What are wildlife crossings?
Wildlife crossings are structures built over or under roads, highways, and railways to enable the safe movement of wildlife across these human-made barriers. These structures allow animals to cross roads and other infrastructures without the risk of being hit by vehicles or exposed to other dangers associated with the hindrances caused by linear infrastructures.
Wildlife underpasses are tunnels or culverts constructed under the road or highway, while overpasses are bridges built over the roadway. The design of these structures takes into account the movement patterns and behaviors of different wildlife species, as well as the specific characteristics of the landscape and the road. For example, underpasses designed for large mammals, such as deer and elk, are usually wider and taller than those designed for smaller animals, like rabbits and reptiles.
In addition to providing safe passage for wildlife, underpasses, and overpasses can also help to reduce the number of wildlife-vehicle collisions, which can be dangerous for both humans and animals. By providing wildlife with a safe route to crossroads and highways, these structures can promote the connectivity of habitats and prevent the fragmentation of wildlife populations.
So where are wildlife crossings used?
Wildlife crossings have been implemented in many parts of the world, including the United States, Canada, Europe, and India, to address the negative impact of roads and other infrastructure on wildlife populations. These structures have proven to be effective in reducing wildlife-vehicle collisions, enhancing the connectivity of habitats, and promoting the movement of wildlife across fragmented landscapes.
Wildlife underpasses and overpasses have become popular solutions for mitigating the negative impacts of roads and highways on wildlife populations. These structures are designed to provide safe crossing opportunities for animals to move between fragmented habitats, reducing the risk of collisions with vehicles and improving connectivity between populations. But the question remains, are wildlife under/overpasses effective?
The short answer is yes, wildlife crossings have proven to be effective in reducing wildlife-vehicle collisions and improving habitat connectivity. Studies have shown that underpasses and overpasses can reduce wildlife mortality rates by up to 90% compared to areas without such structures. In addition, they can promote genetic diversity and increase population sizes by facilitating the movement of individuals between habitats
Case studies of successful wildlife crossings
One study published in the journal Biological Conservation analyzed 89 wildlife overpass and underpass projects in North America, Europe, and Australia and found that these structures were highly effective at facilitating wildlife movement across roads and highways. The study found that the frequency of wildlife crossings was significantly higher at sites with wildlife overpasses and underpasses compared to control sites without these structures.
One example of the success of wildlife crossings is in Banff National Park in Canada, where 44 wildlife crossings were constructed along the Trans-Canada Highway over the last few decades. The structures have helped reduce the number of large mammal-vehicle collisions by more than 80%. Similarly, in the Netherlands, a series of overpasses and underpasses were built to connect fragmented habitats, resulting in a 96% reduction in roadkill for some species.
Banff National Park, Canada wildlife crossing
However, the effectiveness of wildlife crossings depends on various factors, including location, design, and maintenance. For example, a study in California found that some underpasses were ineffective due to their location, which did not correspond to the movements of wildlife in the area. Similarly, a poorly designed crossing structure can discourage animals from using it, or worse, create a barrier that prevents animals from crossing safely.
Furthermore, the maintenance of wildlife crossings is critical to their success. If vegetation is allowed to grow over or around the structure, or if the structure becomes blocked with debris, it can deter animals from using it or create hazardous conditions for those that do.
Another consideration is the cost of building and maintaining wildlife crossings. While the benefits of these structures are clear, they can be expensive to construct, with costs ranging from tens of thousands to millions of dollars depending on the location and design. In addition, ongoing maintenance costs can add up over time.
Despite these challenges, wildlife crossings are gaining popularity and have been successful in many locations. They are a promising solution for improving habitat connectivity and reducing the negative impacts of roads on wildlife populations. However, careful planning, design, and maintenance are necessary to ensure their effectiveness. As we continue to expand our transportation networks, we must prioritize the protection and conservation of our wildlife and the habitats they depend on. Wildlife crossings are an important tool for achieving this goal.
Ramnagar-Kotdwar Highway
Wildlife underpasses and overpasses have been implemented in India to address the negative impact of roads and highways on the country’s wildlife populations. India is a country with diverse ecosystems, and wildlife underpasses and overpasses have been designed to suit the specific needs of different species in different regions.
One example of a successful wildlife underpass project in India is the one built on the Ramnagar-Kotdwar highway in Uttarakhand. This region is home to a significant population of tigers and elephants. The underpass was constructed to mitigate the impact of the highway on the movement and breeding patterns of these animals. Furthermore, the underpass was built to accommodate the height and weight of elephants, with a width of 15 meters and a height of 5 meters. The construction of this underpass has been credited with reducing the number of human-elephant conflicts and enhancing the connectivity of different habitats.
Kanha Pench Corridor
Another example is the construction of wildlife overpasses in the Kanha-Pench corridor in central India. This is an important landscape for the conservation of tigers and other large mammals. These overpasses were built to enable the safe movement of wildlife across the highway that was bisecting their habitat. Additionally, this helped promote gene flow and breeding between populations. The overpasses were designed to suit the movement patterns and behaviors of different species, including tigers, leopards, and ungulates.
There are several challenges in implementing wildlife underpasses and overpasses in India. The lack of awareness and understanding of the importance of wildlife corridors and their ecological significance is a significant hurdle. Additionally, limited funding and resources, combined with the need for collaboration and coordination among different government agencies, can pose challenges to the successful implementation of these projects.
Conclusion
In conclusion, while there are challenges to the successful implementation of wildlife underpasses and overpasses in India, these structures have proven to be effective in mitigating the negative impacts of roads and highways on wildlife populations. Further investment and collaboration among government agencies, conservation organizations, and other stakeholders could lead to greater success in promoting the conservation and connectivity of India’s wildlife habitats.
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Written by: Aditi Dave