Its identification often requires a combination of morphological, chemical, and molecular data due to its similarity to other Parmelia species.

[2] Parmelia ernstiae is widely distributed in Europe[3] and has been recorded in Fennoscandia, including Denmark, southern Finland, and southwestern Sweden.

[2] In 2023, P. ernstiae was reported for the first time from Madeira, an archipelago of Portugal, expanding its known distribution to the Macaronesian region.

[3] The species appears to be adaptable to various environmental conditions, occurring in both forested areas and more open, anthropogenic habitats.

Its presence in Madeira suggests that it may have a broader distribution than previously thought, potentially extending to other Atlantic islands or coastal regions with suitable microclimates.