More than 40% of insect species may disappear in the next decades, according to the report "Decline of the entomofauna in the world: an overview of its factors", published in the journal Biological Conservation.
The report reveals that the biomass of insects decreases by 2,5% per year, indicating widespread extinctions over a century.
In addition to the endangered 40%, one-third of the species are at risk - number of people who could cause the collapse of the planet's ecosystems with a devastating impact on life on Earth.
The report, co-authored by scientists from the Universities of Sydney and Queensland and the Academy of Agricultural Sciences of China, examines dozens of existing reports on insect dieback published over the past three decades, as well as the reasons the decline in the number of insects. to produce the alarming global picture.
Its lead author, Francisco Sanchez-Bayo, of the School of Life Sciences and Environment at the University of Sydney, called the study a truly comprehensive first review of the problem.
While in the past the focus was on the decline of vertebrate animal biodiversity, this study emphasized the importance of insect life for interconnected ecosystems and the food web. The bugs represent about 70% of all animal species.
The impact of the extinction of insects would be "catastrophic, to say the least," according to the report, because insects were at "the structural and functional base of many ecosystems in the world since their appearance ... there are nearly 400 million years. "
The main causes of the decline include "habitat loss and conversion to intensive agriculture and urbanization", pollution, particularly by pesticides and fertilizers, and biological factors, such as "pathogens and introduced species" and climate change.
While a large number of specialized insects filling a specific ecological niche and insects in general were declining, a small number of adaptable insects saw their numbers increase, but not enough to stop the decline, according to the report.
Small creatures that lead the world
Don Sands, a retired entomologist and scientist with the Commonwealth Scientific and Industrial Research Organization, said he "strongly" agreed that the effects of insect loss were "serious". ".
"If we do not have insects as moderators of other pest populations, we have insect populations that come alive and ruin crops and make it difficult to grow," he said. .
He added that the ecosystem at this level must "be in balance. It is the bottom layer and, if we do not approach it, all our lives could be hard hit.
"(Insects are) the little creatures that rule the world," he said.
Insect reports Declines are not new: researchers warn of the phenomenon and its impact for years.
"These are not agricultural areas, they are places to preserve biodiversity, but we still see insects get out of our hands," said co-author Caspar Hallman.
Scientists say that insect-dependent species - and predators high up in the food chain that eat them - are likely to suffer from this decline. Pollination of wild crops and plants would also be affected, as would the nutrient cycle in the soil.
According to the study, about 80% of wild plants use insects for pollination, while 60% of birds use them as a food source. Sands stated that the immediate decline of insects poses an immediate threat, namely the loss of insectivorous birds and the risk of larger birds feeding each other on insects.
In his native Australia, "birds that lack insects are turning around," he said, adding that it was probably a global phenomenon.
Radical action needed
The report's authors called for radical and immediate action.
"Since insects are the most abundant and diverse group of animals in the world and provide essential services within ecosystems, such events can not be ignored and must prompt decisive action to prevent a catastrophic collapse. natural ecosystems, "they wrote.
They suggested revisiting existing farming methods, "in particular a significant reduction in pesticide use and its substitution with more sustainable and ecological practices".
"The conclusion is clear: unless we change our methods of food production, the insects as a whole will fall on the road to extinction in a few decades," they concluded.
This article appeared first on https://www.cnn.com/2019/02/11/health/insect-decline-study-intl/index.html