1 Tahrcountry Musings: Effectiveness of Wildlife fencing in combination with crossing structures – An interesting study

Friday, March 18, 2016

Effectiveness of Wildlife fencing in combination with crossing structures – An interesting study

Effectiveness of short sections of wildlife fencing and crossing structures along highways in reducing wildlife–vehicle collisions and providing safe crossing opportunities for large mammals
Marcel P. Huijser,Elizabeth R. Fairbank, Whisper Camel-Means, Jonathan Graham, Vicki Watson,Pat Basting and Dale Becker
Biological Conservation.Volume 197, May 2016, Pages 61–68

Here is a good paper for those interested in wildlife fencing.  Wildlife fencing in combination with crossing structures is the most effective strategy to reduce large mammal–vehicle collisions while also maintaining wildlife connectivity across roads. The down side is that it affects the beauty of the environment and it is costly. To overcome this, length of fencing is often reduced arbitrarily.

Here the researchers investigated 1) whether short fenced road sections were similarly effective in reducing large mammal–vehicle collisions as long fenced road sections (literature review), and 2) whether fence length influenced large mammal use of underpasses (two field studies).

The researchers found that   1) short fences (≤ 5 km road length) had lower (52.7%) and more variable (0–94%) effectiveness in reducing collisions than long fences (> 5 km) (typically > 80% reduction); 2) wildlife use of underpasses was highly variable, regardless of fence length (first field study); 3) most highway crossings occurred through isolated underpasses (82%) rather than at grade at fence ends (18%) (Second field study); and 4) the proportional use of isolated underpasses (compared to crossings at fence ends) did not increase with longer fence lengths (up to 256 m from underpasses) (second field study). 

The authors signs off with the remark “Data suggest fence lengths of at least 5 km. While longer fence lengths do not necessarily guarantee higher wildlife use of underpasses as use varies greatly between locations, wildlife fencing can still improve wildlife use of an individual underpass.”

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