The purpose of this action plan is to improve conditions for viable populations of the following three species of charophytes in Sweden:
Chara horrida is found in brackish water along the Baltic sea coast, from the border between the counties of Scania (Skåne) and Blekinge in the south to Uppland in the north, including the shores of the Baltic islands of Öland and Gotland. Chara horrida is probably endemic to the Baltic Sea. Outside Sweden, the species has only been found in a small number of sites in Denmark, Germany, Estonia and Finland.
Chara braunii is a freshwater species. Today its main Swedish population is found in very low salinity areas in the Bothnian Bay, where conditions much resemble freshwater habitats. Lamprothamnium papulosum is a very rare marine species that in Sweden presently only occurs in Bohuslän on the west coast.
Charophytes grow on softer bottoms where finer sediments can accumulate. The species that occur around the Swedish coast are therefore generally only present in relatively wind and wave protected environments, in shallow, protected bays, and in estuaries. Charophyte habitats are important nursery habitats for fish.
All three species are sensitive to eutrophication and especially to the growth of filamentous algae caused by eutrophication. Coastal development and other physical disturbances such as dredging and boat traffic, are important threats. Vulnerability to eutrophication and a shared threat assesment with a wide range of species in similar coastal environments makes the three species suitable as indicator and/or umbrella species.
In order to stop ongoing habitat loss and aiming towards a recovery with viable populations of Chara horrida, Chara braunii and Lamprothamnium papulosum along the Swedish seaboard actions against eutrophication are of highest priority. Presence and environmental requirements of these species have to be considered when exploiting or otherwise disturbing their habitats. New protected areas in shallow marine environments as well as customized management of existing protected areas are recommended. Knowledge about the species needs to be made easily available and distributed.
The cost for conservation measures recommended by this action plan is estimated at 11 900 000 SEK during 2020-2024.