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STATUS and TRENDS
of EUROPEAN POLLINATORS
1
STATUS AND
TRENDS OF
EUROPEAN
POLLINATORS
Key Findings from the STEP project
The research leading to these results has received funding from the
European Community’s Seventh Framework Programme (FP7/2007-2013)
under grant agreement no 244090, STEP Project (Status and Trends of
European Pollinators, www.step-project.net)
Citation: Potts S., Biesmeijer K., Bommarco R., Breeze T., Carvalheiro L., Franzén M., González-Varo J.P., Holz-
schuh A., Kleijn D., Klein A.-M., Kunin, B., Lecocq T., Lundin O., Michez D., Neumann P., Nieto A., Penev L., Ras-
mont P., Ratamäki O., Riedinger V., Roberts S.P.M., Rundlöf M., Scheper J., Sørensen P., Stean-Dewenter I.,
Stoev P., Vilà M., Schweiger O. (2015) Status and trends of European pollinators. Key ndings of the STEP
project. Pensoft Publishers, Soa, 72 pp.
Front cover: Wikimedia Commons
Disclaimer: The views expressed in this publication are those of the authors and do not necessarily reect
the views or opinions of the funders or reviewers.
First published 2015
ISBN: 978-954-642-762-5
ISBN: 978-954-642-763-2
Pensoft Publishers
12, Prof. Georgi Zlatarski St.
1700 Soa, Bulgaria
e-mail: info.pensoft.net
www.pensoft.net
All content is Open Access, distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided that the
original author and source are credited.
Printed in Bulgaria, 14 January 2015
Design by
Contents
Project Partners........................................................................................................................................... 5
Foreword....................................................................................................................................................... 7
Background............................................................... .................................................................................. 8
Chapter 1: Status and Trends of Pollinators across Europe........................................................ 10
1.1 Biodiversity loss among bees and wild owers slows in NW-Europe........... 11
1.2 First ever Red List of European bees......................................................................... 14
1.3 Drastic historic shifts in bumblebee community composition
in Sweden........................................................................................................................... 17
Chapter 2: Drivers and Pressures on Pollinators........................................................................... 20
2.1 Combined eects of global change pressures on animal-mediated
pollination.......................................................................................................................... 21
2.2 The relative importance of broad-scale drivers for the distribution of
European pollinators...................................................................................................... 25
2.3 Future climatic risks for European bumblebees.................................................... 27
2.4 Expansion of mass-owering crops leads to transient pollinator
dilution and reduced wild plant pollination........................................................... 30
2.5 Impact of chronic neonicotinoid exposure on honeybee colony
performance and queen supersedure..................................................................... 33
Chapter 3: Wider Impacts of Changes in Pollinators................................................................... 36
3.1 Wild pollinators enhance fruit set of crops regardless of honeybee
abundance......................................................................................................................... 37
3.2 Agricultural policies exacerbate honeybee pollination service
supply-demand mismatches across Europe.......................................................... 39
4
3.3 Contribution of pollinator-mediated crops to nutrients in the
human food supply......................................................................................................... 41
3.4 Ecological intensication: harnessing ecosystem services for
food security...................................................................................................................... 43
3.5 Annual dynamics of wild bee densities: attractiveness and
productivity eects of oilseed rape........................................................................... 46
Chapter 4: Mitigating Against Pollinator Losses........................................................................... 49
4.1 Environmental factors driving the eectiveness of European
agri-environmental measures in mitigating pollinator loss –
a meta-analysis................................................................................................................. 50
4.2 Late-season owers benet bumblebees............................................................... 53
4.3 Landscapes with wild bee habitats enhance pollination,
fruit set and yield of sweet cherry............................................................................... 56
4.4 Early mass-owering crops mitigate pollinator dilution
in late-owering crops................................................................................................... 59
Chapter 5: Informing Policy.................................................................................................................. 62
5.1 How can pollination ecology research help answer
important questions?..................................................................................................... 63
5.2 Multi-level analysis of mismatch and interplay between
pollination-related policies and practices .............................................................. 65
5.3 Conceptual model for evidence analysis to support policy............................. 68
Conclusion and Future Steps............................................................................................................... 70
List of Authors........................................................................................................................................... 71
4
5
Project Partners
The STEP project ran from 2010-2015, combining the expertise of 22 research institu-
tions from 17 European countries with more than 120 researchers.
University of Reading, UK (Project Coordinator)
Helmholtz Centre for Environmental Research, Germany
Swedish University of Agricultural Sciences, Sweden
Stichting Dienst Landbouwkundig Onderzoek (Alterra), Netherlands
Aarhus University, Denmark
University of Leeds, UK
University of Bayreuth, Germany
National Institute of Agronomic Research, France
Federal Department of Economic Aairs, Switzerland
Finnish Environment Institute, Finland
Lund University, Sweden
6
Spanish Council for Scientic Research, Spain
University of Tartu, Estonia
PENSOFT Publishers, Bulgaria
University of Bern, Switzerland
University of Novi Sad, Faculty of Sciences, Serbia
University of Mons, Belgium
Jagiellonian University, Poland
University of Pisa, Italy
University of the Aegean, Greece
Julius Maximilians University Würzburg, Germany
Stichting Naturalis Biodiversity Center (Naturalis), Netherlands
University of Freiburg, Germany
Collaborative organisations:
International Union for Conservation of Nature (IUCN)
The Food and Agriculture Organization of the United Nations (FAO)
7
Foreword
Natural Capital, and the ecosystem services derived from it, are essential to human well-be-
ing and economic prosperity. Indeed, nature inspires and provides many solutions that can
help us tackle some of the most pressing challenges of our time. For example, pollinators
matter because a majority of European crops depend or benet from insect pollination.
Another example is the contribution of pollinators to preserving cherished natural and
cultural landscapes through wildower pollination.
However, due to a cocktail mix of drivers of change, pollinator species are disappearing and
pollinator populations are declining. ese losses accentuate several of our societal chal-
lenges, including food security and ecosystem degradation. Hence, building knowledge on
the causes behind pollinator decline, and the eects of pollinator decline on other species
and ecosystems is essential. e STEP project has contributed signicantly within this eld,
with a particular focus on the status and drivers behind trends in European pollinators.
Furthermore, research into the dierent solutions for maintaining or enhancing pollinator
populations is crucial. ese activities enrich the knowledge base on Nature-based solu-
tions, solutions that are inspired by or supported by nature and address societal challenges
while maintaining or enhancing our natural capital. Overall, research and innovation ac-
tions such as those successfully supported by the STEP project, contribute to greening the
economy and making development sustainable.
Soe Vandewoestijne
Policy Ocer,
DG Research & Innovation, European Commission
7
8
Background
Society benets in a multitude of ways from nature in the form of food production, the pro-
visioning of clean drinking water, the decomposition of wastes, and the pollination of crops
amongst many others. ese ‘ecosystem services’ are all underpinned by biodiversity, which
remains under threat globally, and so the conservation and sustainable use of biodiversity
is a key challenge for all sectors of society.
e majority of global, and European, biodiversity is made up of insects, but we still know
relatively little about the distribution and abundance of most species, and even less about
their dynamics and the threats they face. is lack of knowledge on the status and trends of
the majority of Europe’s species is of concern, and is particularly important for species that
play important functional roles, such as pollinators.
e most widely managed pollinator in Europe is the honeybee (Apis mellifera), with most
wild and feral colonies already lost. e remaining colonies are managed by beekeepers and
have been shown to have undergone severe and widespread declines throughout much of
Europe. Wild pollinators in Europe are dominated by approximately 2,000 species of wild
bees (e.g. bumblebees and solitary bees) and hoveries, with a smaller contribution of but-
teries, beetles and other y species. Declines in wild bees and hoveries have been clearly
documented in some parts of Europe (e.g. the Netherlands, Belgium and UK), however,
the geographic extent, scale and identity of those species in decline is largely unknown
for most of Europe. While several European countries have established Red Lists for bees
of conservation concern, until recently there is no European Red List with which to help
direct conservation priorities at the continental scale.
Many individual causes of pollinator decline have been documented and include habitat
loss and fragmentation, pesticides, loss of oral resources, pests and diseases, alien invasive
species and climate change. However, the relative importance of these drivers and their
interacting eects have been poorly explored until recently.
e majority, 84%, of European crops benet, at least in part, from insect pollination and
78% of temperate wildowers need biotic pollination. An estimated ~10% of the total eco-
nomic value of European agricultural output for human food amounted to €22 billion in
2005 (€14.2 for the EU) was dependent upon insect pollination. However, more informa-
tion is needed on the vulnerability of crops and regions to pollination loss, and also on the
contribution of insect pollinated crops to food security.
Loss of pollinators can be mitigated through a number of interventions including on-farm
management and protection of semi-natural habitats in the wider landscape. However, infor-
mation is fragmentary on the range of mitigation options available in Europe and their relative
eectiveness in delivering pollinator conservation. Further, while there are a variety of options
for enhancing pollination, such as supplementing managed pollinators, supporting wild pol-
linators and articial pollination, there is no broad picture of these practices across Europe.
9
As a response to the need for a better understanding of the science of pollinators and pollina-
tion services, and how this can be used to help support policy and better practices, a number
of national and international initiatives have been established. One of these, the STEP project
(Status and Trends of European Pollinators) was funded by the European Commission.
e STEP project has helped science and policy move forward on many of the above chal-
lenges which are illustrated in the following chapters. Specically STEP has:
Documented the status and trends of pollinators (managed honeybees, wild bees
and hoveries) and animal-pollinated plants.
Assessed the importance of multiple pressures that are driving changes in pollinators
and animal-pollinated plants at scales ranging from single elds, to landscapes, to
the whole of Europe.
Quantied the impact of changes in pollinator populations and communities on
wild plants and crops.
Evaluated the eectiveness of strategies to mitigate the impacts of changes in polli-
nators and animal-pollinated plants.
Developed ways to improve the interface between the scientic knowledge-base
on pollinator shis and policy instruments.
Developed communication and educational links with a wide range of
stakeholders and the general public on the importance of recent shis in pollinators,
the main drivers and impacts of pollinator shis and mitigation strategies through
dissemination and training.
e following chapters summarise some of the key ndings of the STEP project as a series of
short case studies. Each case study presents a summary of the main scientic evidence fol-
lowed by a short description of its policy relevance. ese case studies are not an exhaustive
list of all the outputs of the STEP project, but simply a small sample to highlight some of the
main outcomes; a full list of publications and other outputs can be found on the STEP website
(www.STEP-project.net). All the case studies include members of the STEP team and many
also involved extensive collaborative eorts with researchers from all round the globe. e
case studies have been authored by members of the STEP project, and the full list of contribu-
tors to each study can be found in the authorship lists of the relevant publications, with those
who are STEP members highlighted.
Chapter 1 starts by documenting the current status and trends of European pollinators
and insect-pollinated plants; Chapter 2 then addresses a range of drivers of change, and
Chapter 3 the resulting societal impacts of shis in pollinators and pollination services.
Mitigation responses to loss of pollinators and services are explored in Chapter 4, and -
nally Chapter 5 looks at how evidence from the STEP project, and elsewhere, can be used
to better inform policy making. Taken together these case studies demonstrate how a large-
scale project bringing together a range of international expertise can generate important
new knowledge to help safeguard Europe’s pollinators and the benets they bring society.
Prof. Simon Potts, Coordinator of STEP
10
Chapter 1: Status and Trends of
Pollinators across Europe
Koos Biesmeijer
Documenting trends in European pollinators (e.g. bees, hoveries and butteries) and
plants that depend on animals for their pollination is not straightforward as historic data
are very dispersed or lacking. Moreover, pollinators include the European honeybee, main-
ly kept by beekeepers, as well as hundreds of wild species, many of which are barely known
and studied. Still, we have made considerable progress in collating data from many dierent
sources, developing analytical methods to improve the detection of patterns, and producing
solid evidence for recent trends in pollinating insects and plant for several parts of Europe.
Unfortunately, data availability is still the main bottleneck and has restricted the scope of
some of our ndings to specic species groups or a few countries. Below, and in the case
studies 1.1-1.3 we will summarize some major recent ndings.
European managed honeybees are oen said to be in decline, but information was patchy
and localized until Potts et al. (2010)* set out to compile data for 18 European countries.
ey observed consistent declines between 1985-2005 in colony numbers in Central Euro-
pean countries and some increases in Mediterranean countries, while beekeeper numbers
declined in all countries examined. is supports the view that honeybees and beekeeping
are in decline at least in some regions. Further conclusions are hampered, however, by lack
of standardized methodologies, which they recommend to be adopted at the national and
global level. e EU COST Action COLOSS has made signicant progress on this. Infor-
mation on other pollinators is scarce and dispersed, but a serious attempt to assess trends
in wild bees has been initiated in collaboration with the IUCN in the ‘European Bees Red
List – project’ (case study 1.2). e rst group that was assessed were the 68 species of
bumblebees, important pollinators of many crops and wild plants. Of these species 46% are
declining, 29% are stable and 13% are increasing in population or distribution.
Another study (case study 1.1) brought together more than 30 million species observation
records on pollinators and plants from the Netherlands, the UK and Belgium, which have
been collected largely by amateur naturalists with expert knowledge on these groups. e
study shows that severe declines and homogenization of communities has occurred since
the 1950s. However, declines seem to have stabilized and sometimes even reversed for a few
groups in recent years. Ideally, one would obtain insight into shis in abundance of species.
is is rarely possible, as standardized surveys of biodiversity are fairly recent. Case study
1.3, explains how historic data on the number of bumblebee foragers visiting red clover
owers in Sweden, was used to assess shis in relative abundance of dierent species. Sev-
eral historically common species have now virtually disappeared and current bumblebee
communities are dominated by very dierent species than past communities.
*Potts S.G., Roberts S.P.M., Dean R., Marris G., Brown M., Jones R., Settele J. (2010) Declines of managed hon-
eybees and beekeepers in Europe. Journal of Apicultural Research 49: 15-22.
11
1.1 Biodiversity loss among bees and wild flowers slows in
NW-Europe
Koos Biesmeijer, Luisa Carvalheiro and Bill Kunin
Summary of the science
A study published Ecology Letters in 2013 found evidence of dramatic reductions in the di-
versity of species of bees, hoveries, butteries and wild owers in Britain, Belgium and the
Netherlands in the post war period. But the picture brightened markedly aer 1990, with a
slowdown in local and national biodiversity losses among bees, hoveries and wild plants.
For example, the study found a 30% fall in local bumblebee diversity in all three countries
between the 1950s and the 1980s. However, by 2010 that decline slowed to an estimated
10 per cent in Britain, whilst in Belgium and the Netherlands bumblebee diversity had
stabilised.
e picture was better for other wild bees, with an 8 per cent reduction in diversity in the
Netherlands and a stable picture in Great Britain turning into signicant increases (7 per
cent in the Netherlands and 10 per cent in Britain) over the past 20 years. While these soli-
tary bees continued to decline in Belgium, hovery diversity improved there, shiing from
stable diversity in the 1980s to signicant (20 per cent) increases in recent decades. British
wildower diversity had declined about 20 per cent from the 1950s to the 1980s, but again
the declines have ceased in the past 20 years. Not all groups fared so well. Buttery diversity
continued to fall in all three countries at roughly the same rates as in the past.
is work is based on a very large dataset of species records and sophisticated analytic meth-
ods. However, while we can use biodiversity records to measure changes in the diversity of
pollinators, we cannot tell what is happening to their overall abundance or to the quality of
the pollination services they provide to wildowers or agricultural crops. To study these issues
would require a proper long-term monitoring programme to be set up.
Moreover, it is still unclear what drove the patterns of richness change reported here. It is
possible that by 1990 the most sensitive species had already gone and were, partially, re-
placed by generalist species. But that is probably not the whole story, as there are still plenty
of rare and vulnerable species present in recent records. ere is a much more encouraging
possibility: reducing environmental pollution, conservation work and agri-environment
programs paying farmers to encourage biodiversity may be having a positive eect.
We may also be seeing a slowdown of the drivers of decline. e post war emphasis on
getting land into production and on more intensive farming has given way to a more stable
situation in which the rate of landscape change has slowed and in which agrichemical ex-
cesses are regulated.
