Chara braunii (C. C. Gmel. 1826) (Charophyta)

Compiled by: Georg Martin, Estonia

1. Description of the habitat/autecology of the species

Chara braunii  can be characterised as a stenochaline freswater species and in the Baltic Sea it is restricted to low salinities of about 0-3 psu. Species grows only in shallow and quite sheltered habitats, often inside extensive reed vegetation, but may withstand weak wave action. In Finland, the species often occurs on bottoms eroded by ice. Most records are from depth of 0.1-0.6 m. C. braunii is described as warm water species which may explain its restriction to shallow water. The species is most commonly found on soft substrates like sand with varying organic content, silt, or sometimes on sand with stones and gravel.  

2. Distribution (past and present)

In the Baltic Sea, C. braunii is restricted to northern and easternmost areas. It is found from the northern part of the Gulf of Bothnia and along the northern and eastern coasts of the Gulf of Finland.

3. Importance (sub-regional, Baltic-wide, global)

Species is considered to be cosmopolitan and occurs between latitudes 65° N and 35° S. Mostly occurring in fresh water; rare in the Baltic Sea area.

4. Status of threat/decline

Distribution area of the species has declined in Finland and Sweden. Distribution in Russian waters most propably has not changed recently.

5. Threat/decline factors

Main known factors of threat are eutrophication and other mechanical disturbance. Disturbance by cattle grazing may detoriate the water quality, but on the other hand, grazing inhibits over-growth of coastal meadows, hence supporting living-conditions for C. braunii.

6. Options for improvement

Combatting local sources of eutrophication as well as improving conservation measures, such as restrictions against dredging, in shallow coastal lagoons and archipelago areas. 

7. References

Luther, H. ja Munsterhjelm, R. 1983. Inverkan av strandbetets upphörande på hydrolitoralens flora i Pojoviken. Memoranda Societatis pro Fauna et Flora Fennica 59: 9-19.

Zhakova V. L. 2003. Chara braunii. In Schubert H., Blindow I. (eds.), Charophytes of the Baltic Sea. Koeltz Scientific, Koeninstein/Taunus, 64-69.