An investigation of mining impacts on bats in South-West England Submitted by Emma Theobald to the University of Exeter as a thesis for the degree of Masters by Research in Biological Sciences in March 2018 This thesis is available for Library use on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. I certify that all material in this thesis which is not my own work has been identified and that no material has previously been submitted and approved for the award of a degree by this or any other University. Signature: …………………………… 1 Acknowledgements: First of all a massive thank you to my research tutors Prof. David Hosken and Dr. Kelly Moyes for introducing me ‘bat world’ and for their continued guidance and support, also to Prof. Patrick Foster for his insight into the mining industry. I am very grateful to Wolf Minerals for providing the funding for this research and would like to thank Jess Easterbrook and Hannah Clarke of the Environmental Team and Michel Hughes for introducing me to the Drakelands site and answering my questions. I really appreciate the cooperation of the landowners who let me climb fences and wander through their fields and to set up detectors (David Cobbold in particular) - without your permission this research would not have been possible. Last but not least, I would like to thank Reece and my family and friends for their support and encouragement and for listening to my bat chat over the past year and a half! 2 An investigation of mining impacts on bats in South-West England Abstract: The extraction of minerals through open-pit mining can result in sudden and extensive land use change, often posing threats to local biodiversity. Bats are particularly vulnerable to the impacts of mining, but their metapopulation structure and wide-ranging roosting habits can make it challenging to monitor local populations. Here, we investigated the impacts of habitat loss and disturbance at Drakelands open-pit mine, the first new metal mine to be established within Britain in the past 45 years. This was addressed in two parts, firstly by analysing data collected by contracted ecologists at the site, in order to identify potential short-term shifts in bat activity and to evaluate the efficacy of mitigation measures. Secondly, by monitoring bat activity in the wider landscape to identify potential further-ranging impacts of the mine on local bat populations. In conjunction with this work we incorporated a field trial of a novel bat detector designed for long-term monitoring of bat activity. The results highlighted the multitude of factors which influence bat activity at a local level, and may provide a platform for continued research into the impacts of habitat fragmentation and anthropogenic noise at a species/ genus level. The information presented here will help to inform management decision making in regards to bat conservation, both at the Drakelands site and potentially at mining operations elsewhere. 3 Table of contents: Title page and declaration …………………………………………………………… 1 Acknowledgements ...………………………………………………………………... 2 Abstract …...………………………………………………………………………...… 3 Table of contents ……………………………………………………………………... 4 List of tables ………………………...………………………………………………… 6 List of figures ………………………………………………………………………….. 7 List of appendices ……………………………………………………………………. 8 Chapter 1: Introduction ………………………………………………………………. 9 1.1 Order Chiroptera……………………………………………………………… 9 1.2 Bat conservation ...……………………………………………………….…. 11 1.3 Bats in relation to mining activities ………………………………………... 16 1.4 Introduction to the study site: Drakelands Mine …………………………. 19 Chapter 2: Investigating short-term trends in bat activity at a new open-pit mining development …..….………………………………………………………… 25 2.1 Abstract …..………….…………………………………………………….… 25 2.2 Introduction ...……….……………………………………………………….. 25 2.21 Mitigation for bats at the study site …..………………….………….. 28 2.3 Methods ……………………………………………………………………… 29 2.31 Data collection ………………………………………………………… 29 2.32 Analysis ...……………………………………………………………… 31 2.4 Results ……………………………………………………………………..… 34 2.41 Effect of monitoring year on emergence counts …………………… 34 2.42 Effect of monitoring year on bat species richness ……………...… 35 2.43 Effect of monitoring year on total bat activity …………………….… 37 2.44 Effect of monitoring year on bat activity on a species/ genus level.39 2.45 Environmental conditions …………………………………………….. 45 2.5 Discussion …………………………………………………………………… 47 2.6 Conclusion ...………………………………………………………………… 54 Chapter 3: Investigating the impacts of open pit mining on bats in the wider landscape ….…………………………………………………………………. 56 3.1 Abstract …...……………………………………………………………….… 56 3.2 Introduction ………………………………………………………………….. 56 3.3 Methods ……………………………………………………………………… 58 4 3.31 Sampling location ..