Climate change and habitat loss from big farming are combining to crush global insect populations, with each problem aggravating the other, according to a new study.
Although insects can sometimes bother people, they are also essential for pollinating plants to feed people, making the soil more fertile, and they include beautiful butterflies and fireflies. Scientists have noticed a dramatic drop in both the total number of insects and the diversity of insect species, calling this a slow-motion death per 1,000 cut. These reductions include pesticides and light pollution.
Large, single-crop agriculture that leaves less habitat and leafy food for insects, along with higher temperatures due to climate change, are huge problems for insects, but a new study in the journal Nature Wednesday based over 750,000 samples of 18,000 different species of insects says that is not the case. just these two threats acting on their own. It’s the way habitat loss and climate change interact that really crushes insect populations.
In about half of the cases where insect numbers dropped, the researchers found that climate change and habitat loss from agriculture multiplied each other. In more than a quarter of the cases of loss of biodiversity, ie fewer species, the same dynamic was at work.
“We know that insects are under threat. We now get a much better idea of what threatens them and by how much,” said study author Charlotte Outhwaite, an ecologist at University College London.
“In this case, habitat loss and climate change can often be worse than if they acted alone, as one can worsen the impact of the other and vice versa,” Outhwaite said. “We miss part of the picture if we only look at these things individually.”
For example, monoculture agriculture often reduces shade from trees, making it warmer in a given location. On top of that comes climate change, she said. Then, insects that need relief from the heat or must move north to cooler climates may encounter problems with a lack of suitable habitat on large farms.
It’s particularly a problem in countries like Indonesia and Brazil, where forests are being cleared and temperatures are warming more than in other parts of the globe, Outhwaite said.
It’s hard on insects like the pesky gnat.
“Cocoa is pollinated mainly by midges and people don’t like midges. You know it’s the annoying ones that bite you, they harass you at picnics,” Outhwaite said. “But if you like chocolate, you should be grateful because without them we would have a lot less cocoa.”
The same can be said for bees, which are struggling with warming due to climate change and monoculture, Outhwaite said.
Pollinating insects are responsible for about a third of the human diet, according to the US Department of Agriculture. And 2 out of 5 species of pollinating invertebrates, such as bees and butterflies, are on the verge of extinction, according to a 2016 United Nations science report.
What makes this study important is that it is the first to link climate change and industrialized agriculture to explain insect damage, said University of Connecticut entomologist David Wagner, who was not part of the study. Because the study used so many different samples and species and looked around the world, it lends more credence to its findings, Wagner said.
Seth Borenstein, Associated Press
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