12
Policy relevance
Most observers suggest the 1992 Rio Earth Summit targets to slow biodiversity loss by 2010
failed, but what we are seeing here is a signicant slowing or reversal of the declines for wild
plants and their insect pollinators. If what we take from the Rio targets is that the investment
in conservation gave us no results, then that is a counsel of despair. is study brings a pos-
itive message for conservation. But some important groups are undoubtedly still declining,
so continued and increased investment in conservation practices is essential to guarantee the
persistence of a diverse assemblage of species.
Reference
Carvalheiro L.G., Kunin W.E., Keil P., Aguirre-Gutiérrez J., Ellis W.N., Fox R., Groom Q.,
Hennekens S., Van Landuyt W., Maes D., Van de Meutter F., Michez D., Rasmont P., Ode B.,
Potts S.G., Reemer M., Roberts S.P.M., Schaminée J., WallisDeVries M.F. and Biesmeijer J.C.
(2013) Species richness declines and biotic homogenization have slowed down for NW-Euro-
pean pollinators and plants. Ecology Letters 16: 870-878.
Figure 1. The pollen specialist bee Andrena hattorana (Fabricius) (Hymenoptera: Andrenidae) is rare in the
study region and foraging on Dipsacaceae (Photo: Nicolas Vereecken).
13
-40-20 0204060
-40-20 0204060-40-20 0204060
-40-20 0204060
-40-20 0204060
160
km
10
km
20
km
40
km
80
km
Whole
country
160
km
10
km
20
km
40
km
80
km
Whole
country
dependent on insects
intermediate dependenc
e
independent of insects
Fl
ower visitors
Change (%)
Netherlands
Netherlands
Belgium
Belgium
Great Britain
Change (%)
Change (%)Change (%)
Change (%)
Plants
Change (%)
-40-20 0204060
bumblebees
hoveries
butteries
other bees
1950-1969 vs. 1970-1989 1970-1989 vs. 1990-2009
P1 P2 P2 P3
a) b)
c) d)
e) f)
g) h)
i) j)
k) l)
Great Britain
Figure 2. Change of species richness (estimated weighted mean ± 95% condence intervals) of ower
visitors and plants through time at dierent spatial scales. For most taxa and countries richness change
estimates (% of change) of ower visitors and plants were more accentuated between P1 and P2 (the
Netherlands, a, g, Belgium, c, i and Great Britain, e, k) than between P2 and P3 (the Netherlands, b, h,
Belgium, d, j and Great Britain, f, l). Due to insucient number of grid cells, results from some spatial scales
are not presented for some groups. The horizontal line represents no change (0%). Filled symbols indicate
that change was signicantly dierent from zero, otherwise symbols are open (reprinted from Luisa
Carvalheiro, Ecology Letters).
-40-20 0204060
-40-20 0204060-40-20 0204060
-40-20 0204060
-40-20 0204060
160
km
10
km
20
km
40
km
80
km
Whole
country
160
km
10
km
20
km
40
km
80
km
Whole
country
dependent on insects
intermediate dependence
independent of insects
Flower visitors
Change (%)
Netherlands
Netherlands
Belgium
Belgium
Great Britain
Change (%)
Change (%)Change (%)
Change (%)
Plants
Change (%)
-40-20 0204060
bumblebees
hoveries
butteries
other bees
1950-1969 vs. 1970-1989 1970-1989 vs. 1990-2009
P1 P2 P2 P3
a) b)
c) d)
e) f)
g) h)
i) j)
k) l)
Great Britain
-40-20 0204060
-40-20 0204060-40-20 0204060
-40-20 0204060
-40-20 0204060
160
km
10
km
20
km
40
km
80
km
Whole
country
160
km
10
km
20
km
40
km
80
km
Whole
country
dependent on insects
intermediate dependence
independent of insects
Flower visitors
Change (%)
Netherlands
Netherlands
Belgium
Belgium
Great Britain
Change (%)
Change (%)Change (%)
Change (%)
Plants
Change (%)
-40-20 0204060
bumblebees
hoveries
butteries
other bees
1950-1969 vs. 1970-1989 1970-1989 vs. 1990-2009
P1 P2 P2 P3
a) b)
c) d)
e) f)
g) h)
i) j)
k) l)
Great Britain
14
1.2 First ever Red List of European bees
Denis Michez, Pierre Rasmont, Stuart P. M. Roberts and Ana Nieto
Summary of the science
Extinction drivers vary in space and time, interact synergistically, and aect species and/or
functional groups dierently (Figure 1 A, B). One of the main challenges of the STEP project
was to assess how each bee species among the 1,965 species native in Europe is potentially
experiencing a risk of extinction. Assessing the status of all European bees was a major task
that required a coordinated large-scale eort involving specialists from across Europe, as
well as a standardized framework of assessment. e STEP project collaborated with IUCN
and applied the internationally recognized IUCN (International Union for Conservation
of Nature) Red List procedures (www.iucnredlist.org) to guide the development of a
Red Data Book for European bees. As the knowledge base for this assessment was both
taxonomically and geographically incomplete, we involved the majority of the European
bee expert community (i.e. taxonomists and ecologists). We also built a partnership with
the European team of IUCN to coordinate and guide this process. A team of more than 40
experts participated in the development of the assessments and the review process for this
rst European bee Red List. e following information was collected for all the species:
nomenclature, distribution, country records, population size and trend, preferred habitats,
general ecology, modes of utilisation, major threats, ecosystem services provided and
current and future conservation measures.
e rst outcome was an updated checklist of European bees, which now includes 1,965
species. is is an important step forward as the last comprehensive list of European bees
was published in 1901 by Friese. e team gathered all the available observations to produce
detailed maps of 1,585 species including 2.5 million data points; these maps are available
on the IUCN and Atlas Hymenoptera websites, and example is given in Figure 2. ese de-
Figure 1. (A) Bombus confusus (Apidae), Endangered generalist social species. (Photo: Pierre Rasmont).
(B) Dasypoda hirtipes (Melittidae), Least Concern specialist solitary species (Photo: Nicolas Vereecken).
15
tailed maps allowed us to estimate the Extent of Occurrence (EEO) and Area of Occupancy
(AOO) of each species. Of all the European native bees, 7 species were assessed as Criti-
cally Endangered, 46 as Endangered, 24 as Vulnerable, 101 as Near reatened, 663 species
as Least Concern, 1,101 as Data Decient and 23 as Not Applicable (Figure 2). e main
threats identied were habitat loss due to habitat loss as a result of agriculture intensica-
tion (e.g., changes in agricultural practices including the use of pesticides and fertilisers),
urban development, increased frequency of res and climate change.
Some life history traits were associated to the most threatened species: sociality (e.g. bum-
blebees), host-plant specialisation (e.g. bee species specialised in the pollen of teasel family,
Dipsacaceae) and habitat specialisation (e.g. bee species associated to coastal areas). e
species richness of bees increases from north to south in Europe, with the highest species
richness being found in the Mediterranean climate zone. e Iberian, Italian and Balkan
peninsulas are important areas of species richness. e largest numbers of threatened spe-
cies are located in South-Central Europe and the pattern of distribution of Data Decient
species is primarily concentrated in the Mediterranean region.
e quality of the data available was highly variable across the various genera of wild bees.
Some groups like leaf-cutting bees (i.e. genus Megachile) presented many taxonomic ques-
tions limiting the access to high quality data. Other groups like the majority of kleptopar-
asitic genera (i.e. cuckoo bees) are very rare and are seldom collected. Status and trends of
the populations of these groups were impossible to assess based on the available data (i.e.
resulting in a Data Decient assessment).
For a small proportion of the species, the data included a large amount of historical data,
allowing the team to characterise the trends in their populations. is was mainly possible
for the Bumblebees (genus Bombus). For this group, 891,619 data points were compiled for
the 68 species recorded in Europe. e assessment showed that, of the 68 bumblebees pres-
ent in Europe 9 species have an increasing population trend (13.2%), 20 are stable (29.4%),
31 are decreasing (45.6%) and 8 (11.8%) are unknown (Figure 3).
Figure 2. Left, map of Bombus confusus including 2712 specimens (http://zoologie.umh.ac.be/
hymenoptera/), (Pierre Rasmont). Right, summary of the Red List status of European bees (CR= Critically
Endangered, EN= Endangered, VU= Vulnerable, NT= Near Threatened, LC= Least Concern, DD= Data
Decient), (Ana Nieto & Denis Michez).
16
Policy relevance
A Red List is a set of precise criteria to evaluate the extinction risk of species, with the ob-
jective of conveying the urgency of conservation issues to the public and policy makers, as
well as help the international community to try to reduce species extinction. e aims of
the European bee Red List are to:
Provide scientically based information on the status of species at the European level;
Draw attention to the magnitude and importance of threatened species;
Inuence national and international policy and decision-making; and
Provide information to guide actions to conserve bee biodiversity.
Reference
Nieto A., Roberts S.P.M., Kemp J., Rasmont P., Kuhlmann M., Biesmeijer J.C., Bogusch
P., Dathe H.H., De la Rúa P., De Meulemeester T., Dehon M., Dewulf A., García Criado
M., Ortiz-Sánchez F.J., Lhomme P., Pauly A., Potts S.G., Praz C., Quaranta M., Radchenko
V.G., Scheuchl E., Smit J., Straka J., Terzo M., Tomozii B., Window J. and Michez D. (2014)
European Red List of bees. Luxembourg: Publication Oce of the European Union.
!
i
Figure 3. Assessment of the European bumblebees. Left, summary of the Red List status of European
bumblebees (CR= Critically Endangered, EN= Endangered, VU= Vulnerable, NT= Near Threatened, LC=Least
Concern, DD= Data Decient), (Ana Nieto & Pierre Rasmont). Right, population trends of European
bumblebees (Ana Nieto & Pierre Rasmont).
11.8%
45.6%
29.4%
13.2%
Unknown
Decreasing
Stable
Increasing
CR
1.5%
EN
10.3%
VU
11.8%
NT
4.4%
LC
63.2%
DD
8.8%
CR
EN
VU
NT
LC
DD
11.8%
45.6%
29.4%
13.2%
Unknown
Decreasing
Stable
Increasing
CR
1.5%
EN
10.3%
VU
11.8%
NT
4.4%
LC
63.2%
DD
8.8%
CR
EN
VU
NT
LC
DD
17
1.3 Drastic historic shifts in bumblebee community
composition in Sweden
Ola Lundin
Summary of the science
Wild bees are threatened by many factors. Two important drivers are land use change and
intensication. Declines in species richness of bumblebees have received particular attention,
especially in Europe and North America. Many pollinator-dependent crops rely on bees for
yield, and the threats that bees are facing have raised concerns that crop pollination might also
be at risk. is concern depends on how drastic the changes in bee composition have been,
how important the declining bee species are for crop pollination, and the extent to which crop
yields are sensitive to changes in pollination service. We addressed these questions, using his-
toric data for a highly pollination dependent crop – red clover.
Charles Darwin noted that bees, primarily bumblebees, are essential for red clover seed
production, as the owers do not set any seeds unless bees pollinate them. Sweden has
Figure 1. The garden bumblebee (Bombus hortorum) on red clover. B. hortorum is one of several species
that has declined in relative abundance in red clover elds (Photo: Maj Rundlöf).
18
a long tradition of producing red clover seeds, and the details of this crops’ pollination
requirements were investigated during the 1900’s in Sweden. Because of this research, we
had access to detailed historic records with bumblebee visitation data from red clover elds
from both the 1940’s and the 1960’s. We compared these records with data that were collect-
ed between 2008 and 2010. In total, we analysed bumblebee visitation records from more
than 100 red clover elds distributed throughout Sweden during the period 1942-2010. e
bumblebee visitation observations were in each case collected with similar methodology.
Information on how much time was spent sampling bees in each eld was, however, lacking
Figure 3. Trends in red clover seed yields in the last 90 years. (a) Yearly statistic of yield per hectare. (b)
Variability in yield presented as the coecient of variation calculated from 5 year moving average (with
minimum four values), (reprinted from Bommarco et al., Proc. Roy. Soc. B.).
Figure 2. Proportional shifts in bumble-bee community composition in red clover seed elds in Sweden
(reprinted from Bommarco et al., Proc. Roy. Soc. B.).
19
for much of the historic records. erefore, we focused on analysing how the proportion
of each bumblebee species had changed over time, as this measure is relatively stable to
dierences in sampling eort. We also compiled and analysed data on red clover yields in
Sweden during the last 90 years.
We found drastic shis in the relative abundance of several bumblebee species over time (Fig-
ures 1 and 2). Two generalist species had increased in relative abundance, such that they now
completely dominate the bee community at the expense of several other more specialized
bumblebees, including some that are specialized on pollinating deep owers, such as red clo-
ver. We suggest that this shi in the bumblebee community is related to the loss and frag-
mentation of key bumblebee habitats, such as hay meadows and semi-natural pastures, in the
agricultural landscape. We also highlighted that legumes in general, and especially red clover,
which are important nectar and pollen resources for bumblebees, have become much rarer in
the landscape. is reduced availability and increased fragmentation of resources, is a proba-
ble reason why only generalist and highly mobile bumblebee species have been able to main-
tain large populations in intensively managed agricultural landscapes. In fact, they might even
have been favoured by these changes due to release from competition from other bumblebee
species. In parallel to the shis in functional composition of pollinator communities across
Sweden, we found that red clover seed yields have declined since the 1960’s and that the vari-
ation in seed yields has doubled in the last decades (Figure 3). Our approach cannot conrm
a causal link between changes in the relative abundances of bumblebees and lower and more
variable yields, but we do provide some strong evidence consistent with this explanation.
Policy relevance
e case study illustrates that there are important opportunities to better understand trends
in pollinator communities by using historic data from the literature, and there may be fur-
ther historic information available in libraries and archives, which could be used to better
understand trends in other species in other regions. Our study, however, also illustrates the
limitations of such approaches, as the available data did not allow us to draw conclusions
about shis in absolute bumblebee abundances. erefore, more standardized monitoring
and documentation of the occurrence and abundance of pollinators are needed to enable
comprehensive assessments of pollinator trends.
From a conservation perspective, the study highlights that management practices which
contribute to conservation of the diversity of pollinators is important, but probably not
sucient to secure and stabilise yields of insect pollinated crops. To achieve production
benets, there is also a need for management which safeguards a wide range of functionally
important pollinators at sucient abundances.
Reference
Bommarco R., Lundin O., Smith H.G., Rundlöf M. (2012) Drastic historic shis
in bumblebee community composition in Sweden. Proceedings of the Royal Society
B-Biological Sciences 279: 309-315.
20
Chapter 2: Drivers and Pressures on
Pollinators
Oliver Schweiger
Status and trends of pollinators are determined by a variety of drivers and pressures and
many of them are prone to changes as a result of anthropogenic activities. Major glob-
al change pressures are climate change, landscape alteration, agricultural intensication,
non-native species and spread of pathogens. Climatic conditions set the general precondi-
tions for the occurrence and performance of wild species according to their specic phys-
iological limits. Current climate change shis the suitable climatic conditions in time and
space, and pollinators that cannot compensate for this or have limited abilities to follow
these changes, can be seriously threatened. e major impact of land-use change concerns
the loss of habitat area or degradation of its quality (e.g. loss of nectar, pollen and nesting
resources). Agricultural intensication, such as the increased use of fertilisers and pesti-
cides, is a highly sensitive issue because the increased demand for food grown on a limited
amount of suitable land can favour intensication to increase yields per hectare, while the
consequences for pollinators may be detrimental. e wide-ranging concerns about pesti-
cides, especially of systemic pesticides, resulted in the temporary ban of three major neon-
icotinoids by the European Commission. In addition to land use and climate pressures, the
introduction of non-native pollinators can increase the risk of pathogen spread, especially
of non-native pathogens which likely show higher virulence in their novel hosts. All these
dierent environmental drivers rarely act in isolation and interactive eects, where one
driver increases the severity of another driver, are likely to be important. Awareness of
this importance is increasing, yet most studies have only analysed single specic drivers in
isolation, but to develop eective management strategies, a solid framework of such inter-
action mechanisms is needed (see case study 2.1).
ere is also an urgent need to know about the relative importance of the multiple drivers.
