A comparison between 1928 and 2000 indicates major changes in the macrozoobenthos species composition and abundance on the SW coast of Finland /Olulised muutused Soome edelaosa rannikumere pohjaloomastiku liigilises koosseisus ja arvukuses--1928. ja 2000. aasta vordlus

• Published in: Proceedings of the Estonian Academy of Sciences. Biology, ecology Vol. 52; no. 1; p. 3
• Main Authors: Laine, Ari O, Luodekari, Kaisa, Poikonen, Minna, Viitasalo, Markku
• Format: Journal Article
• Language: English
• Published: Estonian Academy Publishers 01.03.2003
• ISSN: 1406-0914

In 1928, Sven G. Segerstrale made detailed analyses of benthic communities in the Tvarminne region (SW coast of Finland). In addition to traditional presentation, he included illustrative photographs where the collected macroinvertebrates were laid on black background, in natural density, and reproduced in their natural size. This approach was replicated in the present study. The photographs highlight changes that have taken place during the past century in the benthic communities. In the deeper area there has been a change from an amphipod (Monoporeia affinis) dominated community to one dominated by the Baltic clam Macoma baltica. In the shallower study area the diverse Corophium volutator-M. baltica-chironomid community has been replaced by a community dominated by Macoma and a North American invader, the polychaete Marenzelleria viridis. Furthermore, the density of macroinvertebrates has declined considerably. The causes for these changes remain unclear, but are most likely connected to eutrophication related factors in the coastal ecosystem and concurrent interspecific interactions. Key words: macrozoobenthos, long-term change, Baltic Sea. 1928. aastal uuris Sven G. Segerstrale Tvarminne regiooni pohjakooslusi (Soome edelaosa rannikumeri). Lisaks traditsioonilisele esitusele ta ka fotografeeris uuritud kooslusi. Loomad olid asetatud mustale taustale ning nende paigutus vastas looduslikule asustustihedusele. Siinses uuringus kasutati sama metoodikat. Fotode vordlus naitab, et loomakooslused on viimase sajandi jooksul oluliselt muutunud. Sugavamatel aladel on kirpvahi (Monoporeia affinis) kooslus asendunud balti lamekarbi (Macoma baltica) kooslusega. Madalamatel aladel on mitmekesine Corophium volutator'i-Macoma baltica-Chironomidae kooslus asendunud Macoma baltica ja Pohja-Ameerika tulnukliigi Marenzelleria viridis'e kooslustega. Lisaks on suurselgrootute asustustihedus oluliselt vahenenud. Muutuste pohjused on ebaselged, kuid suure toenaosusega voib neid seostada eutrofeerumisnahtustega ning sellest tulenevate muutustega liikidevahelistes vastastikmojudes.