He estimated that only 30% of Australian insect species were identified. Job cuts by scientists, including government agencies, have made it difficult to monitor populations of known species, not to mention the identification of new species.
Dr. Sanchez-Bayo and Kris Wyckhuys report in the April Biological Conservation that one-third of all insect species are threatened in the countries studied. Total biomass of insects is also declining at a rate of 2.5% globally, according to a review of 73 historical reports.
The document identified habitat loss – such as expanding cities and intensifying agriculture – increasing use of long-lived pesticides and other agricultural chemicals, increased pathogens and climate change as the major drivers behind the decline .
"The general public does not consider insects important – they find them a nuisance," said Sanchez-Bayo. "It's a reality – insects are disappearing everywhere."
In fact, insects are critical for pollination, recycling soil materials and purifying water. They also provide the primary source of food for birds, bats, fish and many other species of vertebrates that generally attract more scientific interest and friendliness from the public.
"If we exhaust the source of food, as it is happening now, all these animals will go hungry," said Sanchez-Bayo. "They will disappear simply because they have no food."
The other 99% & # 39;
Richard Kingsford, director of the Center for Ecosystem Science at the University of NSW, said that invertebrates are often referred to as "the other 99%" because they make up the bulk of the world's biodiversity.
"They are a little out of sight, when we measure and monitor biodiversity with a focus on megafauna – birds, mammals, reptiles, frogs and fish – but it is they who make the world of the environment," said Professor Kingsford.
"They do a lot of things for humanity that cost us nothing. And they are essential for the future of the planet," he said, adding that the new article reported "a worldwide trend of alarming drops in biodiversity."
Dr. Sanchez-Bayo said that much of the public can feel, from everyday experiences, that numbers of insects are in the skids.
He said driving in the Australian bush used to fill the windshield with insects. On the other hand, a recent trip from Sydney to Cooma in the Snowy Mountains left a "untouched" windscreen.
& # 39; Many pesticides & # 39;
Although your article with Dr. Wyckhuys focused primarily on research from North America and Europe, the likelihood is that insect population decline related to pesticide use will be higher elsewhere, such as in Africa and North America. South.
"Farmers are using a lot of pesticides," he said. "So the impact of these agricultural practices in these countries is probably much greater than the impact they are having on European and North American countries."
Farmers need to "reverse the way we have done things in the past," said Sanchez-Bayo, as the reintroduction of hedge or other habitats to foster diverse species – some of which would control insects without chemicals.
While climate change would increase the range of certain insects, the impact on other regions would probably be negative, especially in the tropics.
"We know that insects in tropical areas are less resistant to temperature changes," he said.
Peter Hannam writes about environmental issues for The Sydney Morning Herald and The Age.