Land transformation is currently thought to be the most important driver but most of the
suitable land in Europe has already been converted to agricultural elds and, and so further
shis in land use to farming may be limited. is leads to the question of whether the impact
of other drivers such as climate change, or an increase in agrochemicals, will gain importance.
A question addressed in case study 2.2, where we show that climate predominantly deter-
mines the geographic distribution of European pollinators at large spatial scales, followed by
land use and agricultural intensity.
Given the high impact of climate on pollinator distributions, knowledge of potential future
changes is of particular relevance. In case study 2.3 we show that future climate change will
indeed pose serious risks to bumblebees.
An increased pressure from land-use intensity is explored by case study 2.4, where de-
clines in pollinator densities in European mass-owering crops are described. In such
21
intensively utilised agricultural areas, pesticides represent a major source of potential
concern for pollinators and thus fair test guidelines for pesticide approval are needed.
Unfortunately, the eects of chronic exposure to sub-lethal dosages, as they appear in
the eld, and their interactions with other environmental pressures such as common
parasites may not be fully relevant in current pesticide certication procedures, although
some pesticides can be shown to have severe impacts on pollinator colony performance
and tness (see case study 2.5).
2.1 Combined effects of global change pressures on
animal-mediated pollination
Juan P. González-Varo and Montserrat Vilà
Summary of the science
Pollination is essential in the sexual reproduction of seed plants and a key ecosystem service to
human welfare as many crops depend on animal pollination for yield production (Figure1).
Increasing evidence of pollinator declines has been reported as a consequence of ve major
global change pressures: climate change, landscape alteration, agricultural intensication, in-
troduction of non-native species, and spread of pathogens. Our study reviewed the current
evidence for these drivers acting simultaneously on pollinators and pollination services.
Climate change entails changes in community composition through shis in the geographi-
cal range and/or phenology of pollinator and plant species. Landscape alteration comprises
the degradation, destruction and fragmentation of natural habitats, resulting in associated
changes in landscape conguration, habitat diversity, and community composition. Inten-
sive agriculture is characterised by an increase in input of pesticides and fertilisers, farm
size, monocultures and simplied crop rotations. e eects of biological invasions on an-
imal-mediated pollination have usually been addressed by considering non-native plants
and non-native pollinators, both aecting the natural patters of plant-pollinator interac-
tions. Further, the huge increase during the past decades in the trade of managed pollina-
tors has promoted pathogen transmission to wild pollinators, and vice versa.
ese global change pressures dier in their biotic and abiotic nature and also in their spa-
tial and temporal scales of actions. For example, climate warming usually acts at the region-
al scale, while other pressures, such as the spread of pathogens, are typically more localised,
although they might expand very quickly through the landscape.
A given pressure can impact animal-mediated pollination directly by disrupting the oc-
currence, abundance and phenology of ower and pollinator species. However, a pressure
can also impact pollination indirectly, by interacting with other pressures, either additively
or non-additively. Non-additive eects occur if the impact of a given pressure is amplied
22
(synergistic eects) or buered (antagonistic eects) when it occurs in combination with
another pressure.
As exemplied in Figure 2, landscape alteration might impact native pollinators directly
by reducing oral and nesting resources. Indirect impacts of landscape alteration include
(i) favouring the abundance of non-native pollinators, and (ii) the increase in its per capita
impact through resource limitation, which additionally would increase the probability of
pathogen spillover.
To date, only a few empirical studies have explicitly tested the interactive eects of multi-
ple global change pressures on pollinators and/or animal-mediated pollination (Table 1).
Consequently, our knowledge on the interaction between various pressures is still limit-
ed and many interaction combinations are still underexplored. For example, given that
pathogen spillover is considered a major driver for observed bumblebee declines, more
attention should be placed to pathogen spread under contrasting scenarios of landscape
alteration. Also unexplored are those interactions between climate change and landscape
alteration, agricultural intensication or non-native species. Climate change is expected
to cause phenological mismatches in the low diversity plant-pollinator communities of
highly modied or intensively cultivat-
ed landscapes, jeopardizing both plant
reproduction and pollinator feeding.
Nevertheless, non-native plants and
pollinators could potentially provide
food supply and pollination function,
respectively, to resident native species
in periods where native plants and pol-
linators have curtailed their phenology.
Overall, the outstanding challenges are
to combine observational and manip-
ulative experimental designs to analyse
explicitly pair-wise, and further multi-
ple, interactions between pressures.
Policy relevance
Our review of the empirical evidence
about the eects of multiple global
change pressures on pollinators and
pollination highlights that we are far
from understanding their combined
eects. Management actions aimed at
buering the impacts of a particular
pressure could prove ineective if an-
Figure 1. The bee Lasioglossum albocinctum visiting
owers of Spanish lavender (Lavandula stoechas) in a
small woodland remnant (Photo: Juan P. González-Varo).
23
other pressure is present. In the case of synergistic eects, the reduction of one pressure will
ultimately lead to the reduction in the combined eect.
ere is evidence of synergic eects between agricultural intensication and landscape al-
teration aecting pollinators negatively. Accordingly, the positive eects of organic farm-
ing on pollinators can be negligible in well-preserved landscapes, but highly benecial in
highly altered landscapes. Similarly, conserving and restoring (semi-) natural habitats and
increasing landscape heterogeneity can be highly benecial within intensive croplands.
Synergistic eects also occur between agricultural intensication and pathogen virulence,
demonstrating that both infection rates and damage caused by pathogens are higher in
pollinators exposed to pesticides. In addition, infection rates are higher in landscapes with
intensive crops that typically use commercial bee hives for pollination.
A better understanding of how interacting pressures impact pollinators is essential to direct
the most appropriate mitigation and adaptation options to conserve plant and pollinator
biodiversity and manage pollination services.
Table 1. Summary of studies that have simultaneously addressed the eects of two global change drivers
on animal-mediated pollination. ‘POSITIVE’ and ‘NEGATIVE’ denote the type of combined eect between
pairs of pressures on diverse response variables related to pollinators (assemblages, species, populations
and individual tness) and/or pollination-associated processes (visitation rates, pollen limitation, mating
patterns and fecundity). I: studies that explicitly tested for interactive eects between drivers; C: studies that
assessed simultaneously the eects of two drivers but not the interaction; R: review studies; M: meta-ana-
lytical study. Numbers denote the number of studies within each category. (Modied from González-Varo
et al. 2013 Trends in Ecology and Evolution, Table 1).
GLOBAL CHANGE
Landscape alteration
POSITIVE
C: 1
NEGATIVE
I: 1
NEGATIVE
R: 1
NEGATIVE
I: 1
–
POSITIVE
R: 2
C: 1
POSITIVE
C: 3
POSITIVE
M: 1
I: 5
C: 2
POSITIVE
I: 4
C: 2
Non-native species
Agricultural intensification
Spread of pathogens
PRESSURES
Climate
change
Landscape
alteration
Non-native
species
Agricultural
intensification
POSITIVE
POSITIVE
I: 4
C: 2
C: 2
24
Figure 2. Scheme showing possible synergistic eects between landscape alteration, invasion by a non-
native pollinator, and pathogen spread impacting native pollinators and their pollination services. Black
arrows represent direct eects, whereas red arrows represent (indirect) interactive eects by which a
pressure (landscape alteration or pathogens) change the per capita impact of the non-native pollinator on
the native pollinator. Positive or negative signs in the arrows denote an increase or a decrease, respectively,
in the variable of study, whereas the text close to each arrow denotes the mechanism(s) responsible for
its eects. The shaded ellipse denotes a higher probability of pathogen spillover due to ower resource
limitation in altered landscapes. The pollination services provided by both pollinators will depend on
whether they perform legitimate visits or nectar robbing. (Photo reproduced with permission from
A.Montero-Castaño (top), H. Szentgyorgyi (right), and J.P. González-Varo (bottom and left); reprinted from
González-Varo et al. 2013 Trends in Ecology and Evolution, Figure 1 in box 3).
Reference
González-Varo J.P., Biesmeijer J.C., Bommarco R., Potts S., Schweiger O., Smith H.,
Stean-Dewenter I., Szentgyörgyi H., Woyciechowski M., Vilà M. (2013) Combined ef-
fects of global change pressures on animal-mediated pollination. Trends in Ecology and
Evolution 28: 524-530.
25
2.2 The relative importance of broad-scale drivers for the
distribution of European pollinators
Markus Franzén, Pierre Rasmont and Oliver Schweiger
Summary of the science
The diversity of pollinators such as wild bees, hoveries and butteries contributes tremen-
dously to the pollination of crops and wild plants. Knowledge of the drivers causing ob-
served declines and potential future changes of pollinators is indispensable for target-ori-
ented management, the sustainable provision of pollination services and to secure sucient
production of agricultural goods. Because of this central role, knowledge of the relative
impact of dierent factors on the distribution of pollinator groups at larger scales is import-
ant to understand species declines and to assess potential future risks. A major shortcoming
here is that the relative importance of dierent drivers has never been quantied for polli-
nators at larger spatial scales.
We explored how major drivers of global change such as climate, land cover, agrochemicals
and soil conditions aect the European-wide distribution of pollinators. e relationships of
these drivers and the geographical distributions of over 1,000 buttery, bumblebee, hovery,
and solitary bee species were modelled at a rather coarse spatial resolution of 50 km x 50 km
(Figure 1, 2).
Climate is the most important driver of the large-scale occurrence of all investigated groups of
pollinators in Europe (Figure 3). Land cover and soil conditions are the second most import-
ant drivers, but their relative importance diers among the taxonomic groups reecting their
ecological requirements. Most important, agrochemicals like fertilisers and pesticides have a
Figure 2. Distribution of the solitary bee Andrena
hattorana in Europe shown as occupied 50 km x
50 km grids in red (Franzén et al., in prep.).
Figure 1. Example of an the analysed species, the
mining bee Andrena hattorana.
(Photo: Markus Franzén)
26
signicantly negative impact on pollinators,
even at the European scale. us, eects of
agrochemicals are not restricted to the lo-
cal scale, as usually thought, but are already
aecting large-scale pollinator occurrence
across Europe.
Policy relevance
Land cover changes and accompanying
changes in soil conditions are regarded
important drivers currently aecting
European pollinators, and our results show
that across Europe, climatic conditions
are the most important overall driver of
occurrence and richness of pollinators.
e large eects of climatic conditions, in
combination with projected future climate
changes, indicate a likely shi of importance
from land cover to climate change.
However, land cover is still an important determinant of pollinators which highlights the
large potential of well-designed land management strategies to mitigate the increasing-
ly negative eects of climate change. Further, agricultural intensity is a serious driver of
pollinator occurrence and richness at the European scale, which calls for strong Europe-
an-wide regulatory schemes. However, since the severity of agricultural practice is highly
context-dependent, such regulatory schemes should still provide enough exibility to take
regional dierences in the eects of the dierent drivers into account.
e recent implementation of the EC habitats directive, and the ban or reduction in use of
selected pesticides like neonicotinoids in the European Union, could result in large scale
changes in landcover and land use intensity, potentially improving the situation for many
pollinators across Europe. Further, the Common Agricultural Policy of the European Union
could be a powerful instrument to ensure sustainable pollination service provision, if the
importance of pollinators and their services are fully recognised and appropriate incentives
are in place to implement greening measures targeted at increasing pollinator habitats and
limiting harmful impacts of agrochemicals.
Reference
Franzén M., Heikkinen R., Gyldenkærne S., Harpke A., Helm A., Kuhlmann M., Michez
D., Pauly A., Rasmont P., Settele J., Vujic A., Wiemers M., Welk E., Schweiger O. e rela-
tive importance of broad-scale drivers for the distribution of European pollinators. In prep.
Figure 3. Climatic conditions are the most important
drivers for European pollinators. Land cover and soil
are the second most important drivers, but their
eect size diers among pollinator groups. Also the
eects of agrochemicals were considerable at the
European scale and were largest for solitary bees
and hoveries. (Franzén et al., in prep.)
27
2.3 Future climatic risks for European bumblebees
Pierre Rasmont, Marcus Franzén, Thomas Lecocq and Oliver Schweiger
Summary of the science
Bumblebees are important wild and managed pollinators but future climate change will pose
serious risks on them. Based on species distribution data for all 69 European bumblebee spe-
cies, gathered within STEP (see Atlas Hymenoptera; www.atlashymenoptera.net) and cor-
responding, biologically relevant climate data, we modelled their climatically suitable areas
under current conditions. Based on these models, we projected future suitable areas accord-
ing to three climate change scenarios for 2050 and 2100*: (i) SEDGE: Sustainable European
Development Goal scenario (expected temperature increase for Europe in 2100 is 3.0°C), (ii)
BAMBU: Business-As-Might-Be-Usual scenario (expected temperature increase for Europe
in 2100 is 4.7°C) and (iii) GRAS: GRowth Applied Strategy scenario (expected temperature
increase for Europe in 2100 is 5.8°C). Taking into account a careful assessment of the disper-
sal capability of the species, we found that the vast majority of bumblebees (up to 46 species
in 2050 and up to 52 species in 2100) will suer from range contractions. Only four to ve
species might be able to expand their ranges, and up to eleven species will keep their status
quo. e future fate of the bumblebees also diered considerably among the three scenarios.
Under the most severe climate change scenario (GRAS), 22 species would lose nearly all their
suitable area, leading them at the verge of extinction in Europe. Under the less severe climate
change scenarios (SEDGE and BAMBU), it would be only two or three species. ese dra-
matic projections are in accordance with the present conservation status as proposed by the
IUCN Red List (see case study 1.2).
Future changes in the distribution of single species will nally add up to overall changes
in species richness of bumblebees. We found that reductions in bumblebee diversity will
already be noticeable in most of the considered areas by 2050 (median potential loss of 22
to 38%) while this reduction will be drastic in 2100 for all scenarios (median potential loss
of 42 to 88%). Only a few areas in the north and some mountain areas of Europe would be
able to conserve a substantial part of their present diversity.
Policy relevance
e considerable future losses of bumblebee species and their diversity across large areas in
Europe give rise to serious concerns. Even the most abundant and widespread species are
expected to contract (see Figures 1-2). Since bumblebees are presently one of the most ef-
fective and abundant wild and managed pollinators in temperate areas, and so their decline
would lead to a reduction in the pollination of many wild plants and agricultural crops with
potentially severe socio-economic consequences. is is further exacerbated by the fact
that these potential reductions of pollination services are unlikely to be compensated for by
other (managed) pollinators such as the honeybee (see Chapter 3).
*see Spangenberg et al. (2012) Scenarios for investigating risks to biodiversity. Global Ecology and Biogeography 21
28
e projected situation is so severe that it seems dicult to propose mitigation policies
for the long term. If we do not manage to drastically decrease the emissions of greenhouse
gases, conservation actions must focus on: (i) enabling the long-term survival in areas with
increasingly worsening climatic conditions (i.e. at the southern range margins); and, (ii)
Figure 1. (A) Bombus terrestris, one of the most common European bumblebees; (Rasmont et al.) (B)
Starting with actual 1970-2010 distribution (black circles), we assessed the present suitable climatic area of
each species (yellow area); here, for Bombus terrestris. (Rasmont et al. ) (C) Future climatically suitable area
for Bombus terrestris (GRAS scenario), 2050; at this time, even such an abundant species could already suer
from considerable regression in the south of Europe. (Rasmont et al.) (D) idem, 2100, at this time, all of
Europe south of the Paris parallel would present unsuitable climates for Bombus terrestris, meaning climatic
conditions as warm and dry as presently at the edge of Saharan desert. Red, lost areas with suitable climatic
conditions; yellow, still suitable; green, new suitable conditions (Rasmont et al.).
29
increasing species abilities to keep track with changing climates and to establish viable pop-
ulations in new climatically suitable areas (i.e. at the northern range margins).
Microclimatic heterogeneity could help to increase the survival probabilities at the southern
range margins when average conditions get worse, since such areas would still provide a
certain amount of suitable conditions. Such heterogeneity is given in mountains and deep
valleys, which could conserve a highly diversied fauna, but it should also be targeted in
agricultural areas by careful management, and thus would require concerted new actions
through instruments such as the Common Agricultural Policy of the EU.
At the northern range margins, natural dispersal can be facilitated by increasing connectivity
and quality of semi-natural areas. Agri-environment schemes appear as an eective measure
in this context and their implementation in a climate change context should be fostered
through policy support.
