Summary

Estimated observations of the biotope AA.M1Q2, AA.H1Q2, AA.I1Q2 and AA.J1Q2 were collected from the Baltic Sea area by expert judgements for HELCOM Red List of biotopes, habitats and biotope complexes.

Description

Baltic photic mixed substrate, mud, coarse sediment or sand dominated by stable aggregations of unattached Fucus spp. (dwarf form) The HELCOM Red List of Baltic Sea underwater biotopes, habitats and biotope complexes (2013) is an updated and improved version of the Red List assessment of marine and coastal biotopes and biotope complexes published in 1998. The classification of the report follows the proposed International Union for Conservation of Nature (IUCN) criteria and assessment principals but with some modifications for the Baltic Sea.Altogether, the HELCOM Underwater Biotope and habitat classification (HELCOM HUB) includes 209 biotopes of which 59 were red-listed. Many of the red-listed biotopes are located in deep areas of the Baltic Sea due to oxygen-free nature as well as in the southwestern Baltic Sea due to the salinity restricted distribution of species in certain biotope. The HELCOM assessment relies heavily on expert judgment and inference, and the questionnaire data represents the estimated presence-absence data not in-situ measured data. This must be taken in account when observing the map presentation. The biotopes are shown on the map using the EEA 100 km grid. This dataset displays estimated presence of AA.M1Q2, AA.H1Q2, AA.I1Q2 andAA.J1Q2according to HELCOM RED LIST assessment experts:The Fucus spp. dwarf form is known from Sweden, Finland, Germany andEstonia. In all countries plusPoland also unattached Fucus spp. occurswidespread in sheltered areas. But it is not clear for each ofthose countries, ifthese unattached forms are built of the typical F. vesiculosus morphology, thedwarfform or both forms. In Poland the unattached Fucus biotope hasdisappeared from the Puck Lagoon, soit might be difficult to clear this question.Presently this biotope is only known to occur in Sweden andGermany. InGermany it exists only in very few coastal lagoons with low to moderateeutrophicationpressures and salinities of around 7–10 psu (Vitter Bodden,Kubitzer Bodden, Wieker Bodden.Distribution map indicates the area in the 100 x 100 km grid where biotope is known to occur.AA.M1Q2, AA.H1Q2, AA.I1Q2 andAA.J1Q2have been placed in the Red List classification to the category of Critically Endangered (CR) biotopes. (Data (expert judgements) collected in HELCOM RED LIST project, released in May 2013)