UNIVERSITY OF READING Delivering biodiversity and pollination services on farmland: a comparison of three wildlife- friendly farming schemes Thesis submitted for the degree of Doctor of Philosophy Centre for Agri-Environmental Research School of Agriculture, Policy and Development Chloe J. Hardman June 2016 Declaration I confirm that this is my own work and the use of all material from other sources has been properly and fully acknowledged. Chloe Hardman i Abstract Gains in food production through agricultural intensification have come at an environmental cost, including reductions in habitat diversity, species diversity and some ecosystem services. Wildlife- friendly farming schemes aim to mitigate the negative impacts of agricultural intensification. In this study, we compared the effectiveness of three schemes using four matched triplets of farms in southern England. The schemes were: i) a baseline of Entry Level Stewardship (ELS: a flexible widespread government scheme, ii) organic agriculture and iii) Conservation Grade (CG: a prescriptive, non-organic, biodiversity-focused scheme). We examined how effective the schemes were in supporting habitat diversity, species diversity, floral resources, pollinators and pollination services. Farms in CG and organic schemes supported higher habitat diversity than farms only in ELS. Plant and butterfly species richness were significantly higher on organic farms and butterfly species richness was marginally higher on CG farms compared to farms in ELS. The species richness of plants, butterflies, solitary bees and birds in winter was significantly correlated with local habitat diversity. Organic farms supported more evenly distributed floral resources and higher nectar densities compared to farms in CG or ELS. Compared to maximum estimates of pollen demand from six bee species, only organic farms supplied sufficient pollen in late summer. The density and species richness of pollinators did not vary between schemes. Both CG and organic farms supported more insect-flower visitation than ELS farms. Pollination services were higher on organic farms. The results showed that prescriptive schemes (e.g. CG) and organic farming are important for supporting habitat diversity and that this is particularly beneficial for butterflies. Late summer emerged as a priority time of year to increase pollen supply on non-organic farms and management options to achieve this are discussed. The data can be used further to inform our understanding of how land management affects biodiversity, particularly pollinators. ii Acknowledgements I would like to give very special thanks to my supervisors Simon Potts and Ken Norris for their insight, guidance, support, enthusiasm and good humour throughout my PhD. I am extremely grateful to my funders Conservation Grade (CG) and Biotechnology and Biological Sciences Research Council (BBSRC). I would like to give a big thank you to Tim Nevard and Brin Hughes at CG for their input and support for this scientific research and for linking me with CG farmers. I am extremely grateful to the farmers and land owners for giving me farm access and information. For assistance with site selection, I was grateful to have the help of Harold Makant at Natural England (NE). I also thank Adam West and Martin Ruddy at NE for providing Environmental Stewardship data. In carrying out pollinator, phytometer and botanical surveys, I was capably assisted by Kerri Watson, Emily Edhouse and Amandine Beugnet in 2012, Cassie-Ann Dodson, Laurine Lemesle, Chris Reilly and Matthew Wisby in 2013 and Victoria Burton in 2014. For carrying out bird surveys, I thank the local ornithologists: Rob Yarham, Ian Esland, Giles Darvill, Alan Jackson, Tony Birch, Helen Lumley, Hugh Netley, Glynne Evans, Sheila Evans, Sarah Priest, Jan Jupp, Tim Thomas, Simon Boswell and Neil Fletcher. For collecting winter bird survey data I thank Dominic Harrison and for comments on Chapter 3 I thank Dominic’s supervisor Pete Shaw at the University of Southampton. I am incredibly grateful to Stuart Roberts, Ellen Moss and Rebecca Evans for assisting me in bee species identification, as well as providing training in pollinator field survey methods. I thank all my colleagues in the Centre for Agri-Environmental Research for being a pleasure to work with. Particular thanks go to Jane Adkins for her administrative support and Tom Breeze for comments on Chapters 3 and 4. I also thank Mathilde Baude and Mark Gillespie for advice on floral resource survey methodology and pollen and nectar data. Thanks also to Mathilde Baude for comments on Chapter 5. Thanks to Lynn Dicks for contributing pollen demand estimates. I thank three anonymous reviewers for comments on Chapter 3. I would like to thank my partner Rory McCann for