Mossaträsk-Stormyran is one of the largest forest-mire complexes in north-eastern Sweden. The Site consists of well-developed string fens and forested fens with old-growth forests and swamp forests. It is important for carbon storage and it contributes to hazard reduction through flood control. Because the Site is largely unaffected by human activities, water quality and ornithological values are high. The Site is important for breeding birds such as the nationally red-listed ruff Philomachus pugnax and Eurasian curlew Numenius arquata. The inland location makes the Site valuable for migratory birds on their way to the mountains. As a nature reserve since 1998, a management plan is in place and the Site is included in the National Mire Protection Plan. Visitor facilities include a birdwatching tower, footpath, footbridges and outdoor information boards on the protected area.