'Stop using the bloody things': pesticides linked to bee collapse now blamed for bird declines

Jeremy Hance
mongabay.com
July 15, 2014



In recent years the evidence has piled up that neonicotinoids—a hugely popular group of pesticide—may be at least partly responsible for ongoing bee and pollinator collapse. But new research in the journal Nature find that these pesticides could also be taking a heavy toll on other species, in this case common birds.

Using longterm data of bird populations in the Netherlands, researchers found that where water samples showed high contamination levels of imidacloprid, a neonicotinoid pesticide, bird populations plunged. The scientists could find no other explanation—including habitat loss—for the decline in birds that are abundant elsewhere.

According to lead author, Hans de Kroon from Radboud University, their research took an unusual approach on the impact of neonicotinoids.

"All the other studies build up from toxicology studies. But we approached this completely from the other end. We started with the bird population data and tried to explain the declines," de Kroom told the Guardian. "Our study really makes the evidence complete that something is going on here. We can't go on like this any more. It has to stop."

In areas where the researchers found imidacloprid levels of 20 nanograms per a liter of water, bird populations were declining at 3.5 percent every year. And in some places imidacloprid levels were 50 times higher.

The barn swallow was one of 15 birds studied by the scientists. Photo by: Malene Thyssen.
The barn swallow was one of 15 birds studied by the scientists. Photo by: Malene Thyssen/Creative Commons 3.0.

The researchers believe that at such levels the pesticides are wiping out many of the insects the birds depend on, especially for reproduction, essentially starving out the population. Although it's possible the pesticides are harming the species in other ways, though more research would be required. In all scientists measured declines in 14 insect-eating birds out of the 15 species surveyed.

The researchers note that if vanishing insects are hurting bird populations, the trend would likely also impact other animals, such as bats and other insectivores. However, whether or not the pesticides are directly impacting the birds would require more research.

The most heavily used pesticides in the world today, neonicotinoids employ a nerve agent similar to nicotine to tackle crop pests. While the pesticides don't usually kill pollinators outright, scientists are increasingly convinced that they have longterm impacts on them, affecting behavior to such an extent that populations collapse over time. Neonicotinoids are commonly spread on the seeds of plants and it is thought the chemicals linger in the soil and water for years after use.

"One after another, new studies are revealing the extreme hazards these poisons pose for pollinators and the environment," said Jonathan Evans with the Center for Biological Diversity in response to the new research. "It's time we learn from the mistakes in our past with these dangerous pesticides and stop recklessly approving toxics at the behest of chemical companies."

The pesticides may also be unsafe for humans. A research review by the European Food Safety Authority (EFSA) last year found that neonicotinoids may harm human learning and memory. The pesticides have long-been billed as being both environmentally-safe and less hazardous to mammals than older pesticides, but rising evidence suggests longterm impacts that were never thoroughly tested in trials.

Honeybee on a milk thistle flower. Photo by: Fir0002/Flagstaffotos
Honeybee on a milk thistle flower. Photo by: Fir0002/Flagstaffotos/GFDL v1.2.

Last year, the EU installed a partial ban on the use of neonicotinoids for two years, a decision that pesticide companies have condemned. Meanwhile, last month President Obama issued an Executive Order to investigate pollinator health, including reviewing the impact of neonicotinoids. Unlike the EU, the U.S. has not banned the chemicals use on any crops and any federal review is likely to be years away from completion.

Yet, a recent independent review by 29 scientists via the International Union for the Conservation of Nature (IUCN) found sufficient evidence of neonicotinoid harm to warrant urgent action. Looking at 800 studies, the researchers found that not only were neonicotinoids harming bees, butterflies, and other pollinators, but also earthworms, birds, snails and other invertebrates.

"The evidence is very clear. We are witnessing a threat to the productivity of our natural and farmed environment equivalent to that posed by organophosphates or DDT," said one of the researchers, Jean-Marc Bonmatin with the National Centre for Scientific Research. "Far from protecting food production, the use of neonicotinoid insecticides is threatening the very infrastructure which enables it."

Pesticide companies continue to deny that neonicotinoidsare harming pollinators or birds for that matter. A spokesperson for Bayer said the chemicals are "safe to the environment when used responsibly according to the label instructions."

However, increasingly scientists are attacking such claims.

"We need to identify when [neonicotinoids] are important [to crop yields] and restrict use to those sites; it's not difficult," Dave Goulson from the University of Sussex, who was unaffiliated with the study, told the BBC. "You need to do field trials, and try not using the neonicotinoid seed dressing. If you don't get a reduction in yield then stop using the bloody things; its not rocket science!"















AUTHOR: Jeremy Hance joined Mongabay full-time in 2009. He currently serves as senior writer and editor. He has also authored a book.




Related articles

More is better: high bee biodiversity boosts crop yields

(06/12/2014) Scientists have discovered that blueberry plants visited by more diverse bee species increased their seed number, berry size and fruit set, and quickened their ripening time. They hope their findings encourage farmers to help support local wild bee communities.


