Brown long‐eared bat roost monitoring scheme for Republic of Ireland: synthesis report 2007‐2010 Irish Wildlife Manuals No. 56 Brown long‐eared bat roost monitoring scheme for the Republic of Ireland: synthesis report 2007‐2010 Tina Aughney1, Steve Langton2 and Niamh Roche1 1. www.batconservationireland.org 2. [email protected] Citation: Aughney, T., Langton, S. & Roche, N. (2011) Brown long‐eared bat roost monitoring scheme for the Republic of Ireland: synthesis report 2007‐2010. Irish Wildlife Manuals, No. 56. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland. Keywords: bats, monitoring, roosts, Plecotus auritus, volunteers, woodland, NPWS, Ireland Cover photos: Brown long‐eared bat by Frank Greenaway © NPWS The NPWS Project Officer for this report was: Dr Ferdia Marnell; [email protected] Irish Wildlife Manuals Series Editors: F. Marnell & N. Kingston © National Parks and Wildlife Service 2011 ISSN 1393 – 6670 Brown long‐eared bat monitoring 2007‐2010 __________________________________ Contents Executive Summary ........................................................................................................................................ 3 Acknowledgements ........................................................................................................................................ 4 Introduction ..................................................................................................................................................... 5 Why Monitor Brown Long‐eared Bats? ................................................................................................... 5 Red & Amber Alerts ................................................................................................................................... 6 Factors Influencing the Design of the Brown Long‐eared Roost Monitoring Scheme ...................... 7 Potential Problems with Monitoring from Colony Counts ................................................................. 10 Volunteers .................................................................................................................................................. 11 Weather Conditions from 2007 to 2010 .................................................................................................. 11 Aims of the Brown Long‐eared Roost Monitoring Scheme ................................................................ 12 The Aims of this Synthesis Report .......................................................................................................... 13 Methods .......................................................................................................................................................... 14 Preliminary Roost Assessment ................................................................................................................ 14 Annual Roost Counts ............................................................................................................................... 15 AnaBat Frequency Division Bat Detectors ............................................................................................ 16 Power Analysis .......................................................................................................................................... 17 Trend Analysis .......................................................................................................................................... 18 GIS Analysis .............................................................................................................................................. 18 Brown Long‐eared Bat Habitats and Roosting Requirements ............................................................ 18 Results ............................................................................................................................................................ 20 Volunteer Participation ............................................................................................................................ 20 Volunteer Training and Survey Time ................................................................................................ 21 Volunteer Contribution: A Financial Perspective ............................................................................. 21 Buildings Surveyed ................................................................................................................................... 22 Roosts Monitored .................................................................................................................................. 22 Roost Categories .................................................................................................................................... 25 Additional Roosts Surveyed ................................................................................................................ 26 Roost Colony Size ................................................................................................................................. 29 Ease of Monitoring & New Roosts ..................................................................................................... 30 Survey Period ............................................................................................................................................ 31 AnaBat Frequency Division Bat Detector Recordings ......................................................................... 32 Power Analysis .......................................................................................................................................... 33 Trend Analysis .......................................................................................................................................... 36 1 Brown long‐eared bat monitoring 2007‐2010 __________________________________ GIS Analysis .............................................................................................................................................. 37 Percentage of Woodland & Forestry Habitat .................................................................................... 37 Proximity to Woodland & Forestry Habitat: Commuting Routes ................................................. 38 Brown Long‐eared Bat Habitat and Roosting Requirements ......................................................... 39 Discussion ...................................................................................................................................................... 44 Survey Effort .............................................................................................................................................. 44 Volunteer Teams ................................................................................................................................... 44 Roost Owner Participation .................................................................................................................. 45 Cost Efficiency ....................................................................................................................................... 45 Survey Methodology ................................................................................................................................ 45 Geographic Coverage ............................................................................................................................... 46 Potential Roosts for Investigation ....................................................................................................... 47 Buildings Surveyed .................................................................................................................................. 48 Roost Loss from Dataset .......................................................................................................................... 48 Monitoring Dataset and Trend Analysis ............................................................................................... 49 Power Analysis ......................................................................................................................................... 49 Effects of Reducing the Survey Protocol ............................................................................................ 50 Automated Roost Counts using AnaBat ................................................................................................ 50 GIS Analysis .............................................................................................................................................. 51 Percentage of Woodland & Forestry Habitat .................................................................................... 51 Proximity to Woodland & Forestry Habitat: Commuting Routes ................................................. 51 Brown Long‐eared Bat Habitat and Roosting Requirements ......................................................... 52 Recommendations ........................................................................................................................................ 53 Bibliography & Relevant Literature ........................................................................................................... 54 Appendix 1 .................................................................................................................................................... 56 Appendix 2 ...................................................................................................................................................