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Key Message

The indicator and some of its associated threshold values are still being tested in some countries.

Further development may be necessary to make the indicator suitable in all subbasins. The current results should thus to be considered as intermediate.

 

The indicator evaluates the status of the soft-bottom macrofauna community occurring in the open sea areas of the Baltic Sea. In Northern Baltic Proper, Gulf of Finland, Eastern Gotland Basin and Western Gotland Basin only areas above the permanent halocline are assessed. The current assessment result shows good status in most of the evaluated assessment units.

The indicator is not used in coastal areas which are assessed by national methods or in areas below the halocline which should be assessed using the Oxygen debt indicator. The indicator takes into account the relative proportion of sensitive and tolerant species, as well as species richness and abundance.

The current evaluation spans the years 2011-2016, and is based on monitoring data reported by HELCOM Contracting Parties. The status of the indicator is good in all assessed subbasins, except the Bay of Mecklenburg.

 

Softbottom macrofauna Key message figure 1.png

Key message figure 1. Status assessment results based evaluation on the indicator 'State of the soft-bottom macrofauna community'. The assessment is carried out using Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). The indicator evaluates the open sea areas of the Baltic Sea. The right panel shows the open sea areas and the areas below the permanent halocline (grey) that are not assessed with this indicator. Striped assessment units are not assessed due to lack of agreed threshold values. Click here to access interactive maps at the HELCOM Map and Data Service: State of the soft-bottom macrofauna community


The confidence in the indicator result is considered to be high. The spatial data coverage is low in the Northern Baltic Proper, the Gulf of Finland and the Eastern and Western Gotland Basins. Temporal coverage of data is intermediate in all assessment units.

The indicator is applicable in the open sea areas from all countries bordering the Baltic Sea. Currently it is operational only in the evaluated areas due to the lack of agreed threshold values in some assessment units.

 

Relevance of the core indicator

Soft-sediment macrofauna species in the Baltic Sea include animals such as clams, mussels, worms and crustaceans. The animals live on the seafloor as well as burrowed into the sediments, thus forming an important link between sediments and the water column. Soft-sediment macrofauna species act as predators and decomposers and also form an important link in the marine food web by coupling the pelagic and benthic environments as well as constituting an important food source for other animals, such as fish and water birds.

This indicator evaluates the status of the environment using an index developed to show changes in the relative abundance of sensitive and tolerant species, as well as the diversity of the community in soft sediments.

 

Policy relevance of the core indicator

  BSAP Segment and ObjectivesMSFD Descriptors and Criteria
Primary link

Biodiversity

  • Thriving and balanced communities of plants and animals

 D6 Sea-floor integrity

D6C5 The extent of adverse effects from anthropogenic pressures on the condition of the habitat type, including alteration to its biotic and abiotic structure and its functions (e.g. its typical species composition and their relative abundance, absence of particularly sensitive or fragile species or species providing a key function, size structure of species), does not exceed a specified proportion of the natural extent of the habitat type in the assessment area.

D5 Eutrophication

D5C8 The species composition and relative abundance of macrofaunal communities, achieve values that indicate that there is no adverse effect due to nutrient and organic enrichment.

Secondary link 

D4 Food-web

D4C1 The diversity (species composition and their relative abundance) of the trophic guild is not   adversely affected due to anthropogenic pressures.

 

Cite this indicator

HELCOM (2018). State of the soft-bottom macrofauna community. HELCOM core indicator report. Online. [Date Viewed], [Web link].

ISSN 2343-2543

 

Download full indicator report

State of the soft-bottom macrofauna community HELCOM core indicator report 2018 (pdf).