Some scientists suggest the impact of pesticides on declines in pollinators has been overstated
Controversial pesticides linked to 'total ecological collapse' of insects and birds
Dearbhla Crosse and Tom Levitt
16th November, 2010
Widespread use of insecticides affecting bee populations but also causing decline in numbers of birds, butterflies and moths, warns Dutch toxicologist
A new book is blaming the significant decline of bird and bee numbers across Europe on the use of certain pesticides in agriculture.
In The Systemic Insecticides: A Disaster in the Making, toxicologist Dr Henk Tennekes suggests that dangerous insecticides known as neonicotinoids are seriously affecting bird and insect life, and their continued use could result in an ‘environmental catastrophe’.
Neonicotinoids are often used as seed-dressing for maize, sunflower and rapeseed. However, Tennekes says as well as spreading throughout the entire plant and into the nectar and pollen, they also have a high leaching potential and seep into soils and groundwater. Even low concentrations of the pesticide may be more deadly then previously thought due to their high persistence in soil and water, he adds.
In a study published in the journal Toxicology earlier this year, Tennekes had suggested this could be a factor behind declining bee numbers across Europe. He now believes bees are not the only victims.
‘Any insect that feeds on the crop dies. Any bee or butterfly that collects pollen or nectar from the crop is poisoned. Neonicotinoids behave like carcinogens, and easily contaminate ground and surface water. There could be dire long-term consequences of environmental pollution with these insecticides, and my fears were confirmed by extensive research,’ says Tennekes.
In his book, Tennekes writes that even minute traces of these pesticides could be fatal to insects, as continued use affects food availability for birds, a lack of weeds resulting in a loss of insects, as well as seeds. This decline is also linked to a lack of larger insects upon which chicks depend for their survival, which in turn affects breeding.
‘An ecological collapse is already taking place before our eyes,’ Tennekes told the Ecologist. ‘Numerous bird species do not find enough food for their chicks as insects are being exterminated by pesticides. Insects are vital in ecosystems. In fact, we need them for human survival.’
The Soil Association, which along with Buglife and Pesticide Action Network UK has previously called for neonicotinoid pesticides to be banned, says the decline in bee numbers alone should serve as an early warning.
‘In the UK alone, beekeepers [have in the recent past] reported a loss of one in three bee colonies,’ said a spokesperson. ‘This has serious consequences for worldwide food security, because bees are our most important pollinators and play a vital role in the food chain – it is estimated that one-third of human food supplies depend on bee pollination. Bees are therefore like the "canary in the coal mine" – their deaths are a warning to us all that the health of the planet is under threat.’
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