The indicator and some of its associated threshold values are still being tested in some countries and may be further developed in HELCOM as a result of the outcome of the testing, or the results may show that the indicator is not suitable for use in a specific sub-basin. The results should thus to be considered as intermediate.
The indicator evaluates the status of the soft-bottom macrofauna community above the permanent halocline in the open sea areas of the Baltic Sea. 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 are 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 2011-2015, and is based on monitoring data reported by the Contracting Parties of HELCOM. The status of the indicator is good in all assessed sub-basins, except the Bay of Mecklenburg.
Key message figure 1: Status assessment results based evaluation of 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) so that the indicator is only applicable in the open sea assessment units. National indicators are used to assess the coastal assessment units.
The confidence of the indicator evaluation varies between the sub-basins. The spatial representativity of the data is low in Northern Baltic Proper, Gulf of Finland and Eastern and Western Gotland Basins.
The indicator is applicable in the open sea waters of all countries bordering the Baltic Sea but operational only in the evaluated areas due to the lack of threshold values in some of the assessment units.
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 soft sediments, thus forming an important link between the sediment and the water column. Soft-sediment macrofauna also forms an important link in the marine food web by constituting an important food source for other animals such as fish and water birds, as well as acting as predators and decomposers.
This indicator evaluates the status of the environment through 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.
BSAP segment and objectives
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.
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
D4C1 The diversity (species composition and their relative abundance) of the trophic guild is not adversely affected due to anthropogenic pressures
HELCOM (2017). State of the soft-bottom macrofauna community. HELCOM core indicator report. Online. [Date Viewed], [Web link].
II component - Core indicator report – web-based version July 2017 (pdf)