What Are Wildlife Corridors?
As the human population expands, we require an increasingly large amount of resources to support our basic needs.
Because only so many people can live comfortably in a single area, ballooning populations have led to the lateral expansion of cities, towns, and other centers of residence. Such expansion—sometimes referred to as urban sprawl—has displaced millions of organisms, fragmenting hearty populations into small, disparate cohorts.
The effect of this fragmentation is to create populations with reduced numbers of breeding pairs, increasing the likelihood that incest will occur among eligible mates. Moreover, because fragmentation prevents migration between populations, gene flow can‘t occur. That is, the set of alleles present in one section of a fragmented population remains essentially the same generation to generation—there are no genes coming in from neighboring populations. The only opportunity for changes in genetic diversity, then, is rare—and random—mutations, which may or may not prove lethal to the individual expressing them. The effects of inbreeding depression and fixed gene pools combine to dramatically reduce the population‘s fitness.
The question now is, what can we do to prevent population fragmentation?
When human settlements block migratory routes, gene flow between neighboring populations cannot occur.
Wildlife Corridors: A Solution to the Problem
Although it’s economically and logistically unfeasible to reverse the effects of urban sprawl, leading figures in environmental policy have proposed no shortage of alternative solutions.
One promising proposal centers on building wildlife corridors between habitats, linking disparate populations through physical means. At present, wildlife corridors exist in India, Nepal, Australia, Canada, and Norway; they service species ranging in size from elephants to bees—and everything in between. There’s even one for migratory crabs.
Yes, they’re exactly what you think they are.
According to Steve Michel, a specialist in the contentious relationship between humans and nature, such corridors “have been really, really effective for wildlife.” In Canada alone, for whose national parks service Michel is employed, manmade bridges spanning roads have eliminated 80% of collisions between cars and animals, knocking out a key barrier to inter-population migration.
In the US, environmental legislators are working diligently to emulate Canada’s success. They proposed the Wildlife Corridors Conservation Act to the House and Senate in 2018, and plan to reintroduce the act this year. If accepted, the legislation will “establish a continental system of connected wildlife corridors“ to facilitate the movement of animals across areas populated by humans. “In the face of climate change,“ says Susan Holmes, a representative of the nonprofit environmental organization Wildlands Network, “protecting wildlife corridors will ensure America’s treasured wildlife will survive for generations to come.”
Why Should I Care?
Maintaining wildlife diversity is important to human survival because we rely on products made in nature. Pharmaceuticals, for example, are often derived from plants whose numbers may be threatened by increasing population fragmentation. Further, agricultural products that aren’t traditionally produced on a factory scale, such as bushmeat, may become more expensive—or in the case of species extinction, unavailable—if populations continue to fragment.
Beyond physical products, habitats with abundant species diversity render useful ecological services. Bogs filter water and reduce soil damage due to intense rains; flower-filled plains are active sites for pollination; and forests have sparked the creation of an entire industry dedicated to enjoying nature’s beauty. If we continue to disrupt ecosystems without considering the consequences of doing so, we’ll lose these valuable services.