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Tuesday
Apr102018

Creating Man–Made Wildlife Corridors 

Image adapted from original by Qyd As the world’s population continues to expand, so does the volume of infrastructure and land required to support it. This can have a negative impact on wildlife species whose habitats can become separated by acres of inhospitable land.

What are wildlife corridors?

Wildlife corridors are habitats that connect fragmented larger patches of habitat. They may differ greatly in their size, shape and composition however they all function in the same way. The purpose of corridors is to assist the movement of species through dispersal and migration, ensuring gene flow, and species diversity is maintained between local populations. By consequently linking these populations through corridors, it lowers the probability of extinction and supports greater species richness.

Anthropogenic activities such as urbanisation, agriculture and forestry fragment patches of natural habitat therefore reducing species’ richness and genetic diversity. Animals and plants use natural corridors for migration and dispersal. Human dominated habitats create barriers for species to cross, and areas such as these pose more threats such as a higher abundance of predators, lack of resources and reduced shelter.

 Wikimedia Commons | BMC Ecology image competition 2014: the winning imagesCorridors however present opportunities and access for species movement across these fragmented patches, by providing a safe passageway for species to travel with minimal threat, especially when they are passing through areas dominated by agriculture and urbanisation.

Types of wildlife corridors

Wildlife corridors can occur naturally such as riparian corridors that connect two different populations dependant on isolated wetlands, but they can also be constructed through management practices.

Corridors can be created artificially to facilitate species’ movements, such as overpasses and underpasses on highways. These management techniques have proven to be very successful in both North America and Africa with the main purpose being to limit instances of anthropogenic interactions and threats. Corridors have also been implemented in aquatic systems to provide migration and dispersal. Stream corridors consist of a network of protected watersheds allowing fish to travel without the hindrance of road blockages and damns.

Examples of Man-Made Corridors

Banff National Park - Alberta, Canada

The TransCanada Highway dissects itself through one of the country’s most iconic national parks which boasts a wealth of flora and fauna. The highway fragments critical habitat which the park’s resident wildlife are dependent on. Numerous overpasses and underpasses were created to facilitate the movement of large species that demand large home areas such as elk, grizzly bear and wolverines.  The intention of these structures was to provide free movement and to funnel species from one side of the park to the other. Despite some species taking time to be become accustomed to the new structure it has ultimately provided connectivity between fragmented forests; promoting gene flow.

Natuurbrug Zanderij Crailo - The Netherlands

The Netherlands holds over 600 artificial corridors consisting of underpasses and overpasses along highways, the longest of which is the Natuurbrug Zanderij Crailo which is 50m wide and 800m long. Completed in 2006, it spans a rail line, business park, river and sports complex. The corridor provides access for numerous species including roe deer, wild boar and the endangered European badger.  

Christmas Island National Park – Australia

An overpass for crab migration? Surely not! Believe it. The annual migration route of millions of crabs on Christmas Island crosses roads, golf courses and beaches. To assist the migration an overpass was created and 20km of barriers were implemented to navigate the crabs away from roads and into the 31 crab underpasses. The infrastructure also includes a 5m high bridge that crosses one of Australia’s busiest roads.    

Mt. Kenya National Forest – Kenya

The underpass was opened in 2010 in Mt Kenya National Park to allow elephants to easily move between forest systems. The underpass re-establishes the only existent connection between Kenya’s 2nd largest elephant population in Samburu with the ones located in Mt Kenya.

Underpasses specifically designed for elephant movement have also been constructed in China’s Menyang Nature Reserve and South Africa’s Addo Elephant National Park, with proposed infrastructure planned for India’s Hosur Krishnagiri section too.

By Matt Couldwell - Online Media Intern

Frontier runs conservationdevelopmentteaching and adventure travel projects in over 50 countries worldwide - so join us and explore the world!

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