The sunny slope habitat or sun-exposed areas of esker forests are classified as an endangered biotope. sunny slope areas are found on sandy slopes facing south or west. Previously sun-exposed environments stayed open especially as a result of forest fires, but also forest grazing created and sustained the biotope. Without management measures sun-exposed areas are quickly overgrown.

The flora and fauna of sunny slope areas have adapted to drought, intense solar radiation, great temperature changes and oligotrophic environment. The specialized species do not thrive in other kinds of habitat, so many species of sun-exposed environments are endangered.