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article imageDecline in insect numbers may have catastrophic effect on planet

By Karen Graham     Feb 11, 2019 in Environment
A scientific review of insect numbers suggests that 40 percent of species are undergoing dramatic rates of decline around the world, threatening a “catastrophic collapse of nature’s ecosystems."
Over 40 percent of insect species could become extinct in the next few decades, according to the "Worldwide decline of the entomofauna: A review of its drivers" report, published in the journal Biological Conservation.
Our planet is at the start of the sixth mass extinction in its history, according to a peer-reviewed study published in the journal Proceedings of the National Academy of Sciences on July 25, 2017. The rate of extinction among insects is eight times faster than that of mammals, birds, and reptiles.
Even with this shocking rate of insect losses, they are, by far, the most abundant and varied of animals - outweighing the Earth's human population by 17 times over. But we have to keep in mind that insects are essential to the proper functioning of our ecosystems, regardless of how much we may dislike them.
Further Reading: Climate change cited in dwindling of Puerto Rico insects
Besides being a food source for birds and many bats and small animals, insects pollinate over 75 percent of our food crops, help in replenishing the soil and keep other insects in check. As for pollinators, we have already documented the decline in butterflies and bees, so essential to our agricultural needs.
Bumble bees travel up to two kilometres to collect pollen and nectar from flowers. They are social i...
Bumble bees travel up to two kilometres to collect pollen and nectar from flowers. They are social insects, which live in colonies.
Taking a broader look
The report was co-authored by a team of scientists from the universities of Sydney and Queensland and the China Academy of Agricultural Sciences. The scientists reviewed 73 studies from around the world published over the last 13 years to reach their conclusions.
The researchers found the main driver for insect losses was the use of "intensive agriculture," a method of farming that is cost and labor intensive- using large amounts of fertilizers and pesticides for crops, and medication for animal stocks.
Further Reading: Climate driven crash in insect populations decimating food web
"The main factor is the loss of habitat, due to agricultural practices, urbanization and deforestation," lead author Dr. Francisco Sánchez-Bayo, from the University of Sydney, told BBC News.
Scientists warn that a predicted mass death of pollinators like bees will result in higher food pric...
Scientists warn that a predicted mass death of pollinators like bees will result in higher food prices and the risk of shortages
Mikko Stig, Lehtikuva/AFP/File
"Second is the increasing use of fertilizers and pesticides in agriculture worldwide and contamination with chemical pollutants of all kinds. Thirdly, we have biological factors, such as invasive species and pathogens; and fourthly, we have climate change, particularly in tropical areas where it is known to have a big impact."
The research team also found the rate of loss for insects was about 2.5 percent a year, globally. Sánchez-Bayo told the Guardian: “It is very rapid. In 10 years you will have a quarter less, in 50 years only half left and in 100 years you will have none.” Most of the studies reviewed were done in western Europe and the US, with a few ranging from Australia to China and Brazil to South Africa, but very few exist elsewhere simply because they are not being done.
The researchers also note this is the first study of its kind to provide a global picture of insect decline. While we have focused on the decline of vertebrates, this study shows the interconnection of insects with all ecosystems and the food chain.
The United Nations said last year that 40 percent of invertebrate pollinators -- particularly bees a...
The United Nations said last year that 40 percent of invertebrate pollinators -- particularly bees and butterflies -- risk global extinction
JACK GUEZ, AFP/File
Don Sands is an entomologist and retired Commonwealth Scientific and Industrial Research Organization scientist. He entirely agrees with the research paper. "If we don't have insects as moderators of other pest populations, we have insect populations that flare up and ruin crops and make them difficult to grow," he said.
Radical action needed now
"Because insects constitute the world's most abundant and (species-diverse) animal group and provide critical services within ecosystems, such events cannot be ignored and should prompt decisive action to avert a catastrophic collapse of nature's ecosystems," the researchers wrote.
"The conclusion is clear: unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades," they concluded.
More about Extinction, Pesticides, intensive agriculture, urbanization, Insects
 
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