The Vätsäri Wilderness Area (, ) is located along the northeastern shore of Lake Inari in Inari, northern Finland, stretching all the way to the Finland–Norway border. The landscape is dominated by taiga forests of Scots pine, bog and bodies of water. The northeastern part rises as a treeless fell ridge. Vätsäri is one of twelve wilderness areas in Lapland and covers an area of . The wilderness has one marked trail and a few cabins. The reserve is under the management of Metsähallitus (Administration of Forests) and was established with the other wilderness reserves in 1991. It is part of Pasvik–Inari Trilateral Park along with Øvre Pasvik National Park and Øvre Pasvik Landscape Protection Area in Norway, and the joint Norwegian–Russian Pasvik Nature Reserve. The area has a short growing season, cold winters, little precipitation and poor soil quality created by the gneiss bedrock. Lake Inari has been affected by acid rain and loss of fish from the Paatsjoki River Hydroelectric Plants. The reserve is an important habitat of the brown bear and also has a large moose population; reindeer husbandry is practiced by the Samis. Whitefish and vendace are the most common species of fish, the latter being an introduced species. Geography The wilderness area is located on the northeastern shore of Lake Inari and stretches northeastwards into a treeless fell ridge. It is located entirely within the municipality of Inari, and the reserve's eastern border is the Finland–Norway border. The landscape consists of taiga forests of Scots pine in the lower areas, bog, thousands of small lakes, and creeks. The reserve covers an area of . Most streams in Vätsäri flow into Lake Inari, which has the Pasvik River as its outflow. Construction of the Paatsjoki River Hydroelectric Plants has changed the hydrology considerably, providing for a more stable regulation of Lake Inari, but reducing the flow speed. Water levels are now highest during autumn and lowest during spring, opposite of before. The bedrock consists of basement gneiss with occasional slate and volcanic rock. The Inari Basin was created after the last glacial period when an ice blockage in the Pasvik River hindered the draining of melted water in the area. The climate is harsh and allows only a limited growing season of between 110 and 120 days. Temperatures may rise to during summer, but fall to in winter. The northeastern part of the reserve is moderated