Starship Asterisk*

bystander wrote:
Why don't they just build them overpasses?

http://en.wikipedia.org/wiki/Wildlife_crossing wrote:

[b][color=#0000FF]Because of the building of an overpass, animal lovers worried about toads being killed by cars commuting from South Davis to North Davis, California, since the toads hopped from one side of a dirt lot (which the overpass replaced) to the reservoir at the other end. After much controversy, a decision was made to build a toad tunnel, which runs beneath the Pole Line Road overpass which crosses Interstate 80. The project cost $14,000. The tunnel is 21 inches wide and 18 inches high. The tunnel has created problems of its own. The toads originally refused to use the tunnel and so the tunnel was lit to encourage its use. The toads then died from the heat of the lamps inside the tunnel. Once through the tunnel, the toads also had to contend with birds who grew wise to the toad-producing hole in the ground. The exit to the toad tunnel has been decorated by the Postmaster to resemble a toad town.[/color][/b]

---

<<Wildlife crossings are structures that allow animals to cross human-made barriers safely. Wildlife crossings may include: underpass tunnels, viaducts, and overpasses (mainly for large or herd-type animals); amphibian tunnels; fish ladders; tunnels and culverts (for small mammals such as otters, hedgehogs, and badgers); green roofs (for butterflies and birds). Wildlife crossings are a practice in habitat conservation, allowing connections or reconnections between habitats, combating habitat fragmentation. They also assist in avoiding collisions between vehicles and animals.

The first wildlife crossings were constructed in France during the 1950s. European countries including the Netherlands, Switzerland, Germany, and France have been using various crossing structures to reduce the conflict between wildlife and roads for several decades and use a variety of overpasses and underpasses to protect and reestablish wildlife such as: amphibians, badgers, ungulates, invertebrates, and other small mammals.

The Humane Society of the United States reports that the more than 600 tunnels installed under major and minor roads in the Netherlands have helped to substantially increase population levels of the endangered European Badger. The longest "ecoduct" viaduct, near Crailo in the Netherlands, runs 800 m and spans a highway, railway and golf course.

Wildlife crossings are becoming increasingly common in Canada and the United States. Recognizable wildlife crossings are found in Banff National Park in Alberta, where vegetated overpasses provide safe passage over the Trans-Canada Highway for bears, moose, deer, wolves, elk, and many other species. The 24 wildlife crossings in Banff were constructed as part of a road improvement project in 1978. In the United States, thousands of wildlife crossings have been built in the past 30 years, including culverts, bridges, and overpasses. These have been used to protect Mountain Goats in Montana, Spotted Salamanders in Massachusetts, Bighorn Sheep in Colorado, Desert Tortoises in California, and endangered Florida Panthers in Florida.

The benefits derived from constructing wildlife crossings to extend wildlife migration corridors over and under major roads appear to outweigh the costs of construction and maintenance. One study estimates that adding wildlife crossings to a road project is only a 7-8% increase in the total cost of the project. Theoretically, the monetary costs associated with constructing and maintaining wildlife crossings in ecologically important areas are trumped by the benefits associated with protecting wildlife populations, reducing property damage to vehicles, and saving the lives of drivers and passengers by reducing the number of collisions caused by wildlife. A study completed for the Virginia Department of Transportation estimated that underpasses for wildlife become cost effective, in terms of property damage, when they prevent between 2.6 and 9.2 deer-vehicle collisions per year, depending on the cost of the underpass. Approximately 300 deer crossed through the underpasses in the year the study took place.>>

http://en.wikipedia.org/wiki/Bat_bridge wrote:

[b][color=#0000FF]Bat Bridge on the A38 Dobwalls Bypass, Cornwall, UK. (2009)[/color][/b]

---

<<A bat bridge is a structure of varying construction crossing a new or altered road to aid the navigation of bats following the destruction of a hedgerow, and to cause the bats to cross the roadway at a sufficient height to avoid traffic. Bats are thought to follow the lines of hedgerows and woods, and removing these may confuse the bats.

The theory is that these "bridges" will be seen by the bats' sonar as linear features sufficiently similar to the old hedgerows as to provide an adequate substitute. The Highways Agency is performing a study of those on the Dobwalls bypass to determine if this assumption is justified.>>