Introduced species in the Baltic Sea and its coastal ecosystems
Leppäkoski, E. (1984). Introduced species in the Baltic Sea and its coastal ecosystems. Ophelia. Supplement 3: 123-135
In: Ophelia. Supplementum. Ophelia Publications: Helsingør. ISSN 0107-5896, more
|  |
| Abstract |
More than 30 species of anthropochorous immigrants have been reported from the Baltic Sea (east of the Arkona Basin, approx. 13°E). About one third of them originate from North America. Introduced species are mainly restricted to the freshened hays and river mouths of the Southern Baltic region. Most of them belong to the littoral or shallow sublittoral subsystems. Examples of modes of dispersal and some food chains based on introduced species are given. Some relationships between exotic and native species are discussed. There are a few harmful species among these invaders. Immigration with man's aid is still occuring. This process can be characterized as (a) an undesirable contamination of the Baltic Sea biota by alien elements, (b) an artificial, anthropogenic increase of species diversity, and (c) an ongoing recovery from the heavy reduction in the number of species caused by the last glaciation and the subsequent developmental phases of the Baltic Sea. |
|