Reference
Rasmont P., Franzen M., Lecocq T., Harpke A., Roberts S.P.M., Biesmeijer K., Castro L.,
Cederberg B., Dvorák L., Fitzpatrick Ú., Gonseth Y., Haubruge E., Mahé G., Manino A., Mi-
chez D., Neumayer J., Ødegaard F., Paukkunen J., Pawlikowski T., Potts S.G., Reemer M.,
Straka J., Settele J., Schweiger O. (2015) Climatic Risk and Distribution Atlas of European
Bumblebees. Penso Publishers, Soa.
Figure 2. (A) Bombus haematurus, one of the few bumblebees that would nd an expanded suitable area in
each of the scenarios. This species is already expanding its distribution towards the west. (Rasmont et al.) (B)
Future climatically suitable area for Bombus haematurus (GRAS scenario), 2050. Red, lost areas with suitable
climatic conditions; yellow, still suitable; green, new suitable conditions (Rasmont et al.).
30
2.4 Expansion of mass-flowering crops leads to transient
pollinator dilution and reduced wild plant pollination
Andrea Holzschuh and Ingolf Steffan-Dewenter
Summary of the science
Negative consequences of land-use intensication and habitat loss for biodiversity and as-
sociated ecosystem services have oen been reported, but the exact mechanisms are still
poorly understood. Although biodiversity loss is mostly assumed to be a direct result of
decreasing habitat area and of impeded organism exchanges between habitat fragments, in-
direct eects mediated by changed species interactions might be just as important. Indirect
eects of land-use intensication via species interactions can be expected to be ubiquitous
where managed and natural habitats adjoin (Figure 1), or where species using multiple
habitats connect managed and natural habitats on a larger scale.
Figure 1. Protected semi-natural habitat in a landscape with mass-owering oilseed rape elds (Photo:
Andrea Holzschuh).
31
We conducted a large-scale eld study on 67 study sites to assess interactions between
mass-owering oilseed rape and semi-natural grasslands, and their potential eects on wild
plants and bees (Figure 2). Our results show that interactions between these habitats occur
at dierent spatial scales, alter resource use of pollinators and reduce the reproduction of
the protected plant Primula veris (cowslip) in conservation areas. Abundances of bumble-
bees, which are the main pollinators of cowslip but also pollinate oilseed rape, decreased
with increasing proportion of oilseed rape cover in the landscape. is landscape-scale di-
lution of pollinators strongly aected bumblebee abundances in oilseed rape elds (Figure
3 A), and marginally in grasslands, where bumblebee abundances were generally low at
the time of cowslip owering. Seed set of cowslip, which is owering during oilseed-rape
bloom, was reduced by 20% when the proportion of oilseed rape in 1 km radius increased
from 0 to 15% (Figure 3 B).
Our data suggests that the current expansion of bee-attractive biofuel crops will increase
cross-habitat exchanges of bees and competition between oilseed rape and wild plants for
pollinators. Spillover eects of bees from semi-natural nesting habitats to crop habitats, and
Figure 2. Landscape-scale dilution of bees in oilseed rape, and consequences for pollinator abundances
and seed set. The number of blue dots indicates number of produced seeds. (A) High amount of oilseed
rape results in high dilution of pollinators, in low pollinator abundances per site and low reproduction of
pollinator-dependent grassland plants. (B) Low amount of oilseed rape results in high pollinator abundances
per site and high reproduction of pollinator-dependent grassland plants. Eects on oilseed rape have not
been studied here and hence its seed production is not indicated (reprinted from Holzschuhet al. (2011)
Proc. Roy. Soc. B 278: 3444-3451).
32
bee-mediated spillover of food resources from crop to nesting habitats may have a strong
impact on population dynamics of bees and plants which depend on pollinators. Although
there is little additional evidence up to now, similar spillover eects connecting crop and
natural habitats can be expected for many types of species interactions in landscapes where
highly productive sites and less productive, more natural sites co-occur.
Policy relevance
We showed that the expansion of mass-owering crops can reduce the tness of wild plants
in conservation areas, because competition between mass-owering crops and wild plants
for pollinators increased. To optimize pollination of protected wild plants and of insect-pol-
linated crops we need diverse pollinator populations whose growth can keep pace with the
increasing area of pollinator-dependent crops. Management policies should specically target
at factors potentially limiting population growth of pollinators. An expansion of heteroge-
nous semi-natural habitats providing non-disturbed soils and below- and above-ground cav-
ities will enhance the availability of nesting sites for many wild bee species. Artical nesting
aids could complement the conservation and restoration of habitats providing natural nesting
sites. Even though these policies will not impede the distraction of pollinators from semi-nat-
ural habitats to crop elds, they will contribute to mitigate the negative eects on wild plants
by enhancing pollinator populations at the landscape scale.
Reference
Holzschuh A., Dormann C.F., Tscharntke T., Stean-Dewenter I. (2011) Expansion of
mass-owering crops leads to transient pollinator dilution and reduced wild plant pollina-
tion. Proceedings of the Royal Society B 278: 3444-3451.
Figure 3. Relationship between the proportion of oilseed rape in 1 km radius and (A) bumblebee
abundances per 400 m² and 60 min in oilseed rape elds (simple regression: n=34, F=7.1, P=0.012) and (B)
the reproductive success of cowslip (Primula veris) in grasslands, as mean number of seeds per fruit (simple
regression: n=19, F=10.3, P=0.005), (reprinted from Holzschuh et al. (2011) Proc. Roy. Soc. B 278: 3444-3451).
33
2.5 Impact of chronic neonicotinoid exposure on honeybee
colony performance and queen supersedure
Peter Neumann
Summary of the science
Honeybees provide economically and ecologically vital pollination services to some crops
and wild plants. During the last decade elevated losses of managed colonies have been doc-
umented in Europe and North America. Despite growing consensus on the involvement of
multiple causal factors, the underlying interactions impacting on honeybee health and col-
ony failure are not fully resolved. Parasites and pathogens are among the main candidates,
but sub-lethal exposure to widespread agricultural pesticides may also aect honeybees.
To investigate eects of sub-lethal dietary neonicotinoid exposure on honeybee colony per-
formance, a fully crossed experimental design was implemented using 24 colonies, includ-
ing sister-queens from two dierent strains, and experimental in-hive pollen feeding with
or without environmentally relevant concentrations of the neonicotinoids thiamethoxam
and clothianidin.
Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles ex-
hibited decreased performance in the short-term resulting in declining numbers of adult
bees (-228%) and brood (-213%), as well as a reduction in honey production (-229%) and
pollen collections (-219%), but colonies recovered in the medium-term and overwintered
successfully (Figure 1, Table 1). However, signicantly decelerated growth of neonicoti-
noid-exposed colonies during the following spring was associated with queen failure, re-
vealing previously undocumented long-term impacts of neonicotinoids: queen supersedure
was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but
not for control colonies. Linked to this, neonicotinoid exposure was signicantly associated
with a reduced propensity to swarm during the next spring. Both short-term and long-term
eects of neonicotinoids on colony performance were signicantly inuenced by the hon-
eybees’ genetic background.
Sub-lethal neonicotinoid exposure did not provoke increased winter losses of honeybee
colonies. Yet, signicant detrimental short and long-term impacts on colony performance
and queen fate suggest that neonicotinoids may contribute to colony weakening in a com-
plex manner. Further, we highlight the importance of the genetic basis of neonicotinoid
susceptibility in honeybees which can vary substantially. Even though honeybee colonies
constitute buered systems, the data show clear eects of the neonicotinoids.
Policy relevance
Taken together with the clear evidence in other species, and with other substances, it is
becoming increasingly clear that systemic neonicotinoids may potentially compromise pol-
34
Figure 1. Dynamics of honeybee colony
performance. Data of all three endpoints number
of adult bees (A), eggs and larvae (B) and pupae
(C) for the dierent pollen feeding treatments
(black = control; red = neonicotinoids) and
honeybee strains (circles = strain A; crosses
= strain B). The data were obtained at four
successive colony assessment dates (X-axis
subpanels within gures) performed before
(Spring 2011) and directly after the 1.5 months of
experimental pollen feeding (Summer 2011), 3.5
months after the treatment (Autumn 2011) and
one year later (Spring 2012). Estimated numbers
on the Y-axes are truncated for adult bees and
pupae for better overview. (Christoph Sandrock,
PLoSOne, DOI: 10.1371/journal.pone.0103592)
Table 1. Model-based estimates of contrasts and corresponding signicance levels of the treatment eect
(neonicotinoid versus control) and honeybee genetics (strain A vs. strain B). (Christoph Sandrock, PLoSOne,
DOI: 10.1371/journal.pone.0103592)
35
lination services in Europe and elsewhere via weakening of bee populations. While the EU
ban of the neonicotinoids was a rst signicant step allowing more time for relevant evi-
dence to be collected and assessed, further policy actions must be taken to safeguard crop
pollination and species conservation in Europe, such as instruments to reduce the usage of
agrochemicals known to harm polinators.
Reference
Sandrock C., Tanadini M., Tanadini LG., Fauser-Misslin A., Potts S.G., Neumann P. (2014)
Impact of chronic neonicotinoid exposure on honeybee colony performance and queen su-
persedure. PLoS ONE 9(8): e103592.
Figure 2. Honeybee queen and attending workers (Photo: Peter Neumann).
36
Chapter 3: Wider Impacts of Changes
in Pollinators
Riccardo Bommarco
In STEP we set out to explore how observed declines in wild and managed pollinators
impact plant-pollinator interactions, and the pollination services provided by the honey-
bees, wild bees, hoveries and other insects that visit the owers of cultivated and wild
plants. We further assessed how these changes aect the wider society, economies and
human health.
We have addressed impacts on crop pollination by gathering and synthesising a com-
prehensive set of primary data from crop pollination researchers around the world (case
study 3.1), supplemented with strategically placed empirical case studies (e.g. 3.5). We
consistently found that high quality natural or semi-natural habitat provides an essen-
tial basis for abundant and species rich bee communities in agricultural landscapes
worldwide. Pollinator visitation decreased with distance from natural areas, resulting
in decreased crop fruit set and stability of pollination services. Conserving, restoring
and re-creating natural habitat are, together with decreasing agricultural inputs, pri-
mary steps to secure sucient provisioning of pollination services to agriculture (case
study 3.4). Interestingly, we also discovered that wild insects, compared to honeybees,
pollinate crops more eectively than previously thought. Pollination by managed hon-
eybees supplements, rather than substitutes pollination by wild insects emphasising the
importance of monitoring and protecting wild as well as managed crop pollinators (case
study 3.1).
Pollinator declines may impact society, economy and human well-fare, directly through
degraded crop pollination in agriculture, and in the long-term through declining bio-
diversity and ecosystem functioning. Two aspects that we focused on were the impacts
on crop yield and quality. We found that increased cultivation of pollination dependent
crops drove up demand for pollination at a rate greater than could be supplied by hon-
eybee stocks across Europe, thereby creating a pollination decit (case study 3.2). Future
increased cultivation of biofuels is expected to increase this decit. In another case study
(3.3) we show that the contribution of nutrients from animal-pollinated crops to the hu-
man diet is paramount. ese crops provide almost all vitamin C, vitamin A and other
micronutrients such as carotenoids, calcium, uoride, folic acid and several antioxidants
in human diets. Pollinators thus contribute substantially to the quality of our diet, and
pollination declines may increase the risk of poor quality diets for the global human
population. Overall, and despite some knowledge gaps, it is clear that severe pollinator
declines will have drastic and widespread impacts on our daily lives, global economies
and food security.
37
3.1 Wild pollinators enhance fruit set of crops regardless of
honeybee abundance
Riccardo Bommarco
Summary of the science
ere is an increasing concern that the observed declines of both wild and managed pol-
linators might impact the pollination, and thereby production, of world agricultural crops
negatively. Whether the declines among wild pollinators, or of managed pollinators (mainly
honeybees, Apis mellifera), have equally severe consequences for crop yields has, however,
remained unclear. It has generally been assumed that most of the pollen in crops worldwide
is transferred by honeybees. Wild pollinators have been thought to play a supporting and
complementary role to the honeybee in cross-fertilizing crops. Earlier work indicated that
wild pollinators might be important as service providers (Garibaldi et al. 2011), so continu-
ing this we quantied the relative contribution to cross-pollination in crops by managed
honeybees and wild insects.
We rst tested whether wild insect and honeybee visitation enhanced pollen deposition on
stigmas of crop owers. Second, we assessed to what extent visitation to the crop owers by
wild insects or honeybees improved fruit set. ird, we explore if visitation by honeybees
might aect the benet derived from wild insects. We wanted to understand whether fruit
set is promoted by a higher number of species or individuals of wild pollinator that visit the
owers, only in situations when few honeybees visit the owers.
To reach general answers to these questions, we contacted scientists that perform research
on crop pollination from all over the world. We asked them to send us their original data
on ower visitation and fruit set in crops. e response was extremely positive, and we were
able to collect primary data from 600 agricultural elds on all continents, except Antarctica,
and for 41 crops.
We found a universally positive association of fruit set with increased ower visitation by
wild insects in cropping systems worldwide (Figure 1). In contrast, fruit set increased with
ower visitation by honeybees in only 14% of the cropping systems included. Overall, wild
insects pollinated crops more eciently than we had previously thought and had hypothe-
sised. In fact, an increase in wild insect visitation enhanced fruit set by twice as much as an
equivalent increase in honeybee visitation. Visitation by wild insects and honeybees pro-
moted fruit set independently, such that pollination by managed honeybees supplemented,
rather than substituted pollination by wild insects. Our results suggest that new practices
for integrated management of both honeybees and diverse wild insect assemblages will
enhance global crop yields.
38
Policy relevance
We found that wild insects, compared to
honeybees, pollinated crops more eec-
tively than previously thought. An increase
in visits to the crop owers by wild insect
enhanced fruit set by twice as much as an
equivalent increase in honeybee visitation.
Flower visitation by wild insects and honey-
bees promoted fruit set independently. is
implies that crop pollination by managed
honeybees supplements, rather than substi-
tutes pollination by wild insects.
Wild pollinators clearly contribute more to
the level and stability of crop pollination ser-
vices than previously thought. Considering
their enormous value for crop production
world-wide, there is a need for continued
assessments of the contributions in terms of
yield quantity and quality, provided by the
wild fauna to agriculture in dierent crops
and regions across the world.
We also need to integrate an active management of pollinators and pollination into mainstream
agricultural practices, something that is largely lacking today. is is especially the case for the
majority of crop species that only partly depend on pollination by insects to set a fruit or a seed.
Reference
Garibaldi L.A., Stean-Dewenter I., Kremen C., Morales J.M., Bommarco R., Cunning-
ham S., Carvalheiro L., Chaco N., Dudenhöer J.H., Greenleaf S., Holzschuh A., Isaacs
R., Krewenka K., Mandelik Y., Mayeld M., Morandin L., Potts S.G., Ricketts T., Szent-
györgyi H., Winfree R., Klein A.M. (2011) Stability of pollination services decreases with
isolation from natural areas despite honeybee visits. Ecology Letters 14: 1062-1072.
Garibaldi L.A., Stean-Dewenter I, Winfree R., Aizen M.A., Bommarco R., Cunningham
S.A., Kremen C., Carvalheiro L.G., Harder L.D., Ak O., Bartomeus I., Benjamin F., Bo-
reux V., Cariveau D., Chaco N.P., Dudenhöer J.H., Freitas B.M., Ghazoul J., Greenleaf
S., Hipólito J., Holzschuh A., Howlett B., Isaacs R., Javorek S.K., Kennedy C.M., Krewenka
K., Krishnan S., Mandelik Y., Mayeld M.M., Motzke I., Munyuli T., Nault B.A., Otieno
M., Petersen J., Pisanty G., Potts S.G., Rader R., Ricketts T.H., Rundlöf M., Seymour C.L.,
Schüepp C., Szentgyörgyi H., Taki H., Tscharntke T., Vergara C.H., Viana B.F., Wanger
T.C., Westphal C., Williams N., Klein A.M. (2013) Wild pollinators enhance fruit set of
crops regardless of honeybee abundance. Science 339: 1608-1611.
