In the past, foresters in our country reforested many rocky hills, mainly with stands of black pine. In addition, they have stopped pastures which have become overgrown with shrubs. This is how the Apollo butterfly (Parnassius apollo) lost its habitat in most of its locations of occurrence in Slovakia, thus recording more than 90% decline! in abundance. The species is existentially linked to the early successional stages of sites with exposed geological substrate and the presence of caterpillar host plants: various stonecrops and Sempervivum species. These are pushed out by the trees, suffering from shade and the fall of acidic needles. The Apollo butterflies on Vápeč Hill in the Strážov Mountains area of European importance will no longer have this problem, because we have made this site ‘cosy’ for them.
