It covers one of the largest bogs in Latvia, and the bog itself is one of the largest in the country - 7240 hectares. As a result of human activities, the plant life in the nature reserve has undergone significant changes.
In the bog, mainly in the northern part of the Seda River, there have been findings of 10 protected plant species and 7 protected moss species. One of the rarest among them is the European protected moss - the shiny bog moss.