Native ladybird species in the UK and Europe are declining rapidly due to the spread of the invasive harlequin ladybird, according to scientists.

Harlequin ladybird

Invasive alien

Native to Asia, the harlequin ladybird (Harmonia axyridis) has been introduced to many countries as a pest control agent, but is now spreading rapidly and has itself become a pest species.

Introduced to North America in 1988, the harlequin is now the most widespread ladybird on the continent, and the species has also invaded much of northwest Europe. It was first spotted in Belgium in 2001, and arrived in the UK and Switzerland in 2004.

Since the harlequin’s arrival, scientists have warned about its potentially harmful impacts on native ladybird species. However, new research published in the journal Diversity and Distributions has now measured the scale of these impacts and demonstrated a strong link between the spread of the harlequin and rapid declines in native ladybirds.

Harlequin ladybirds showing some of the colour variation in this species

Rapid declines

Led by the Centre for Ecology and Hydrology in the UK, the study was made possible by thousands of records submitted as part of “citizen science” projects that record ladybird observations across Britain, Belgium and Switzerland.

Using this data, the researchers found that in the five years following the harlequin ladybird’s arrival in the UK, seven out of eight native ladybird species declined. Similar declines were also found in Belgium and Switzerland.

Particularly badly affected was the two-spot ladybird (Adalia bipunctata), which is estimated to have declined by 44% in the UK and 30% in Belgium. It is now difficult to spot in some areas where it was once common.

Outcompeted

Like many other native ladybirds, the two-spot ladybird is smaller than the harlequin and likely to be outcompeted for food and habitat. The harlequin is also likely to prey on the eggs and larvae of native ladybird species. In addition, the harlequin ladybird may potentially be more toxic than native species, giving it better protection against predators.

Harlequin ladybird in flight

Speaking about the results, Helen Roy of the Centre for Ecology and Hydrology said, “It’s a very real decline, which should be put amongst a whole other set of factors putting ladybirds in a more fragile situation.”

Such factors may include the intensification of agriculture and climate change.

The only UK species apparently unaffected by the harlequin’s arrival was the seven-spot ladybird (Coccinella septempunctata), which is similar in size to the harlequin and not in such direct competition for habitat as other native species.

Seven-spot ladybird feeding on aphids

Ecosystem impacts

The researchers have warned of potentially serious consequences if the harlequin ladybird continues to spread. Ladybirds play an essential role in ecosystems, keeping pests such as aphids in check. Although the harlequin ladybird also feeds on aphids, having just one species playing this role could make the overall ecosystem weaker.

Tim Adriaens of the Research Institute for Nature and Forest (INBO) in Belgium, said, “At the continental scale, the arrival of the harlequin could impact on the resilience of ecosystems and severely diminish the vital services that ladybirds deliver.”

Read more on this story at BBC News – Ladybird decline driven by ‘invading’ harlequin and at The Telegraph – Harlequin ladybirds threaten British species.

Find out more about how to record UK ladybird sightings at The Harlequin Ladybird Survey and UK Ladybird Survey.

View photos and videos of ladybirds on ARKive.

Liz Shaw, ARKive Species Text Author

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Two common otters spotted in Kent, in the South East of the UK, mark the return of this charismatic mammal to every English county, according to the UK Environment Agency.

Return from near extinction

Also known as the Eurasian or European otter, the common otter had declined drastically in England due to persecution, habitat degradation, and poisoning by pesticides washed into waterways. By the 1970s, the species had almost entirely disappeared from the country.

Fortunately, legal protection and improvements in water quality have seen the common otter return from the brink of extinction. A survey of over 3,000 river sites in England between 2009 and 2010 found that the number of areas with evidence of otters had increased tenfold in the last 30 years, and otters are even starting to reappear in cities such as Bristol, Birmingham, Manchester and London.

According to the Environment Agency, the return of otters indicates that English rivers are at their healthiest for over 20 years.

“The recovery of otters from near-extinction shows how far we’ve come in controlling pollution and improving water quality,” said Alastair Driver, the Environment Agency’s national conservation manager.

“Rivers in England are the healthiest for over 20 years and otters, salmon and other wildlife are returning to many rivers for the first time since the Industrial Revolution.”