Bee-harming pesticides may impact human nervous system

(12/23/2013) Neonicotinoid pesticides, which have been increasingly blamed for the collapse of bee populations, may also impact human's developing nervous system, according to a review of research by the European Food Safety Authority (EFSA). The EFSA says that current safety guidelines for two pesticides—acetamiprid and imidacloprid—may be too lax to protect humans, especially the developing brains of unborn children


Amphibians evolve resistance to popular pesticide

(10/04/2013) Rachel Carson and, more recently, Sandra Steingraber have successfully drawn popular attention to the risks of pesticides on wildlife. Many of the environmental consequences of pesticides have now been well documented by scientists; however, studies investigating the evolutionary consequences of pesticides on non-target species are largely missing. Not surprisingly, most studies looking at how species evolve in response to pesticide-use have been on target species such as mosquitoes and crop pests, which show that some target species have evolved resistance to common pesticides.


Pesticide problems in the Amazon

(08/21/2013) As the world’s population increases and agricultural frontiers expand into native tropical habitats, researchers are working furiously to understand the impacts on tropical forests and global biodiversity. But one obvious impact has been little studied in these agricultural frontiers: pesticides. However a new study in the journal Philosophical Transactions of The Royal Society B seeks to shine a light on the problem.


Habitat loss and pesticides causing decline in Europe's butterflies

(07/31/2013) Europe's grassland butterfly population has plummeted in the past two decades, new research published on Tuesday shows, with a near halving in the numbers of key species since 1990.


Losing just one pollinator species leads to big plant declines

(07/22/2013) A shocking new study finds that losing just one pollinator species could lead to major declines in plant productivity, a finding that has broad implications for biodiversity conservation. Looking at ten bumblebee species in Colorado alpine meadows, two scientists found that removing a single bee species cut flower seed production by one-third. Pollinators worldwide are in major trouble as they are hit by habitat loss, pesticides, disease and other impacts. In fact, the EU has recently banned several pesticides that have been linked to the global bee decline.


Pesticides decimating dragonflies and other aquatic insects

(06/18/2013) While recent research (and media attention) has focused on the alleged negative impacts of pesticides on bees, the problem may be far broader according to a new study in the Proceedings of the US Academy of Sciences (PNAS). Looking at over 50 streams in Germany, France, and Australia, scientists in Europe and Australia found that pesticide contamination was capable of undercutting invertebrate biodiversity by nearly half.


EU labels another pesticide as bad for bees

(06/18/2013) A widely used insect nerve agent has been labelled a "high acute risk" to honeybees by the European Food Safety Authority (EFSA). A similar assessment by the EFSA on three other insecticides preceded the suspension of their use in the European Union.


Local economy ruined by pesticide pollution in the Caribbean

(05/29/2013) On 15 April more than 100 fishermen demonstrated in the streets of Fort de France, the main town on Martinique, in the French West Indies. In January they barricaded the port until the government in Paris allocated €2m ($2.6m) in aid, which they are still waiting for. The contamination caused by chlordecone, a persistent organochlorine pesticide, means their spiny lobsters are no longer fit for human consumption. The people of neighboring Guadeloupe are increasingly angry for the same reason. After polluting the soil, the chemical is wreaking havoc out at sea, an environmental disaster that now threatens the whole economy.


U.S. loses nearly a third of its honey bees this season

(05/09/2013) Nearly a third of managed honeybee colonies in America died out or disappeared over the winter, an annual survey found on Wednesday. The decline—which was far worse than the winter before—threatens the survival of some bee colonies. The heavy losses of pollinators also threatens the country's food supply, researchers said. The US Department of Agriculture has estimated that honeybees contribute some $20bn to the economy every year.


Europe bans pesticides linked to bee collapse

(04/29/2013) The EU has banned three neonicotinoid pesticides (imidacloprid, clothianidin and thiamethoxam) linked to the decline of bees for two years. The ban will apply to all flowering crops, such as corn, rape seed, and sunflowers. The move follows a flood of recent studies, some high-profile, that have linked neonicotinoid pesticides, which employ nicotine-like chemicals, to the widespread decline of bees seen both in Europe and North America.


Common pesticides disrupt brain functioning in bees

(03/27/2013) Exposure to commonly used pesticides directly disrupts brain functioning in bees, according to new research in Nature. While the study is the first to record that popular pesticides directly injure bee brain physiology, it adds to a slew of recent studies showing that pesticides, especially neonicotinoids, are capable of devastating bee hives and may be, at least, partly responsible for on-going Colony Collapse Disorder (CCD).







CITATION:
Jeremy Hance
mongabay.com (July 15, 2014).

'Stop using the bloody things': pesticides linked to bee collapse now blamed for bird declines.

http://news.mongabay.com/2014/0715-hance-neonicotinoids-birds.html