Stag beetles face a range of threats.
The most obvious problem for stag beetles is a significant loss of habitat. Many woodlands were sold for development in the inter-War years; just think of all the suburbs built since the 1920's. The introduction of the Green Belt in 1947 did restrict suburban expansion but since then many of London's surviving open spaces have sadly been developed, including many woodlands. Development will continue to reduce stag beetle habitats, but increased awareness of their existence can help defend the Beetles against developers.
In addition to the loss of habitat, the removal of wood from woodland is also a problem. In previous decades dead or rotting wood, which is the stag beetle's food source, would have been tidied away. Although some tidying up still continues in woodlands and parks, managers are now much more aware of the need to retain dead wood as part of the woodland ecosystem. The Royal Parks' management plans for Richmond Park, and other Royal Parks, include the retention of suitable dead wood to help encourage stag beetles to settle.
Changes in weather patterns also have an impact on our Lucanidae friends. Recent long dry summers seem to have resulted in more and more predators digging up and eating eggs or larvae. Predators such as cats, foxes, crows, kestrels and others may also have an adverse impact at the most vulnerable stage in the beetle's life cycle, when adults are seeking to mate and lay eggs. Though this is largely natural predation, it has been suggested that the rise in the numbers of magpies and carrion crows in the last decade may be having a significant impact on Stag Beetle populations.
Humans are, unfortunately, a direct threat to the stag beetle. Adult beetles are attracted to the warm surfaces of tarmac and pavements, making them particularly vulnerable to being crushed by traffic or feet. Stag beetles have a fearsome appearance and sometimes people kill them because they look 'dangerous'. We need more volunteers to help with research so that we can further understand these intriguing insects.
The good news is that stag beetle protection is one of the priorities of the UK Biodiversity Action Plan. Organisations like The Royal Parks are working hard with other groups to preserve the environment and habitats that the beetles need, so with your support we can help ensure the future will turn out well for these 'gentle giants'.