Photo: Pekka Lehtonen
Altogether, 317 species of algae, aquatic vascular plants and aquatic bryophytes were assessed in the HELCOM Red List assessment and seven of them were considered threatened (Critically Endangered, Endangered or Vulnerable).
Three species were assigned to the category Endangered (EN): one charophyte, Lamprothamium papulosum, and two vascular plants Persicaria foliosa and Hippuris tetraphylla. Four species were categorised as Vulnerable (VU), charophytes Chara braunii and Nitella hyalina and the vascular plants Alisma wahlenbergii and Zostera noltii. Four species were assessed Near Threatened (NT): two charophytes Chara horrida and Nitellopsis obtusa and two vascular plants Crassula aquatica and Potamogeton friesii. Additionally, six species were categorised as Data Deficient (DD).
All threatened and Near Threatened species are characteristic for soft bottom, sheltered environments that suffer from various construction activities, traffic, tourism and other commercial use and where the effects of eutrophication are also more pronounced.
It is essential also to notice that a large proportion of macrophytes present in the Baltic Sea, 187 species in all, were left completely unevaluated due to serious or complete lack of data (Not Evaluated).