This electronic thesis or dissertation has been downloaded from Explore Bristol Research, http://research-information.bristol.ac.uk Author: Carr, Andrew Title: Investigating the effects of management in temperate broadleaved woodland on bats and their insect prey General rights Access to the thesis is subject to the Creative Commons Attribution - NonCommercial-No Derivatives 4.0 International Public License. A copy of this may be found at https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode This license sets out your rights and the restrictions that apply to your access to the thesis so it is important you read this before proceeding. Take down policy Some pages of this thesis may have been removed for copyright restrictions prior to having it been deposited in Explore Bristol Research. 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INVESTIGATING THE EFFECTS OF MANAGEMENT IN TEMPERATE BROADLEAVED WOODLAND ON BATS AND THEIR INSECT PREY Andrew Carr A dissertation submitted to the University of Bristol in accordance with the requirements for award of the degree of PhD in the Faculty of Science School of Biological Sciences November 2018 Word count: 35,469 ABSTRACT Woodland is an important natural resource providing wood-derived biomass for use as a carbon lean source of heating and electricity. The role of biomass in reducing our dependence on fossil fuels should not be underestimated, nor should the potential negative impacts on biodiversity as land managers are incentivised to bring under-managed woodland back into production to meet renewable targets. The effect of woodland management on wildlife needs more scientific research. In this thesis, I investigate the influence of the silvicultural practice involving selective thinning of woodland over time on bats and their insect prey, and use emerging technologies to identify the ecological requirements of a woodland specialist bat species at different spatial scales. When compared to unmanaged woodland (minimal intervention and underutilised), bat species richness was higher in managed woodland (selective thinning) because uncluttered understory vegetation provided opportunities for edge and open foraging bats, in addition to woodland interior specialists. Common and adaptable edge foragers were more active in managed woodland. Interior foragers and tree-roosting bats were more active in unmanaged woodland and often absent from managed woodland. Bats responded positively to standing dead trees and tree cavities, and to a relatively open and heterogeneous canopy architecture. Standing dead trees were three times more abundant, and tree cavities five times more frequent in unmanaged woodland. Canopy architecture was similar between managed and unmanaged woodland. Bats and insects had contrasting non-linear temporal responses to time since last management with bat activity reducing, and insect numbers peaking in early stage successional woodland. The woodland-dwelling bat Barbastella barbastellus roosted primarily in ancient semi-natural broadleaved woodland which contained more tree cavities than adjoining younger plantation woodland. High energetic demands of pregnant and lactating bats influenced roost selection and behaviour. B. barbastellus specialises in feeding on moths. Linear landscape features such as hedgerows provide food for moth larvae and were used by B. barbastellus for feeding on adult moths. Bats respond well to characteristics that form in old age woodland. The relatively low frequency of standing dead trees and number of cavities in shorter rotation production woodland limits its value to bats. Tree roost availability and canopy architecture characteristics can be encouraged in young woodland by minimal intervention management, or in production woodland through positive thinning management. Improving B. barbastellus roosting and foraging habitat will conserve habitat suitable for all developmental stages of their moth prey. i AUTHOR’S DECLARATION I declare that the work in this dissertation was carried out in accordance with the requirements of the University's Regulations and Code of Practice for Research Degree Programmes and that it has not been submitted for any other academic award. Except where indicated by specific reference in the text, the work is the candidate's own work. Work done in collaboration with, or with the assistance of, others, is indicated as such. Any views expressed in the dissertation are those of the author. Andrew Carr Signed: ………………………………………………………. Date: ………………………………………………………. ii DISCLOSURE Chapter 3 uses some raw field data taken, with permission, from a PhD thesis (Zeale, 2011) combined with field data collected by myself. All desktop measurements were re-calculated and additional airborne LiDAR imagery measurements included before the full dataset was analysed. Justifications for combining this existing raw field data with data collected by myself are (i) that meta-analysis review of papers exploring roost selection by forest-dwelling bats advises at least three years of study are needed to avoid conclusions based on years with unusual amounts of precipitation or warmth or other stochastic events (Naďo and Kaňuch, 2015), and (ii) to allow reproductive status differences between breeding and non-breeding bats to be analysed. Chapter 4 uses a molecular approach to identify the diet of B. barbastellus. DNA extraction and next generation sequencing was undertaken at Queen Mary University of London (QMUL) by Beth Clare. Subsequent bioinformatics was undertaken by myself following training provided at QMUL. The faecal pellets used for prey DNA extraction were collected by myself and were also provided by Ian Davidson-Watts and Jane Harris. iii ACKNOWLEDGEMENTS Many institutions and people have contributed to the development of this thesis. Firstly, I would like to thank the Scottish Forestry Trust, Forestry Commission and Woodland Trust for funding my PhD, the University of Bristol for providing the equipment I used during each of my field seasons, and the University of Bristol Alumni Foundation for providing a conference travel grant. Thanks also to the Forestry Commission, Woodland Trust and other landowners for granting permission to survey on their land. I am very grateful to my supervisors Gareth Jones and Andrew Weatherall for supporting me through my PhD, for helping develop my initial research idea, for providing the guidance I required to develop as a researcher, for their roles in securing funding, and for their encouragement throughout. I am grateful to Matt Zeale for his role in securing funding and encouragement; Jérémy Froidevaux for his assistance with LiDAR; Marc Holderied and Steve Harris for their invaluable input and guidance as part of my annual progress monitoring; Beth Clare of Queen Mary University of London for extracting and sequencing bat faecal samples and for training me in bioinformatics, and Ian Davidson Watts of Davidson Watts Ecology and Jane Harris for providing bat faecal samples. I am also grateful to Carol Williams of the Bat Conservation Trust and Tom Blythe of the Forestry Commission for their encouragement and advice during the early stages of my research, and Susan Young for her collaboration during fieldwork in Devon. I would like to thank the many volunteers that participated in my project. Their assistance made this research possible. I thank Penelope Fialas for searching the literature as part of her internship within the Batlab, Moth Broyles and Andy Wakefield for insect identification. I am greatly indebted to my fellow researchers in the Batlab for their peer support, in particular Angelica Rodriquez, Jérémy Froidevaux, Lia Gilmour, Liz Rowse, Matt Zeale and Parvathy Venugopal; you guys are BADASS. iv There are three people I have met through this research that have helped above and beyond my expectations and who I now consider as friends. I would like to thank David Rickwood of the Woodland Trust for his continued encouragement and forestry insight that helped to develop my appreciation for the implications of my work to the wider forestry sector; Tom ‘the tracker’ Williams and Mike ‘the trapper’ Treble for their outstanding assistance collecting field data during 2015. I owe all three of you a personal debt and I wish you well. Above all I thank my wife, Karolina, and daughter, Hanna. You have helped me through the difficult times and made the good times so much better. Kocham was. I am looking forward to our next adventure together. “the sound of the bat flying in the thicket is dark” Masaoka Shiki (1867 - 1902) v PUBLICATIONS AND CO-AUTHORS’ CONTRIBUTIONS Chapter 3 forms the basis of a published manuscript (Appendix A). AC designed the study with assistance from GJ, AW and MZ. AC and MZ collected radio tracking data on B. barbastellus (AC pregnant, lactating and non-breeding bats; MZ post-lactating and non-breeding bats). AC and MZ collected field data on woodland structure.