The dark bush-cricket Pholidoptera griseoaptera is one of the many declining insect species in Central Europe. Credit: © Beat Wermelinger
Key points:
- A new study identifies the main causes of the drastic decline of insect numbers and diversity.
- These include land-use intensification, global warming, and the escalating dispersal of invasive species.
- Researchers propose the creation of interconnected nature reserves as a countermeasure.
In the past few years, researchers have seen an incredible decline in not only the number of insects, but their diversity as well.
Now, a new paper sheds light on the troubling phenomenon, linking it to growing land-use intensification for agriculture and development, climate change and the spread of invasive animal species as a result of human trade.
Researcher Florian Menzel from the Institute of Organismic and Molecular Evolution at Johannes Gutenberg University Mainz published a special issue of Biology Letters featuring 12 articles, two opinion papers, and an extensive editorial on the causes and consequences of the worldwide insect decline as well as recommended countermeasures.
Menzel says its not only the main drivers that are hurting insect populations, it’s how those drivers interact with each other. For example, ecosystems deteriorated by humans are more susceptible to climate change, as are are their insect communities. Added to this, invasive species can establish easier in habitats damaged by human land-use and displace the native species.
“It looks as if it is the specialized insect species that suffer most, while the more generalized species tend to survive. This is why we are now finding more insects capable of living nearly anywhere while those species that need specific habitats are on the wane,” said Menzel.
The consequences of this development are proving to be detrimental for ecosystems. For example, the loss of bumblebee diversity has resulted in a concomitant decline in plants that rely on certain bumblebee species for pollination. Fewer species means there are fewer insects capable of pollinating plants and keeping pests in check.
In terms of countermeasures, the researchers advocate for standardized techniques to monitor insect diversity across many habitats and countries. They also propose the creation of a network of interconnected nature reserves and measures to reduce the dispersal of invasive animal and plant species through globalized trade and tourism.