Chris Damant/Toby Thorne NTPL/Bat Conservation Trust/Hugh Clark NTPL/Andrew Butler Mitigation for bats: the National Trust experience Jo Hodgkins, National Trust Jude Smith, WildWorks Ecology
Introduction NT buildings and bats The Bat Mitigation Project Key conclusions NTPL/NaturePL/Steve Packham Phil Richardson NTPL/NaturePL/Philippe Clement
NT Buildings & Bats Chris Damant Jude Smith Jude Smith NTPL
The Bat Mitigation Project - Background 10 NT case studies (Appleton, 2003) Effect of barn conversion (Briggs, 2004) Analysis of licences 2003-05 (Stone et al, 2011) NT Bat Mitigation Project 2012 critical appraisal - Mitigation for bats: the National Trust experience (Smith, 2012)
Locations of case studies
NTPL/Geraint Tellem NTPL/Robert Morris Jude Smith Jude Smith Toby Fisher
Results 62% maternity roosts 18% hibernation roosts 72% roosts brown long-eared bat 42% roosts common pipistrelle NTPL/Bat Conservation Trust/Hugh Clark NTPL/Bat Conservation Trust/Hugh Clark
Is mitigation successful? Defining & monitoring success For the 40 post 2002 case studies: % cases monitored post works 86% EPSL 47% MS % cases where method suitable for determining numbers of bats: 71% EPS 26% MS Jude Smith NT
Is mitigation successful? Results Success? Comparison of EPSL and stand-alone MS where monitoring has taken place % successful % unsuccessful % partial success EPSL (N=19) 79 (N=15) 10.5 (N=2) 10.5 (N=2) MS (N=8) 100 (N=8) 11 (N=1) 0
Is mitigation successful for all types of building works? Level 1 Retain full Continued Ecological Functionality Timing for low disturbance of bats or when bats absent Preserve / maintain most access to roosts No physical change to roost Same dimensions e.g. Re-roofing and/or patch repairs to roofs, firewalls with open doors, masonry repairs, insulation(?) Level 2 Major works involving: Reduced dimensions / volume of bat roosts Partial exclusions and replacement roosts (partial compensation) in same building Changed access points Significant impacts on wider environment e.g. flight lines & surrounding habitat. Includes some Continued Ecological Functionality as above Level 3 Major works involving: Full exclusions Roost destruction New roost provision Full compensation
Results - EPSL EPSL subset in relation to success of mitigation EPSL cases Success Partial success Failed No data % Success Level 1 5 5 0 0 0 100 Level 2 12 11 1 0 2 92 Level 3 2 0 0 2 0 0 Totals 19 16 1 2 2 84 Two sites for which there are no post work monitoring data at Level 2 are not included in the analysis
Case study Ickworth House Vaults Chris Vine 140 120 100 NTPL 80 60 Daubenton Natterer's Brown long-eared Total 40 20 0 04 to 05 05 to 06 06 to 07 07 to 08 08 to 09 09 to 10 10 to 11 11 to 12 Numbers of hibernating bats by species. Data courtesy of Chris Vine
Case study Dinefwr Farm Buildings Carl Morgan
Results MS only MS subset in relation to success of mitigation MS cases Success Partial success Failed Level 1 5 5 0 0 100 Level 2 3 2 0 1 66 Level 3 1 1 0 0 100 Totals 9 8 0 1 88 % Success Eight sites for which there are no post work monitoring data at Level 1 and two sites at Level 2 are not included (N=9) in the analysis. Sample size is very small!
Case study High Wray Base Camp Toby Fisher Toby Fisher 250 200 150 Soprano pipistrelle 100 50 Toby Fisher 0 2006 2007 2008 Peak emergences of Soprano pipistrelle at High Wray Basecamp: data courtesy of Toby Fisher
Summary 84% re-occupation rate post works for NT EPS cases compared with 2003-05 study (Stone et al 2011) (bats were recorded at 53% of sites post-development; 68% of roosts destroyed) Simple vs complex projects / mitigation Our study showed inconsistencies in the type & quality of post work monitoring data collected, making an in-depth analysis of the success or otherwise of mitigation difficult Therefore success had to be based on simple presence of roosting bats post works
Recommendations Clear objectives & definitions of success Consistent, fit for purpose monitoring strategies needed Provisional monitoring guidelines more research needed?
Lessons for NT Ensure post-project monitoring incorporated across the board Continue to mentor staff as to the importance and purpose of post-project monitoring Work with staff, volunteers and the profession to develop post project monitoring that is fit for purpose and as a charity, cost effective.
Thank you for listening John Altringham
Acknowledgements Thank you to all the National Trust staff, ecological consultants and Natural England, who kindly provided information for this presentation and associated report.