These new survey methods should improve the efficiency of planning processes, thereby benefitting both developers and wildlife.
The researchers’ new report highlights the need for a more rigorous, evidence-based approach to protecting wildlife during development.
Professor Altringham and his colleagues argue that previous work has not been based on good ecological understanding, while a lack of effective monitoring has hidden failure.
Describing bats as ‘the canary in the mine’ – key indicators of biodiversity – the researchers believe more attention should be given to the potential effects of transport infrastructure on biodiversity.
They found that bat activity was much lower close to major roads than in the surrounding countryside. The number of species of bat was also reduced.
Based on a relatively small but representative sample, they also found that existing mitigation structures such as underpasses were frequently not working sufficiently well and wire gantries (bat bridges) were not working at all.
“The study reports some successes on which to build better conservation practice and provides a clear steer on how to make the design and monitoring of future mitigation more effective,” said Professor Altringham, who is Professor of Animal Ecology and Conservation in the School of Biology at Leeds.
He added that better, tried and tested mitigation measures, such as suitable “green” overpasses and underpasses, should prove more cost-effective than existing solutions and – crucially – speed up planning approval processes for major infrastructure projects, not slow them down.
o A landscape scale method using transects to assess the effects of linear infrastructure on bats at a population level
o A local scale observational method to assess the effectiveness of mitigation measures, such as crossing structures over or under linear infrastructure.
“The effects of transport systems on bats are clearly significant and, given the density of our transport network, very pervasive,” said Dr Anna Berthinussen, the project’s lead researcher.
“Roads and railways fragment the countryside, separating bats from important feeding and roosting sites. They confine bats to smaller and smaller patches of land that can sustain fewer individuals. Those bats that attempt to cross run the risk of being killed by traffic, since most fly close to the ground.”
“But this is not just about bats – they are the canaries in the mine alerting us to greater dangers,” said Professor Altringham. “There is substantial evidence, from many studies conducted around the world, of significant effects of roads on other mammals, birds, amphibians and reptiles, and even bees and butterflies.
“But the effects of roads on biodiversity have received relatively little attention compared to the many other things that we humans do to the environment.”
He added that the damaging effects of roads had not gone completely unnoticed; some effort had gone into trying to make roads safer and easier for bats to cross.
Various designs of underpass and overpass have been built in an attempt to conduct bats safely under or over roads. Wire bridges, sometimes known as bat gantries, are designed to act as “echolocation guides” for bats: structures they will navigate along, safely above the traffic.
“Unfortunately, poor design or poor connectivity to the bats’ own ‘flyways’ along streams, hedges and woodlands has meant that few attempts have been successful,” said Professor Altringham.
“‘Poor monitoring, or a complete absence of monitoring, has meant that this failure has gone undetected, and we have continued to build structures that don’t work.”
“We should certainly stop building wire gantries. All those tested, in this and in our previous study (http://goo.gl/9J4evd), were totally ineffective. But well-designed underpasses that are effectively connected to existing wildlife corridors can clearly do a good job. The failures of the past have been in making underpasses too small, putting them in the wrong place or leaving them isolated from green corridors.
“Green bridges – wide bridges planted with grass, shrubs and trees – have considerable potential for bats and other wildlife and the one we tested was very effective.”
Dr Berthinussen added “It is important that we test new designs and if necessary improve them before building more. We must learn from past mistakes if mitigation is to be both effective and cost-effective.”
Ralf Richter, David Brockwell, Eric Hewitt, Jessica Kwok, Emanuele Paci and MAPS/FMH, BBSRC (Jun 2017), £600,000
Eric Blair, Adrian Whitehouse, Nicola Stonehouse, Alison Baker, Richard Bayliss, Joan Boyes, Ryan Seipke, Sally Boxall and MAPS/FMH, BBSRC (Jun 2017), £376,000
Stefan Kepinski, Yoselin Benitez-Alfonso, Tom Bennett, Michelle Peckham, BBSRC (Jun 2017), £331,000
Roman Tuma, Lars Jeuken, Paul Millner, Sheena Radford, Peter Stockley and MAPS/FMH, BBSRC (Jun 2017), £222,000
Vas Ponnambalam, Darren Tomlinson, Stephen Wheatcroft, BHF (May 2017), £107,878
Graham Askew in collaboration with Bangor University, BBSRC (Mar 2017), £477,383
Stephen Muench, BBSRC (Mar 2017), £132,945
Nic Stonehouse, MRC (Mar 2017), £906,341
Bill Kunin, Steve Sait, BBSRC (Mar 2017), £602,831
Adrian Goldman, EU (Mar 2017), £546,576
Sheena Radford, Wellcome Trust (Mar 2017), £1,836,482
Beatrice Filippi, Royal Society (Mar 2017), £15,000
Jamie Johnston, Royal Society (Mar 2017), £15,000
Tom Bennett, Royal Society (Mar 2017), £15,000
Ryan Seipke, BBSRC (Feb 2017), £52,116
Mary O'Connell, BBSRC (Feb 2017), £46,986
Hannah Dugdale, NERC (Feb 2017), £504,138
Anastasia Zhuravleva, EPSRC (Jan 2017), £100,792
Richard Bayliss, Cancer Research UK (Jan 2017), £1,600,000
John Barr, EU (Jan 2017), £339,000
Mark Harris, Royal Society (Jan 2017), £250,000
Alison Dunn, NERC (Jan 2017), £105,000
Alex Breeze, Pancreatic Cancer Research Fund (Jan 2017), £180,000
Alison Dunn, NERC (Dec 2016), £18,000
Lisa Collins, BBSRC (Dec 2016), £1,681,835
Brendan Davies, Leverhulme Trust (Dec 2016), £247,555
Alan Benson, Mark Drinkhill, Ed White, British Heart Foundaion (Dec 2016), £217,223
Adrian Goldman, Royal Society (Dec 2016), £82,999
Lisa Roberts, Alex Breeze, Brendan Davies, Timothy Devinney, Oliver Harlen, Joseph Holden, Anthea Hucklesby, Pamela Jones, Philip Mellor, RCUK (Nov 2016), £484,172
Lisa Roberts, Alex Breeze, Brendan Davies, Timothy Devinney, Oliver Harlen, Joseph Holden, Anthea Hucklesby, Pamela Jones, Philip Mellor, Wellcome Trust (Nov 2016), £119,343
Katie Field, Rank Prize Funds (Nov 2016), £20,000
Jessica Kwok, Royal Society (Nov 2016), £14,948
John Ladbury, Cancer Research UK (Oct 2016), £4,250
Miriam Wittmann, Martin Stacey, Edward Vital, Lupus UK
(Oct 2016), £34,010
Valerie Speirs, NC3Rs
(Oct 2016), £90,000
Nicola Stonehouse, Morgan Herod, David Rowlands, BBSRC
(Sep 2016), £436,424
Joseph Cockburn, Wellcome Trust
(Sep 2016), £100,000
John Barr, Public Health England
(Sep 2016), £94,471
Helen Miller, DSM Nutritional Products A/S
(Sep 2016), £54,680
Steven Clapcote, Vitaflo International Ltd
(Sep 2016), £39,285
Juan Fontana Jordan De Urries
, Royal Society
(Sep 2016), £21,793
Jing Li, Sarah Calaghan, Mark Drinkhill, British Heart Foundation
(Sep 2016), £117,585
Sheena Radford, Alison Ashcroft, BBSRC (Sep 2016), £457,216
Patricija Van Oosten-Hawle, An-Jung Chen, David Westhead, NC3Rs
(Sep 2016), £354,456
Glyn Hemsworth, BBSRC (Sep 2016), £1,024,034