31 August 2009 - Wild
plants as well as cultivated crops are impacted
by lack of pollination. - The number of
bees, hoverflies and butterflies is on the
decline in Denmark and the rest of Europe.
The decline is not just a threat for the
species themselves, but also for the plants
they pollinate. Wild plants as well as cultivated
crops are affected by the lack of pollination.
Loss of honey bee colonies costs professional
beekeepers in EU countries in direct loss
of output and the indirect loss of output
due to lack of pollination of crops
is estimated to be even higher. Denmark’s
National Environmental Research Institute
(NERI), Aarhus University is participating
in a five-year, pan-European research project
that will shed light on the threats and
opportunities for the most important pollinator
species.
The EU-financed research
project, STEP (Status and Trends of European
Pollinators) will aim to fill a wide range
of holes in the knowledge shared in Europe
on the fate of honey bees, bumblebees, hoverflies
and butterflies.
Common to these insect
species is that they play a crucial role
in pollination of cultivated and wild plants
and are often specialised to a few plant
species. Honey bees are the absolute most
dominant species in terms of pollination
of arable and horticultural crops and accounts
for approx. 85 per cent of all pollination
in this sector. But the number of ’domesticated’
honey bee colonies have in recent decades
been in continuous decline due to disease
and chemicals in the environment and other
environmentally related stressors.
Bumblebees in the danger
zone
Senior researcher, Beate Strandberg, NERI
singles out bumblebees among wild bees as
being especially at risk in Denmark:
‘We see various tendencies,
but bumblebees are the most vulnerable.
If you look through the Red List, then almost
half of bumblebee species are threatened.
But there is great pressure on pollinators
in general. This means that crops are inadequately
pollinated. This is also true for wildflower
species.’
Denmark’s National Environmental
Institute (NERI), Aarhus University is involved
in two main work areas under STEP. According
to Beate Strandberg one of the main tasks
is to map the extent of the pressure from
various sources on pollinators on the large,
regional and local scale.
‘A species can be thought
to be reasonably well represented on a large
scale, but be totally absent in certain
smaller geographic areas. We will especially
continue our work with pesticides, both
direct effects on pollinators and indirect
effects through impacts on plants, and thereby
pollinators, and seek a better understanding
of the interactions. Also in relation to
pesticide management, when the wind blows
pesticides out into the wild flora during
spraying.
But factors other than
pesticides play a role in the decline in
pollinators, and it will probably be hugely
complicated to unravel all the reasons and
their scale’, explains Beate Strandberg.
She points out that
a range factors will presumably point in
the same direction and comprise a cocktail
of negative factors for pollinators:
‘It can be fragmentation
of the landscape, with longer distances
between habitats, that makes it more difficult
for pollinators to find nesting sites and
food, and it can be pesticides, bee diseases,
invasive self-pollinating plants, climate
change, direct control of the insects by
humans and deterioration in the natural
environment in general.’
Beate Strandberg believes
that safety levels for pesticide approval
can become a topic for discussion in connection
with the research and mapping of the situation
for pollinators.
‘When approving new
pesticides the so-called bee test is used,
where the danger associated with the individual
agent is tested on honey bees – but not
on bumblebees. And this can be a problem,
as bumblebees are more vulnerable than honey
bees. At least, some of studies point to
bumblebees being more vulnerable to pesticides
– should the safety level then be made stricter?'
Rescue plan for pollinators
The other main task for NERI in STEP is
continually to keep the project, in which
20 research institutions from 16 European
countries are taking part, on track, with
the University of Reading, England as project
coordinator.
‘Really it is a question
of a type of project management’, explains
Senior researcher, Peter Borgen Sørensen.
‘We will be managing the project on an ongoing
basis, so that the most important science
gaps are addressed over the five years it
runs for. This will presumably also involve
evaluation of the entire project annually,
using the new knowledge revealed to identify
whether we are on the right track. We need
to ensure that the research can support
a rescue plan for pollinators in the best
possible way. This type of project management
can be hard for some universities, but it
is something we are good at NERI.’
As well as important
new knowledge on European pollinators the
end result for STEP will be a range of recommendations
and guidelines for authorities and legislators.
But also a clarification of where gaps in
scientific knowledge remain.
Another actual result
will be preparation of a European Red List
for bees and a draft Red List for hover
flies. Together with the existing date of
European butterflies the aim it to prepare
a joint Red List for European pollinators.
Contact: Senior researcher, Beate Strandberg
