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Providing evidence to improve practice

Individual study: Florida Key deer Odocoileus virginianus clavium underpass use and movements along a highway corridor

Published source details

Braden A.W., Lopez R.R., Roberts C.W., Silvy N.J., Owen C.B. & Frank P.A. (2008) Florida Key deer Odocoileus virginianus clavium underpass use and movements along a highway corridor. Wildlife Biology, 14, 155-163


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Install barrier fencing and underpasses along roads Terrestrial Mammal Conservation

A before-and-after study in 1996–2004 in Florida, USA (Braden et al. 2008, same experimental set-up as Parker et al. 2008 and Parker et al. 2011) found that two underpasses, along with roadside barrier fencing, reduced Florida Key deer Odocoileus virginianus clavium collisions with vehicles by 94%. There were 2 collisions/year over two years after fence construction compared to 12–20 collisions/year over five years before construction (total 79 collisions). Underpass use increased over time, with 22 photographs of deer/month over the first six months and 59/month over the following six months. Average annual deer ranges and core areas did not change after underpass construction. Only 45% (5/11) of radio-collared deer were located on both sides of the highway after construction compared to 100% (9/9) before. In 2002, two box underpasses (14 × 8 × 3 m) were constructed with 2.6-km-long barrier fencing (2.4 m high) and four deer guards (modified cattle guards) installed between them, along a two-lane highway. Deer mortalities on roads were recorded from 1996, by direct sightings, law enforcement reports and observations of vultures. Underpass use was monitored using infrared-triggered cameras from February 2003–January 2004. Deer were radio-tracked between January 1998 and December 2000 (44 deer) and between February 2003 and January 2004 (32 deer) and were located 6–7 times/week.

(Summarised by Rebecca K. Smith)