Figure 1A.
Photograph of a typical bat gantry (A590).
Figure 1B. Map of the study sites on the A590.
Figure 2.
Boxplots of the number of bats crossing per survey at each underpass.
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).
Table 1.
The crossing behaviour of all bats from all surveys for each study site (NB the number of bats crossing at safe heights at the gantries includes those ‘using’ the gantry).
Figure 3.
Boxplots of the number of bats crossing per survey at each bat gantry.
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.
Figure 4.
Kernel intensity estimation of the density of crossing bats across the A66 site.
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.
Figure 5.
Boxplot of flight height above verge height of identified crossing bats at all sites.
Median with upper and lower quartiles. Significant differences shown for Myotis and Pipistrellus species ** P<0.0005, *** P<0.0001. Excludes underpass sites. Verges are elevated on either side of the road and are above road height, therefore negative values indicate bats flying across the road below the height of the verge.