Urban Green Space Management for Invertebrates and House Sparrows
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Urban green space management for invertebrates and house sparrows Jacqueline Elizabeth Sarah Weir Imperial College London, Department of Ecology and Evolution A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy May 2015 1 Declaration of Originality I declare that this thesis is my own work, other than where appropriately referenced. The thesis contains results from two Masters projects which were co-supervised by me, and sections summarising these projects are acknowledged accordingly. Copyright Declaration The copyright of this thesis rests with the author and is made available under a Creative Commons Attribution Non-Commercial No Derivatives licence. Researchers are free to copy, distribute or transmit the thesis on the condition that they attribute it, that they do not use it for commercial purposes and that they do not alter, transform or build upon it. For any reuse or redistribution, researchers must make clear to others the licence terms of this work 2 Abstract Urban house sparrow nestlings can develop poorly through lack of invertebrate food (Peach et al., 2008). Productivity can be increased by providing invertebrates (Peach, Sheehan & Kirby, 2014; Peach et al. in press). This study tested the effectiveness of three habitat treatments in increasing invertebrates and seeds in London parks, and their usage by house sparrows. Treatments were: annually sown ‘wildlife seed’ plots; sown perennial wildflower meadows; and existing grass grown taller. Treatment establishment and seed abundance were assessed by vegetation measurements, and practicality qualitatively assessed through questionnaires. Invertebrate abundance and variety were measured using sweep netting and vacuum sampling, and relationships tested with treatment type and modelled air pollution levels. Bird usage, and local house sparrow populations and productivity, were monitored over three years and relationships tested with treatments and air pollution. All treatments provided more invertebrates and seed than short grass. Wildlife seed plots contained the most seed during both autumn and winter. Wildflower meadows supported the most invertebrates, while each treatment benefited particular groups. Invertebrate variety at family level was highest in wildflower meadows and wildlife seed plots, probably through increased plant diversity. Abundance for numerous groups related positively to sward height. Varied vegetation structure should benefit the most invertebrate groups. Wildlife seed plots were most used by house sparrows, largely in the breeding season for invertebrates, while wildflower meadows were not used. Open vegetation structure probably permitted birds access. Wildlife seed plots may have buffered colonies against breeding season food shortages in one year. No strong relationships were found between invertebrate abundance and air pollution. Relationships between house sparrow population parameters and air pollution were mixed. Heterogeneous vegetation structure is important for invertebrates, and for bird access to food. Habitat homogenisation at various scales, combined with other pressures, may contribute to limiting urban house sparrow populations. 3 Acknowledgements This project was mainly funded by SITA Trust through the Landfill Communities Fund, with some additional funding from ICB-Diadem, Northern Trust, Edward Harvist Trust, The London Natural History Society, and individual donors - especially John Vail. It was managed through RSPB and Imperial College, and involved eight other partner organisations. These were: City of London, The London Borough of Camden, The London Borough of Islington, Lee Valley Regional Park Authority, The Royal Parks, The London Borough of Southwark, The London Borough of Sutton, and The London Borough of Wandsworth. I would like to thank the funders and all the project partners for their support, as without them this work would not have been possible. I enjoyed working with you. I would like to thank the research assistants and interns who have worked with the project for their dedication and hard work. Thanks to: Alison Beresford, Emily Crockford, David Feltham, Gwendolen Hitchcock, Caroline Nash, Kathrin Stoetzel, Eniko Szucs and Adam Wilson for all their effort and help. The project could not have achieved the huge amount of data collection that it did, without the support of numerous volunteers. I would like to thank them for giving their time to help. Thank you to my supervisors Simon Leather and Linda Davies at Imperial College, and to Tilly Collins, for their support. Thanks to Laura Hill (now Gosling) for carrying out the pollution modelling. Thanks also to the students at Imperial who worked with the project. Henry Johnson and Kyle Shackleton’s projects are summarised within this thesis. I would especially like to thank Will Peach at RSPB for his advice and support throughout this work, and Adam Butler at BioSS for his statistical advice. Many thanks also to the other RSPB staff who have supported me: Martyn Foster, John Day, Jan Heath, Sarah Farney, Tim Webb, Mark Gurney, Nigel Symes, Richard Winspear, and so many others colleagues and friends. Thanks to Mark for all the cooking. This thesis is dedicated to my Grandma, Jessie Smith; my Great Aunt, Winnie Gracey; and my friend Nene Das, now departed. 