All studies lead to the same conclusion. The insects disappear at one speed worrying. Up to 2% of the population would thus be swept off the surface of the Earth each year. In the UK, a project research team Buglife — a nature conservation charity — has just published new results more specifically about flying insects. Results that confirm the sad trend.
To get an idea of the insect population flying in the United Kingdom, they made available to the public, a application called Bugs Matter. Understand “on the importance of small animals”. Users had the task of carefully cleaning their license plate before setting off on a trip. Then, on the way back, to take a picture of said plate and count how many insects had stranded there. The operation was carried out over fifteen years, between 2004 and 2021.
Result: between the beginning and the end of the survey, the number of insects crushed on license plates decreased by… 58.5%! A judged figure “dramatic and alarming” which suggests that the total number of flying insects in the UK has declined by around 34% per decade since the start of the 21st century.and century. As main suspects, scientists point to theuse of insecticidesloss of habitat and food and of course, climate change.
Global warming is harming insect diversity
Remember that three-quarters of our food crops and more than 80% of wild plants depend on pollination by insects. A service estimated at some 550 billion euros per year worldwide. So what can be done to halt the decline? From researchers of the Julius-Maximilians-University (Germany) asked themselves the question.
Based on data collected on more than 3,200 species ofpollinating insects evolving in nearly 180 sites in forests, meadows or habitats arable and urban areas spread over the whole of Bavaria (Germany), they first note that changes in land use are primarily responsible for the massive disappearance of pollinating insects. Hot climates have a rather negative impact on the biodiversity of these little beasts. This raises fears of a global loss in the future.
Forests and their edges provide conditions that buffer extreme heat and drought
However, the researchers observe that, even if the responses to the heat and dryness from one to the other differ, a general pattern emerges. The forest seems to play a beneficial role. It maintains more diverse pollinator communities despite high temperatures.
“Probably because the forests and their selvedges provide largely natural conditions that dampen the heat and the drought extremes compared to more human-influenced habitats”advances Cristina Ganuza, doctoral student at the laboratory ofecology animal of the Julius-Maximilians-Universityin a communicated. Woodlands, then, as a haven for insects on a warming planet. And on which diversity could prove increasingly essential to maintaining the performance of pollinators. One more reason also to campaign for the greening of urban areas…
Disappearance of insects: the main causes and culprits
A study of theUniversity College of London claims that 49% of the insect population has disappeared in areas that are degraded by theAgriculture intensive and affected by the global warming.
Article of Karine Durand published on 04/25/2022
The study published in the journal Natureis the first to identify the link between rising temperatures, intensive land use, and massive disappearance of insects across the entire planet. The researchers studied 20,000 different species of insects in 6,000 localities spread over all regions of the globe.
They compared the number and diversity insects on each area in relation to the level of land degradation linked to agriculture and the progression of global warming in the place. In areas where the land has been transformed by intensive agriculture and where the rise in temperatures is the greatest, the number of insects is 49% lower than in areas that have remained natural and with limited warming.
In these more preserved areas, with agriculture present but more limited and a less significant rise in temperatures, the reduction in the number of insects remains significant despite everything: their population has also decreased by 29%. In habitats that remained 75% natural, the insect population decreased by 7%. Areas where the land is 75% degraded, and where only 25% of natural habitat remains, have seen their insect population decrease by 63%.
Insects are disappearing at an alarming rate in the tropics
tropical regions, known for their biodiversity particularly rich, are those most affected by the disappearance of insects. Intensive agriculture and global warming serve as a double penalty for insects: most of them, especially in tropical areas, need the shade provided by trees and wild plants to survive the heat and the sun hot all day. However, in a warmer context linked to global warming, intensive agriculture has removed a large part of this shadow.
Part of the insects had already begun to disappear before the study and probably even before the discovery of many species
In areas degraded by intensive agriculture, populations of pollinators are 70% lower than in natural soils. The study authors point out that the loss estimated in their study is only the tip of the iceberg and could in fact be much greater.
Part of the insects had already begun to disappear before the study and probably even before the discovery of many species, the world of insects still remaining largely unknown. In addition, the researchers limited themselves to the parameters of warming and land use, without taking into account the effects of pollution.
What are the proposed solutions? There is no question of calling into question the vital need for agricultural fields, but it is necessary to preserve the natural habitats around agricultural areas (hedges, wooded areas…), to stop the expansion of intensive agriculture, and reduce the emissions greenhouse gases to limit global warming.
London researchers recall the primordial importance of insects in theecosystem : these are key species essential to the food chain, but also for the survival of the human species. Continuing to lose insect populations, and particularly those of pollinators, could threaten our food security In the coming years.
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