Good and bad news from the world of beetles
Photo: Esko Hyvärinen
There are now 333 threatened species of beetle (Coleoptera) – 14 fewer than in the 2000 evaluation. However, the number of Near Threatened species has risen dramatically, as has the number classified as Regionally Extinct. The rate at which forest beetles are becoming threatened seems to be slowing, but remains unchanged in other habitats.
About 40 per cent of threatened and Near Threatened beetles live in forests and just under a third in traditional rural biotopes. Shores are the third most significant habitat and are home to about a fifth of all species. Almost half of all Regionally Extinct beetles live in traditional rural biotopes. The major threat factors for beetles are associated with the commercial use of forests. The overgrowing of open habitats, such as meadows and shores, constitutes the second most significant threat.
Red List of Beetles (Coleoptera)
|Threatened (categories CR, EN, VU)
|Near Threatened (NT)
|Regionally Extinct (RE)
Conservation areas and tree retention in commercial forests have helped
All in all, 41 species of forest beetle have experienced a clear improvement, while the status of 12 species has deteriorated. Certain species that live on decaying wood, such as Agrilus ater and Xylotrechus rusticus, have benefited from retention trees. The number of prescribed burnings carried out as part of habitat restoration and management increased during the 2000s, which has benefited, for example, Sericoda bogemannii. In recent years, climatic conditions have been advantageous for many beetles inhabiting southern regions. Beetles react quickly to changes in their habitats. Sustained and improved habitat management is necessary if the favourable trend detected in forest beetles is to continue. Sufficient and correctly targeted measures must be employed in commercial forests, and conservation areas must be restored and managed.
Increased threat to shoreline species
The number of threatened and Near Threatened beetles living on shores has increased and constitutes a significant rise on the previous evaluation. The major cause of this – the overgrowing of shoreline meadows – continues. Species that live on sandy beaches are threatened by the spread of Rosa rugosa, eutrophication and its effects, such as the overgrowing of open areas, as well as other pressures associated with shore usage.
Beetles continue to disappear from traditional rural biotopes
The number of threatened beetles living in traditional rural biotopes has remained almost the same. Genuine alterations in species’ statuses have led to a downgrade in the red list category of 26 species and an upgrade for 24 species. An improvement has been seen in the status of species that have adapted to life on wastelands or roadside verges, or those that have benefited from warmer climatic conditions during the early part of the century. The status of species associated with traditional animal husbandry has further weakened due to the reduction in traditional farms and wild pastures.
Climate change a threat
The impact of climate change on beetles has not yet been thoroughly analysed. Warming in particular is estimated to threaten those species that have adapted to colder conditions, such as those living in snow beds and the small, coldwater streams that flow from them, or in the northernmost mires. These species usually have a very narrow area of distribution. Climate change is estimated to pose a threat to four per cent of threatened and 11 per cent of Near Threatened beetles. On the other hand, climate change has enabled many southern species to expand their areas of distribution northwards within Finland.
- Senior Researcher Ilpo Mannerkoski, Finnish Environment Institute (SYKE), tel. +358 (0)400 148 684
- Conservation Biologist Esko Hyvärinen, Metsähallitus, Natural Heritage Services tel. +358 (0)400 208 591