Natural habitats of the West-Estonian Archipelago

Wooded meadows and alvars
Nearly half of the territory of the large islands of West-Estonia is covered with forests. The area of woodlands has significantly increased in the last half of the century, as many wooded meadows, previously very characteristic of these islands, have grown over with forests.

Large islands — Saaremaa, Hiiumaa, Muhu and Vormsi — lie to the west of the mainland of Estonia. The climate of West-Estonian islands is more influenced by the sea than is the rest of the territory of Estonia. Long warm autumns, mild winters, late cool springs, strong winds, long sunny periods and low precipitation are characteristic of this region. The end of spring and beginning of summer are the driest periods. As the period during which the sea around the islands is ice-free is relatively long, the mean air temperature on the western coast of Hiiumaa and Saaremaa in February is –3.5° to –4°C, i.e. 3–4 degrees higher than in East-Estonia. Permanent snow cover forms on the islands at the beginning of January and stays until the second half of March. Also, winters without a permanent snow cover are not rare here and the period without night frosts is two months longer than in the central part of Estonia.

Alvars are dry areas with a thin soil layer covered with calciphilous vegetation. Currently, only a small number of alvars has been preserved in the world: besides the limestone and dolomite areas of North-Estonia and West-Estonia, alvars also occur in Sweden, on the islands of Gotland and Öland and, in places, on the Aland Islands of Finland. In the areas where the limestone bedrock lies near the ground surface, only low grassy vegetation or junipers grow. Due to cessation of grazing, typical alvars have started to grow over with brush.

Wooded meadows are sparse natural stands with a grass cover that needs regular mowing. Besides North-Estonia and West-Estonia, such meadows were also common in the southern parts of Sweden and Finland. Wooded meadows are the most species-rich ecosystems in Estonia. With regard to richness in vegetation species over small areas, some plant communities of wooded meadows are among the most species-rich plant communities in the world.

Rare plant species
The species-rich flora of the islands includes many rare plants. Of 185 vascular plants currently included in the national list of protected species, 122 can be found in the territory of Saaremaa and on the neighbouring islands, and 17 of them are unique to the islands. Some of the protected species are relicts from the past when the climate was more suitable for them (common ivy and yew tree), several of them grow on the boundary of their distribution area (mostly on the northeastern and northern boundary) and some of them are remarkable for their beauty (orchids). The rarest plant species here is Saaremaa yellow rattle, the only endemic species of Saaremaa, i.e. a species originating in this area. It grows in spring fens and paludified meadows. The regions especially rich in rare plant species encompass the surrounding areas of Viidumäe, and Sõrve, Tagamõisa and Kuusnõmme peninsulas, and Abruka, Vilsandi and Ruhnu islands.

Coastal areas
Nowadays the coastal areas of these islands are extremely diverse and varied. Here all coast types occurring in Estonia are represented. A limestone coast is associated with limestone scarps most of which are located on the West-Estonian Clint running along the northern coast of Saaremaa and Muhu. The largest scarps are Kesse cliff (7–8 m) on Kesselaid, Püssina (5 m) in the northeastern part of Muhu, and Panga or Mustjala (2.5 km long; maximum height up to 21 m), Ninase (6 m) and Suuriku (8 m) cliffs on the northwestern coast of Saaremaa.

As the ground surface gradually slopes towards the sea, the coasts of the islands are mainly flat. Depending on their exposure to waves, various types of sediment and rock, morainic or silty beaches are dominant. Also, sandy beaches can be seen. The major part of the open coastal area is a morainic shore with numerous boulders. Most of it, except for steeper sections exposed to waves, has become turfed.

Silty beach areas grown over with reed can be seen at bights and in shady places. Near cliffs, shingly beaches can be seen. These are coasts of accumulation where, as a result of sediment movement, the formation of beach ridges and spits is ongoing. This process is active for example on the coast of Küdema Bay, in the area to the south of Panga scarp, in the northern part of Ninase and Tagamõisa peninsulas, on the coast of Harilaid Peninsula and on Sõrve Spit. Järve coast located to the west of Kuressaare, the eastern coast of Sõrve Spit and the coast of Harilaid, are considered to be the most beautiful sandy beaches in Saaremaa.

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