Project background

Strawberry

Why are pollinators important?

Animal pollination is essential for the reproduction of many plant species. Pollinators feed on the nectar and pollen produced by plants. This results in the transfer of pollen between plants leading to fertilisation and the production of seeds.

In the UK our main pollinators are insects, with bees, butterflies and hoverflies just some of the important insect groups that provide a pollination service for plant species. The bee diversity in the UK comprises far more than the domesticated honeybee, Apis mellifera - there are also 26 bumblebee species and more than 250 solitary bee species.

Many wild flowers and crop plants depend on insect pollinators to set seed so it is essential that we conserve these important insects. For example, tomatoes, apples and strawberries all depend on insect pollination so if these important insects were to disappear we could lose many types of food from our shopping basket. Economically, the total value of crops pollinated by insects is estimated to be £510m per year in the UK (Breeze et al. 2012). The actual cost of replacing the pollination services provided by these insects with hand pollination is estimated at £1.8bn per year (Breeze et al. 2012).

Solitary bee

Why are insect pollinators declining?

There are several possible causes of pollinator decline.

Firstly loss of natural habitat results in the loss of important food and nesting resources for pollinators. For example, 97% of the UK’s wild flower meadows, a rich source of forage for many UK insect pollinators, have been lost since the 1930s (Fuller 1987).

Secondly modern farming practices which promote crop monocultures can negatively affect populations of these important insects. Large areas of crops or grazing land leaves little room for wild flowers that are essential food for pollinating insects.

Thirdly, extensive use of pesticides in farming practices may be having a detrimental effect on insect pollinators (Henry et al. 2012; Whitehorn et al. 2012).

Fourthly, diseases such as Deformed Wing Virus and a fungus-like microorganism called Nosema ceranae affect honeybees, bumblebees and possibly other pollinating insects (Breeze et al. 2012).

Honey bee on lavender

Why study pollinators in urban habitats?

Pollinators supply a crucial ecological service, and finding ways to improve their lot is a major challenge. Urban environments are growing across the UK and flower-rich oases in otherwise uninviting city habitats could support large numbers of pollinators.

Although urban areas are expanding, outside urban nature reserves they offer little formal protection for biodiversity. Urban habitats have the potential to provide excellent conditions for pollinators. For example, half of Germany’s entire bee fauna have been found in Berlin (Saure 1996), 35% of British hoverfly species were sampled in a single Leicester garden (Owen 1991) and honey bees produce more honey in urban Birmingham than in the surrounding countryside (Thomson 2006).

Previous research has shown that flower-rich oases in an otherwise uninviting urban matrix can support substantial numbers of native pollinators (Lopezaraiza-Mikel et al. 2007). However, studies of pollinators in urban environments have not been replicated and whilst gardens have been widely studied, there have been no city-wide surveys of all urban habitats.

In this project we first investigated the current status of insect pollinators found in UK urban areas by simultaneously sampling plant-pollinator communities in towns and cities in England, Scotland and Wales. We then assessed whether the addition of large-scale pollen and nectar resources in the form of introduced flower meadows can benefit urban pollinator populations.

The project team is comprised of academic researchers from four leading UK research institutions, conservation practitioners from four local councils and three Wildlife Trusts and taxonomists. (Link to team page).

The data we have collected will be used to inform practical conservation strategies for insect pollinators across four major urban areas and the findings from this research will be conveyed to the rest of the UK practitioner community via a fully funded practitioners’ conference at the end of the project.

This research investigated three questions:

  1. How does the pollinator biodiversity in urban areas compare to that of nature reserves and farmland?
  2. Where are the hot-spots of pollinator biodiversity in urban areas?
  3. What can we do to improve pollinator diversity and abundance in urban areas?

For further information about each stage of the project please refer to the relevant web page.

References

Breeze, T. D., Roberts, S. P. M. & Potts, S. G. 2012. Decline of England’s Bees: Policy review and Recommendations (PDF). Friends of the Earth report.

Fuller, R. M. 1987. The changing extent and conservation interest of lowland grasslands in England and Wales: A review of grassland surveys 1930–1984; Biological Conservation 40, 281-300.

Henry M. et al. 2012. A common pesticide decreases foraging success and survival in honey bees; Science 336: 348-350.

Lopezaraiza-Mikel, M. E. et al. 2007. The impact of an alien plant on a native plant-pollinator network: an experimental approach. Ecology Letters 10, 539-550.

Owen, J. 1991.The Ecology of Garden: The First Fifteen Years. Cambridge University Press, Cambridge, UK.

Saure, C. 1996. Urban habitats for bees: the example of the city of Berlin. In: The Conservation of Bees, eds. A. Matheson et al. pp. 47–54. Academic Press, New York, USA.

Thomson, K. 2006. No Nettles Required: the Reassuring truth about Wildlife Gardening. Eden Project Books, London, UK.

Whitehorn P.R. et al. 2012. Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science 336: 351-352.

Hoverfly on Aster