Checklist of Baltic Sea Macro-species - IOW
Checklist of Baltic Sea Macro-species - IOW
Checklist of Baltic Sea Macro-species - IOW
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2.3 Defining parameters<br />
The aim has been to compile a checklist valid for the<br />
<strong>Baltic</strong> <strong>Sea</strong> area as defined by HELCOM (see Figure 1).<br />
Species included in the macrophyte checklist were<br />
required to fulfil the following criteria:<br />
1. All <strong>species</strong> should be listed in at least one <strong>of</strong> the<br />
international databases given in Section 2.2 to<br />
verify the taxonomic reference.<br />
2. All <strong>species</strong> should form stable populations in<br />
brackish waters with a minimum salinity <strong>of</strong> at<br />
least 0.5 (identification <strong>of</strong> ‘borderline’ cases with<br />
freshwater and/or land environments).<br />
3. Records for all <strong>species</strong> must be geographically<br />
located within the <strong>Baltic</strong> <strong>Sea</strong> itself and not just in<br />
nearby ponds, rocky pools or rivers.<br />
4. Species identification must be reliable. Therefore,<br />
<strong>species</strong> with a very low number <strong>of</strong> records will<br />
be checked by macrophyte experts and doubtful<br />
identifications will be excluded.<br />
2.4 Distribution<br />
The checklist includes presence/absence data for<br />
the <strong>Baltic</strong> <strong>Sea</strong> sub-basins. The sub-basins used in<br />
the HELCOM Red List project are shown in Figure<br />
1. The total number <strong>of</strong> <strong>species</strong> per sub-basin is<br />
shown in Figure 3.<br />
For the macrophyte checklist a few modifications<br />
were necessary:<br />
• Great Belt and Little Belt were combined<br />
• Bothnian <strong>Sea</strong> and the Quark were combined<br />
• All records from the island <strong>of</strong> Bornholm were<br />
included in the Bornholm Basin<br />
• All records from the island <strong>of</strong> Gotland were<br />
included in the Western Gotland Basin.<br />
Bothnian Bay<br />
10<br />
The Quark<br />
Bothnian <strong>Sea</strong><br />
Gulf <strong>of</strong> Finland<br />
9<br />
Archipelago<br />
<strong>Sea</strong><br />
Åland <strong>Sea</strong><br />
Northern <strong>Baltic</strong><br />
Proper<br />
Western<br />
Gotland Basin<br />
Little Belt<br />
Great Belt<br />
Kattegat<br />
The Sound<br />
Bornholm<br />
Basin<br />
Gulf <strong>of</strong> Riga<br />
Eastern<br />
Gotland Basin<br />
Gulf <strong>of</strong> Gdańsk<br />
2a<br />
1a<br />
1b<br />
1c<br />
1d<br />
1e<br />
2d<br />
2c<br />
2b<br />
4a<br />
3a<br />
8b<br />
8a<br />
6 5c<br />
4b 5a<br />
3b<br />
5b<br />
7<br />
Arkona Basin<br />
Bay <strong>of</strong> Mecklenburg<br />
Kiel Bay<br />
Figure 6. <strong>Baltic</strong> <strong>Sea</strong> sub-basins used for the HELCOM checklist (left) and the geographical areas used by Nielsen et al. (1995);<br />
the publication used as the basis for data compilation (right).<br />
10