Changes in altitude are quite dramatic in the wilderness area and the terrain is at points extremely demanding. In the northwest corner of the area, called Yliperä, there are several fells, which are over 1 000 m high. The tops of these fells are often covered with piles of scree rock. The highest fell here as well as in all of Finland is Halti. Around 3 000 people climb to the top of this fell every year. Animals in the fells include the Norway Lemming (Lemmus lemmus), the Root Vole (Microtus oeconomus), the Least Weasel (Mustela rixosa) and of course the Reindeer (Rangifer tarandus). There are no pine trees in the wilderness area. The only trees in the area are fell birches. Much of the area is taken up by the treeless tops of the fells.
The conditions in the wilderness area are unique in Finland. The bedrock in the Käsivarsi area is younger than in the rest of Finland. As it is made-up of a more alkaline rocktype it is more favourable as a growth spot for demanding species. For thisreason there are various plants, which do not grow in any other part of Finland. Most of these rarities are protected by law.
High in the Käsivarsi Wilderness Area fells there are spectacular fell plants, such as the Glacier Crowfoot (Ranunculus glacialis), the Hairy Lousewort (Pedicularis hirsuta) and the Arctic Bellflower (Campanula uniflora). The Ranunculus sulphureus grows in the area's snow beds and Mountain tobacco (Arnica angustifolia ssp. alpina) and the Snow cinquefoil (Potentilla nivea) are found on calciferous cliff-faces. Many plants which are otherwise rare in Finland grow in Käsivarsi Wilderness Area. Some of these are the Alpine Fleabane (Erigeron borealis), the Antennaria villifera and the Rhododendron lapponicum.
The Territory of the Lemming and the Willow Grouse
Permanent inhabitants of Käsivarsi Wilderness Area are the Fox (Vulpes vulpes), the Stoat (Mustela erminea) and the Grey Red-backed Vole (Clethrionomys rufocanus). The mostimportant habitat of the Norway lemming is on the snow beds of KäsivarsiWilderness Area. Snow beds have a short growth season, but they are not aslikely to suffer from dryness or the freezing wind during winter as otherareas. From there lemmings wander as far as the southern boundary of theProvince of Lapland. The last time the area's lemmings went wandering was inthe early 1980s.
Rare mammals met in the area are the Lynx (Lynx lynx), the Arctic Fox (Alopex lagopus), and the Wolverine (Gulo gulo). Wolves and bears also sometimesvisit the area.
As the winter is so cold in the Käsivarsi region and there is so much snow very few bird species can survive through the winter there. Species which have adapted to these extreme conditions are the two northern tetraonids the Willow Grouse (Lagopus lagopus) and the Rock Ptarmigan (Lagopus mutus) and the Gyrfalcon (Falco rusticolus), which preys on them. The Willow Tit (Parus montanus) and the Siberian Tit (Parus cinctus) also spend winters in the area.
A total of 89 bird species nest in Käsivarsi Wilderness Area, most of which are migrating species. Migrating species which manage to come this far north are the Peregrine Falcon (Falco peregrinus), the Red-Throated Diver (Gavia stellata), the Long-tailed Skua (Stercorarius longicaudus) and the Brambling (Fringilla montifringilla). There are some rare birds in the area, such as the Lesser White-fronted Goose (Anser erythropus) and the Snowy Owl (Nyctea scandiaca).
A Fishing Paradise
The fell area in the Käsivarsi region is a fishing paradise. Arctic Char (Salvelinus alpinus) livesin many of the areas lakes. Their size can vary greatly even within one lake. Adwarf form of arctic char also lives in many of the lakes.
The rivers in Käsivarsi Wilderness Area are filled with an abundance of Trout (Salmo trutta) and Grayling (Thymallus thymallus). The largest graylings caught in Käsivarsi Wilderness Area have weighed up to 2 kg. Good fishing rivers are the Rivers Poroeno, Rommaeno, Valtijoki and Lätäseno up which even Salmon (Salmo salar) have swam the past few years.
Rare Butterflies and Moths
The area surrounding Kilpisjärvi village, especially Saana Fell, is known for its abundance in butterfly and moth species. There are also many rare butterflies and moths in Käsivarsi Wilderness Area. Species found on Kuonjarvaara Hill and on the cliff walls of Urttasvankka are the Entephria nobiliaria and the Yellow-ringed Carpet (Entephria flavicinctata).
The butterfly species Acerbia alpina was named after the Italian explorer Giuseppe Acerbi. This species inhabits the fell highlands in Käsivarsi Wilderness Area. Other species found in these areas are Dusky-winged Fritillary (Boloria improba) and the Hepialus fuscoargenteus, neither of which are found in other parts of Finland.