Landscape and nature in Kvarken

The northern Kvarken is the narrowest place in the Gulf of Bothnia. The Kvarken strait serves as a shallow threshold between the Bothnian Sea and the Bothnian Bay. The Kvarken area is heavily characterised by the land uplift, with the land surface always increasing, and by the bedrock and moraine soil that provide the landscape with its shapes. The sea moderates the climate so that summers are cooler and winters are milder in the archipelago than on the mainland. Although the Kvarken archipelago is a small area, visitors to its different parts will discover great variation. The archipelago on the east side of Kvarken is larger and more expansive than on the west side. In the western portion of Kvarken the Holmöarna island group is the single largest area of the archipelago, but to the south there are also the archipelagos at Kronören and around Snöan. In eastern Kvarken, the southern parts of the archipelago are flat and rocky, while the northern portions offer the visitor greater elevation changes and more navigable waters.

In general, Kvarken is a flat area. Stones and boulders are the predominant feature on beaches, while bare cliffs and sand beaches are rare. Low beaches are often bordered by a line of alder trees which transition into forests of birch or spruce, often with the occasional rowan. Spruce trees grow on the larger islands and the inner archipelago. Pines are less common, but can dominate dry hilly areas.

The rising land has a significant impact on the development of vegetation in shoreline areas. Since the shoreline is constantly moving outwards, maritime plants hardly have time to put down roots before the habitat has changed. In just 50 years, a small rock that can hardly be seen above the surface of the water can become an islet where plants try to gain a foothold. The uplift is most noticeable in flat areas and since the Kvarken archipelago is mainly shallow and level, the area is truly in a constant state of flux.

The uplift of the land and the climate are not the only factors that impact vegetation. People have always moved about in the archipelago and they have left behind more than just objects and buildings. On large islands and smaller islets, people have raised sheep and other livestock on pastures, gathered meadow grass, thinned trees and in more recent times, clear-cut areas on the larger spruce covered islands. Open heaths and points have even been burned to remove juniper bushes in an attempt to improve grazing conditions. Grazing is still common on several islands today, especially in eastern Kvarken.

The bedrock and soil also determine the appearance of the flora. The bedrock in Kvarken mainly consists of granite and gneiss, which are relatively acidic. This limits the number of species, since plants that thrive with lime have a difficult time. There are small differences in the flora of western and eastern Kvarken. More common in the eastern Kvarken are species such as alder (Alnus glutinosa), bittersweet nightshade (Solanum dulcamara) and field dock (Rumex pseudonatronatus), while purple moor grass (Molinia caerulea), sweet gale (Myrica gale) and seaside plantain (Plantago maritime) are more common in western Kvarken. However, the flora of the outer and inner archipelagos can differ greatly, in part because the water at the coast is less saline than on the outskirts of the archipelago, and because the fewer hours of sunshine and the waves have less of an impact in the inner archipelago.

Differences can also be found in the animal life in eastern and western Kvarken. For example, eastern Kvarken is home to the common European hare (Lepus europaeus) and the raccoon dog (Nyctereutes procyonoides), while the Norway lemming (Lemmus lemmus) and the wood lemming (Myopus schisticolor) are only found by the Västerbotten coast. The otter (Lutra lutra) is rare in the archipelago in both Sweden and Finland. Lynx (Lynx lynx) can be seen regularly along both coasts. On larger islands in the archipelago the fox (Vulpes vulpes), badger (Meles meles), pine marten (Martes martes), ermine (Mustela erminea), least weasel (Mustela rixosa) and ferret (Mustela putorius) (the latter only in eastern Kvarken) can all be found. Mink (Mustela vison) were introduced from North America and their numbers have increased in the archipelago, at times leading to great damage to the bird population; this is also the case for the fox and raccoon dog. Moose (Alces alces) live in the archipelago and along the coast during the summer half of the year and in winter they make their way inland. Two seal species are found in Kvarken, the grey seal (Halichoerus grypus) and the ringed seal (Phoca hispida botnica).

Below the surface of the water is a separate world that humans rarely see. Like the landscape above the surface, the seafloor varies in the different parts of the archipelago. There are shallow places where sunlight reaches the bottom and deep, dark places completely without vegetation; there are hard rock bottoms and soft bottoms and they all look different with respect to flora and fauna. The saline content decreases throughout the Gulf of Bothnia as you move north and a few marine species can be found in Kvarken at the northern border of their habitat. There are also freshwater species not found farther south in the Gulf of Bothnia. Few species have been able to adapt to the low salinity (0.2-1.0%) in the Baltic Sea (in Kvarken, 0.4-0.5%), and thus there are few species here compared with the oceans.

Almost all fish species found in Kvarken live along the coast and depend on the archipelago environments and estuaries for reproduction. Commonly found year round in the waters of the archipelago are perch (Perca fluviatilis), roach (Rutilus rutilus) and ruffe (Gymnocephalus cernuus). Whitefish (Coregonus lavaretus) and sea trout (Salmo trutta trutta) thrive in colder water and therefore stay farther out to sea during the summer. Smelt (Osmerus eperlanus) are strongly established in Kvarken and are an important fodder fish for many larger fish species. Grayling (Thymallus thymallus) have decreased in the Gulf of Bothnia and are somewhat more common in the western portions of Kvarken than in the eastern. The Baltic herring is the most common marine fish species in Kvarken, where most fish are freshwater species.

Bird life in Kvarken has a chapter of its own, Birds.

Read more:

Natural habitats and species: Metsähallitus, http://www.luontoon.fi/page.asp?Section=7869

Marine biology: (in Swedish)
http://tmbl.gu.se/universeum/hemsidan/jasonxiv/

Sea life (Tjärnö Marine Biology Laboratory, Strömstad):
http://www.vattenkikaren.gu.se/defaulte.html