Rapport nr 155: Kartering och habitatsklassificering av undervattensmiljön i Geta
Valkonen, L. (2020)
Valkonen, L.
Åbo Akademi, Husö biologiska station
2020
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This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-12-3930-4
https://urn.fi/URN:ISBN:978-952-12-3930-4
Tiivistelmä
As assigned by the Provincial Government of Åland Islands on the request of Geta Municipality, a mapping of underwater vegetation was carried out in the coastal waters of Geta, in the archipelago of Åland Islands. The aim of the project was to obtain a comprehensive picture of the underwater environment, i.e. the distribution of the various habitats and species, as well as the general state of the area. The study points were randomized according to exposure and depth.
To collect data the drop-video method was used. In shallow areas, detailed and more specific mapping of the species composition was done with the help of dive transects. The drop-video method is suitable for mapping large coastal areas and for fast data collection. The method is also well suited for mapping habitat-forming key species, such as blue mussels, red algae and bladderwrack communities.
In total 217 sites where mapped, 14 of them where mapped by SCUBA diving. The collected data was analyzed with a habitat classification model developed by the NANNUT-project. The model grades the locations from zero to five depending on their ecological status. A total of 32 species of macroalgae were encountered, where blue mussels (Mytilus edulis), red algae and bladderwrack (Fucus vesiculosus) where the most common communities found.
As the exposure rate increased, the species distribution went from being dominated by vascular plants to a predominance of blue mussels. Vascular plants were not found at the exposed locations in the outer archipelago. At the more protected sites, vascular plants and bladderwrack dominated, also mixed communities of these were found. Blue mussels were found throughout the study area at all depths studied. Dense and healthy bladderwrack communities were found in both the middle and outer archipelago, red algae were also found in all archipelago zones.
To collect data the drop-video method was used. In shallow areas, detailed and more specific mapping of the species composition was done with the help of dive transects. The drop-video method is suitable for mapping large coastal areas and for fast data collection. The method is also well suited for mapping habitat-forming key species, such as blue mussels, red algae and bladderwrack communities.
In total 217 sites where mapped, 14 of them where mapped by SCUBA diving. The collected data was analyzed with a habitat classification model developed by the NANNUT-project. The model grades the locations from zero to five depending on their ecological status. A total of 32 species of macroalgae were encountered, where blue mussels (Mytilus edulis), red algae and bladderwrack (Fucus vesiculosus) where the most common communities found.
As the exposure rate increased, the species distribution went from being dominated by vascular plants to a predominance of blue mussels. Vascular plants were not found at the exposed locations in the outer archipelago. At the more protected sites, vascular plants and bladderwrack dominated, also mixed communities of these were found. Blue mussels were found throughout the study area at all depths studied. Dense and healthy bladderwrack communities were found in both the middle and outer archipelago, red algae were also found in all archipelago zones.