Studies of insect populations over decades are scarce. UK’s leading ecologists previously wrote the report for the Wildlife Trusts. The previous studies have told that the average global insect is declining by 25% per decade. There will be a mass insect extinction event will take place and will have a huge effect on the world’s ecosystem. But the insect apocalypse is complex than previously thought.
A team of scientists from around the world analyzing 166 long-term survey of insects from 1,676 sites worldwide made their findings.
According to the new research published in the journal Science today, the authors assessed 166 surveys that cover insect data from 1925 to 2018. They observed that the average decline in terrestrial insect life has been nearly 9% per decade and some freshwater insect populations like midges and mayflies are increasing at an average rate of 11% per decade globally. This could be a result of efforts to clean up the water supply.
German Center for Integrative Biodiversity Research (iDiv) and Leipzig University Research-
Roel van Klink, a researcher at the German Center for Integrative Biodiversity Research (iDiv) and Leipzig University said in a study that Insect populations are like logs of wood that are tried to push underwater. The log of wood wants to come up, but we keep pushing it down. But we can reduce the pressure so that they can rise again.
The freshwater insects have shown us this is possible. It’s not always easy to identify the cause of the decline and to take effective measures to reverse them. The causes and the solution also differ between locations.
Ann Swengel, co-author of the study says-
Ann Swengel, the co-author of the study, said that after spending 34 years studying butterflies populations across hundreds of sites in Wisconsin and nearby states in the US many observations emerged.
There is so much decline in many protected sites. But there are some sites where butterflies are continuing to do well. It takes years to understand both the failures and successes in species by species and site by site.
‘We’ve seen so much decline, including on many protected sites. But we’ve also observed some sites where butterflies are continuing to do well.
‘It takes lots of years and lots of data to understand both the failures and the successes, species by species and site by site. There are several things beyond everybody’s control. But choices we each make in each site do matter.
Dr Roel van Kink, from the German Centre for Integrative Biodiversity Research statement-
Dr Roel also said butterflies, grasshoppers and other land insects had declined by 0.92% per year in the past 75 years. This won’t be sounding like much but it means 24% fewer insects in 30 years and 50% fewer over 75 years.
Insect decline does not take place in a day. It’s a slow process which happens quietly and one cannot notice from one year to the next. This can be taken as going back to the place where you grew up and suddenly you realise the fact that how much place has changed with the passing time.
Professor Jonathan Chase, from iDiv statement-
The researchers also explained the ‘windscreen phenomenon’. In this phenomenon, the bugs get splatted on their windscreens than 30 or 40 years ago.
The researchers claim their findings confirm the so-called ‘windscreen phenomenon’ – that fewer bugs get splatted on the windscreens than 30 or 40 years ago.
Professor Jonathan Chase, from iDiv, said that many insects can fly, and it’s those that get smashed by car windshields.
The analysis on this shows that flying insects have indeed decreased on average. The majority of the insects live out of sight like in soil, in tree canopies or the water.
The study published in the journal Science also revealed the facts that fewer insects are living in the grass and on the ground than in the past. The number living in tree canopies has, on average, stayed roughly the same.
Decline strongest in the US and Europe
The US and Europe observed the biggest drops in the year since 2005, especially in Germany. The insects and species live underwater showed an average increase of 1.08 % per year. That works out at a 38 per cent leap over 30 years for water-based insects.
Hope of reversing the numbers
The researchers said that its not too late to reverse the man-made effects on bugs. The number can be reversed. Over the past 50 years, several efforts have been taken to clean the polluted rivers and lakes across the world. Through this many freshwater insects recovered. There is still a hope that the trend for populations that are currently declining can be reversed.
