Bijensterfte, oorzaken en gevolgen

Bublebee Conservation Trust (BBCT) response to the Avaaz anti-pesticide campaign
(reproduced from e-mail newsletter)

Avaaz is a 6.5-million-person global campaign network that works to ensure that the views and values of the world's people shape global decision-making

Yesterday they launched a campaign to urge the US and EU to suspend neonicotinoid pesticides. The full text of their campaign publicity can be read here. Many of you may subscribe to the Avaaz newsletter (as do I) so I wanted to write to you and clarify BBCT's position on this. If the issue of bee declines is as simple to solve as a ban on neonicotinoids then you might well wonder why BBCT is diverting most of its resources to habitat creation and restoration.

Our response to them, posted publicly on our website, is as follows:

BBCT share concerns about growing evidence suggesting that some pesticides, including neonicotinoids, are harmful to bees. [Note to BBCT supporters - if you share our concerns you might consider printing, signing and posting a letter to your MP. A template is available here on the website of our conservation partners, Buglife.]

However, there are some statements in the Avaaz summary which, based on BBCT's understanding of the scientific evidence, are not well supported. This weakens their position and threatens to make hard-won signatures less valuable. Furthermore, they make a strong case for pesticides being the root cause of global bee declines. In some instances pesticides may be seriously affecting honeybees, but it is BBCT's view that many of our wild bee species have declined primarily due to habitat loss and other factors, besides pesticide use. With honeybees the situation is also more complicated than the Avaaz literature implies. Disease has a significant role in ongoing declines.

BBCT value the efforts of Avaaz in raising awareness of important issues and galvanising mass support and peaceful protest. However, in this instance the arguments are oversimplified and at times incorrect. Calling for a ban on neonicotinoids as a precaution until thorough independent research confirms their safety seems prudent and has our support. However, the campaign materials risk polarising a complex issue and undermining efforts to tackle global bee declines from all necessary angles.

Points of clarification:

Only one of the UK’s ~250 species of bee makes honey that is harvested commercially by man. Globally there are ~7 species of honeybee and ~20,000 known species of bee.

90% of the agricultural and horticultural crop species that we grow are at least partially pollinated by bees (all bee species). Pollination is either essential for any yield, or increases yield size or quality. It is estimated that bee-pollinated foods comprise around 1/3 of our diet by volume.

Although many scientific studies suggest reason for concern, there are other scientific studies that suggest these chemicals may present a low risk. To date they have not been banned in the UK on the basis that the science isn’t clear. Pesticides, sadly, seem to work on the basis of 'innocent until proven guilty'. Further independent research will be invaluable. BBCT support the view that a precautionary ban would be wise.

BBCT are not aware of scientific evidence which demonstrates that bee populations soared in four European countries as a result of the banning of certain chemicals.

BBCT agree that a ban on neonicotinoids would probably make a significant difference in some instances to bee populations in some areas of intensive arable agriculture, where flowering crops are common. However, sadly this would not ‘save our bees’ because the root cause of most wild bee declines is thought to be the drastic loss of flower-rich grasslands and other habitats which healthy bee populations depend on. The issues for honeybees are also complex, and better understanding, treatment and control of diseases will be important.

For populations of wild bees at least, sustainable populations require an integrated approach which combines a ban on the most harmful pesticides and a sympathetic approach to farming which supports and encourages pollinators. To bring about this it is essential to gain wider recognition of the ecosystem services that bees provide, backed up by policy-level support.

Wild bee populations in grazed or mixed-farming areas need supporting through a return to species-rich hay meadows instead of silage monocultures and clover ley crops instead of widespread fertiliser use (97% of lowland species-rich meadows have been lost since WWII). In arable areas, farms should be encouraged to manage low productivity areas (margins and corners) as flower-rich habitats. There is scientific evidence showing that this management causes a large increase in foraging bee numbers, although the evidence for population-level increases is harder to gather and hence less robust.

We believe that the figures for the economic importance of pollination in the Avaaz literature are incorrect. Gallai et al (2009) estimated that the total economic value of pollination to the world agricultural output amounted to €152.9 billion, which represented 9.5% of the value of the world agricultural production used for human food in 2005. They stress that their valuation demonstrates the economic importance of insect pollinators but cannot be considered as a scenario since it does not take into account the strategic responses of the markets. In the EU25 in 2005 the insect pollination economic value was estimated at €14.2 billion. In the UK, studies are somewhat out of date, but insect pollination has previously been valued at £440 million.

In summary, BBCT agree that it is worthwhile to make voices heard, but in order to be taken seriously by policy makers and scientists it is essential that campaigns are based on the available scientific evidence. Inaccuracies are likely to weaken the impact. Further, by simplifying the issue and ignoring the importance of other factors in global bee declines the campaign risks undermining ongoing conservation efforts. Studies suggest that the causes of bee declines differ between species and include factors such as disease, habitat loss, pesticides, inbreeding, climate change and others.

BBCT have contacted Avaaz and offered to help them reach a more robust campaign stance. To date we have not heard back from them. If you would like to join us in urging Avaaz to clarify these important details and correct errors then please use the contact us form on their website.

Dr Ben Darvill
BBCT Director

http://www.bumblebeeconservation.org