A University of Sussex PhD thesis Available online via Sussex Research Online: http://sro.sussex.ac.uk/ This thesis is protected by copyright which belongs to the author. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Please visit Sussex Research Online for more information and further details 1 UNIVERSITY OF SUSSEX Linda Joy Birkin (for) Doctor of Philosophy Pollination ecosystem services and the urban environment September 2017 --- 2 Statement I hereby declare that this thesis has not been and will not be, submitted in whole or in part to another University for the award of any other degree. Signature: ..................................................................................... 3 Acknowledgements I knew when I started this PhD that I was going to need an awful lot of bean seeds, but I don’t think I quite realised how much the enthusiasm, encouragement, and gardening skills of so many other people would contribute to my research. So now it is time for me to express my gratitude to those who have ‘bean’ with me on the way. First thanks have to go to my supervisors. To Professor Dave Goulson for giving me this opportunity, and then for his support and advice throughout the course of the last four years. For puzzling through my humour and my phraseology, and giving guidance on Statistical Analysis – and additionally for pints, proofreading, and reminders that publication is actually rather important! I would also like to thank Professor Francis Ratnieks for his comments, expertise and encouragement to consider all viewpoints. I deeply grateful for the support from the "PhD Ladies of 5B20": Kate Basley, Andreia Penado and Janine Griffiths-Lee. We’ve had camaraderie, cakes, tears, battles with Excel, all while keeping each other (arguably) sane. Further thanks go to the others in the Goulson Lab Group, for listening to my updates (and my rants), offering suggestions, and generally being an excellent group of people to work with. Plus a particular mention to Rob Fowler for statistics help, tomato plant chauffeuring around Brighton, and putting up with the state of my greenhouses! And also to Leila Simpson, for planting assistance and video skills tuition in my first year. My friends and family have been incredible, and I thank them all dearly for support, humour, and tea (in pretty much equal measures). Plus extra thanks are due to those who took part in the pilot questionnaires. A very special thank you here is due to my partner, Matt Oakley; for his love, patience and being a voice of reality. Also for his humour, and for being an enthusiastic enabler of emergency takeaways. I am indebted to my parents (occasionally literally), Joan and Rob Birkin, for their unwavering support; their acceptance of late-night phone calls; for proofreading instructions and for running the best at-home field station I could have asked for, regardless of what odd thing I asked them to do. Putting jewellery bags on the alliums. Wrapping net curtains around the fox gloves. Distributing several large crates of plants to friends and neighbours. No problem! Last, by no means the least (and certainly the most numerous group): I thank my volunteers, from all years. I am grateful to everyone who has sprouted, counted, weighed, podded, snipped, watered, calculated, measured, emailed, tweeted, fought slugs and battled with blackfly. They were fantastic, and I quite literally couldn’t have done this PhD without them. 4 Summary Insect pollination is a vital ecosystem service, essential for both wild and domesticated plants, yet to-date there are no standardised national schemes to monitor its status. Thus this PhD focused on assessment of pollination provision in UK urban green spaces, using a combination of citizen science and field/laboratory methods. Each of the following thesis chapters considers a specific pollination-related theme: The need for pollination. Demonstrating how much gardeners need insect pollination is important to underpin public support for pollinator conservation. During 2014-2015, online questionnaires were used to collect information about the crops grown in domestic green spaces and gardening practices used. Participants highly valued ‘growing their own’, and three of five crops grown by the majority (tomatoes, apples, strawberries) have high requirements for insect pollination. A ‘garden shop calculator’ spreadsheet was also tested (positively) as a quick way to calculate the equivalent bought-value of garden crops and the proportion directly attributable to insect actions. Assessment of pollination provision. Citizen science volunteers undertook a simple direct pollination experiment (exclusion, hand pollination, local), requiring treatment randomisation and accurate yield recording. The main ‘Bees ‘n Beans’ projects used Vicia faba to monitor bumblebee pollination, detecting no national deficit during 2014- 2016. This suggests that the domestic pollination needs of V. faba are currently met, and that urban populations of long-tongued bumblebees are sufficient to provide it. The potential of using other plants to cover wider pollinator populations was also explored, identifying Allium hollandicum as suitable. The effects of companion planting. Using tomato plants to examine whether co- planting crops with flowering plants boosts pollination provision (‘magnet species’ effects), or distracts insects. Provided plants were hosted in volunteered gardens and school grounds in Brighton in 2015 & 2016. No effect (improved or detrimental) of co- flowering plants was found on tomato yields at either site type. Using citizen science to monitor pollination services. This chapter combined findings from other chapters and a final questionnaire, which focused on participants’ motivations and willingness to make behavioural changes after taking part. It concludes that the projects have demonstrated volunteers’ ability and willingness to follow experimental protocols under guidance, to collect meaningful data at otherwise-impractical geographical scales. Suggested protocol. This details the finalised Bees ‘n Beans approach and how it relates to other potential pollination monitoring methods. I propose that this style of project is suitable for incorporation into national monitoring scheme development. 5 Contents Statement ..................................................................................................................................... 2 Acknowledgements ....................................................................................................................... 3 Summary ....................................................................................................................................... 4 Contents…………………………………………………………………………………………………………………………………..5 Chapter 1: Ecosystem services and the urban environment – introduction and aims. .............. 10 1.1. Ecosystem Services ............................................................................................................ 11 1.1.1. What is an ecosystem service? ................................................................................. 11 1.1.2. Valuing ecosystem services. ...................................................................................... 12 1.2. Pollination .......................................................................................................................... 14 1.2.1. The pollination service. ............................................................................................. 14 1.2.2. Measuring pollination ............................................................................................... 15 1.2.3. Pollinator decline and conservation ......................................................................... 16 1.3. The buzz about town – urban areas and pollination ......................................................... 18 1.3.1. Biodiversity in urban spaces ..................................................................................... 18 1.3.2. The need for pollination in urban areas ................................................................... 20 1.4. Project aims and the use of citizen science ....................................................................... 21 Chapter 2: Assessment of the existing requirement for pollination services in urban areas. .... 25 2.1. Introduction: urbanisation, ecosystem services, and public understanding. ................... 25 2.2. ‘Growing Towns’ (2014) .................................................................................................... 28 2.2.1. Methods .................................................................................................................... 29 2.2.2. Results and progress ................................................................................................. 31 2.2.3. Discussion .................................................................................................................. 34 2.3. ‘The Need for Bees’ (2015) ................................................................................................ 36 2.3.1. Results ......................................................................................................................