Chara connivens (Salzm. ex A. Braun 1835) (Charophyta)

Compiled by: GeorgMartin, Estonia

1. Description of the habitat/autecology of the species

Chara connivens occurs in brackish waters as well as lakes, ponds and ditches. In the Baltic Sea species is found within salinity range of 1-8 psu. It is found mainly from sheltered, rarely from relatively exposed, locations at a depth range of 0.2-4 m.

2. Distribution (past and present)

This species is very rare in the Baltic Sea. Confirmed former records exist from Greifswald-Rügen region and Öregrund archipelago. Single findings were reported also from Gdansk area and Kuronian lagoon. Recent records exist from Åland archipelago, West Estonian Archipelago region and Gräsö-Uppland area in Sweden.

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

Species is considered to be very rare. It is suggested that this species is not native to the Baltic Sea area but was introduced here with ballast sand and stones several centuries ago. The present findings along the Swedish coast are restricted to be close to former ballast dumping sites.

4. Status of threat/decline

A general decline is recorded in the Baltic Sea area except in Estonian waters where the distribution area of this species has increased during recent decades.

5. Threat/decline factors

Main known factors of threat are eutrophication and mechanical disturbance in form of habitat destruction and habitat disturbance. Activities as boating, dredging and cutting of reeds are described as major threat factors.

6. Options for improvement

Combatting local sources of eutrophication as well as conservation measures, such as restrictions on dredging, in shallow coastal lagoons and archipelago areas can prevent species from further decline. 

7. References

Appelgren K., Snickars M. & Mattila J. 2004: Chara connivens Saltzm. Ex. A. Braun 1835 found in the Åland archipelago – a newspecies to Finland. Memoranda Soc. Fauna Flora Fennica 80:11-13.

Luther H. 1979: Chara connivens in the Baltic sea area. Ann. Bot. Fennici 16: 141-150.

Torn K., Martin G. 2003:  Chara connivens. In Schubert H., Blindow I. (eds.), Charophytes of the Baltic Sea, Koeltz Scientific, Koeninstein/Taunus, 82-88.