4 Contents Cover page..................................................................................................…………….......1 Declaration of Originality………………………………………………………………...2 Copyright Declaration………………………………………………………………….....2 Abstract………………………………………………………………………………….….3 Acknowledgements………………………………………………………………………....4 Chapter 1 – Introduction…………………………………………………………………..11 1.1 Thesis aims and outline……………………………………………………………...11 1.2 Literature review – house sparrows…………………………………………………12 1.3 Literature review – lessons from rural areas on habitat management…......……......45 1.4. Literature review – conservation management of urban habitats............………… .71 1.5 Thesis objectives………………………………….......................…………………..79 Chapter 2 - Trial plot instatement and establishment…………………………………..….81 2.1 Introduction………………………………………………………………………....81 2.2 Aims and objectives ……...........................................................................................84 2.3 Methods ………………………………………………………………...84 2.4 Results…………………………………………………………………………….. .95 2.5. Discussion………………………………………………………………………....107 2.6 Conclusions - Practical and financial considerations for park managers……….....112 Chapter 3 – Seed food resources………………………………………………………...115 3.1 Introduction………………………………………………………………………..115 3.2. Aims and objectives……………………………………………………………….116 3.3 Methods……………………………………………………………………………118 3.4 Results - vegetation response to trial plot management……………………………122 3.5 Discussion………………………………………………………………………….131 3.6 Conclusions………………………………………………………………………...133 Chapter 4 - Invertebrate response to trial plot management……………………………...134 5 4.1 Introduction………………………………………………………………………..134 4.2 Aims and objectives………………………………………………………………..135 4.3 Methods - Invertebrate monitoring………………………………………………...136 4.4 Results – Invertebrate abundance………………………………………………….144 4.5 Results - Invertebrate variety and species ecology…..…………………………….161 4.6 Discussion………………………………………………………………………….166 4.7 Conclusions...............................................................................................................175 Chapter 5 - Bird response to trial plot management……………………………………..177 5.1 Introduction………………………………………………………………………..177 5.2 Aims and objectives………………………………………………………………..178 5.3 Methods……………………………………………………………………………179 5.4 Results……………………………………………………………………………...187 5.5 Discussion………………………………………………………………………….201 5.6 Conclusions………………………………………………………………………...208 Chapter 6 - General Discussion………………………………………………………….210 6.1 Likely drivers of house sparrow decline and contribution of project……………...210 6.2 Key findings............…….........................................................................................212 6.3 Implications of project results for urban land managers.…………………………..222 6.4 Study limitations...............................………………………………………………224 6.5 Knowledge gaps and future research………………………………………………....230 Bibliography..……………………………………………………………………………..231 Appendix 1 Summary of site management prior to trial plot creation………………...267 Appendix 2 Long grass trial plot specifications (2011 work plan)…………………….268 Appendix 3 Summary of seed mixes used in wildflower meadow plots……………...269 Appendix 4 Wildflower meadow trial plot specifications (2011 work plan)………….271 Appendix 5 Wildlife Seed trial plot specifications (example of 2011 work plan)…….272 6 Appendix 6 Closest locations of house sparrow nests to trial and control plots, recorded during 2008 presence absence surveys and 2009 – 2011 breeding surveys…………...274 Appendix 7 Partner questionnaires 2009 and 2010-11 (wildflower meadow)………..276 Appendix 8 Feedback questionnaire sent to partners at end of project……………….282 Appendix 9 Online feedback questionnaire for Friends groups……………………….284 Appendix 10 Examples of established trial plots……………………………………...286 Appendix 11 Methods used in London Atmospheric Emissions Inventory modelling of air pollutant levels……………………………………………………………………...288 Appendix 12 NO2 gradients within Peckham Rye Park, Southwark………………....290 Appendix 13 Carabidae species found in samples from 2011 and habitat associations.....291 List of Tables Table 1.1 Historical house