Road crossing structures for amphibians and reptiles: informing design through behavioral analysis

Published source details Woltz H.W., Gibbs J.P. & Ducey P.K. (2008) Road crossing structures for amphibians and reptiles: informing design through behavioral analysis. Biological Conservation, 141, 2745-2750.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Install barriers along roads/railways Action Link
	Install barrier fencing along roads Action Link
	Install tunnels/culverts/underpasses under roads/railways Action Link
	Install culverts or tunnels as road crossings Action Link

Install barriers along roads/railways

A replicated study in 2005–2006 in a Wildlife Management Area, in New York, USA (Woltz et al. 2008) found that plastic fences of at least 0.6 m high excluded all painted Chrysemys picta and snapping turtles Chelydra serpentina. Fences 0.6 m and 0.9 m high were more effective at excluding turtles (100% excluded) than 0.3 m high fences (84–100%). Opaque, corrugated plastic fences were used to construct three nested, circular enclosures of heights 0.3, 0.6 and 0.9 m high. Local painted (74 individuals) and snapping turtles (62 individuals) were placed in the centre of each arena and left for 15 minutes to attempt to scale the fences.

(Summarised by: Maggie Watson, Katie Sainsbury)
Install barrier fencing along roads

A replicated study in 2005–2006 of different height barrier fencing in a Wildlife Management Area, New York, USA (Woltz, Gibbs & Ducey 2008) found that fences of at least 0.6 m excluded most green frogs Rana clamitans and leopard frogs Rana pipiens. Fences 0.6 m high were more effective at excluding frogs (97–100%) than 0.3 m fences (77–80%). Only one leopard frog climbed over the 0.9 m high fence. Opaque, corrugated plastic fences were used to construct three nested, circular enclosures of heights 0.3, 0.6 and 0.9 m. Local green frogs (n = 135) and leopard frogs (n = 187) were placed in the centre of each arena and left for 15 min to attempt to scale the fences.
Install tunnels/culverts/underpasses under roads/railways

A replicated study in 2005–2006 of tunnels in a Wildlife Management Area in New York, USA (Woltz et al. 2008) found that painted Chrysemis picta and snapping turtles Chelydra serpentina showed some preferences for particular tunnel widths and lengths, but not for different substrates or light levels. Both turtle selected mid-sized diameter tunnels (0.5 m: selected by 39–44% of individuals, 0.6 m: 31–39%) more often than narrower (0.3 m diameter: 6–17%), or wider tunnels (0.8 m: 6–19%). Painted turtles avoided the longest tunnels (3 m long: selected by 10–30% of individuals, 6.1 m: 45%, 9.1 m: 15%), whereas snapping turtles did not show any significant preference for tunnel length (3 m: 20–37%, 6.1 m: 27%, 9.1 m: 17%). Neither turtle showed preferences for substrate type (concrete: 19–37%, gravel: 24–29%, soil: 20–26%, PVC: 20–26%) or light permeability (0% permeability: 26–31%, 0.6%: 14–23%, 1.3%: 15–24%, 5%: 31–36%). Snapping turtles were more likely to not choose any of the tunnels (56%) than painted turtles (16%). Choice arenas had four different PVC culverts radiating out, which painted (74 individuals) and snapping turtles (62) could select to exit through. Separate arenas were constructed to test tunnel diameter (0.3, 0.5, 0.6 or 0.8 m), length (3, 6.1 or 9.1 m), substrate (concrete, soil, gravel or bare PVC) and light (overhead punctures of 0, 0.6, 1.3 or 4% of surface). Turtles were tested individually, once/arena. Trials lasted 15 minutes, after 5 minutes acclimatization, in June–August 2005–2006.

(Summarised by: Maggie Watson, Katie Sainsbury)
Install culverts or tunnels as road crossings

A replicated study in 2005–2006 of tunnels in a Wildlife Management Area in New York, USA (Woltz, Gibbs & Ducey 2008) found that green frogs Rana clamitans and leopard frogs Rana pipiens showed some preference for particular tunnel types. Green frogs showed a significant preference for soil (40%) and gravel (38%) linings, compared to concrete (13%) and PVC (9%). Leopard frogs showed no preference (19%, 32%, 29%, 19% respectively). Leopard frogs tended to prefer larger diameters (0.8 m: 35%; 0.6 m: 12%; 0.5 m: 28%; 0.3 m: 25%) and avoid the longest tunnels (9 m: 15%; 6 m: 40%; 3 m: 22–24%). Green frogs showed no preference for diameter (0.8 m: 33%; 0.6 m: 24%; 0.5 m: 27%; 0.3 m: 16%) or length (9 m: 32%; 6 m: 23%; 3 m: 19–26%). Tunnels with the greatest light permeability were preferred (4% light permeability: 39–41%; 1.3% light: 14–17%; 0.6% light: 24–26%; no light: 17–24%). Choice arenas had four different PVC culverts radiating out, which local green frogs (n = 135) and leopard frogs (187) could select to exit through. Frogs were tested in groups of 1–17 individuals, once per arena. Trials lasted 15 minutes, after 5 minutes acclimatization, in June–August 2005–2006. Pitfall traps captured animals at the end of each tunnel.