Although there is abundant anecdotal evidence that there are fewer and fewer insects on the planet, recent studies have shown that the populations of these species are in sharp decline.
“Insects make up about half of all known living organisms. They play key roles in pollination, nutrient cycling, the food chains of birds and other insectivores, and are one of the pillars of our ecosystems. However, the widespread use of insecticides, habitat fragmentation and climate change pose multiple threats to them. , and their populations are suffering a sharp decline, "warned a summary of forecasts by UN Environment in January 2019.
"The most widespread service provided by insects, and possibly the most undervalued, is their role in developing and maintaining soil structure and fertility," the document says.
A recent study found that the number of insects in West German nature reserves decreased by more than 76% between 1973 and 2000. The European Union's Biodiversity Strategy aims to halt the loss of species and ecosystem services by 2020.
A new global study indicates that the main cause of the decline of insects is the loss of habitats due to the expansion of intensive agriculture. Agrochemical pollutants, invasive species, and climate change are additional reasons.
“A rethinking of current agricultural practices is urgently needed, in particular a serious reduction in pesticide use and its replacement by more sustainable and ecologically based practices to slow or reverse current trends, allow the recovery of declining insect populations and safeguard Vital ecosystem services they provide. In addition, effective remediation technologies must be applied to clean and polluted waters, in both agricultural and urban settings, ”says the study.
40% of insect species are in decline
According to the analysis, more than 40% of insect species are declining and a third are in danger of extinction. Their extinction rate is eight times faster than that of mammals, birds and reptiles. The total insect population is declining at a rate of 2.5% per year, according to the best available data, suggesting that these species could disappear within a century.
Lepidoptera, hymenoptera, and earth beetles (Coleoptera) are the taxa (groups of organisms) most affected; Four aquatic taxa are in danger and have already lost a large proportion of their species.
The insects of the world are hurtling down the road to extinction. Their disappearance would lead to a catastrophic collapse of nature's ecosystems, ”said Marieta Sakalian, a biodiversity expert at UN Environment. "We need to act urgently on many fronts to stop this decline."
The researchers presented their conclusions in unusually striking terms for a scientific paper: “[insect] trends confirm that the sixth most important extinction event is profoundly affecting life forms on our planet (…). Unless we change our ways of producing food, insects as a whole will end up on the road to extinction in a few decades (…). The repercussions this will have for the planet's ecosystems are catastrophic, to say the least. "
UN Environment experts consider that the study is a call for reflection. "Like the recent report of the Intergovernmental Panel on Climate Change, which emphasized that we have about a decade to change the way we live, this is a compelling analysis," says Sakalian.
"Food systems must change and remedial measures, such as planting indigenous tree species and rebuilding degraded landscapes, must be expanded," he added.
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.
In addition to losing their habitat due to climate change, another factor that can contribute to their disappearance is light pollution.
What can we do?
There are many actions to take in favor of insects. We share a few below:
- Crop yields could be increased if flower strips and hedges are planted, providing nesting resources.
- Pesticides could be used in a more specific way.
- Pollinator diversity could be increased by restoring semi-natural and natural areas.
- Insect shelters and butterfly farms could be set up.
Source: UN Environment