Conflicts between humans and wildlife have been a common occurrence since civilization came into existence. Humans have repeatedly been forced to hive off vast swathes of land that was initially home for wildlife to create their homes. The situation has gained intensity as the human population increased to over 7 billion individuals. This rapid human expansion, if unchecked, is wreaking havoc in the animal world, and this is where wildlife bridges come into the picture. They are structures that make it easy for animals to cross human-made structures like roads, railway lines, dams and canals that have cut through their habitats. The idea of a wildlife bridge dates back to 1837 when Richard McFarlan, a Canadian, designed a fishway to bypass a dam at his mill. His small idea became the blueprint upon which future wildlife bridges were d.
The Necessity of Wildlife Bridges
Wildlife bridges do more than just protecting animals from the expanding reach of urbanization, they protect humans from the dangers of road accidents caused by animals. America, for example, sees many road collisions between cars and animals with an average death toll of about 200 people in a year. The animals have it worse, the smaller ones like tortoises and amphibians are usually squashed to death because of their slow speeds and tiny sizes. The situation is so dire in some parts of the US that road mortalities are further threatening 21 endangered species of animals. Fewer road accidents also translate to fewer insurance claims which free up more funds for the construction of more wildlife bridges across the major highways. Some places with the most productive wildlife bridges that have positively impacted nature around the country include the following.
Banff National Park, Canada
Before it was constructed in the 1980s, the Trans-Canada Highway was a hotspot for animal road kills since the busy highway cut right across Banff National Park, home to prized animals of the North like the Grizzly bear. The 4-lane highway was notorious for wildlife-vehicle collisions with elk and deer bearing the brunt of it all. As of 2014, the 51-mile stretch of the highway has 38 wildlife underpasses and six overpasses strategically distributed along the routes most frequently used by wildlife to cross over. As a result, this has translated to an 80% reduction of wildlife-related road kills.
Natuurbrug Zanderij Crailoo, Netherlands
The Netherlands holds the record of being home to over 600 wildlife bridges. With the most famous being the 2624.7 feet long and 164 feet wide Natuurbrug Zanderij Crailoo overpass which is the longest in the world; it bypasses a business park, a roadway, a railway line, a sports complex, and a river. The overpass was constructed in 2006 and has reduced wildlife deaths that had become synonymous with the N524 roadway. Other notable wildlife overpasses in the Netherlands are the Highway A50 overpass and the Borkeld in Hoge Veluwe national park that has both a path for animals and a walkway for pedestrians and cyclists.
Interstate 78, Watchung Reservation, USA
The Interstate 78 is a long stretch of road that cuts through the Watchung Reservation in New Jersey. Being close to New York means that the road experiences heavy traffic all year round and this, for a long time, was a danger to the animals that attempted to cross the road. The road is now dotted with overpasses reinforced with concrete walls and fences on either side to guide deer, foxes, raccoons, squirrels, skunks and other small animals native to the area. The overpasses have dense vegetation that mimics a natural forest making it easy for the animals to get used to.
Christmas Island Crab Bridges, Australia
Every year, millions of red crabs on Christmas Island start their macabre migration to the Pacific Ocean passing through human settlements. This migration brings them into direct contact with highways where most get crushed under cars and at times cause accidents thanks to their hard pincers that could pierce tires. Crab bridges and tunnels have been constructed across many roads frequently used by the tiny crustaceans, these small metal bridges have helped save the crabs from being run over on the roads.
Turtle Tunnels, Japan
Turtles are slow animals that do not stand a chance when faced with the prospect of being run over by a car or a train. Their nature makes crossing a dangerous undertaking for them, especially in Japan where roads and high-speed railway lines cover the country from one end to the other. To counter this, the West Japan Railway Company came up with the ingenious idea of creating tunnels in the middle of rail tracks. The tunnels are made of concrete dugouts, and each leads to water sources like ponds and swamps. These small tunnels have reduced turtle deaths along the railway, besides eliminating train delays caused by dead turtles stuck between track switches.
Rope bridges in Victoria, Australia, were made to help the endangered squirrel glider from being crushed by cars every time they fell on roads because of reduced vegetation cover. In Oamaru, New Zealand, there are the blue penguin underpass tunnels that connect the penguins from the ocean to their nests in abandoned quarries. There are also elephant underpasses at the foot of Mt. Kenya that have helped reduce human-wildlife conflict that leads to elephants destroying farms in their paths and people killing them in retaliation. Oslo in Norway is home to the unique bee highways which are routes filled with green roofs and flowers to provide a home and a resting point for bees that live and migrate between habitats.
The Cost of Wildlife Bridges
Wildlife bridges can be considered as mega-structures and constructing such comes at no small price. Unlike other structures, wildlife crossings have to be built in particular locations frequently used by animals, to achieve this a lot of feasibility is undertaken. Many deliberations have to be taken into account to avoid a situation where the crossings end up inflicting more damage to the environment. Therefore achieving the opposite of what they are intended to achieve. On average, overpasses cost between $2 million and $4 million to build, and underpasses cost a lot less, the average cost of maintaining these crossings stands at about $18,123 a year. These figures help explain why most roads and railway lines that need an animal crossing do not have any.
It is an accepted fact that urbanization will never stop spreading as long as human populations increase, human encroachment into wildlife habitats is an unavoidable consequence. However, there are things that they can do to lessen the impact on wildlife. Wildlife bridges come with many benefits. They create safe crossing points for animals with minimal chances of conflict, therefore, reducing deaths and damages from both sides. The bridges also serve as habitat connectors for animals that lost their homes to roadways and railway lines. By opening up areas that had been cut off by roadway and railway lines, they expand territories and increase the chances of animals accessing food and mates.
These crossings also help integrate roads, railway lines, and other structures into the surrounding landscape. As much as human-made structures end up being obstacles, there are ways in which they can be designed to complement nature, making them part of it rather than disruptors. Most wildlife bridges end up turning into green bridges that provide homes to smaller animals and act as tourist attraction sites since they become an assembling point for animals during crossings. By reducing accidents on the road, wildlife bridges have helped save up to $6.4 billion in car repairs and insurance claims in the United States.
Challenges and the Way Forward
Despite the good intentions for the creation of animal crossings, there remains the issue of maintaining the delicate balance between nature and urbanization. Leaving natural habitats untouched is the best option which, unfortunately, does not work for human civilization. As much as the wildlife bridges are providing animals with a solution to road kills, they are still unnatural structures that hinder their free movement. It takes a lot of time for an animal to get used to these crossings, and many could die in the process. The cost of maintaining these crossings is also prohibitive, and this exposes the animals to new dangers if the bridges are neglected. The presence of onlookers and tourists at these bridges also works against their intended purposes, and animals avoid areas that have crowds of people and crowded crossings are no exception to this. Shortcomings aside, there is no denying the impact that the crossings have on animal populations. The bridges may not be ideal for the animals, but they are doing an excellent job of addressing the immediate concern they were created for, stopping animal deaths on the highways. Better designed bridges are coming up in all major urban areas close to wildlife, and this is a testament to the willingness of humans to go the extra mile to accommodate wildlife to benefit all mutually.