2. Bat Conservation

Expert assessors John Altringham, University of Leeds, UK James Aegerter, Animal and Plant Health Agency, UK Kate Barlow, Bat Conservation Trust, UK Anna Berthinussen, University of Leeds, UK Fabio Bontadina, SWILD — Urban Ecology & Wildlife Research, Switzerland David Bullock, National Trust, UK Paul Cryan, Fort Collins Science Center, US Geological Survey Brock Fenton, University of Western Ontario, Canada Anita Glover, University of Leeds, UK Joanne Hodgkins, National Trust, UK David Jacob..

Do Bat Gantries and Underpasses Help Bats Cross Roads Safely?

Major roads can reduce bat abundance and diversity over considerable distances. To mitigate against these effects and comply with environmental law, many European countries install bridges, gantries or underpasses to make roads permeable and safer to cross. However, through lack of appropriate monitoring, there is little evidence to support their effectiveness. Three underpasses and four bat gantries were investigated in northern England. Echolocation call recordings and observations were used to determine the number of bats using underpasses in preference to crossing the road above, and the height at which bats crossed. At gantries, proximity to the gantry and height of crossing bats were measured. Data were compared to those from adjacent, severed commuting routes that had no crossing structure. At one underpass 96% of bats flew through it in preference to crossing the road. This underpass was located on a pre-construction commuting route that allowed bats to pass without changing flight height or direction. At two underpasses attempts to divert bats from their original commuting routes were unsuccessful and bats crossed the road at the height of passing vehicles. Underpasses have the potential to allow bats to cross roads safely if built on pre-construction commuting routes. Bat gantries were ineffective and used by a very small proportion of bats, even up to nine years after construction. Most bats near gantries crossed roads along severed, pre-construction commuting routes at heights that put them in the path of vehicles. Crossing height was strongly correlated with verge height, suggesting that elevated verges may have some value in mitigation, but increased flight height may be at the cost of reduced permeability. Green bridges should be explored as an alternative form of mitigation. Robust monitoring is essential to assess objectively the case for mitigation and to ensure effective mitigation

Tapping into non-English-language science for the conservation of global biodiversity.

The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non-English-language science to scientific communities and the application of science is rarely quantified. Here, we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate in 6 out of the 12 languages where there were a sufficient number of relevant studies. Incorporating non-English-language studies can expand the geographical coverage (i.e., the number of 2° × 2° grid cells with relevant studies) of English-language evidence by 12% to 25%, especially in biodiverse regions, and taxonomic coverage (i.e., the number of species covered by the relevant studies) by 5% to 32%, although they do tend to be based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenges. Please see the Supporting information files for Alternative Language Abstracts

What Works in Conservation 2018

This book provides an assessment of the effectiveness of 1277 conservation interventions based on summarized scientific evidence. The 2018 edition contains new chapters covering practical global conservation of primates, peatlands, shrublands and heathlands, management of captive animals as well as an extended chapter on control of freshwater invasive species. Other chapters cover global conservation of amphibians, bats, birds and forests, conservation of European farmland biodiversity and some aspects of enhancing natural pest control, enhancing soil fertility and control of freshwater invasive species. It contains key results from the summarized evidence for each conservation intervention and an assessment of the effectiveness of each by international expert panels. The accompanying website www.conservationevidence.com describes each of the studies individually, and provides full references

The effect of roads on bats in the UK: a model for evidence based conservation

Despite their protected status, little research has been done into the effects of roads on bats or the effectiveness of current mitigation practice. We conducted broadband acoustic surveys on 20 walked transects perpendicular to two major roads in the UK, the M6 in Cumbria, and the M5 in Somerset. Bat activity and habitat variables were recorded at different distances from the road, and the relationship between these variables were investigated using generalised estimated equations (GEE), and ordinal logistic regression. Total bat activity and the activity of Pipistrellus pipistrellus (the most abundant species) were positively correlated with distance from both roads, although the magnitude of the effect was greater by the M6. Distance from the road was positively correlated with the number of bat species by the M6 only. Higher quality habitat surrounding the M5 may have reduced the negative road impacts. The use of direct sampling to collect acoustic data revealed a greater road effect than time expansion methods, which is likely due to increased accuracy through continuous sampling and a larger dataset. Three underpasses and four wire bat gantries were investigated in northern England using echolocation call recordings and observations. The bat gantries were ineffective and used by a very small proportion of bats. Only one underpass located on a pre-construction commuting route could be considered to be effective, and attempts to divert bats were unsuccessful. Further research should focus on crossing structures built on original bat commuting routes, such as underpasses and green bridges. We suggest an integrated approach to mitigation, combining crossing structures and habitat improvements. New crossing structures need to be developed and tested, given the poor success of current structures. Robust pre- and post-construction monitoring using a standardised methodology is essential to assess the effectiveness of mitigation schemes and build an evidence-base for successful conservation

Boxplots of the number of bats crossing per survey at each bat gantry.

<p>Boxplots (median with upper and lower quartiles) of the number of bats crossing per survey (n = 10) at the four bat gantries, together with data on total number crossing, the numbers crossing at safe and unsafe heights, numbers ‘using’ the gantry according to both estimates (within 2 and 5 m), and the numbers crossing at nearby, unmitigated, severed commuting route nearby.</p

Boxplots of the number of bats crossing per survey at each underpass.

<p>Boxplots (median with upper and lower quartiles) for the number of bats crossing per survey (n = 10) at each underpass (numbers crossing using underpass, over the road above and at safe and unsafe heights over the road), and at the unmitigated commuting route on the A590 which was diverted to underpass A (numbers crossing over the road and at safe and unsafe heights).</p

Kernel intensity estimation of the density of crossing bats across the A66 site.

<p>Gaussian kernel and bandwidth of 1 m used (n = 1078). The section of severed woodland at the A66 site is shown. The gantry is located at distance 0 m (height marked by square), and the pre-construction commuting route at 10–15 m. ‘Unsafe’ crossing heights are located below the dashed line. The dotted line marked verge shows the decrease in verge height above the road from left to right.</p