Humans don't exactly have a stellar record when it comes to environmental stewardship, but that doesn't mean we aren't trying. Numerous projects around the world are working to rebuild lost habitats, protect vital wildlife highways, and regenerate lost populations. Here are a few man-made structures built on behalf of our four-footed brethren.
Cattle Creeps: The Doggy Door of Modern Agriculture
Moving a heard of cattle from one pasture to the next can be a harrowing task, especially if it involves driving that herd across a roadway or train tracks. To prevent cow-car collisions ranchers will install cattle creeps, essentially underpasses that allow the animals to avoid dangerous, immovable obstacles like roads, canals, and railway embankments. Similarly, sheep creeps act as semi-permiable barriers designed to be just big enough for a sheep to pass through but too small to allow cows or horses to do the same.
Image: Rick Sykes
Man-made structures such as highways and railways pose very real threats to wildlife. These transportation arteries built for the convenience of man arbitrarily divide wild habitats, potentially separating existing animal populations from food and water sources, forcing them to cross the road and endure the dangers entering traffic entails.
Wildlife crossings reduce that risk by providing animals with an alternative means of avoiding the road—either traversing over or under the obstacle—reconnecting fragmented habitats and reducing road kill.
Banff National Park - Alberta, Canada
Alberta's Banff National Park is home to a wide array of wildlife, from badgers and wolverines to bears and elk. However, the TransCanada Highway also happens to cut straight through this national park, fragmenting the habitat and presenting four lanes of potential death for animals wishing to get to the other side.
To accommodate both vehicular and ungulate foot traffic, the TransCanada Highway incorporates a wooded overpass for animals to safely travel across. Safety netting and barricades effectively funnel first timers across the raised pathway, though the local wildlife have quickly adapted to using it, and the crossing has become a vital corridor for animal traffic within the region. [Friends of Banff]
Natuurbrug Zanderij Crailo - Goois Natuurreservaat, The Netherlands
The Dutch don't mess around when it comes to protecting wildlife from the dangers of human traffic, having already built more than 600 wildlife crossings throughout the country. This is the longest such structure: Natuurbrug Zanderij Crailo, an 800 meter long, 50 meter wide overpass that whisks wildlife past a railway line, business park, river, roadway, and sports complex. Completed in 2006, the bridge is routinely used by multiple species of deer, wild boar, and the endangered European Badger.
Crab Bridge - Christmas Island, Australia
Every year around mid-October, more than 50 million red crabs march from their summer homes in the rain forests of Australia's Christmas Island out the the ocean where they breed. These crustaceans form a massive, skittery red tide that pays no heed to things like busy roadways and, as such, as many as 50,000 individuals die each migration under the wheels of passing motorists.
To combat these senseless killings, the government has worked since 1995 to install a series of enclosed bridges and more than 40 tunnels over and through which the crabs can pass. According to the Australian Parks Service, more than 7.5 miles of aluminum siding has been installed along busy roadways to help funnel the crabs to the proper crossing locations. This not only saves thousands of crabs each year, the structures have allowed a new tourist industry to emerge, bringing a significant influx of business to the area each spring.
I-75 Alligator Alley - Collier and Lee counties, Florida
Generous estimates put the remaining population of Florida panthers at around 100 individuals, making this mountain lion subspecies one of the most critically endangered large mammals in North America. The big cats' biggest threat isn't poaching or habitat loss, its vehicular accidents. 11 panthers died in 2006 after being struck by cars, another 14 died the following year.
In response, the Florida Fish and Wildlife Conservation Commission (FWC) took aggressive measures to protect the official state animal from dangerous freeway crossings, installing 24 highway underpasses, building 12 wildlife bridges, and installing continuous fencing along a 40-mile stretch of Interstate 75. And it's worked, in areas that have both fencing and nearby crossings—not a single panther has died since 2007. What's more, the underpasses are now routinely used by bobcats, deer, and raccoons—all of which have seen drastic declines in roadkill since the crossings' installations.
Vole Ladder - Grand Union Canal, England
Water Voles are among the UK's most endangered mammals, their numbers plunging by 90 percent since the 1970s, victims of habitat fragmentation that has left numerous groups isolated from the rest of the breeding population. Part of this fragmentation is due to the impassably tall edges of the Grand Union Canal, which runs from Birmingham to London.
The Canal and River Trust organization spent £100,000 in 2013 to not only redevelop more than .9 miles of habitat along the canal, providing better burrowing space and planting more of the plants that voles prefer. The group has also built and installed a number of vole ladders that will allow the rodents to ascend over the lip of the canal, effectively transforming what was an impassable barrier into a vole superhighway.
Image: The Canal and River Trust
Salamander Tunnels - Amherst, Massachusetts
The Yellow Spotted Salamanders of Amherst, MA faced a harrowing ordeal back in the late 1980s: they had to cross a busy city street in order to reach their breeding ponds, however many never made it to the other side, instead getting squished under the tires of passing motorists. Then, in 1988, public outcry prompted city officials to install a series of three 19-inch-high tunnels under the street with funnel fencing to guide the amphibians in.
While the first few (dozen) salamanders did not initially use the tunnels—they were instead carried across the road by volunteers—the amphibian population eventually learned to employ the crossings with great success. The system was so effective that it is now employed throughout the country, including in Santa Rosa, California, where it is helping the endangered tiger salamander reach vital breeding pools.
Top image: Adam Ford