his wonderful support. I am extremely appreciative of the support from all my friends and family, in particular mum, dad, Emma Hardman, and the McCann family. Thanks to Cath and Quentin Shaw for providing me with an excellent working space for writing up. iii Data accessibility statement Habitat diversity and species richness data used in Chapter 3 were deposited in the Dryad repository: http://dx.doi:10.5061/dryad.8n2c0 (Hardman et al. 2015) as part of the publication of the Journal of Applied Ecology article associated with this chapter. Data used in Chapters 4 and 5 were deposited in the University of Reading Research Data Archive: http://dx.doi.org/10.17864/1947.69 iv Table of contents Abstract ii Acknowledgments iii Data accessibility statement iv Table of contents v List of tables x List of figures xi List of appendices xiii Chapter 1: Introduction 1 1.1 Global land use change 1 1.2 Agricultural intensification 1 1.3 Biodiversity and agriculture 2 1.4 Pollinators and pollination services 2 1.5 European agri-environment schemes 3 1.6 Entry Level Stewardship 4 1.7 Organic agriculture 5 1.8 Higher Level Stewardship 5 1.9 Countryside Stewardship 6 1.10 Conservation Grade 6 1.11 Spatial and temporal scales 7 1.12 Research aim and objectives 8 1.13 References 10 Chapter 2: Study design and overview of methods 16 2.1 Study farms 16 2.2 Habitat mapping 19 2.3 Proportional stratified sampling design 19 2.4 Farm habitat composition 20 2.5 Farm intensity 22 2.6 Landscape mapping 23 2.7 Scope of sampling 24 2.8 Plant surveys 25 2.9 Pollinator surveys 25 2.10 Bird surveys 26 v 2.11 Phytometer surveys 26 2.12 Floral resource surveys 26 2.13 General statistical approach 27 2.14 References 28 Chapter 3: Supporting local diversity of habitats and species on farmland: a comparison of 30 three wildlife-friendly schemes 3.1 Summary 30 3.2 Introduction 31 3.3 Methods 33 3.3.1 Defining spatial scales 33 3.3.2 Study sites 33 3.3.3 Habitat mapping 34 3.3.4 Biodiversity sampling strategy 34 3.3.5 Habitat diversity calculations 34 3.3.6 Biodiversity survey methods 34 3.3.7 Statistical analysis 34 3.3.7.1 Wildlife-friendly farming scheme differences in habitat diversity 34 3.3.7.2 Habitat diversity as a predictor of species richness 35 3.3.7.3 Effects of wildlife-friendly farming scheme and habitat diversity 35 on species richness 3.4 Results 35 3.4.1 Wildlife-friendly farming scheme differences in habitat diversity 35 3.4.2 Habitat diversity as a predictor of species richness 36 3.4.3 Effects of wildlife-friendly farming scheme and habitat diversity on 37 species richness 3.5 Discussion 39 3.5.1 Conclusions and policy recommendations 40 3.6 References 42 Chapter 4: Delivery of floral resources and pollination services on farmland under three 47 different wildlife-friendly schemes 4.1 Summary 47 4.2. Introduction 47 4.3 Methods 49 vi 4.3.1 Study sites 49 4.3.2 Habitat maps 50 4.3.3 Landscape variables 50 4.3.4 Floral resource surveys 51 4.3.5 Pollinator surveys 51 4.3.6 Pollination service surveys 52 4.3.7 Data analysis 53 4.4 Results 54 4.4.1 Spatially differentiated results 54 4.4.1.1 Spatial distribution of floral resources between habitats 54 4.4.1.2 Differences between crop and non-crop habitats in flower density 55 and diversity 4.4.1.3 Differences between crop and non-crop habitats in pollinator 56 density and diversity 4.4.1.4 Differences between crop and non-crop habitats in insect- 57 wildflower visitation 4.4.1.5 Differences between crop and non-crop habitats in pollination 57 services 4.4.2 Farm level results 58 4.4.2.1 Flower density 58 4.4.2.2 Pollinator density and species richness 58 4.4.2.3 Insect-wildflower visitation 59 4.4.2.4 Pollination service 59 4.5 Discussion 59 4.5.1 Spatial distribution of floral resource, pollinators and pollination services 59 4.5.2 Farm level of floral resource, pollinators and pollination services 60 4.5.3 Implications for management 60 4.5.4 Conclusion 61 4.6 References 62 Chapter 5: Seasonal supply of floral resources for pollinators on farms in three different 66 wildlife-friendly schemes 5.1 Summary 66 5.2 Introduction 67 vii 5.3 Methods 69 5.3.1 Site selection 69 5.3.2 Sampling strategy 69 5.3.3 Floral resource surveys 70 5.3.4 Pollinator surveys 70 5.3.5 Local scale density calculations 70 5.3.6 Farm scale density calculations 71 5.3.7 Statistical analysis 71 5.3.7.1 Local density analysis 71 5.3.7.2 Density of floral resource from individual plants at the local scale 71 5.3.7.3 Farm density analysis 71 5.3.7.4 Comparing pollen supply and demand 71 5.3.7.5 Contributions of habitats at the farm scale 72 5.3.7.6 Density of floral resource from individual plants at the farm scale 72 5.4 Results 72 5.3.1 Local scale density 72 5.3.2 Density of floral resource from individual plants