The abundance of the UK’s larger moths has crashed during the past 40 years with three species becoming extinct in the last decade, a major scientific report reveals today.
Elephant Hawk-moth – Rachel Scopes, Butterfly Conservation
The State of Britain’s Larger Moths 2013 found that the Orange Upperwing, Bordered Gothic and Brighton Wainscot had all become extinct in the last 10 years; these follow the extinctions of an additional 62 species during the 20th Century.
The report by Butterfly Conservation and Rothamsted Research revealed that two-thirds of common and widespread larger species (macro-moths) declined in the last 40 years. The losses in abundance were much greater in the southern half of Britain than the north.
Some once common garden species such as the V-moth, Garden Tiger and the Spinach have decreased by more than 90% from 1968-2007 and now face the real threat of extinction in the future.
Ongoing habitat loss and the deteriorating condition of the countryside are believed to be the major factors behind these declines.
The report is based on continuous records running from 1968 to 2007 on common and widespread species. These records represent the longest running national population trends of insect species known anywhere in the world.
Some two-thirds of the species recorded declined over the 40-year study, 37% of species decreased by at least 50%.
In the southern half of Britain, larger moth populations decreased by an average of 43% in comparison to an average 11% decline in northern Britain. Total abundance of moths decreased by 40% in southern Britain but showed no overall change in the north, where declines of some moth species were balanced out by other moths faring well.
The reason for the disparity between the two regions is likely to be due to higher levels of habitat loss in the south and the beneficial effect of climate warming on some moths in the north.
Moths are key indicator species for assessing the health of the environment. These findings point strongly to a wider insect biodiversity crisis and mirror declines of butterflies and bees and carabid beetles. The declines could have a knock-on effect for plant pollination and animals reliant on moths for food, such as garden and woodland birds, bats and small mammals.
While moth populations have declined substantially in the last few decades, the period has also seen an unprecedented influx of new moth species to Britain.
More than 100 species have been recorded for the first time in Britain this century and 27 species have colonised Britain from the year 2000 onwards. Climate change is seen as a major driver for these new colonisers as conditions become more suitable for continental species.
Butterfly Conservation Surveys Manager and lead author of the new report, Richard Fox said: “This report paints a bleak picture about Britain’s biodiversity. Much has been made of the decline of butterflies and honey bees but moths represent the massive, but largely un-noticed diversity of insects that form the vast majority of animal life in Britain.
“The severe declines of once common garden moths and overall decrease in moth abundance that we found are a damning indictment of how recent human activity has devastated our native wildlife.”
Chris Packham, Butterfly Conservation Vice-president
Chris Packham, Butterfly Conservation Vice-president said: “Larger moths are key indicator species that let us know how our environment is faring in a period of unprecedented environmental change.
“As well as being important pollinators, moths are an absolutely vital cog in the food chain for other species such as birds and bats. The dramatic and ongoing loss of moth abundance highlighted in this report signals a potentially catastrophic loss of biodiversity in the British countryside.”
David Brooks, an ecologist at Rothamsted Research who analysed the data, said: “This study highlights the value of long-term investment in monitoring of species populations, for discovering fundamental changes taking place in the ecology of the British landscape. The study would also not have been possible without the help of numerous volunteers and amateur naturalists, who increasingly make invaluable contributions to ecological research.”
TOP FIVE LOSERS AND WINNERS IN TERMS OF ABUNDANCE
Losers
1. V-moth Macaria wauaria 99% decrease
2. Garden Dart Euxoa nigricans 98% decrease
3. Double Dart Graphiphora augur 98% decrease
4. Dusky Thorn Ennomos fuscantaria 98% decrease
5. Hedge Rustic Tholera cespitis 97% decrease
Winners
1. Least Carpet Idaea rusticata 74,684% increase
2. Blair’s Shoulder-knot Lithophane leautieri 7,878% increase
3. Treble Brown Spot Idaea trigeminata 4,312% increase
4. Buff Footman Eilema depressa 3,884% increase
5. Scarce Footman Eilema complana 3,590% increase
The State of the UK’s Larger Moths 2013 report can be downloaded here
I haven’t found this report the remotest bit surprising, due to my observation decades ago that moths are hopelessly attracted to artificial lighting, such as has been flooding a huge proportion of the countryside from motorways and other “important” roads with no consideration of the environmental impacts (in this respect or otherwise for that matter). We have seen the same sick indifference of governments in respect of tree diseases being spread by unnecessary intercontinental transporting of tree products. All they think about is profit profit profit (like those “Argent” people.)
What proportion of the countryside (percentage-wise), would you say is ‘flooded’ by artificial lighting Robin? Feel free to go to at least four decimal points below zero in answering.
Steve’s answer appears to show confidence that the impact of the lighting must be very small and negligible. I lived for decades in the countryside and I think urban people have rather limited perspective on many things. Prior to artificial lighting the nighttime could be very dark indeed, apart from the occasions of moonlight which moths etc must have evolved not to try to fly up to.
There’s further an error of assuming things look to insects the same way they do to humans. It should already be obvious that that is profoundly untrue, else we too would be insanely trying to fly into the lightbulbs in our rooms. Who knows how the insects perceive the lights? Who knows how great is their sensitivity? The lights nowadays spread across huge swathes of land; road lighting is high up on poles. The lights of a city such as Bham prevent vision of the galaxy for miles around.
And this lighting does not just affect a few moths. When I lived next to a farm (and next to a main rd junction I should add) all manner of creepy things tried to get in my window if the curtains weren’t closed. Who has ever bothered to study the extent of this impact? Humans are playing with utmost blind recklessness with their very life-support system in this regard. Nature doesn’t need us but we ourselves cannot survive without nature. In my experience too many city people are too ignorant to understand this most basic fact of life.
Thank you Robin, I am aware of most of the issues you raise, having been to the countryside on at least one occasion. I was really just pointing out your rather lazy use of the term ‘huge proportion’. I intrepret a huge proportion to mean perhaps 70-80%. Such as in the phrase: “A huge proportion of the countryside is still fields, woodland, meadows, even unlit tracks, lanes or roads.”
“rather lazy use of the term ‘huge proportion’.”
I think you may be over-estimating the laziness there (notwithstanding that words are not my first language). As explained in my previous reply there is a huge amount of unknown involved. For all we know, the proportion illuminated (from an insect point of view) could be more like 100%. It is potentially (i.e. could well be in reality) an exceptionally important problem, which should be addressed in terms of precautionary principle rather than waved off in terms of the “absence of evidence is as good as proof of absence” principle.
Even where the insects are not being exterminated by the light, their populations could still be getting stressed such as to provide a breeding ground for diseases with potential catastrophic consequences for even any which are entirely out of light-range.
“having been to the countryside on at least one occasion.”
Haha, I know cos I went to London once……(etc, continued….)!
I never went back again though…couldn’t stand the bloody insects flying around!
“couldn’t stand the bloody insects flying around!”
Pretty tame compared to being chased by the boars, wolves, and bears that lived in the uk not so long ago.
My sister keeps 156 bears on shelves in a room in my house…and they don’t frighten me in the slightest. I think this conversation’s getting very silly now,.
One presumes,then, that you employ one of those electric devices that indiscriminately sizzles ‘bloody insects flying around’ in your garden of a summer evening.
…and a tazer for the cats.