Because the larval stage is highly dependent on the host food plant "S. pratensis", decline in the availability of the host plant leads to negative effects on the "E. aurinia" population. Decline of natural habitats for "S. pratensis" is correlated with decline in the host plant population. Due to cultivation and shift of land use from traditional farming to grazing, the frequency of "S. pratensis" populations has declined over the past few years. Damp, basic soil is suitable for high "S. pratensis" frequency. Environmental changes such as acidification and eutrophication have led to a decline in available optimal habitat for "S. pratensis", and consequently for "E. aurinia".