According to the scientists behind the new research, insect populations are suffering “a thousand declining deaths”, many of which are declining at a “frightening” rate, “tearing the tapestry of life.”
These insects face multiple overlapping threats, including the destruction of wild habitats from agriculture, urbanization, pesticides, and light pollution. Population collapses are recorded in places where human activities dominate (eg in Germany), but data from regions outside Europe and North America are scarce, especially from wild tropical areas where most insects live.
Scientists are particularly worried that the climate crisis may cause severe damage in the tropics. But despite the need for more data, the researchers said they knew enough to take urgent action.
So far, insects are the most diverse and abundant animals on the earth, with millions of species, 1
Studies have shown that the situation is complex. Some insect populations have increased, such as those that have expanded as global heating curbs cold winter temperatures, and others have recovered from low levels as water pollution has decreased.
The good news is that in the past two years, the trend of declining insect populations has become increasingly obvious, which has prompted the government to take action in some places, and an “extraordinary” number of citizen scientists are helping to study the huge challenges of these tiny creatures.
These 12 new studies were published in the Proceedings of the National Academy of Sciences. “Nature is surrounded [and] Most biologists believe that the world has entered the sixth mass extinction event. “The lead analysis in the packaging concluded. Insects are suffering from “death from a thousand swords” [and] A severe decline in insect populations may have an impact on the global ecology and economy. “
The lead author of the analysis, Professor David Wagner of the University of Connecticut, said that the populations of many insects are declining at a rate of 1-2% per year. This rate cannot be underestimated: “Within ten years, the loss of 10-20% of animals is It’s scary. You are tearing up the tapestry of life.”
Wagner said that most of the reasons for the decline in insect populations are well known. “But there is a really big unknown, and that is climate change. This is what scares me the most.” He said that climate change may “promote [insect] The rate of extinction is unprecedented. “
Wagner said: “Insects are really susceptible to drought because they have a large surface area and no volume.” “Things like dragonflies and damselflies may dry and die within an hour when humidity is low. “
A study found that increasingly unstable climate is the primary cause of the loss of moths and other insects throughout the region in the forests of northwest Costa Rica since 1978. Wagner said.
However, another study is contrary to the 2018 report, which stated that insects in Puerto Rico’s forests were 98% extinct. The new paper says that “in general there is no reduction” and that demographic changes are driven by hurricanes rather than climate change. Brad Lister, who led the 2018 study, said that he is not convinced by the work, but will conduct his own analysis of the data used and submit the conclusions to the PNAS editor.
Wagner said that growing public attention has prompted some actions, such as the European Union’s initiative to protect pollinators, Germany’s commitment of 118 million euros (106 million pounds) for insect protection, and Sweden’s commitment of 25 million US dollars.
Another paper proposed actions that can protect insects. The report says that people can replant gardens, reduce the use of pesticides and limit outdoor lighting, and countries must reduce the impact of agriculture. All groups can help change people’s attitudes towards insects by communicating that they are an important part of the world of life.
To date, the world’s largest systematic assessment of insect abundance was released in April 2020, and has fallen by nearly 25% in the past 30 years, while the decline in Europe has accelerated. This indicates that land insects are declining at a rate close to 1% per year. The previous largest assessment based on 73 studies led researchers to warn that if the loss of insects is not prevented, “disastrous consequences for human survival”. It estimates the rate of decline at 2.5% per year.
Other PNAS papers find rise and fall. A person familiar with the matter said that the number of butterflies in the UK has fallen by 50% since 1976 and has fallen by 50% since 1990. It also shows that the range of butterflies began to shrink very early, dropping by 80% between 1890 and 1940. However, research on moths shows that in the past two decades, the long-term reduction of moths in Ecuador and Arizona in the United States has been zero or only a small reduction.
“The most important thing we learned [from these new studies] It is the complexity behind insect decline. There is no quick solution to this problem. “Said Roel van Klink of the German Comprehensive Biodiversity Research Center. “Of course, the number of insects has dropped sharply in some places, but not everywhere. This is a reason for hope because it can help us understand what we can do to help them. When the situation improves, they can rebound quickly. .”
Wagner said: “We know that nature is under siege, we know that we have a responsibility-we really don’t need more data to start changing our work. What will happen if we don’t start paying attention and changing our consumption patterns This is unreasonable.”
Another paper in the series co-authored by Wagner concludes: “To mitigate the effects of our sixth mass extinction, the following will be necessary: stable (and almost certainly more Low population, consumption, and social justice, which empower the richer people and countries in the world where most of us live.”