Figure 1. Visitation rate to crop owers by wild in-
sects enhances reproduction in all crops examined,
whereas honeybee visitation has weaker eects
overall. Maximum fruit set is achieved with high
visitation by both wild insects and honeybees (up-
per right side of the gure). Fruit set increases from
cyan to dark blue (reprinted from Garibaldi et al.
2013, Science).
39
3.2 Agricultural policies exacerbate honeybee pollination
service supply-demand mismatches across Europe
Thomas Breeze
Summary of the science
Many European farmers rely on insect
pollination services to ensure the best
possible yields and are directly aect-
ed by changes in the availability of
this service. As such, understanding
the supply and demand of pollination
services is essential to understand how
vulnerable European agriculture is to
changes in pollinator populations or
increasing demands for pollination
services. Although they are not the
main pollinators in many crops (see
case study 3.1), managed honeybees
represent an important insurance as-
set to European crop production. is
study examined the security of Euro-
pean pollination services by compar-
ing the available supplies of honeybees
with demand for pollination services
across the continent in two years,
2005 and 2010.
Using ocial statistical data from 41 European countries, the supply of honeybee pollination
services was estimated as double the number of honeybee colonies in each country. ese
values were doubled to represent the capacity for beekeepers to move their hives between
two dierent crops in a single year. Total demand for pollination services was estimated by
multiplying the area of each insect pollinated crop by research estimates of the number of
colonies recommended to provide pollination services to that crop. Summed over all crops,
this produced an estimate of total national demand. By dividing supply by demand the study
was able to estimate the capacity of each country’s honeybee stocks to supply recommended
levels of pollination services.
e ndings indicate that, in both years, 22 of the 41 countries had insucient honeybee col-
onies to supply their demands for pollination services alone. Of these, the UK and Moldova
had the lowest supply relative to their demands in both 2005 and 2010. By contrast Slovenia
and Norway had several times as many colonies than their farming sectors demanded. Tak-
en as a whole, total stocks in all 41 countries were able to supply approximately two thirds
Figure 1. Honeybee colony (Photo: Jake Bishop).
40
of European demands in both
years. Although the total num-
ber of honeybee colonies has in-
creased across Europe, total de-
mand grew nearly ve times as
much in the same time. Most of
this increase was due to substan-
tial growth in the area of oilseed
rape and sunowers, both com-
monly used as biodiesel stock.
is was particularly noticeable
in Greece where the area of oil-
seed rape grew by over 700%.
e increase in demand relative
to supply was most notable in
Latvia, Lithuania, Estonia and
Finland where the capacity of
honeybees to supply services fell
below 25%. Many countries that
saw increased honeybee stocks
were oen those that already
had more colonies than they re-
quired.
Policy relevance
ese ndings highlight that several European countries are vulnerable to pollination ser-
vice losses. Wild pollinators may be able to provide the majority of services, though the
status and trends of these pollinators are largely unknown. As such any decits, current or
future, are likely to reduce farm productivity. Monitoring pollinator populations and ser-
vice delivery, particularly in those countries with few honeybees relative to demand, could
therefore have signicant benets to producers. e observed growth in demand relative to
supply is likely due to the eects of the European Unions’ Renewable Fuel Directive which
was introduced in 2005 alongside a relaxation of the price controls placed on these crops at
the same time. is resulted in substantial growth in both the demand and price for these
crops, encouraging farmers to grow them more widely both within and beyond the Euro-
pean Union. ese ndings also demonstrate the unintended consequences that policy can
have on pollination and potentially other ecosystem services.
Reference
Breeze T.D., Vaissiere B., Bommarco R., Petanidou T., Seraphides N., Kozák L., Schep-
erJ., Biesmeijer J.C., Kleijn D., Gyldenkærne S., Moretti M., Holzschuh A., Stean-De-
wenter I., Stout J., Pärtel M., Zobel M. & Potts S.G. (2014) Agricultural policies exacerbate
pollination service supply-demand mismatches across Europe. PLoS ONE 9(1): e82996.
Figure 2. Capacity of honeybee colonies to supply demands for
pollinaion services at a national level (reprinted from Breeze et al.
PLoS One, DOI: 10.1371/journal.pone.0082996).
41
3.3 Contribution of pollinator-mediated crops to nutrients
in the human food supply
Alexandra-Maria Klein
Summary of the science
Several studies have been conducted to evaluate monetary values of pollination services on
crop pollination. However, it is dicult to assign monetary values to pollination services
because they are frequently not traded in the marketplace and values dier widely depend-
ing on methods, value systems and scales of analysis. Furthermore, the value of money
changes constantly with shiing markets, particularly in the face of the current global -
nancial crisis. In contrast, biophysical measures such as the nutritional composition of an-
imal-pollinated plants and the nutrient requirements to prevent deciency in humans are
relatively stable and may be measured objectively. We used this biophysical approach to
evaluate the global nutritional value of pollinator-dependent crops.
Staple crop production (e.g. cassava, corn, potato, rice, wheat and yam) has doubled in the
past 50 years due to new crop strains, increased use of agrochemicals, irrigation and new agri-
cultural techniques. ese grains and starchy vegetables are mostly wind-pollinated, self-pol-
linated, or vegetatively propagated crops. While they provide the majority of calories in the
human diet, they are poor sources of most micronutrients. What little micronutrients are
present in these sources are mostly lost in processing or preservation. Dependence on these
Figure 1. Proportion of fat-soluble vitamins (K= vitamin K, E= vitamin E, γToco= γ – tocopherol, αCaro
= α-carotene, A= vitamin A, βCaro = β-carotene, δToco= δ – tocopherol, βCrypto = β - cryptoxanthin,
βToco= β – tocopherol) in global crop production (%) produced without pollinators (grey), produced with
pollinators but attributed to autonomous self- or wind pollination (light-yellow), produced with pollinators
and directly attributed to animal pollination (yellow), (Modied from Eilers et al., PLoS One, DOI: 10.1371/
journal.pone.0021363).
42
staple crops, due to food system failures and declines in diet diversity, are responsible for
micronutrient deciency (‘Hidden Hunger’) in over two billion people worldwide, especially
in underprivileged areas. is underscores the importance of diet diversity and the need for
animal-pollinated plants to prevent micronutrient deciency. However, the contribution of
these plants to worldwide micronutrient availability has not been quantied.
We evaluated the nutritional composition of animal-pollinated world crops. We calculated
pollinator dependent and independent proportions of dierent nutrients of world crops, em-
ploying FAO data for crop production, USDA data for nutritional composition and pollinator
dependency data. Crop plants that depend fully or partially on animal pollinators contain
more than 90% of vitamin C, the whole quantity of Lycopene and almost the full quantity of
the antioxidants β-cryptoxanthin and β-tocopherol, the majority of the lipid, vitamin A and
related carotenoids, calcium and uoride, and a large portion of folic acid (see Figure 1 for the
proportion of fat-soluble vitamins attributed to animal pollination in yellow).
is biophysical evaluation of the importance of pollination services for the production of
vitamins and minerals highlights that ongoing pollinator decline may exacerbate current
diculties of providing a nutritionally adequate diet for the global human population.
Policy relevance
Animal-pollinated crops contain the majority of the available dietary lipid, vitamin A, C and
E, and a large portion of the minerals calcium, uoride and iron worldwide. Micronutrient
deciencies resulting from potential declines in animal-pollinated crops can be identied
for dierent regions and are likely to be worse in developing nations (Chaplin-Kramer et al.
2014). Policy makers can use the method demonstrated here to identify the matching regions
of severe pollinator decline with greatest risk of losing essential vitamins and minerals.
Supplementation and fortication of vitamins and minerals are not adequate substitutes
for the loss or reduction of the nutrients from food sources attributed to pollinator loss.
Mandatory fortication has been successful only in some countries, such as the U.S. and
China, but it depends on an organised and regulated food industry. Synthetically fabricated
healthcare products are only available to 25% of the world population, while the other 75%
relies on ethnobotanical remedies and these people depend on the vitamins and minerals
of fruits and seeds that largely depend on pollination services.
Reference
Eilers E.J., Kremen C., Greenleaf S., Garber A.K., Klein A-M. (2011) Contribution of polli-
nator-mediated crops to nutrients in the human food supply. PLoS One 6(6): e21363.
Chaplin-Kramer R., Dombeck E., Gerber J., Knuth K.A., Mueller N.D., Mueller M., Ziv
G., Klein A-M. 2014 Global malnutrition overlaps with pollinator-dependent micronu-
trient production. Proceedings B Royal Society of Publishing 281: 1799. http://dx.doi.
org/10.1098/rspb.2014.1799
43
3.4 Ecological intensification: harnessing ecosystem
services for food security
Simon Potts
Summary of the science
With global population growth, and associated demand for agricultural goods, there is ev-
er-increasing pressure on farming to intensify production. However, this poses greater risks
to environmental quality if conventional approaches to intensication are followed. A ma-
jor opportunity for increasing production sustainably (i.e. ensuring environmental impacts
are minimised while production is maintained or enhanced) is by integrating ecosystem
services into agricultural systems. is can be achieved by replacing and/or augmenting
anthropogenic inputs (e.g. fertilizers and pesticides) with ecosystem services such as pest
regulation by natural enemies, pollination and soil fertility building. is approach is called
“Ecological Intensication” and seeks to manage the biodiversity underpinning the ecosys-
tem services which ultimately support food production (Figure 2).
Many fruit, vegetable and arable
crops show a decit in pollina-
tion services, meaning that they
could produce more yield or bet-
ter quality products if pollination
was improved (Figure 1). ere
are several ways to do this. Farm-
ers could augment pollination
services with managed pollina-
tors such as honeybees, bumble-
bees or mason bees. Alternatively
they could improve the area and
quality of habitats that support
pollinators on their farms or
in the surrounding landscape.
Sowing ower-rich eld margins
is one example where pollina-
tor-friendly habitat is established
next to a eld where there is a
high demand for pollination ser-
vices. e underlying rationale
being that a small economic in-
vestment in pollinator habitats
could result in a long-term boost to productivity and prot. Studies are emerging showing
that this approach is valid, yet there is much that research needs to address before this is es-
tablished as a robust management practice for dierent farming systems across continents.
Figure 1. Red-tailed bumblebee (Bombus lapidarius) visiting
oilseed rape owers (Photo: Jennifer Wickens).
44
A smart approach to ecological intensication is to identify win:win practices which can ben-
et multiple ecosystem services simultaneously. For instance, if ower margins can support
the natural enemies of crop pests (e.g. carabid beetles, spiders and parasitoid wasps), as well
as pollinators, then these benecial insects could also spillover into the crop and reduce yield
losses. Field margins can also play a role in soil protection, help buer water courses from
agricultural pollutants and help support other wildlife valued by the society, such as birds.
As energy prices and population are projected to go up in the next few decades, farming
needs to shi increasingly from being highly dependent upon synthetic inputs to utilising
biodiversity driven ecosystem services. Ecological intensication shows huge promise in
helping this transition and will be an indispensable tool to reconcile the demands of food
security, biodiversity conservation and sustainable societies (Figure 3).
Figure 2. Conceptualisation of the contribution of regulating and supporting services to provisioning
services (production). (a) Production can only attain a level set by the lowest underpinning regulating
or supporting service, in this case pest regulation, despite other services being super-optimal. (b) Pest
regulation is enhanced and so production increases, and the yield gap is reduced, to the level set by the next
limiting service, in this case soil nutrients. (c) Ecological replacement is where a proportion of one of more
underpinning services (e.g. pest regulation) is supplied by biodiversity derived services (e.g. natural enemies,
green bar) rather anthropogenic derived services (e.g. insecticides, red bar); production remains the same
overall but more of the regulating and/or supporting service(s) are provided by biodiversity. (d) Ecological
enhancement is where the level of one of more underpinning services (e.g. pest regulation) is boosted by
biodiversity derived services (green bar) rather than anthropogenic derived services (red bar); with the result
in production increasing overall (reprinted from Bommarco et al. 2013, Trends in Ecology and Evolution).
45
Policy relevance:
e international community is moving forward from the Millennium Development Goals
towards the Sustainable Development Goals, which specically recognises that biodiversity
and ecosystem services can play a key role in poverty alleviation, and so widespread eco-
logical intensication will be essential. Eective development of food security policies from
global and national to local levels will need to continually draw upon a robust scientic
evidence in order to integrate ecosystem services such as pollination into food production.
Understanding the identity of pollinators responsible for crop pollination, and how land-
scapes can be managed to conserve and sustainably manage them, is critical to support
agri-environment schemes, agricultural and conservation policies (e.g. Common Agricul-
tural Policy, EU 2020 Biodiversity Strategy and the Convention on Biological Diversity).
Reference:
Bommarco R., Kleijn D., Potts S.G. (2013) Ecological intensication: harnessing ecosys-
tem services for food security. Trends in Ecology and Evolution 28: 230-238.
Figure 3. Illustration of the limits and alternatives for global food security with a safe area (green) where
global food demands are met (a). Alternative scenarios of ecological (b) and continued conventional (c)
intensication are shown. Conventional intensication is expected to move systems towards the right, with
increased impacts on ecosystems services and the environment. Even if conventional intensication moved
systems into the safe space above minimum global food needs, there remains little room for manoeuvre
close to maximum attainable yields, posing increased risks under further environmental change. As systems
move towards the right-hand boundary of the safe space, maximum attainable food production is expected
to decrease due to degraded ecosystem services. Furthermore, negative impacts on the environment,
biodiversity and other benets are expected to increase in this direction. A complementary strategy
is to widen safe space by dampening demands for food products, such that minimum global needs for
agricultural products are lowered (reprinted from Bommarco et al. 2013, Trends in Ecology and Evolution).
46
3.5 Annual dynamics of wild bee densities: attractiveness
and productivity effects of oilseed rape
Ingolf Steffan-Dewenter, Verena Riedinger and Andrea Holzschuh
Summary of the science
Oilseed rape is one of the most important insect-pollinated mass-owering crops in the Eu-
ropean Union. Understanding the factors that determine the density and species richness of
pollinators on such mass-owering crops is mandatory for an ecient management of pol-
lination services and stable crop yields. Principally, two dierent factors play a role in inu-
encing pollinator densities. First, the attractiveness of oilseed rape in comparison to other
oral resources and the production area of oilseed rape in relation to pollinator population
size determine densities (Figure 1). High attractiveness of oilseed rape and a large cover of
oilseed rape in a landscape lead to the dilution of pollinators and a potential decit in polli-
nation service. Second, oilseed rape provides large amounts of pollen and nectar resources
that can increase population growth of wild solitary and social bee species. High cover of
oilseed rape can result in larger bee populations and thus higher pollinator densities in the
following year (Figure 1). Solitary bee species that reproduce during the owering period of
oilseed rape may benet more from additional pollen resources than social bee species that
require a resource continuum from spring to autumn. Importantly, distinguishing between
these two factors in agricultural landscapes requires data from sequential years and the
parallel inclusion of attractiveness eects, i.e. the dilution or concentration of pollinators
in dependence on the relative cover of oilseed rape in a landscape, and population growth
AAttractiveness of oilseed rape (OSR)
Low % OSR High % OSR
‚no preference‘
,preference‘
Current year
=
>
dilution
no
dilution
Low % OSR High % OSR
Current year Previous year
>
BProductivity effect of oilseed rape (OSR)
higher
productivity
effect OSR
III
III IV
III
III IV
Figure 1. Conceptual model of attractiveness and productivity eects of oilseed rape on pollinator densities.
(A) Preference of pollinators for oilseed rape leads to higher densities in oilseed rape elds compared to
other habitats and dilution in landscapes with high oilseed rape cover. (B) Higher population growth rates
in oilseed rape result in higher pollinator densities in the consecutive year (reprinted from Riedinger et al.
(in press) Ecology, DOI: 10.1890/14-1124.1).
47
eects, i.e. the annual dynamics of pollinator population size in dependence on the avail-
ability of oilseed rape pollen in the previous year.
In a case study in Lower Franconia,
Germany, we selected 16 landscape
sectors of 1 km radius with low to high
oilseed rape cover and monitored pol-
linator densities and oilseed rape cov-
er changes in two consecutive years.
