There Is growing concern about the decreasing number of Lycaena dispar batava in the Netherlands. The Large Copper occurs in reed marshlands and its host plant is chiefly Great Water Dock (Rumex hydrolapathum). Recently several naturalists and land managers visited the peat-bog area in the province Overijssel to ascertain the possible causes of the decline of this butterfly. Changes in the habitat is likely to be the primary cause. Cultivation and drainage of the peat-bogs, acidification of the terrain and fewer host plant are all detrimental to the butterfly. Changes in land management need to be implemented to bring the butterfly back to its natural surroundings.