Climate change beetle

The fogging method allows almost complete collection of invertebrates such as insects from the canopy. All pesticide-affected arthropods fall onto collection sheets and are collected for identification. Upper right: Most F. Excelsior trees died in 2020 as a result of drought and ash death. After the mass development of the ash bark beetle Hylesinus fraxini, the bark beetle destroyed the bark of the dead F. Excelsior tree. This gives the dead trunk a unique structure.Credits: Andreas Floren / University of Würzburg

As a result of recent droughts, significant tree deaths have been observed in Germany, leaving clearly visible gaps in forests and parks. All climate forecasts indicate that such events will occur more frequently in the future.

It also affects insects and other animals in the canopy. Canopies occupy most of biodiversity and provide many functions. Woods It may exist.

In response to Tree mortalityForest scientists are planning to transform commercial forests into more robust mixed forests. This includes planting drought-resistant tree species from other countries.

However, this strategy is risky and controversial. When plants and animals are introduced into non-native species, this can disrupt the biodiversity and function of ecosystems. “The nature and extent of this turmoil cannot be predicted based on current knowledge,” said Andreas Floren and Tobias Müller, scientists at the Department of Ecology and Bioinformatics, Julius-Maximilian University Würzburg (JMU), a scientific journal. Says. sustainability With Peter Horchler of the Federal Bureau of Hydrology in Koblenz.

Exotic tree as a rescue species

ResearchersTraditional trees It can also provide an opportunity during climate change by becoming a rescue species for insects when the host tree dies locally.

Evidence of this was found in the floodplain forests of the Middlede Elbe Biosphere Reserve in Germany. There, the European ash (Fraxinus pennsylvanica) was found near the European ash (Fraxinus excelsior). F. pennslyvanica was planted in the early 20th century due to its high resistance to floods.

“In 2016 and 2017, we analyzed the biodiversity of beetles inhabiting the canopies of two tree species,” explains Andreas Floren of the JMU Systems Ecology Working Group, which combines animal ecology and bioinformatics. The results showed that the largest beetle diversity was found in European ash trees, which was clearly different from the red ash tree beetle community.

Almost complete dieback of European ash as a result of drought

According to Floren, ash dybacks caused by drought stress and fungal infections were not clear between 2016 and 2017. But when the team repeated the analysis in 2020, the situation was completely different. By then, more than 80% of the native ash trees have died, which is close to the “knockout” of this species. The heat and drought of the last few years have been their victims. On the other hand, North American ash trees were less affected.

The fauna of the tree beetle changed dramatically in 2020. “This shows the functional reconstruction of the ecosystem,” explains Floren. Many species have switched to Red Ash, and the number of endangered beetles on the Red List in Saxony-Anhalt has increased, F. It became a secondary pest of Excelsior. These beetles pierce the bark of native ash trees and destroy their base layers.

Surprisingly, no herbivorous beetles were found on all trees. In contrast, more wood-dwelling beetles and feeding beetles were collected. Predatory beetles and fungal-eating beetles are now abundantly collected in red ash trees.

The data were obtained by clouding individual trees with highly specific pesticides. Beetles and other insects fell on a collection sheet placed under the tree and were collected for identification. Natural pyrethrum was used as an insecticide because it was destroyed in the sunlight within a few hours without leaving any residue and was less disturbing to the ecosystem.

Red ash tree provides the second best habitat

“Overall, our data show that F. pennsylvanica could be a rescue species for native animals if the European ash disappears, as the European ash provides the second best habitat. I’m suggesting, “says Floren. “It is very rare for newborns to be important for the preservation of native fauna, only because the two ash species are closely related.”

In biology, newborns are plants introduced to non-native sites by human activity. What happened in floodplain forests can also occur in other forests, so further research on the diversity and function of canopy fauna, including new plants to prepare for possible consequences of climate change, is now needed. It has been with.

Tree species diversity is not protection against bark beetle invasion

For more information:
Andreas Floren et al, The Impact of the Neophyte Tree Fraxinus pennsylvanica [Marshall] About the diversity of beetles under climate change sustainability (2022). DOI: 10.3390 / su14031914

Quote: Climate change beetle (February 21, 2022) obtained February 21, 2022 from https: //

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