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JANUARY 2019 AUTHORS Deborah J Steele1, Katherine C R Baldock2, 3 4 Tom D Breeze , Mark J F Brown , Claire Carvell5, Lynn V Dicks6, Mike P Garratt3, Hannah Norman7, Simon G Potts3, Deepa 3 8 Senapathi , Adam J Vanbergen . Tree bumblebee hovering 1 Defra, Horizon House, Bristol, UK Photo by Alan Titcombe 2 School of Biological Sciences & Cabot Institute, University of Bristol, Bristol, UK MANAGEMENT AND 3 Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, UK DRIVERS OF CHANGE OF 4 School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK POLLINATING INSECTS AND 5 NERC Centre for Ecology & Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, UK POLLINATION SERVICES 6 School of Biological Sciences, University of East Anglia, Norwich, UK 7 Department of Life Sciences, Silwood Park National Pollinator Strategy: Campus, Imperial College London, Ascot, UK 8 for bees and other pollinators in England French National Institute for Agricultural Research (INRA), UMR Agroécologie, Dijon, Evidence statements France and Summary of Evidence Published by: The Department for Environment, Food and Rural Affairs, UK EVIDENCE STATEMENTS Introduction These Evidence Statements provide up-to-date information on what is known (and not known) about the status, values, drivers of change, and responses to management of UK insect pollinators (as was September 2018). This document has been produced to inform the development of England pollinator policy, and provide insight into the evidence that underpins policy decision-making. This document sits alongside a more detailed Summary of Evidence (Annex I) document written by pollinator experts. For information on the development of the statements, and confidence ratings assigned to them, please see section ‘Generation of the statements’ below. Citations for these statements are contained in the Summary of Evidence document. Contents EVIDENCE STATEMENTS INTRODUCTION ................................................................................................................................................... 1 MAIN MESSAGES ................................................................................................................................................. 2 GENERATION OF THE STATEMENTS ...................................................................................................................... 5 1. STATUS AND TRENDS OF POLLINATORS AND POLLINATOR-DEPENDENT PLANTS ............................................ 6 2. VALUES OF POLLINATORS ............................................................................................................................. 9 3. DRIVERS OF POLLINATOR STATUS & CURRENT AND FUTURE RISKS .............................................................. 10 4 EFFECTIVENESS OF MANAGEMENT AND POLICY FOR IMPROVING THE STATUS OF POLLINATORS ................. 14 ANNEX 1 - SUMMARY OF EVIDENCE INTRODUCTION ................................................................................................................................................. 19 1. STATUS AND TRENDS OF POLLINATORS AND POLLINATOR-DEPENDENT PLANTS .............................................. 21 2. VALUES OF POLLINATORS ............................................................................................................................... 35 3. DRIVERS OF POLLINATOR STATUS & CURRENT AND FUTURE RISKS ................................................................. 42 4. EFFECTIVENESS OF MANAGEMENT AND POLICY FOR POLLINATORS ................................................................. 54 REFERENCES ...................................................................................................................................................... 73 Page 1 EVIDENCE STATEMENTS Main messages I. Status and trends of pollinators and pollinator-dependent plants a) Past declines (1950s-1990) in species distributions of wild bees and hoverflies in the UK have slowed, but not ceased, since the 1990s, with the overall trend across species remaining downward (established but incomplete). Fluctuations notwithstanding, in the short-term (since 2010) trends in a number of species in these groups in the UK have stabilised (established but incomplete). b) The number of registered honey bee colonies in the UK has increased over the last decade (established but incomplete), however we have no reliable data source for the number of managed bumble bee colonies or other managed pollinators. Although honey bees are major pollinators of several UK crops, UK stocks of honey bees are far below the levels required to act as the sole providers of pollination services to all crops. The majority of evidence indicates that wild bees are the main pollinators of UK crops (established but incomplete). c) Historical declines in pollinator food (nectar) resources across Great Britain (GB) have slowed since the 1970s (established but incomplete), and the total potential nectar resource (estimated from 260 common nectar- producing plants) increased by 25% from 1998 to 2007, though not returning to estimated 1930 levels (established but incomplete). However, the diversity of nectar-producing plants has continued to decline (established but incomplete). d) The service of pollination, provided by wild and managed insects, is dependent on insect numbers, and can be improved by diverse pollinator communities (established but incomplete). With the long term downward trend in species distributions it is possible that pollination services to crops and wild plants have also declined in the long term (inconclusive). Some pollination deficits (i.e. shortfalls in production due to lower than ideal levels of pollination) have been observed in UK apples, however the extent of deficits in other crops are unknown. e) DNA methods such as illumina barcoding can be used to identify almost all UK bee species and can provide abundance data. However, in its current state of development this method may be prohibitively expensive for UK-scale monitoring, as specimens are analysed individually, increasing time and cost (established but incomplete). II. Values of Pollinators a) Pollinators add substantial economic value to crop production through improving crop quality and quantity (well established). The economic benefits of pollination to crop production in the UK is approximately half a billion GBP a year, based on yield (established but incomplete). This estimate only considers direct benefits to current producer profit, and does not include additional economic benefits such as reduced prices for consumers, costs avoided, and natural capital benefits/losses. b) Estimating the costs and benefits (economic and socio-cultural) of managing land for pollinators is hindered by several knowledge gaps, such as the dependence of crop varieties on pollination, the socio-cultural values of pollinators in the UK, such as landscape aesthetics and the role of pollinator diversity in these services. III. Drivers of pollinator status & current and future risks Land use a) Habitat loss and fragmentation since the 1930s, and intensive land management practices, have negatively affected wild pollinators by reducing food (well established) and nesting resources (established but incomplete). This can lead to simplified pollinator communities dominated by common, generalist species (well established). Page 2 EVIDENCE STATEMENTS b) Chemicals used across agricultural, rural, suburban, and urban landscapes to control pests and weeds have a range of unintended direct and indirect effects on both wild and managed pollinators (well established). c) Following the 2013 EU moratorium and 2018 ban, neonicotinoids still persist in soil leading to uptake and exposure to pollinators through wild plants, and in plants sold for garden use (established but incomplete). Explicit links to bee health, through this mode of exposure, have not been shown – however, neonicotinoid treated crops are known to have negative sub-lethal effects on bumble bees and solitary bees (established but incomplete) and honey bees (unresolved). The impact of neonicotinoid exposure on bee populations remains unclear (unresolved). d) Urban insect pollinator communities are dominated by common, generalist species (well established). Bumble bees appear less adversely affected by urban development than other pollinator taxa like hoverflies (established but incomplete). Climate change e) Climate change has already altered the range (range contraction/poleward movement/higher elevations), abundance, and seasonal activity (overwintering behaviour) of some pollinator species, and will continue to do so; and range alteration is likely to increase in the coming decades (established but incomplete). The combination of climate change with other global change pressures (e.g. land-use changes, invasive alien/non- native species) are likely to pose significant future threats to pollinator communities (established but incomplete). f) Currently in the UK the impact of invasive alien plant and predator species on pollinators and pollination is considered to be less profound than other pressures (e.g. land management, pesticides, pests and pathogens) (established but incomplete). However their importance as a driver of pollinator status may rise with climate change creating new opportunities for invasive alien species, alongside more confounding pressures from climatic or other stressors (established but incomplete).

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