Decrease of dead wood threatens wood-dependent beetles

A recently published IUCN report states that about 18% of the assessed European saproxylic beetles are at risk of extinction. This can be led back to an ongoing decline in large old trees all across Europe. Saproxylic beetles are beetles that mainly live on dead wood. Therefore, old and dead, decaying trees play an essential role in saproxylic beetles lifecycle’s. They highly depend on these habitats at least in parts of their lifes. These beetles are furthermore involved in decomposition processes as well as the recycling of nutrients in natural ecosystems. In addition, they are a major food source for birds and mammals. Some species also contribute to pollination.

Please also read: Good Forest Means Dead Wood

A new European Red List of Saproxylic Beetles

The IUCN assessed the conservation status of nearly 700 saproxylic beetle species. The aim of this project was to develop a new European Red List of Saproxylic Beetles. The project involved around 80 European experts. It was funded by the European Commission and through a LIFE grant. Jane Smart, Director, IUCN Global Species Programme, says about the Red List project:

“The IUCN Red List gives us key intelligence for understanding the status of saproxylic beetles and highlighting conservation priorities to ensure their long term survival. Some beetle species require old trees that need hundreds of years to grow. Therefore, conservation efforts need to focus on long-term strategies to protect old trees across different landscapes in Europe. Their aim should be to ensure that the vital ecosystem services provided by these beetles continue.”

Threats for wood-dependend beetles

Saproxylic beetles highly depend on dead or decaying wood. Consequently, the loss of trees across Europe can be seen as the main reason for the decline in their populations. Further contributing to this are tree age structure gaps and degraded landscapes. Such degraded landscapes are not favourable to tree growth. The post about the IUCN report states Stictoleptura erythroptera as an example. This species depends on large old trees with hollow spaces. The continuing loss of old trees across its range is the main threat to this species. It was assessed as Vulnerable.

The project also identified urbanisation, touristic development and an increase in the frequency and intensity of wildfires in the Mediterranean region as major threats. Logging is another factor minimising habitats for these species. In particular, logging of old forests, which host a lot of old and standing dead trees. A recent example for this, is the illegal logging of the Białowieża old growth-forest in Poland.

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Slow change of thinking about the importance of dead wood in Europe

The forestry sector is acknowledging the importance of dead wood more and more in many countries. A CEEWEB publication from 2014 already focused on forest Wilderness, dead wood and non-intervention management in European forests. Europe and the European Wilderness Network still host some untouched old-growth forests, forest Wilderness and forests managed according to non-intervention management. The recent designation of the UNESCO beech forest network proves that once again. So, there has been some progress in this concern. Humberto Delgado Rosa, Director for Natural Capital, DG Environment, European Commission, leads the recent increase of dead wood back to the integration of the requirements of the EU nature and biodiversity policy into forest management plans. He further states:

“This is having a positive impact on saproxylic beetle populations and demonstrates that the adequate mainstreaming and implementation of the EU environmental policies brings results.”

Further monitoring is needed to discover whole extent of species development

However, the report highlights that there still is a lack of data for many species. According to Keith Alexander, IUCN Saproxylic Beetles Specialis Advisor, the population trend of half of the species assessed remains unknown. He further states that about a quarter of the assessed species showed Data Deficiency. Keith Alexander sees this as a strong sign that more monitoring is neccessary.


Conservation strategies for saproxylic beetles in Europe

The IUCN report recommends the development and implementation of conservation strategies for the European saproxylic beetles that show the highest risk of extinction. Member states should adopt the best habitat management practices. Non-intervention management is an effective management measure to increase dead wood. This management measure consequently contributes to new habitat for these beetles. Another important point stated in the report is the raising of awareness about the importance of dead trees. In particular, for the conservation of beetles that depend on them. Luc Bas, Director, IUCN European Regional Office says:

“It is critical for the Common Agricultural Policy to promote the appropriate management of wood pasture habitats containing veteran trees across Europe. Currently, management practices lead to the transformation of wood pastures into either woodland or grassland. Such a transformation destroys the essential vegetation mosaic many saproxylic beetles need.”


One thought on “Decrease of dead wood threatens wood-dependent beetles

  • I wonder why those who are concerned about saproxylic beetles, and as a bad example cite Białowieska Forest (where in fact most of those species managed to survive), do not object first – forest practices in Germany where they do not leave practically any dead wood at forest floor.

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