We developed a mechanistic model to
evaluate the combined eects of oilseed
rape cover on the dilution or concen-
tration of pollinator densities and the
reproduction of bees. By tting our em-
pirical data with the mechanistic model
we showed that a high cover of oilseed
rape in the previous year enhanced the
densities of solitary wild bees in the re-
spective landscape in the following year
(Figure 2 A, Figure 3). However, for
bumblebees with season-long colonies,
no positive eect on the densities in the
following year could be found (Figure
2 B). Presumably, bumblebees require
other oral resources from semi-natu-
ral habitats or later owering crops (see
case study 4.4) to enhance the produc-
tion of young queens and drones. We
conclude that mass-owering crops can
aect the dynamics of wild bee popu-
lations but eect sizes depends on the
ight period, social status and annual
changes in oilseed rape cover.
Policy relevance
e quantity and quality of oilseed rape
yields can be signicantly improved by
insect cross-pollination. erefore, the
promotion of pollinators in landscapes
with a high cover of oilseed rape elds
is highly relevant for farmers across
Europe. Our results indicate that the
additional pollen resources of oilseed
rape can enhance the size of solitary bee
Figure 2. (A) Relationship between the cover of
oilseed rape (OSR) in the previous year and the
densities of wild bees (excl. Bombus) from 32 OSR
elds across two consecutive years, (B) Relationship
between the cover of OSR in the previous year and
the densities of bumblebees from 32 OSR elds across
two consecutive years (reprinted from Riedinger et al.
(in press) Ecology, DOI: 10.1890/14-1124.1).
48
populations that reproduce during oilseed rape owering. Under the precondition that
other habitat requirements, in particular nesting sites, and protection from negative im-
pacts of pesticides are ensured, mass-owering crops could at least partly sustain wild bee
populations for adequate pollination services. We recommend that agri-environmental
management strategies target the provisioning of suitable nesting sites for below- and
above-ground nesting solitary bees in agricultural landscapes. In order to maintain an
equilibrium between the size of bee populations and the amount of oilseed rape, we rec-
ommend that farmers aim for moderate annual changes in the cover of oilseed rape in a
landscape as far as possible due to crop rotation constraints. Social bumblebees are highly
important crop pollinators, but they require additional wild plant or crop oral resources
throughout the year to build up larger populations. We therefore recommend that land-
scape-scale management tools are developed to inform farmers about the requirements
of pollinators in terms of nesting and food resources to optimise the composition and
conguration of insects-pollinated crops in a region and thereby the provision of natural
pollination services.
Reference
Riedinger V., Mitesser O., Hovestadt T., Stean-Dewenter I., Holzschuh A. (in press) An-
nual dynamics of wild bee densities: attractiveness and productivity eects of oilseed rape.
Ecology, DOI:10.1890/14-1124.1.
Scheda del progetto STEP
I pronubi aiutano
la produzione
agricola
L’Italia ha una ricchezza
di specie di api
selvatiche tra le più alte
d’Europa (nella foto:
Andrena bicolor su ore
di colza). Fotograa
Maurizio Censini
Gli insetti impollinatori sono essenziali per la produttività di un
ampio ventaglio di colture europee di importanza economica perché
incrementano il raccolto e migliorano la qualità del prodotto (Riquadro 1).
Pur ammettendo che l’ape domestica, che è allevata, è in grado di provvedere
alle necessità di impollinazione di alcune colture, sono però i pronubi selvatici
come i bombi, le api solitarie e le mosche sirdi a risultare, in tutta Europa, gli
impollinatori più ecaci. Nel Regno Unito, ad esempio, le api mellifere sono
sucienti ad impollinare solo un terzo delle colture agricole che ne hanno
necessità, mentre sono gli impollinatori selvatici a compiere il grosso del lavoro.
Riquadro 1: Colture che beneciano dell’impollinazione entomola
• Frutta – melo, arancio, pero, pesco, melone e anguria, limone, fragola,
lampone, susino, albicocco, ciliegio, kiwi, mango e ribes
• Ortaggi – pomodoro, carota, cipolla, peperone, zucca, fava, zucchina,
fagiolo, melanzana, zucca e cetriolo
• Colture industriali – cotone, colza, girasole, senape, soia e grano saraceno
• Frutta secca – mandorlo e castagno
• Piante aromatiche – basilico, salvia, rosmarino, timo, coriandolo,
cumino e aneto
• Foraggio per gli animali – erba medica, trifoglio e meliloto
• Piante ocinali – camomilla, lavanda ed enotera
In Europa gli insetti
impollinatori
contribuiscono alla
produzione agricola
di 150 colture (84%)
Queste colture
dipendono parzialmente
o interamente
dagli insetti per
l’impollinazione e
il raccolto
Si stima che il valore
degli insetti
impollinatori
in Europa si aggiri
intorno ai 22 miliardi
di euro all’anno
Oltre alle api mellifere
anche le api selvatiche
ed altri insetti sono
importanti impollinatori
Status and trends
of European pollinators
STEP-project
www.step-project.net
Figure 3. Flower-visiting wild bee Andrena bicolor on oilseed rape (Photo: Maurizio Censini).
49
Chapter 4: Mitigating Against
Pollinator Losses
David Kleijn
roughout Europe, the main strategies to promote pollinators are the establishment of pro-
tected areas and the implementation of agri-environment schemes that provide nancial incen-
tives to farmers for biodiversity conservation on their land. Some farming practices, such as the
cultivation of mass-owering crops, can also have positive side-eects on pollinators, although
largely unintentional. While many of the measures make sense intuitively, management pre-
scriptions are rarely based on scientic evidence. For instance, the establishment of agri-envi-
ronmental wildower strips aim to enhance oral resources for pollinators, but this is mostly
done by introducing a cheap seed mixture of easily establishing owering plant species. Which
species of pollinators will benet from these measures is rarely considered. Studies evaluating
the impact of mitigation measures therefore nd highly variable results depending on the genus
or order of pollinators that is being considered, the type of mitigation measure that is being
evaluated and the structure of the landscape in which the measures are being implemented.
In STEP we have made signicant progress in understanding the eects of measures mitigating
pollinator loss (case study 4.1). Studies have shown that the response of pollinators to conserva-
tion management depends on the extent to which specic oral resources have been enhanced
by the mitigation management (e.g. case study 4.2). Pollinator species show pronounced dier-
ences in oral preferences indicating that what is good for one species is not necessarily good
for another. e general pattern therefore is that the number of species benetting from mea-
sures will increase with the number of plant species being enhanced. However, the response
to mitigation management of a mobile group such as insect pollinators also depends on the
amount of alternative suitable resources in the surrounding landscape (e.g. case study 4.3). For
example, a particular wildower strip will attract more pollinators in a landscape with few al-
ternative sources of owers than in a landscape with many such sources. Finally, it becomes
increasingly clear that the timing of measures is of the essence. A late-owering red-clover crop
may enhance bumblebee pollinators whereas an early-owering oil seed rape crop does not (e.g.
case study 4.2). However, growing early-owering oilseed rape in combination with sunower
can enhance pollinator densities in this late-owering crop (e.g. case study 4.4).
e general picture that emerges is that mitigation strategies need to address the key
resources that limit the population size of a species during its entire ight period. is is
more dicult for species with long ight periods, such as bumblebees, than for species with
short ight periods (many solitary bees). Also, the key resources may dier from species
to species. However, little research has addressed whether mitigating pollinator loss results
in an enhanced pollination service. Very little research has addressed this particular issue.
What limited evidence there is gives cause for optimism. Landscapes with more pollinator
habitat have higher pollination rates and, in the USA, wildower strips next to blueberry
elds resulted in a signicant increase in blueberry yields.
50
4.1 Environmental factors driving the effectiveness of
European agri-environmental measures in mitigating
pollinator loss – a meta-analysis
David Kleijn and Jeroen Scheper
Summary of the science
Farmland represents one of the dominant land-uses in Europe, covering more than 45% of
the area of the European Union. is farmland has traditionally supported high levels of
biodiversity and about half of the species are associated with habitats that have been shaped
by agriculture. However, the intensication of agriculture since the second half of the 20th
century has caused severe declines in farmland biodiversity. Agri-environment schemes are
the main tool to counteract this biodiversity decline. Yet, the success of agri-environment
schemes on biodiversity is unpredictable. is variability of eectiveness has been hypoth-
esized to be caused by factors such as landscape structure (e.g. the amount of semi-natural
habitat), farming intensity and the extent to which agri-environmental prescriptions suc-
ceed in improving habitat quality for the targeted species.
Focusing on pollinating insects, we provide the rst comprehensive analysis of the factors that
potentially inuence the eectiveness of agri-environment schemes. We perform a quantita-
tive analysis of published studies examining the eectiveness of agri-environment schemes.
Although thus far most agri-environment schemes are not specically targeted at pollinators,
many schemes may potentially be benecial to pollinators. For instance, schemes reducing
the intensity of farming practices and schemes involving the creation or restoration of non-
cropped farmland habitats can, either directly or indirectly, enhance the availability of oral
resources and nesting sites and/or reduce sources of mortality (i.e. pesticides).
Our results show that by improving oral resource availability, agri-environment schemes
generally promote pollinators in agricultural landscapes. However, it is easier to enhance
resource availability in structurally simple (few semi-natural habitats) than in cleared (no
semi-natural habitats) or complex landscapes (many semi-natural habitats) and in crop-
lands than in grasslands. In complex landscapes, where availability of oral resources and
nesting sites is already high, the introduction of additional resources by means of agri-en-
vironment schemes results in relatively small increases. In simple landscapes, arable farm-
ing systems are much more devoid of essential pollinator resources, it is easier to increase
resource availability signicantly with agri-environmental management. is results in the
counter-intuitive situation that the most pronounced increases in pollinator diversity can
be obtained in landscapes with low levels of biodiversity where measures will mainly benet
the species that are least aected by agricultural intensication.
Dierent types of measures showed signicant dierences in their eects on pollinators.
Sowing ower strips generally resulted in the largest increase and organic farming in the
51
lowest increase (Figure 1). e response of pollinators to individual measures also seemed
to be mediated by their eect on oral resources. For example, pollinator species richness
and abundance in sown ower strips were generally positively related to the number of
owering plant species that were sown (Figure 2)
Policy relevance
Insight into the ecological factors that explain the success or failure of agri-environmen-
tal measures is essential if we want to contribute to halting or reversing biodiversity loss
on farmland. is study shows that agri-environmental measures generally enhance local
pollinator species richness and abundance in agro-ecosystems, and are most eective when
implemented in structurally simple, resource-poor landscapes dominated by arable elds
where they readily enhance resource availability for pollinators. However, these landscapes
mainly support common generalist species with good dispersal capabilities that are of rela-
tively little interest from a biodiversity conservation perspective. As the common generalist
pollinator species are the species that contribute most to the pollination of crops, from the
-0.6
0.0
0.6
1.2
1.8
2.4
3.0
3.6
FS OF GS/NR
d species richness
24
23
20
(a) Cropland
-0.6
0.0
0.6
1.2
1.8
2.4
3.0
3.6
FS EG OF
d species richness
4
34
5
(b) Grassland
-0.6
0.0
0.6
1.2
1.8
2.4
3.0
3.6
FS OF GS/NR
d abundance
31
27
30
(c)
-0.6
0.0
0.6
1.2
1.8
2.4
3.0
3.6
FS EG OF
d abundance
4
34 9
(d)
Figure 1. Eects of dierent types of agri-environmental measures on species richness (top) and abundance
(bottom) of pollinators in croplands (a, c) and grasslands (b, d). Indicated are mean eect sizes ± 95%
CI, with positive values indicating positive eects. Numbers indicate sample sizes. FS: sown ower strip;
OF: organic farming; GS/NR: grass-sown or naturally regenerated eld margin or set-aside; EG: extensive
grassland (Modied from Scheper et al. 2013, Ecology Letters).
52
perspective of ecosystem service delivery the implementation of agri-environment schemes
should preferentially be directed at these relatively simple, resource-poor landscapes. In
contrast, if the objective is to preserve intrinsic values of biodiversity, agri-environmental
management should target more complex landscapes that support species rich pollinator
communities and are likely to support threatened pollinator species. Ultimately, the design
and implementation of agri-environment schemes should be governed by clear conserva-
tion or ecosystem service targets, although each does not necessarily exclude the other.
Reference
Scheper J., Holzschuh A., Kuussaari M., Potts S.G., Rundlöf M., Smith H.G., KleijnD.
(2013) Environmental factors driving the eectiveness of European agri-environmental
measures in mitigating pollinator loss – a meta-analysis. Ecology Letters 16: 912-920.
-3
-2
-1
0
1
2
3
4
010 20 30 40
d species richness
Number of sown flower species
P = 0.006
(a)
-2
-1
0
1
2
3
4
010 20 30 40
d abundance
Number of sown flower species
P = 0.0009 P = 0.006
(b)
Figure 2. Relationship between the number of forb species sown in ower strips and eects of ower
strips on species richness (a) and abundance (b) of all pollinators (all circles, dashed regression lines) and
bees separately (lled circles, solid regression lines). Regression lines and P-values are shown for signicant
meta-regressions (Modied from Scheper et al. 2013).
Figure 3. Intensively farmed land-
scapes generally contain very few
oral resources on which pollinators
rely on for food. In such landscapes it
is relatively easy to enhance resource
availability of pollinators, for example
by establishing wildower strips, but
generally common pollinator species
benet from such measures. (Photo:
David Kleijn).
53
4.2 Late-season flowers benefit bumblebees
Maj Rundlöf
Summary of the science
Wild bees need a safe nesting place and owering plants, providing nectar and pollen, to thrive.
e intensied management of agricultural landscapes that has occurred in many parts of the
world has, however, reduced and separated nesting and foraging resources for bees. Bees can
nd abundant forage resources in mass-owering crops, but oen only for a short period of
time. It is important that the wild bees have access to forage resources throughout their whole
lives, as they seldom build large storages. For nest-building pollinators, like the bees, ower
resources also have to be within their ight range from the nest.
In the agricultural landscape, we wanted to nd eective measures which can be used to
support bee populations and potentially also the pollination services that they provide.
Sown ower strips are seen as a promising measure to support bees. Several previous stud-
ies have focused on the attractiveness of such ower strips to bees and other pollinators,
but this says little about the inuence of the ower strips on bee populations in the wider
agricultural landscape.
Bumblebees have annual colonies of one queen and several workers. e colony grows
over the season and, if successful, produces new queens and males at the end of the sea-
son. ese new queens are essential because they form the basis for next year’s bumblebee
population. Bumblebee populations have been suggested to be limited by the availability
of late-season ower resources. We have tested this hypothesis in a study with replicated
landscapes by examining whether an addition of a 4-16 ha eld of late-season owering
red clover (Trifolium pratense) to a ~1,200 ha landscape, aects worker, queen and male
bumblebee densities.
In our study we show two things. First we found that the vibrant pink red clover elds
(Figure 1) are a favoured forage habitat over wild owers in uncultivated eld borders
for bumblebee workers and queens (Figure 2a). Secondly, we show that ve times more
queens and 70% more males are found in landscapes with red clover elds compared to
in control landscapes (Figure 2b), despite these elds constituting less than 0.2 % of the
landscape surface area. is supports the conclusion that the reduced ower resource
availability, particularly in the late-season, may in fact be key to the changes observed in
bumblebee communities.
e results from our study support the use of ower strips as a measure to mitigate loss of
bumblebees in agricultural landscapes, but the oral resources need to be provided at the
right time. Late-season resources are lacking and are particularly important to bumblebees,
with their long colony cycles compared to other wild bees. Red clover is a suitable late-
season owering plant which could be used to provide nectar and pollen (Figure 3).
54
Figure 1. Red clover eld in southern Sweden where clover is grown to produce seeds, used in grass-clover
leys for animal fodder or as green manure (Photo: Maj Rundlöf).
Figure 2. Average density (log individuals per 100 m2) of bumblebee workers, queens and males in (a) red
clover elds and surrounding ower-rich uncultivated eld borders and (b) ower-rich uncultivated eld
borders in landscapes with or without a red clover eld at the centre. (*) < 0.06, * P < 0.05, ** P < 0.01, *** P
< 0.001 (modied from Rundlöf et al. 2014).
