Insect loss plotted
Scientists warn that rapidly declining insect populations spell ‘catastrophic’ trouble.
Pesticide use and other factors mean more than 40 per cent of insect species could become extinct in the next few decades, according to a global review published in the journal Biological Conservation.
Insect biomass is declining by 2.5 per cent a year, indicating widespread extinctions within a century, the report found.
The report by scientists from the universities of Sydney and Queensland and the China Academy of Agricultural Sciences, looked at reports on insect decline over the past three decades, examining the reasons behind the falling numbers.
Lead author Francisco Sanchez-Bayo, of the School of Life and Environmental Sciences at the University of Sydney, said it is the first truly global examination of the issue.
The damage that the loss of insects could create is hard to overstate. The report says insects have been at “the structural and functional base of many of the world's ecosystems since their rise ... almost 400 million years ago”.
But they now face causes of decline including “habitat loss and conversion to intensive agriculture and urbanization”, pollution from pesticides and fertilisers, biological factors like “pathogens and introduced species”, and climate change.
The report calls for action.
“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 authors wrote.
They say farming will need big reforms, “in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices”.
“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.”
Entomologist and former CSIRO scientist Don Sands says the “bottom-up” effects of insect loss are extremely serious.
“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.
He describes insects as; “The small creatures that run the world”.