Performance of arch-style road crossing structures from relative movement rates of large mammals

Published source details Andis A.Z., Huijser M.P. & Broberg L. (2017) Performance of arch-style road crossing structures from relative movement rates of large mammals. Frontiers in Ecology and Evolution, 5, 122.
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This study is summarised as evidence for the following.

	Action	Category
	Install tunnels/culverts/underpass under roads Action Link

Install tunnels/culverts/underpass under roads

A study in 2015 along a highway in Montana, USA (Andis et al. 2017) found that underpasses were used by white-tailed deer Odocoileus virginianus and mule deer Odocoileus hemionus more than expected compared to their movements through adjacent habitats, but no difference was found for black bear Ursus americanus or coyote Canis latrans. Overall, white-tailed deer (recorded at all 15 underpasses) and mule deer (at five of 15 underpasses) had an average of 88% and 472% more movements/day respectively through underpasses than adjacent habitats. Black bear (recorded at seven of 15 underpasses) and coyote (at 13 of 15 underpasses) had an average of 112% and 75% more movements/day respectively through underpasses than adjacent habitats, but the difference was not significant. Fifteen elliptical underpasses were installed in 2006–2011 along a 91 km stretch of highway. Underpasses (7–8 m wide, 4–6 m high, 15–40 m long) were constructed from corrugated metal with a soil substrate and retaining walls extending 10 m from the roadside. Twelve of the 15 underpasses had 2.4-m high wildlife exclusion fencing. Infrared cameras recorded large mammal movements through each underpass (one camera/entrance) and at random locations within an adjacent 300 m² plot on each side (five cameras/plot) for 12–20 days in April–November 2015.

(Summarised by: Anna Berthinussen)