Effectiveness of a highway overpass to promote landscape connectivity and movement of moose and roe deer in Sweden

Published source details Olsson M.P.O., Widén P. & Larkin J.L. (2008) Effectiveness of a highway overpass to promote landscape connectivity and movement of moose and roe deer in Sweden. Landscape and Urban Planning, 85, 133-139.
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This study is summarised as evidence for the following.

	Action	Category
	Install overpasses over roads/railways Action Link
	Install barrier fencing and underpasses along roads Action Link

Install overpasses over roads/railways

A before-and-after study in 2000–2005 in forest and farmland in southwestern Sweden (Olsson et al. 2008, same experimental study site as Olsson & Widen 2008) found that a wildlife overpass was used by moose Alces alces and roe deer Capreolus capreolus and, along with barrier fencing, it reduced road-kills. Deaths were reduced 70% from the 12-year pre-construction averages of 2.7 moose killed/year and 5.3 roe deer killed/year. From March 2002–June 2005, the overpass was crossed 437 times by roe deer and 95 times by moose (mainly at night). Roe deer, but not moose crossings, increased over the six-year study. Five to seven individual moose/year used the overpass. Overpass use declined with increased traffic flow. In 2000–2004, a 12-km section of the European Highway 6 was converted from two to four lanes and 2.2-m-high exclusion fencing was installed. Two overpasses and one underpass were constructed. One hourglass-shaped overpass (29–17 m wide, 80 m long, 2 m high, with grey glass-shields to reduce incursion of highway noise and light) was monitored. Tracks were counted in sand beds twice/week and two infrared remote cameras were set overnight. Twenty-four moose were tracked using GPS collars for 22 months.

(Summarised by: Rebecca K. Smith)
Install barrier fencing and underpasses along roads

A before-and-after study in 2000–2005 in forest and farmland in southwestern Sweden (Olsson et al. 2008; same experimental set-up as Olsson & Widen 2008) found that barrier fencing and three road crossings reduced moose Alces alces and roe deer Capreolus capreolus road-kills. Deaths were reduced 70% from averages of 2.7 moose killed/year and 5.3 roe deer killed/year over the 12 years pre-construction. In 2000–2004, a 12-km section of the European Highway 6 was converted from two to four lanes and 2.2-m-high exclusion fencing was installed along its length. Two overpasses and one underpass were also constructed. Moose and deer casualty rates were collated from casualties reported to police pre-construction (1990–2001) and post-construction (up to 2005).

(Summarised by: Rebecca K. Smith)