The caterpillars feed on grasses (Poaceae and Cyperaceae). Mainly Cyperaceae (e.g. Carex alba and Luzula spp.) seem to be more important.
Erebia ligea colonizes open woods such as floodplain forests, forest gap systems, clearcuts, wooded bog edges, grove rich grasslands etc. Erebia ligea is a montane species, which occurs in the low mountains and the Alps (including the northern foreland) avoids hot, dry and low-lying habitats.
The adults fly from June to August. A two-year development is obviously mandatory. The caterpillar overwinters in the egg shell for the first time and the second time in penultimate instar. I found a larva just in last instar, for example, in mid-May 2011 at the Iller valley (Southern Germany) in a Carex alba dominated light forest and a larva in penultimate instar in late October 2010 on the Adelegg (Eisenbacher Tobel, a low prealpine massif in Southern Germany)) probably already in hibernation in a pure Luzula-spot in moss.
Endangerment: regionally endangered or decreasing
In the Alps Erebia ligea is not so endangered, at least at higher elevations. In the valley bottoms, the low mountains and foothills of the Alps, however it is threatened by darkening of the forests, eutrophication, destruction of riparian forests and so-called natural forest management (dark forest management, single tree selection without clearcutting, separation of forest and pasture).
Additionally, climate change affects especially the populations in lower elevations. On the lower eastern Swabian Alb a strong decline can be observed in recent decades.
The distribution ranges from Central France across Central and Northern Europe to Kamchatka and Japan. To the south Erebia ligea occurs to Northern Greece (own observations e.g. in the vicinity of Mount Vitsi in July 2011).