The granulite bedrock, which reaches from Paistunturit Fells in Utsjoki to Saariselkä in Inari, is about 1 900 million years old. Because of shifting of tectonic plates about 70 million years ago, it rose to form fells in some places, and moved down to form valleys in others. The rift valley of Kevo was also created during that time.
The bedrock in the Kevo valley consists of different kinds of stone, the durability of which vary against weathering and erosion. The last Ice Age which ended about 10 000 years ago, and its melting waters, were the latest factor shaping the ground and the landscape.
The rock walls of the canyon are almost without snow cover during the winter, and they get warmed by the sun quickly. Fertilised by water running down, and birds, these walls make an interesting habitat for plants. Many rare species grow on the slopes, such as some saxifrages and fern-like plants. Therefore these walls are sometimes called miniature botanical gardens. Pines also grow surprisinly well there, because the climate in the canyon is more favourable than in the surroundings. All the waters from the area eventually flow into the Arctic Sea, through the River Tenojoki.
The abundance and diversity of the animal and plant species of the Kevo Canyon stand out from the set of species in the rest of the area. This is due to the varied soils, sufficient water resources and favourable microclimate in the canyon. In the Kevo area, you can find rarities such as the Wall Hawk's-beard (Crepis tectorum subsp. nigrescens) and the Cliff Stickseed (Lappula deflexa), which only grow in very few places in Finland. The steep cliffs of the canyon also make good nesting places for birds, such as the Rough-legged Buzzard (Buteo lagopus) and the Common Kestrel (Falco tinnunculus).
Different fell birch forests and bare fell fields are the dominating vegetation types in the strict nature reserve. In the 1960s, the caterpillar of the Autumnal Moth (Epirrita autumnata) damaged a remarkable part of the forests by eating the leaves of the birch. There are still large areas on slopes of the fells which look a bit ghostly with just the skeletons of the trees without their leaf crowns.
The Arctic fox at Kevo
The Arctic fox is an Arctic species, which has adapted extremely well to the cold climate and scarce food supply. Its thick winter fur and ability to survive for long periods of time without food help the fox cope with the harsh conditions of the far north.
The Arctic fox has two distinct coat colours, both of which can be found in Finland. The white winter coat is most commonly found among Arctic foxes, with only one out of every foxes having a dark winter coat.
Even though the Arctic fox is occasionally quite fearless and can approach people, no wild animal should ever be approached. It is always better to let the fox decide how familiar it wants to be.
The Arctic fox is Finland's most endangered mammal, with only 5-10 individuals reported in the northernmost fells each year. The last confirmed den in Finland was reported in 1996.
Climate warming is the biggest threat to survival of the Arctic fox throughout its area of distribution: the Nordic countries, Russia and North America. Warm winters also make it easier for the red fox, a competitor to the Arctic fox, thrive in the fells.
Arctic foxes have no understanding of national borders, which is why their protection is being promoted as a joint Nordic effort. Protection measures include providing food and hunting red foxes. In addition to this, Arctic foxes raised on farms in Norway and Sweden are being released into nature.