum and/or
Myriophyllum sibiricum)’
AA.H1B4 ’Baltic photic muddy sediment dominated by Charales’
AA.H1B5 ’Baltic photic muddy sediment dominated by spiny naiad (Najas marina)’
AA.H1B6 ’Baltic photic muddy sediment dominated by Ranunculus spp.’
AA.H1B7 ’Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)’
AA.H1B8 ’Baltic photic muddy sediment dominated by spikerush (Eleocharis spp.)’

Assessors
Please indicate the names of the individuals that have assessed the status of the habitat type (the
working group members, first name is the member tasked to write up the draft assessment).
18
HELCOM RED LIST Biotope Expert Team 2013 and Baltic Sea Working Group for the European
Red List of Habitats 2014 and Sofia Wikström.

Contributors
Please indicate the names of the individuals that have contribute to the assessments (including
providers of territorial data, and providers of descriptions of types, and any other contributors).
HELCOM RED LIST Biotope Expert Team, November 2013.

Reviewers
Please indicate the names of the individuals that have reviewed the assessment.

Dates of the assessment
Please indicate the date when the habitat type was assessed (WG assessment workshop and/or
synthesis workshop if changes are made in a later stage).
November 2013.

Date of review
Please indicate the date when the habitat type assessment was peer-reviewed.
9. References
Provide a list of all published and unpublished reference sources used for the information recorded
above, including data sets and other sources of information. If the primary data has not been published,
please provide a copy for archive to support future re-assessments. Please provide full references, and
try to avoid abbreviations (e.g. write Conservation Biology rather than Cons. Biol.).
HELCOM 2013. Red List of Baltic Sea underwater biotopes, habitats and biotope complexes.
Baltic Sea Environmental Proceedings No. 138.
19