Threatened Species: Saproxylic beetles
The IUCN European Red List analyses 693 species of Saproxylic beetles, 17.9 % of which are threatened at the European level and 21.7 % at the EU level. Forest management practices have been identified as a threatening factor for most species.
At a certain stage of their life, the Saproxylic species relate to the dead wood of veterans and dead trees — whether standing or lying — or to other Saproxylic species. This is a common definition, but it is important to know that younger living trees also have small or large dead branches that are, too, used by fungi and invertebrates. Therefore, Saproxylic species can be associated with living trees.
Saproxylic species play an important ecological role in forests, primarily in decomposing dead wood and recycling nutrients to the soil and the ecosystem. It can also be said that these species are ecosystem engineers, as their activities change their environment.
Among the Saproxylic species, we highlight the beetles. A significant proportion of forest beetles — nearly 30 % — are Saproxylic. Some of the better-known species — and Natura 2000 species — are the stag beetle (Lucanus cervus), the great capricorn beetle (Cerambyx cerdo), the alpine longhorn beetle (Rosalia alpina), the hermit beetle (Osmoderma eremita), the violet click beetle (Limoniscus violaceus).
The appearance of the dead wood is varied in terms of species, size, diameter, exposure and degree of decay, and the Saproxylic beetle assemblages associated with it are also very diverse. The different types of deadwood show a continuous transition, with no sharp boundaries between the single categories. The above-listed species are associated with different stages and types of deadwood. The great capricorn beetle develops in still-living but old oaks; the violet click beetle also develops in still-living, near-ground hollows connected to decaying laburnum; the alpine longhorn beetle prefers still-standing trunks without bark and thicker branches remaining on the trunk; and the hermit beetle lives in greater burrows of trunk with more lignicolous, while the larvae of the stag beetle feed in dead roots.
The IUCN European Red List analyses 693 species of Saproxylic beetles, 17.9 % of which are threatened at the European level and 21.7 % at the EU level. Forest management practices have been identified as a threatening factor for most species.
As described above, the preservation of veteran trees and deadwood, as structural elements and microhabitats in forests, are essential for the conservation of threatened Saproxylic beetles. The maintenance of forests with a diverse age and species composition, where dead wood is present in as many forms as possible — thin and thick branches, standing trunks, lying thin and thick trunks, trunks with bark, parting bark and without bark, stools and dead roots — and where their continuous production is ensured through them. Habitat continuity is also important due to the low dispersal ability of Saproxylic beetles. For instance, major clear-cutting areas act as an isolation factor for most species. Therefore, it is essential to use forest management based on natural processes more widely.
Among its objectives related to the network of protected areas, the EU Biodiversity Strategy 2030 highlights the protection of the primary and old-grow forests as strictly protected areas. The EU Forest Strategy for 2030 emphasises the need to increase the structural, functional and compositional diversity of forests and enhance sustainable forest management practices.