Many insect species are under threat - butterflies , dragonflies, beetles; according to the Red List.  In most cases, this can be associated with habitat loss. For example,

• woodland that is no longer coppiced or managed
• traditionally farmed land as livestock farming is no longer viable
• wetland (including brooks and rivers) drying up as more water is extracted for irrigation and drinking supplies.

Other threats include

• Climate change - changing rainfall patterns, long dry spells)
• Forest fires
• Expansion of tourism

All of these have meant that across Europe some 20 plus species of butterfly are at risk, plus different types of dragonfly and many species of saproxylic beetle.  Butterflies are affected by the changing nature of many meadows,  pastures and woodlands.  The removal of livestock from meadows and pastures can mean that 'botanical thugs' (such as nettles) can dominate and there is a concomitant loss of biodiversity.   In woodlands, changing management or the lack of it, means that many are becoming 'darker', more shady; open areas are being lost as coppicing is practised less.   Saproxylic beetles need decaying wood, various species of such beetles are at risk due to a reduction in the number of mature trees (logging etc) and in some cases, the hygienic / aesthetic removal of dead wood from woods and forests.

In some cases, specific anthropomorphic change is responsible for habitat loss.  For example, quarrying has dramatically reduced numbers of the Macedonian Grayling butterfly .   You can visit the website of the Red List here