55
Policy relevance
We found that the addition of late-season ower resources in the form of red clover resulted
in higher densities of bumblebee queens and males in the surrounding landscapes. Pro-
duction of new queens and males are essential in sustaining bumblebee populations, since
bumblebees form annual colonies. Our results suggest that interventions such as the addi-
tion of relatively small areas of ower strips, a frequently used agri-environmental measure
in Europe, can have strong mitigating eects if they provide resources that are limiting bee
populations.
Current mass-owering crops in agricultural landscapes are predominantly early-season
owering (e.g. oilseed rape) which results in landscapes void of ower resources in the
late-season. Mass-owering crops are oen also treated with plant protection products, which
could pose a risk to non-target insects such as bees visiting the crop owers. Agri-environ-
mental measures such as ower strips could be used as a way to introduce forage resources
free of plant protection products and during periods without aer crop mass-owering.
Reference
Rundlöf M., Persson A.S., Smith H.G., Bommarco R. (2014) Late-season mass-ower-
ing red clover increases bumblebee queen and male densities. Biological Conservation
172: 138-145.
Figure 3. Bu-tailed bumblebee (Bombus terrestris) collecting nectar and pollen from red clover (Photo:
Maj Rundlöf).
56
4.3 Landscapes with wild bee habitats enhance pollination,
fruit set and yield of sweet cherry
Andrea Holzschuh
Summary of the science
For the vast majority of crops it is unknown whether managed honeybees or wild bees are
the most ecient pollinators, and how the pollination service provided by wild bees can be
ensured.
Cherries production is in excess of 2 million metric tons annually, and is one of the leading
global food crops which greatly depend on animal pollination (Figure 1). Honeybees have
been assumed to be the main pollinators in cherry, but there is anecdotal evidence that wild
bees provide better pollination services. Although cherry producers might strongly depend
on pollination services provided by bees, there has been no replicated study assessing the
relative importance of honeybees and wild bees for cherry production to date.
We assessed in a landscape-scale study how
sweet cherry production is inuenced by (1)
high-diversity bee habitats, and (2) owering
vegetation which might compete with cher-
ry for pollinators or might facilitate cherry
pollination. Comparing fruit set of a bagged
branch, where insects could not access the
owers, with fruit set of an open-pollinated
branch on 32 cherry trees. Bagged owers
produced only 3% of the fruits produced by
open-pollinated owers. Although two thirds
of all ower visitors were honeybees, fruit set
increased with wild bee visitation only (Fig-
ure 2 A, B), presumably due to the higher
pollination eciency of wild bees. e low
fruit set in orchards with low wild pollinator
visitation was experimentally shown to be
due to pollen limitation. Wild bee visitation
increased with the proportion of high-diver-
sity bee habitats in the surrounding landscape
(1 km radius) and consequently also fruit set
increased with the proportion of high-diversity bee habitats (Figure 2 C, D). An increase in
the proportion of high-diversity bee habitats from 20% to 50% enhanced fruit set by 150%.
Neither ower cover of ground vegetation nor bee densities on ground transects were relat-
ed to ower visitation in trees or fruit set suggesting that ground vegetation neither com-
petes with cherry for pollinators nor facilitates cherry pollination.
Figure 1. Cherry trees in bloom (Photo: Jan-
Hendrik Dudenhöer).
57
Our ndings show that the increase of wild bee visitation and fruit set with the proportion
of high-diversity habitats, is linear at least up to a proportion of 55% of high-diversity hab-
itats in the landscape. is is particularly remarkable because the study region is charac-
terised by relatively high proportions of high-diversity habitats (>18%) compared to many
other agricultural regions in Central Europe. We conclude from our results that farmers
cannot maximise yield by only ensuring small amounts of high-diversity bee habitats in the
surrounding of their orchards. We expect that a decline in amount of high-diversity habitats
has an even stronger negative eect on yield in regions where the proportion of high-diver-
sity habitats is already lower than in our study region.
Figure 2. Eect of (A) wild bee visitation, (B) honeybee visitation and (C) proportion of high-diversity bee
habitats in 1 km radius on fruit set in cherry trees. (D) Eect of the proportion of high-diversity bee habitats
in 1 km radius on wild bee visitation. Visitation rates are number the of individual visits per 1000 owers in
15 minutes. Solid lines indicate signicant regressions (p<0.05), dashed lines non-signicant regressions
(p>0.05), (reprinted from Holzschuh et al. 2012 Biological Conservation 153: 101-107).
58
Policy relevance
Cherry fruit set and the economically important nal cherry yield proved to be highly de-
pendent on insect pollination and increased with wild bee visitation and the proportion of
high-diversity bee habitats in the surrounding landscape. Typical high-diversity bee habi-
tats are semi-natural habitats that provide nesting sites and food resources before and aer
the mass-owering period of the crop, e.g. non-intensively used grasslands, old fallows,
hedges or forest edges (Figure 3).
Our data shows that only the protection or restoration of high-diversity bee habitats will
guarantee pollination and high yields, and that additional high-diversity bee habitat even
enhances yield if the proportion of high-diversity bee habitats is already high (50 % in our
study). High-diversity bee habitat should be located within the foraging distance of the
pollinators, which was 1 km for the wild bees in our study. Farmers who locate their or-
chards surrounded by high-diversity bee habitats should gain a monetary advantage over
competitors without high-diversity bee habitats in the landscape. Cherry yield could not be
maximized in our study if farmers relied on honeybee pollination only.
Reference
Holzschuh A., Dudenhöer J-H., Tscharntke T. (2012) Landscapes with wild bee hab-
itats enhance pollination, fruit set and yield of sweet cherry. Biological Conservation
153:101-107.
Figure 3. Landscape with arable lands and high-diversity bee habitats surrounding a cherry orchard in the
lower middle of the photo (Photo: Jan-Hendrik Dudenhöer).
59
4.4 Early mass-flowering crops mitigate pollinator dilution
in late-flowering crops
Ingolf Steffan-Dewenter, Verena Riedinger and Andrea Holzschuh
Summary of the science
To ensure high yield quantity, quality and stability in crops, an ecient management of
pollinators in agroecosystems is essential. Pollination services can be provided by a broad
variety of insects including non-managed wild bees, syrphid ies and honeybees managed
by beekeepers. In the past the focus of management eorts to ensure high crop yields has
been on few human-managed pollinators, such as the honeybee, and the provision of polli-
nation services by wild pollinators from neighbouring semi-natural habitats. e advantage
of honeybee management is the ease of moving colonies to landscapes or regions with high
cover of insect-pollinated crops based on agreements between farmers and beekeepers.
However, new diseases and parasites, negative impacts of pesticides as well as socioeco-
nomic constrains in beekeeping have recently resulted in signicant declines of honeybees
in Central Europe. Further, the expansion and diversication of insect-pollinated crop va-
rieties across the European Union has increased the need for self-sustaining management
schemes for crop pollination services in agroecosystems. us, instead of relying solely on
honeybees to maintain pollination services, a mix of dierent crop cultures and green infra-
structure elements in an agricultural landscape could be used to build up diverse pollinator
communities throughout the season. Single crops typically ower only for a limited time
in the year leading to peaks in resource availability followed by a shortage aer mass-ow-
ering has ceased. For example, oilseed rape is one of the most dominant mass-owering
crops in Central Europe during spring providing high densities of nectar and pollen. is
resource pulse has been shown to foster the success of nest-founding bumblebee queens, to
enhance the size of bumblebee colonies in landscapes with high oilseed rape cover and, as
a consequence, the density of foraging bumblebees later in the season. However, it is cur-
rently unknown whether early mass-owering crops can enhance pollinator densities and
stabilise yields for late-owering crops in the same landscape, and which combination of
dierent crops and semi-natural pollinator habitat is most ecient to maintain wild polli-
nators in agroecosystems.
In a case study in Germany, we evaluated the seasonal dynamics of pollinator densities in
landscapes with low or high proportion of early and late mass-owering crops and semi-nat-
ural habitats. We selected 16 landscapes that diered in the relative cover of oilseed rape as
an early mass-owering crop, in the relative cover of sunowers, and in the relative cover of
semi-natural habitats. Our results indicated that densities of bumblebees in late-owering
sunower elds were enhanced in landscapes with high cover of early-owering oilseed
rape (Figure 1 a-b) whereas syrphid ies and honeybees showed no increase (Figure 1 c-f).
Highest bumblebee densities in the late-owering crop were reached in landscapes that
combined a high cover of oilseed rape and semi-natural habitats. Further, a low relative
cover of oilseed rape in spring led to the dilution of bumblebee densities in late-owering
60
sunower elds in landscapes with high cover of sunower elds (Figure 1 b, Figure 2 and
3), whereas in landscapes with a high relative cover of oilseed rape, no dilution of bumble-
bees was found (Figure 1 a). us, our results indicate that early mass-owering crops can
mitigate pollinator dilution in crops owering later in the season.
Figure 1. Eects of high and low cover of early-owering oilseed rape on the the density of bumblebees
(a,b), hoveries (c, d) and honeybees (e, f) in relation to the relative cover of sunowers within a 2 km radius.
The data points were split at the median of the relative cover of oilseed rape (high vs. low), (Riedinger et al.
2014 Landscape Ecology 29: 425-435).
61
Policy relevance
Our results suggest that the management of landscape-scale patterns of early and late
mass-owering crops in combination with semi-natural habitats could be used to ensure
crop pollination services across the season. e future management of crop pollination ser-
vices needs to address both permanent semi-natural habitats that provide suitable nesting
sites and a basic supply of mixed pollen and nectar sources, and the annual dynamics of
insect-pollinated crops in a landscape.
e seasonal timing of dierent mass-owering crops could be used to ensure the contin-
uous provision of oral resources and to prevent gaps in food supply that diminish par-
ticularly social pollinator species with high resource demands, such as bumblebees and
honeybees. Based on the current knowledge, we recommend developing a management
decision tool for farmers that provides information about the most suitable composition
and conguration of early- and late-owering crops in a landscape. Optimal wild pollinator
management could signicantly increase crop yield quantity, quality and stability reducing
the dependence of farmers on short-term movements of honeybee colonies. e imple-
mentation of our recommendations will help farmers to take full advantage of the ecosys-
tem service provided by crop pollinators.
Reference
Riedinger V., Renner M., Rundlöf M., Stean-Dewenter I., Holzschuh A. (2014) Early
mass-owering crops mitigate pollinator dilution in late-owering crops. Landscape Ecol-
ogy 29: 425-435.
Figure 2. Sunower eld in the study region in
Lower Franconia, Bavaria, Germany (Photo: Marion
Renner).
Figure 3. Flower-visiting bumblebee (Bombus
terrestris) on sunower (Photo: Marion Renner).
62
Chapter 5: Informing Policy
Peter Sørensen
Understanding European wide trends in pollinator diversity and abundance and relating
this to possible causes of declines is as valuable input for management of this complex
societal challenge. However, even a very comprehensive and highly skilled assessment of
available evidence will not be able to deliver a fully quantied understanding for all relevant
aspects of the problem and associated uncertainties. It is therefore a complex task to put
pollination-related problems into a European policy context, and to develop conceptual
methods that can eectively evaluate scientic evidence in way to support policy options
and recommendations.
In STEP, we analysed the perception of a range of stakeholders in relation to what they be-
lieved were the most important governing question to address eective decision-making re-
lated to pollinators and services. However, there is a need to go beyond the purely academic
perspective and move towards raising awareness of pollination-related topics, including those
of interest to policy-makers, funding agencies and the wider public (e.g. case study 5.1.). e
most important questions concerning the governance of pollination services by a range of
stakeholders were addressed with a combined analysis of an international workshop, local
stakeholder interviews and an in depth policy review (Case study 5.2). Our work demon-
strates that it is naive to believe that actors, as a group, will aim to solve societal problems
together. Instead, we found it was more realistic to take the approach that dierent actors
have dierent understandings of what the problem actually is. Outcomes of a workshop of
national and international stakeholders for pollinators and pollination identied a number of
key governing questions. However, local level interviews show that the societal opportunities
to take account of pollination, and especially the wild pollinators, beyond their economic
value are poorly developed. is is due to the miss-match in everyday practices and objectives
between dierent policy levels. What are urgently needed are institutions and norms which
target the miss-match between dierent governing levels. Instead of focusing on pollination,
nature conservation or agricultural practices, more attention needs to be paid to developing
strategies, institutions and research that address the miss-match (see case 5.2).
For policy, key pollination-related questions (e.g. how can crop pollination services be safe-
guarded) can be broken down into many “sub-questions” (e.g. how dependent are crops on
pollinators? which pollinators are most eective? what resources are necessary to support
crop pollinators? etc.), some of which are addressed in the scientic literature. Howev-
er, a method for structured problem analysis is lacking that can link existing evidence to
sub-questions and identify sub- questions where knowledge is missing (conceptual uncer-
tainty). is type of uncertainty applies primarily to complex problems where many factors
are involved in a complex manner. For instance, the factors that control the abundance of
bees can be identied to develop a model to understand why the abundance of bees is high/
low under a specic set of circumstances, and which mitigation options can increase abun-
dance. If the list of explanatory factors is incomplete and fails to cover all relevant aspects,
63
then the subsequent understanding of the problem, based on the concept model, will also
be incomplete, and important relations can be hidden knowledge gaps. is is a fundamen-
tal problem in modelling and it is, thus, important to carefully map and dene the factors
in order not to ignore critical aspects that may have relevance for the governing question.
An approach to dealing with the issue of complexity in governing questions for pollinators
is described in case study 5.3.
5.1 How can pollination ecology research help answer
Important questions?
Koos Biesmeijer, Luisa Carvalheiro and Peter Sørensen
Summary of the science
While pollination has been studied for centuries, it remains a dynamic field of scientif-
ic research constantly adopting novel methods and improving our understanding of the
interactions between plants and their pollinators. A recent paper (Mayer et al. 2011)
listed the main scientific questions that still need to be addressed in this field, focussing
on the ecological and biological system itself. These questions were put together from a
long list of suggestions from scientific experts in the pollination research field. A close
examination of the paper gives the impression that the scope of the questions is rather
limited. Particularly given that the authors hope the paper will contribute to raising
awareness of pollination-related topics including those of interest to policy-makers,
funding agencies and the wider public. To complement the effort of the Mayer et al.
(2011) paper, we developed a simple framework integrating ecological, societal and
socio-ecological issues relevant to pollinators and pollination and outlined a pathway
to come to a ‘whole-society’ list of key questions for future research in the field of
pollination ecology (Biesmeijer, Sorensen & Carvalheiro, 2011). This case study is an
excerpt of the latter paper.
ere are dierent types of questions one can ask about pollinators and pollination. For in-
stance, questions in the Mayer et al. (2011) paper range from “What is the lifespan of pollen
grains”, a very specic mechanistic question, to “How can we better employ plants and their
pollinators as educational tools for public awareness?”, an educational-societal question. In
fact, questions may address four major, partly separate, realms (Figure 1), namely:
Questions dealing with the workings of nature, including ecology, evolution and be-
haviour; in Figure 1 referred to as “ECOLOGY”.
Questions about how ecosystems and biodiversity provide human society with goods
and services, including crop pollination, honey production and genetic resources of
managed pollinators. (ECOLOGY → SOCIETY)
64
Societal issues in which pollinators and pollination play a role, including policies
such as the convention of biological diversity, Natura 2000, habitat directive, but also
funding for research and awareness of the general public. (SOCIETY)
Questions about how societal actions aect pollinators and pollination. ese in-
clude land management and intensive agriculture, but also the impact of conserva-
tion measures. (SOCIETY → ECOLOGY)
Policy makers, conservation managers, school teachers, researchers, and other stakeholders,
might ask very dierent sub-questions when asked to answer a broad question (Figure2). How-
ever, only all these questions together address the broad question fully. It is therefore important
to reach out to the wider stakeholder community to address broad, policy relevant, questions.
Policy relevance
We are experiencing golden times for research opportunities and media-attention is high for
pollinators and pollination. However, how can our results, that have used up considerable pub-
lic funds, be integrated in better policies for pollinators and their services? e broad assess-
ment of relevant questions and issues, which go beyond the research questions themselves, can
be a vital rst step for most research. It will help to identify the needs of policy-makers, stress
the dierences between stakeholder groups, and provide a solid base for both the direction of
the research and the pathways towards actual use of the research ndings in future policies.
