GMO Myths and Truths

5.8 Myth: GM crops help biodiversity
Truth: The herbicides used with GM crops harm biodiversity
“Many farmland birds rely on seeds from
weeds for their survival and the [UK]
government’s farm scale trials showed
that GM beet and GM spring oilseed rape
[canola] reduced seed numbers by up to
80% compared with conventional beet
and oilseed rape. The commercialisation
of GM beet and oilseed rape could be
disastrous for birds. The government
is committed to reversing bird declines
and has promised to ban GM crops if
they damage the environment. The Farm
Scale Evaluations (FSEs) show that
two GM crops harm the environment
and ministers now have no choice but to
refuse their approval.”
– Dr Mark Avery, director of conservation
at the UK’s Royal Society for the Protection
of Birds (RSPB) and member of the UK
government’s Science Review Panel 116
In the early 2000s the UK government
conducted three-year farm-scale trials to
examine the impacts of managing GM herbicidetolerant
crops (maize, sugar beet and canola)
on farmland biodiversity. Each field was divided
in half, with one half planted with a non-GM
variety managed according to the farmer’s
normal practice, and the other half planted with
a GM herbicide-tolerant variety. The GM beet
was tolerant to the glyphosate-based herbicide
Roundup and the GM maize and canola were
tolerant to glufosinate ammonium. The
herbicide-tolerance genes enabled farmers to
spray the crops with these broad-spectrum (killall)
herbicides, killing all weeds but allowing the
crop to survive.
Weeds provide food and habitat for birds,
insects, and other wildlife, so the farm-scale trials
recorded levels of weeds and invertebrates in the
fields and field margins. Selected groups of other
organisms with wider foraging ranges (beetles,
bees, and butterflies) were also studied. The trials
looked at whether the changes in management
associated with GM crops would reduce weed
levels and have wider impacts on farmland
biodiversity.
The findings showed that the cultivation of
GM herbicide-resistant crops reduces wildlife
populations and damages biodiversity, due to the
effects of the broad-spectrum herbicides with
which they are grown. 117,118,119,120,121,122
GM herbicide-resistant maize was found to
be better for wildlife than non-GM maize, with
more weed species and insects in and around
the field. 117,118,119,120,121,122 But the GM maize was
measured against a non-GM maize grown with
atrazine, a toxic herbicide that was banned in
Europe soon after the trials ended. With such
a toxic control, it was highly likely that the GM
maize would be found to be better for wildlife.A
more useful comparator would have been a
maize grown in an organic or integrated pest
management (IPM) system, which eliminate or
reduce herbicide use.
In the EU, this is not a purely idealistic notion.
A 2009 European Directive asks member states to
implement national plans to adopt integrated pest
management and alternative approaches in order
to reduce pesticide use. 123
GMO Myths and Truths 84