Final piece in the jigsaw

Despite this nationwide recovery, otters have been slow to return to the South East, with experts predicting that the species would not be resident in Kent for another ten years. However, the two otters recently spotted in the county, on the Medway and Eden rivers, means that the common otter has now returned to every county in England.

“The fact that otters are now returning to Kent is the final piece in the jigsaw for otter recovery in England and is a symbol of great success for everybody involved in otter conservation,” said Mr Driver.

Although the common otter still faces threats from human encroachment, road fatalities and conflict with anglers, these sightings are positive news for the comeback of this species, and for the state of English waterways.

Read more about this story at the BBC – Otters return to every county in England.

View photos and videos of otter species on ARKive.

Liz Shaw, ARKive Species Text Author

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Did anyone (in the UK) catch last night’s The One Show on the BBC? If so, you would’ve seen Lizzie Croose from the Vincent Wildlife Trust explaining the ins and outs of pine marten conservation in England and Wales. For those of you who missed it, here’s Lizzie’s guest blog for ARKive explaining all…

The whereabouts of pine martens in England and Wales is one of the greatest mysteries facing UK mammalogists today. The Vincent Wildlife Trust (VWT) has been collecting information on these agile cat-sized carnivores for more than 15 years, and although we are not quite ‘in the dark’ about the status of pine martens south of the Scottish border, there is certainly much more light that can be shed on these elusive mustelids.

The presence of pine martens is confirmed by the occasional scat sample, carcass or blurry photograph that emerges every couple of years, but other than this, we know very little about the distribution and ecology of these secretive creatures. Whilst pine martens are now faring very well in Scotland and Ireland and expanding in number and range, the situation in England and Wales is less clear.

The elusive pine marten

What we do know is that this charismatic mammal is now the rarest carnivore in England and Wales, as a result of years of persecution and woodland clearance. Today, small populations survive in the most remote corners of the country, to where they retreated over 100 years ago, such as Northumberland, the Lake District, North Yorkshire, the Peak District, Snowdonia and parts of mid and west Wales. But even in these ‘hot spots’, pine martens are not easy to spot. They are largely nocturnal, inhabit dense woodlands, live at low densities and can roam vast territories of up to 82km².

Pine martens are adept tree-climbers

So how do we make contact with such an elusive animal? The Vincent Wildlife Trust has been using an array of techniques to try and track down pine martens, including scat surveys, baited hair-collection tubes, scent lures and remote-sensor camera traps. Nevertheless, often our detection efforts are in vain and irrefutable DNA evidence of martens is very hard to come by. As a result, sightings reported by members of the public and naturalists make up the majority of the body of evidence that we have and provide a valuable insight into the secret lives of pine martens.

The pine marten is listed as a Biodiversity Action Plan (BAP) species which means that assisting it to recover and prosper in England and Wales is a conservation priority. A key factor which is limiting the species recovery is probably a lack of suitable arboreal – or above ground – den sites, which provide pine martens with a safe place to raise their young and shelter from the elements, away from foxes and other predators.

Pine marten mother and kits in nest box

Preferentially, martens will den in large tree cavities, usually prevalent in ancient woodland, but today’s relatively young woodland does not provide many above-ground den sites. However, the VWT have come up with a cosy solution: artificial den boxes. Martens take readily to boxes in parts of Scotland where they have successfully raised kits in them, making den boxes a very useful conservation tool. However, boxes can only be a temporary solution and promoting the widespread retention of old trees and encouraging the development of natural cavities is a more sustainable long-term solution.

Pine marten nest box with scats

We hope that in time, habitat and environmental conditions will improve in order to support the recovery of the pine marten south of the Scottish border, but until then, we may have to continue travelling to Scotland in order to get a glimpse of this enigmatic animal.

For more information on the pine marten or to report a sighting in England or Wales, please visit www.pinemarten.info.

Visit ARKive’s great collection of pine marten photos and videos.

Written by Lizzie Croose, Administration and Field Assistant, Vincent Wildlife Trust.

Article contributed by Dr Neil Jordan, Pine Marten Project Manager, Vincent Wildlife Trust

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