Insects make up about half of all known living organisms. They play key roles in, pollination, nutrient cycling, food chains of birds and other insectivores, and are one of the pillars of our ecosystems.
However, the wide use of insecticides, fragmentation of habitats and climate change are placing multiple threats on them, and their populations are under sharp decline.
The single most pervasive service provided by insects, and possibly the most undervalued, is their role in developing and maintaining soil structure and fertility,” says the brief.
Now a new global study of the drivers of insect decline says habitat loss by conversion to intensive agriculture is the main driver of the declines. Agrochemical pollutants, invasive species, and climate change are additional causes.
“A rethinking of current agricultural practices, in particular, a serious reduction in pesticide usage and its substitution with more sustainable, ecologically based practices, is urgently needed to slow or reverse current trends, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide. In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments,” says a 2019 UN Environment Foresight Brief.
Insect species are declining
Across the world, more than 40 percent of insect species are declining and a third are endangered.
The rate of extinction is eight times faster than that of mammals, birds, and reptiles. The total mass of insects is falling by a precipitous 2.5 percent a year.
As a measure to help the situation, food systems need to change and remedial measures such as planting of indigenous tree species and rewilding of degraded landscapes need to take place at scale.
The impact of climate change on some animals and plants and the phenomenon of phenological mismatches is understood to some extent, but we have little information about the fate of insects, the most diverse group of animals on Earth, in a changing climate.
Another contributing factor to insect declines could be light pollution.
What can be done?
Crop yields need to be increased by planting flower strips and hedgerows, providing nesting resources; pesticides could be used in a more targeted way; pollinator diversity could be increased by restoration of semi-natural and natural areas; insect conservatories, butterfly farms and exhibits could be set up.