Well there is far less insects splattered on the windscreen when driving the country lanes of Dorset compared to the 70-80s but the numbers were low even then according to my father when remembering the 50-60s
but overgrazing on heathland and acidic grasslands from livestock introduced by conservation bodies are not as wildlife friendly as we may think, I have seen delicate areas damaged by their introduction such as sand cliffs broken down with the passage of hoofs where mining bees and wasps once bred,
the loss of plant species due to churning up wet bog land areas as well as the routine tracks made to reach these areas that drains water from its natural course ,this all within the past 6-8 years
also the over zealous removal of bramble patches on heathland fringes which has effected the butterfly populations in recent years
I did ask the conservation body about submitting records of insects but was told they were only interested in red data species
well take the hoppers Archaeorrhyncha for example many are indigenous to one food plant if that is lost so to the colony and that's for ever they are not transient like alot of the other insects, yes you do get brachypterous individuals but there not long distance flyers so if their habitat is lost due to overgrazing or poor management that's it for them, as i mentioned they are not interested unless they are on the red data list , so what about the food chain then ? you loose one piece of the jigsaw and that's means those pieces around it are effected, it can never be complete, the whole picture suffers A heath is controlled by the diversity of the marginal lands surrounding and interacting with it,if you don't care for all you loose the red data species
maybe a little off topic though heathland is ancient farmland