The factors threatening fireflies survival are resulting from the powerful human action that in the last centuries has deeply changed landscapes. More specifically, living organisms were subjected to an increasingly selective pressure due to anthropization, which was particularly intensive in the past century, when landscapes were disrupted as a consequence of human populations growth, agricultural intensification and industrialization.
An important limiting factor is urbanization. In Italy the rate of land consumption, especially in lowlands, coastlands and valley bottoms is high, as documented by periodical reports published by the Environmental Italian Institute (ISPRA): urban land has more than doubled over the past decades. Urbanization means either removal of green areas or their fragmentation and light pollution. More information on light pollution are available at the following link: https://www.darksky.org/light-pollution/wildlife/.
The evolution of agriculture to intensive patterns is one more negative factor. From the 50s onward, agricultural intensification has produced first of all an increase in pesticide use and farming polarization (often monoculture). As documented by periodical agriculture census, from 1960 up to now the number of farms in Italy has decreased so re-parcelling the agricultural land. As a result, the land owned by every single farm increased, fields were merged and a great part of margin elements, such as hedgerows, small woods, ditches, was disrupted. This removal was detrimental towild fauna, including fireflies.
Other detrimental actions related to anthropization were wetland drainage and deforestation in lowlands.