Reference
Mayer C., Adler L., Armbruster W.S., Dafni A., Eardley C., Huang S.Q., Kevan P.G., Oller-
ton J., Packer L., Ssymank A., Stout J.C., Potts S.G. (2011) Pollination ecology in the 21st
century: key questions for future research. Journal of Pollination Ecology 3: 8-23.
Biesmeijer J.C., Sorensen P., Carvalheiro L. (2011) How Pollination Ecology research can
help answer important questions. Journal of Pollination Ecology 4: 68-73.
Figure 1. Schematic representation of the pollinator-relevant issues in natural systems (ECOLOGY) in
society and linking both.
Conservation measures
landscape management
intensive agriculture
Pollination services
Honey production
Genetic resources
Biodiversity
Plant-pollinator
Interactions
Ecosystem
function
Policies
Awareness
Research
funding
65
5.2 Multi-level analysis of mismatch and interplay between
pollination-related policies and practices
Thomas Breeze and Outi Ratamäki
Summary of the science
Losses of pollination services pose dierent risks to dierent stakeholders; producers risk
losing the benets of pollination services to crops, while wider society risks the associated
loss of biodiversity dependent upon pollination. is study explores the governance of pol-
lination services from a multi-level policy perspective in order to identify links, potential
mismatch and potential opportunities using three dierent case studies: rst, formalised
group discussions in Brussels between 21 EU level stakeholders, including major national
research organisations, Non-Government Organisations and national government repre-
sentatives aimed at understanding the factors inuencing governance of pollination ser-
vices at a national and cross national level. Second, a series of interviews with six Finnish
stakeholders was conducted to explore the factors aecting local governance of pollination
services. Finally a review of existing policy aecting pollination services was conducted.
Relevant policies were identied through their direct connection to pollination services or
the factors inuencing their declines.
Figure 2. Illustration of the possible relationships and hierarchy of some of the questions presented in
Mayer et al. 2011 (highlighted in black) and others identied by us (in grey). The broad question (Q 80 at the
top) needs input from many dierent areas some already listed by Mayer et al. 2011 (Q48, Q53, Q59, Q62,
Q63), some identied by us (Qxx), some not yet identied (boxes with question marks).
What modications in land use management
are needed to halt/reverse plant and pollinator
declines? Q80
Which
pollinator taxa
and functional
groups are in
decline? Q59
?
? ?? ?
?? ?
What is the relative
importance of the
various drivers of
pollinator decline?
Q62
How does the
diversity of pollinators
vary geographically
at the level of species
and functional
groups? Q53
What proportion
of pollination is
undertaken by the
dierent functional
groups of pollinators
in a community? Q48
How do
drivers of loss
interact, and
how do they
vary in space
and time? Q63
What are
the available
management
options for
mitigation?
Qxx
What laws and
regulations are
relevant to land
use management
for pollinators
and plants? Qxx
Which
management
options for
mitigation are
eective? Qxx
66
Figures 1, 2. STEP Stackeholders meeting, Brussels, September 2010 (Photos: Pavel Stoev).
67
Participants at the Brussels workshop identied four major concerns relating to the im-
pacts of pollinator losses; biodiversity, agriculture, ecosystem services and functions and
human health. e impacts of biodiversity were the primary concern of this group, but
in particular what the loss of pollinator diversity may have on agriculture and human
wellbeing. By contrast, most of the Finnish stakeholders interviewed only regarded hon-
eybees as important pollinators of crops and were primarily focused on the economic
eects of pollination on agriculture. Although they oen recognised the importance of
conservation eorts, local stakeholder motivation to undertake these measures was inu-
enced by a number of apparent barriers, including diculty trusting policy makers and
perceived impracticalities. Analysis of relevant policy identied 15 International poli-
cies that aect pollination services. Most of these concerned agriculture (e.g. the EU’s
Common Agricultural Policy) or biodiversity (e.g. the UN’s Convention on Biological
Diversity) although some broader policies were also found to be relevant (such as the
Plant Protection Products Directive). While many of these policies can directly aect
pollinators, they were not explicitly referenced in most.
e ndings of these three case studies highlight a mismatch between EU and local gover-
nance concerns surrounding the loss of pollination services. National and EU stakeholders
focused on the impacts of pollination on biodiversity while local stakeholders were mostly
concerned with the agricultural impacts. is mismatch is further represented in the policy
review with biodiversity policy taking little account of agricultural impacts and farming
policy oen encouraging practices detrimental to biodiversity.
Policy relevance
e ndings of this study highlight the mismatch between EU and local understanding
of the problem of pollination service loss and governance priorities. is illustrates that,
while larger institutions can form the backbone for wider activities, these policies need to
be tailored at a local level, including nancial incentives for achievable, practical measures
that facilitate rather than hinder local business. For example, although honeybees were con-
sidered to be the main or only pollinator of crops (but see Case 3.1), local stakeholders un-
derstood the role of biodiversity in pollination services. Higher level policy could therefore
incentivise conservation eorts and other social opportunities by highlighting the eective-
ness of wild pollinators as free service providers.
Reference
Ratamäki O., Jokinen P., Sørensen P., Breeze T.D., Potts S.G. (in press) Multi-level Anal-
ysis of Mist and Interplay between Pollination-related Policies and Practices. Ecosystem
Services.
68
5.3 Conceptual model for evidence analysis to support policy
Peter Sørensen
Summary of the science
e summary of the conceptual model is based on Sørensen et al. (in prep.) and the govern-
ing question: “How to manage ecosystems to protect bees (native/domestic)?”. e general
structure is shown in Figure 1, which denes a three step approach .
Step 1: Aims to identify a “complete” list of factors that control the presence and abundance of
bees, including the human activities that have an inuence on these factors. If the dened list
of factors is “incomplete”, then the subsequent understanding, based on the concept model,
will also be incomplete and important topics may be ignored. is is a fundamental problem
in modelling (Walker et al.*, 2003 and Sørensen et al., 2010) and it is, thus, important to make
a careful mind map in Step 1 to dene factors in order not to overlook topics that may have
high relevance to the governing question, see Figure 2. e method in Step 1 is a renement
of the method suggested by Sørensen et al. (2010) and is combined with the hierarchical
sub-divisions of questions suggested by Biesmeijer et al. (2011), which identied important
pollination ecology research questions. Figure 2 shows the principle applied here using a sim-
ple example for illustration. e complete conceptual model can contain up to 100 factors.
Too many factors will make the model inaccessible for practical management purposes and
too few factors will make the model too broad and, thus, result in only trivial conclusions.
Step 2: In Step 2, some factors are dened to have casual eects on other factors. is is shown
through an example in Figure 3, where the application of an insecticide can cause contam-
ination of pollen and thereby expose both larvae and worker (and the other life stages of a
bee; not shown in our simple example). us, in Figure 3, arrow No. 1 relates contamination
of pollen to negative eects on the larvae, while arrow No. 2 relates insecticide application
to contamination of pollen. ese two relations are dierent in the way that arrow No. 1 not
only considers insecticides, and arrow No.2 does not consider how contaminated pollen can
aect larvae, but rather how insecticides can end up contaminating pollen; this is a subtle, but
important, dierence for science based understanding. e nal conceptual model is much
more complex, having hundreds of relations in a network connecting the factors.
Step 3: e importance of the relations dened in Step 2 (shown as arrows in Figure 3) are
evaluated based on available lines of evidences. is forms an ecient way to map the knowl-
edge and to integrate dierent pieces of evidence into a coherent analysis of understanding and
uncertainty. e pieces of evidence are collected from research results and can include a broad
range of sources, such as peer-reviewed studies and expert opinions. Once populated with evi-
dence, the conceptual model can then facilitate policy and practitioners to identify the key rel-
evant evidence available to help inform decision making on a particular aspect of pollinators.
*Walker et al. (2003) Dening uncertainty, a conceptual basis for uncertainty management in model-based decision
support. Integrated Assessment 4 (1).
69
Policy relevance
Interactions between pollinators and agricultural production
are complex to understand and lack of knowledge is, there-
fore, a challenge for legislation and management. Knowledge
tends to be partial and specic to particular systems. us,
there is a critical need for structural knowledge that can gen-
erate an integrated and coherent picture of what is known
and what is not known. is, however, is a complex challenge
that involves application of conceptual models to disclose
knowledge structures and chains of cause and eects. Here
we describe the principle of such a conceptual model for sup-
porting legislation and management to secure the livelihood
of bees. Our model combines mind mapping, graphically based structuring techniques and
evidence evaluation schemes based on a wide range of specic detailed investigations un-
dertaken in the STEP project.
Reference
Sørensen P., Damgaard C., Brüggemann R. (2015) Conceptual model for evidence analy-
sis to support policy, in preparation (for status of the paper contact: pbs@dmu.dk).
Biesmeijer J.C., Sorensen P.B., Carvalheiro L.G. (2011) How Pollination Ecology Re-
search Can Help Answer Important Questions. Journal of Pollination Ecology 4 (9): 68-73.
Sørensen P.B., omsen M., Assmuth T., Greiger K.D., Baun A. (2010) Conscious worst
case denition for risk assessment, part I A knowledge mapping approach for dening most
critical risk factors in integrative risk management of chemicals and nanomaterials. Science
of the Total Environment 408: 3852-3859.
Larvae
1
2
Worker
Pollen
contaminaon
Inseccide
applicaon
Contact
contaminaon
Figure 3. Example showing re-
lations (arrows) between factors
(boxes).
Figure 2. Example of systematic subdivision into detailed factors (life stages of bees). The nal factors of “egg”,
“larvae”, “closed cells”, etc. are added to the list of factors used for Step 3.
Step 1:
Define all factors
that needs to be
addressed
Step 2:
Define all interacons
between the factors
Step 3:
Map the understanding and
uncertainty of each interacon
Evidence
mapping using
project results
Conceptual Model
bee
immature
mature
bee
open cells
closed cells
ferle
inferle (worker)
immature
mature
bee
open cells
closed cells
ferle
inferle (worker)
immature
mature
egg
larvae
queen
drone
Increasing level of detail
Figure 1. General structure of the concept model. The steps 1, 2 and 3 are explained in the text below.
Conclusion and Future Steps
Concerns about pollinators and pollination services continue to rise up the political, sci-
entic and public agendas. Consequently we need to increase our understanding of the
current status and trends of pollinators, determine the causes of declines and develop ways
to sustainably manage pollinators to secure delivery of pollination services now and in the
future. To do this Europe must develop robust scientic evidence to underpin policy and
practice measures to safeguard our pollinators. STEP has strengthened our knowledge base
in all these areas to better inform decision makers, farmers, growers, conservationists and
beekeepers about how we can protect and manage this critical natural resource.
Specically STEP has delivered a Red List of European Bees to help direct conserva-
tion eorts at the national and continental level. e project has provided multi-scale,
multi-species assessment of the shis in pollinators across Europe and identied the key
combinations of drivers of change. By determining the main causes of loss it is possible
to direct policy and management interventions to help reduce these environmental pres-
sures. STEP has also determined which pollinators actually pollinate crops and so help
focus mitigation measures for taxa of greatest economic importance. e project has pro-
duced a set of tools and methodologies to help with future monitoring and assessment of
both pollinators and the services they deliver to support planners and decision makers in
managing the wider landscape.
STEP continues to produce a portfolio of dissemination materials ranging from top inter-
national scientic publications to carefully targeted booklets for end-users such as farm-
ers and beekeepers, as well as delivering ndings directly to a wide range of stakeholders
through talks, workshops, TV and newspaper articles. STEP has also helped train a new
cohort of postdoctoral researchers and PhD students in the eld of pollinator conservation
and pollination services to carry on the aims of STEP.
Prof. Simon Potts
70
List of Authors
B Koos
Naturalis Biodiversity Center, postbus 9517, 2300 RA, Leiden, e Netherlands
B Riccardo
Swedish University of Agricultural Sciences, Department of Ecology, P.O. Box 7044, SE-750
07 Uppsala, Sweden
B omas
Centre for Agri-Environmental Research, School of Agriculture Policy and Development,
Reading University, Reading, RG6 6AR, UK
C Luisa
School of Biology, University of Leeds, UK & Naturalis Biodiversity Center, postbus 9517,
2300 RA, Leiden, e Netherlands
F Markus
Department of Community Ecology, Helmholtz Centre for Environmental Research
GmbH- UFZ, eodor-Lieser-Strasse 4, 06120 Halle, Germany
G-V Juan P.
Estación Biológica de Doñana (EBD-CSIC), Avd. Américo Vespucio s/n, Isla de la Cartuja,
41092 Sevilla, Spain
H Andrea
Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg,
Am Hubland, 97074 Würzburg, Germany
K Alexandra-Maria
Faculty of Environment and Natural Resources, University of Freiburg, Tennenbacher Str. 4,
79106, Freiburg, Germany
K David
Resource Ecology Group, Wageningen University & Animal Ecology Team, Alterra, PO Box
47, 6700 AA, Wageningen, e Netherlands
K Bill
School of Biology, University of Leeds, Leeds, LS2 9JT, UK
L omas
Université de Mons, Laboratoire de Zoologie, Place du Parc 23, B-7000 Mons, Belgium
L Ola
Swedish University of Agricultural Sciences, Department of Ecology, P.O. Box 7044, SE-750
07 Uppsala, Sweden
M Denis
Université de Mons, Laboratoire de Zoologie, Place du Parc 23, B-7000 Mons, Belgium
N Peter
Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bremgartenstr. 109a, CH-3001
Bern, Switzerland
71
72
N Ana
Global Species Programme & Key Biodiversity Areas Programme, IUCN (International
Union for Conservation of Nature), 64, Boulevard Louis Schmidt, 1040 Brussels, Belgium
P Lyubomir
Institute of Biodiversity & Ecosystem Research, Bulgarian Academy of Sciences and Penso
Publishers, Soa, Bulgaria
P Simon
Centre for Agri-Environmental Research, School of Agriculture Policy and Development,
Reading University, Reading, RG6 6AR, UK
R Pierre
Université de Mons, Laboratoire de Zoologie, Place du Parc 23, B-7000 Mons, Belgium
R Outi
Finnish Environment Institute, P.O. Box 140, FIN-00251 Helsinki, Finland; University of
Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
R Verena
Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg,
Am Hubland, 97074 Würzburg, Germany
R Stuart P. M.
Swedish University of Agricultural Sciences, Department of Ecology, P.O. Box 7044, SE-750
07 Uppsala, Sweden
R Maj
Lund University, Department of Biology, Biodiversity, Ecology building, SE-223 62 Lund,
Sweden
S Jeroen
Resource Ecology Group, Wageningen University & Animal Ecology Team, Alterra, PO Box
47, 6700 AA, Wageningen, e Netherlands
S Oliver
Department of Community Ecology, Helmholtz Centre for Environmental Research
GmbH- UFZ, eodor-Lieser-Strasse 4, 06120 Halle, Germany
S Peter
Institute of Bioscience, Faculty of Science and Technology, Aarhus University, Vejlsovej 25,
8600 Silkeborg, Denmark
S-D Ingolf
Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg,
Am Hubland, 97074 Würzburg, Germany
S Pavel
National Museum of Natural History and Penso Publishers, Soa, Bulgaria
V Soe
European Commission, DG Research & Innovation, I3, CDMA 03/081, 1049 Brussels/Belgium
V Montserrat
Estación Biológica de Doñana (EBD-CSIC), Avd. Américo Vespucio s/n, Isla de la Cartuja,
41092 Sevilla, Spain
72
This booklet summarises the key ndings from the European Commission’s
Framework 7 project ‘Status and Trends of European Pollinators’ (STEP) as a series
of short case studies. Each case study presents a summary of the main scientic
ndings followed by a short description of its relevance to policy. Chapters 1 and
2 deal respectively with: the current status and trends of European pollinators
and insect-pollinated plants, and the drivers of change. Chapter 3 provides new
insights on the resulting societal impacts of the shifts of pollinators and pollination
services. Mitigation responses to loss of pollinators and services are explored in
Chapter 4, while Chapter 5 looks at how evidence from the STEP project, and
elsewhere, can be used to better inform policy making. The booklet is aimed at a
wide range of readers – policy-makers, researchers, land managers, beekeepers,
farmers, veterinarians, school-teachers and the wider public.
