Investigations into the protection of migrant amphibians from the threats from road traffic in the Federal Republic of Germany - a summary

Published source details Dexel R. (1989) Investigations into the protection of migrant amphibians from the threats from road traffic in the Federal Republic of Germany - a summary. Amphibians and Roads: Proceedings of the Toad Tunnel Conference, Rendsburg, Federal Republic of Germany, 43-49.
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This study is summarised as evidence for the following.

	Action	Category
	Install culverts or tunnels as road crossings Action Link

Install culverts or tunnels as road crossings

A replicated study in 1987 of tunnels with guide fencing at 13 locations in West Germany (Dexel 1989) found that tunnel use by amphibians varied with site. Some tunnels were not used by amphibians while others were used by the majority of migrating amphibians. Large two-way tunnels (diameter: 1 m; length: 15 m) were used by a larger proportion of common toads Bufo bufo in the area than those with smaller diameters. However, even those with a diameter of 0.3 m were used by some toads. One-way tunnels with vertical entry chutes resulted in high mortality of amphibians. There were no deaths with angled chutes. Three types of tunnels were investigated: two-way systems or one-way systems with angled or vertical entry chutes. One-way tunnels were laid in pairs to allow migration in both directions. At one site, nine two-way systems of various dimensions were investigated. Guide fences were also used at sites.