RAMSAR
 

Please provide additional information on each of the following categories by attaching extra pages (please limit extra pages to no more than 10):


12. Justification of the criteria selected under point 9, on previous page. (Please refer to Annex II in the Explanatory Note and Guidelines document).

A representative example for the region, made up by a mixture of water, wetlands and adjacent terrestrial habitats, which supports a wide range of vegetation types and a rich fauna.


13. General location: (include the nearest large town and its administrative region)

The site consists of two bays in Lake Mälaren and the inland archipelago in between. It is situated in central-eastern Sweden, 15 km north-east of the town of Eskilstuna and 15 km south of the town of Västerås, in the Counties of Södermanland and Västmanland respectively.


14. Physical features: (e.g. geology, geomorphology; origins - natural or artificial; hydrology; soil type; water quality; water depth water permanence; fluctuations in water level; tidal variations; catchment area; downstream area; climate)

Lake Mälaren, is part of the characteristic central Swedish 'fissure valley terrain', with clay rich flatlands and ancient sea bottom, rich in nutrients. The western and eastern surroundings are flat, while there is a large fault in the south. The northern part of the Ramsar site contains an archipelago holding 160 islands and isles. The southern bay (Sörfjärden) is shallow and rich in nutrients, and may even, due to its long and narrow connection to Lake Mälaren, be regarded as a separate lake. Ridge formations run through the area, and several of the islands are parts of the ridges. There are plenty of remains from the latest Ice Age; several different kinds of moraine formations, boulder-ridges, ancient shorelines and elements showing the direction in which the ice cover moved. Because of the special local climate, the area harbours several species favoured by mild temperatures - known as heat-depending relict species. Such species are the remains of a previous flora and fauna, more widespread in warmer periods.


15. Hydrological values: (groundwater recharge, flood control, sediment trapping, shoreline stabilisation etc)

Lake Mälaren is regulated through dams and sluices at Stockholm.


16. Ecological features: (main habitats and vegetation types)

The site displays a wide variety of vegetation types; broad-leaved forests, virgin forests, pastures, marsh fens, seashore meadows (some of which are flooded and waterlogged each year), species-rich groves and meadows, drier grazed meadows and different kinds of wet forest. There are also large areas with emergent water vegetation, mainly reed Phragmites australis, favoured by the regulation of the water level. There are a lot of vascular plants in the open water areas that are favoured by the eutrophic conditions, e.g. several Potamogeton-species. Vegetation is different on the 'ridge islands' compared to the rest of archipelago.


17. Noteworthy flora: (indicating, e.g., which species/communities are unique, rare, endangered or biogeographically important, etc)

Shore meadows and broad-leaved forest support a rich and interesting flora, e.g. southern species and even some marine relicts. The wetlands and the broad-leaved forest are the main reasons for a rich birdlife. The Tidö area in the western part of the site contains an interesting insect fauna, linked to the old, broad-leaved forest. Deciduous forest on the islands is characterised by broad-leaved species such as oak Quercus robur, elm Ulmus glabra, lime Tilia cordata, maple Acer platanoides, ash Fraxinus excelsior and hazel Corylus avellana. Parts of this forest are old and gradually turning into semi-natural forest. Lindön in Söderfjärden is well-known for the great amount of very large and partly hollow limes. The lichen flora on the limes is rare and a lot of red-listed species occur. It is possible that the dominance of deciduous trees has been continuous since the postglacial warmth period. The most well-known plant species of the island group is mistletoe Viscum album. Here, the mistletoe has its northernmost occurrence in Europe, as well as its richest occurrence in Scandinavia. Cultural areas, like the Tidö Castle area in the north-west and the Fiholm Castle area, are also rich in insects and lichens.

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