………………………………………………….... 58 3.32 Bat activity and species richness ..………………………….…….… 60 3.33 Analysis ..…………………………………………………………….… 65 3.4 Results ..……………………………………………………………………… 67 3.41 Effect of distance from the mine on bat species richness ..…….… 68 3.42 Effect of distance from the mine on total bat activity ..………….… 72 3.43 Effect of distance from mine on bat activity at a species/ genus level ....……………………………………………………………….… 76 3.44 Effect of blasting on bat activity ...………………………………....… 87 3.5 Discussion ...………………………………………………………………… 87 3.6 Conclusion ..…………………………………………………………………. 96 Chapter 4: Field trial of a novel bat detector ..………………………………....… 97 4.1 Abstract ..…………………………………………………………………..… 97 4.2 Introduction ...………………………………………………………………... 97 4.3 Methods ...………………………………………………………………….. 103 4.31 Field set-up ...………………………………………………………….103 4.32 Analysis ..…………………………………………………………...… 104 4.4 Results ..……………………………………………………………………. 105 4.5 Discussion ..………………………………………………………………... 108 4.6 Conclusion ..……………………………………………………………….. 110 Chapter 5: Summation ..…………………………………………………………... 112 Appendices ..……………………………………………………………………….. 117 Appendix A: Chapter 1 supplementary material ..………………………….…… 117 Appendix B: Chapter 2 supplementary material ..………………………….…… 120 Appendix C: Chapter 3 supplementary material ……………………….……….. 121 Bibliography ..………………………………………………………………….…... 124 5 List of tables: Table 2.1 Summary table for number of bat passes per species, and detection frequency ………..…………...……………………………………………34 Table 2.2 The full set of models for species richness ….………………………….36 Table 2.3 Summary of parameter estimates for the minimum adequate model for species richness …….………………………………………………...………… 36 Table 2.4 The full set of models for total bat activity ...………………………...… 37 Table 2.5 Summary of parameter estimates for the minimum adequate model for total bat activity ………………………………………........………………….… 37 Table 2.6 The full set of models for bat activity on a species/ genus level: a) P. pipistrellus b) P. pygmaeus c) Myotis species ……………………………... 40 Table 2.7 Summary of parameter estimates for the minimum adequate models for bat activity on a species/ genus level: a) P. pipistrellus b) P. pygmaeus c) Myotis species ……..…………………………………………. 41 Table 2.8 Summary of parameter estimates for the best fitting model for a) N. noctula b) R. ferrumequinum c) Plecotus species presence ...…………… 43 Table 2.9 The proportion of sampling sessions in which species were detected per year and the associated percentage change between monitoring years …………………………………………………………………..… 45 Table 3.1 Summary table for number of bat passes per species, and Detection frequency ….…………………………………………………………….. 68 Table 3.2 The full set of models for species richness for which ΔAICc ⩽ 2 and model-averaged parameter estimates ………………………………………. 70 Table 3.3 The full set of models for total activity for which ΔAICc ⩽ 2 and model-averaged parameter estimates .………...……………………………….… 74 Table 3.4 The full set of models for bat activity on a species level ……………. 79 Table 3.5 Model-averaged parameter estimates for bat activity on a species level ……………….……………………………………………………...… 85 6 Table 4.1 Summary of the features and parameters of the Anabat SD2 and BatBug Ranger ……………………………………………………………..… 102 Table 4.2 The detector settings used in this trial relating to the collection and storage of data ……………………………………………………………..… 103 Table 4.3 Output of GLMMs investigating whether detector model (Anabat/BatBug) had an effect on identified a) species richness b) total bat activity ……………………………………………………………………….…. 107 List of figures: Figure 1.1 Aerial view of the study site, Drakelands Mine ….…………………... 21 Figure 1.2 Results of the phase 1 habitat survey conducted by Michel Hughes Associates in 2009 ….…………………………………………………..… 22 Figure 2.1 Positioning and habitat classification of remote detector monitoring locations at the Drakelands site ………………….………….……...… 31 Figure 2.2 The number of bats observed emerging from the retained roost buildings during summer monitoring sessions from 2014-2016 ...……….. 35 Figure 2.3 Species richness over the three year monitoring period within habitat type, predicted by model 1a ……………………………………………….. 36 Figure 2.4 a) Total activity levels over the three year monitoring period, predicted by the minimum adequate model within habitat type b) Total activity levels over the three year monitoring period (raw data)………………… 38 Figure 2.5 The activity levels of a) P. pipistrellus b) P. pygmaeus over the three year monitoring period, predicted by the minimum adequate models within habitat type ...………………………………… 42 Figure 2.6 The probability of detection of a) N. noctula and b) Plecotus species over the