Millions of miles of fencing is used across the US to contain livestock and define property boundaries. Much of this fencing does not take into account the migration routes of ungulates and other large and small mammals, often leading to perilous outcomes for wildlife populations trying to reach critical resources like food, water, and shelter.
Habitat fragmentation caused by traditional fencing, roads, and development causes an existential threat for countless species around the world, undermining biodiversity and the overall health of the planet. Traditional fences are often either too high for wildlife to jump over or filled with spikes, barbs, and other sharp wire that can be deadly for deer, elk, bighorn sheep, moose, foxes, mountain lions, birds, and more. Problematic fences are built too high to jump over, too low to crawl under, have loose wire or wire spaced too closely together, are hard to see, and/or form an impenetrable barrier.
According to a study at University of Utah, it was found there’s an average of one fatality per 2.5 miles of fencing per year due to conventional fencing practices. This study also found that 70% of mortalities came from fences that exceeded 40 inches of height. Furthermore, juveniles are eight times more likely to die in fences than adults. While problematic fencing can be a death wish for wildlife, it is also more costly long term and labor intensive for farm or land owners.
Fortunately, there are steps you can take whether you have fencing in place or are planning to install it. Fencing can be an opportunity to understand both the ecosystem around you and ungulate migration routes more fully. Design considerations for building wildlife-friendly fencing include crystalizing the purpose of the fence—do you need one in the first place? Wildlife habitat, the species present, use of the land, and the topography—how can a fence work in sync with the land and not be at odds with it? How can you ensure that your fencing is highly visible to ungulates and birds, allow wildlife to jump over or crawl under wires or rails, and effectively enable wildlife access to key habitats and migration corridors? This guide from the Colorado Parks and Wildlife shows how fences ought to be designed with wildlife behavior and agility in mind.
There are a wide array of solutions to the fencing fragmentation problem that include the use of intentional materials, spacing, dimensions, and construction specifications. Fence stewards might consider including vinyl markers on the barbed wire fence. In biologically sensitive areas, there are fences that fold down completely when there are large migrations underway. And what a great opportunity this creates to meet your neighbors to find out what’s working and where there is opportunity for collaboration.
Homeowners, landowners, and public and private lands alike all have an opportunity to model wildlife friendly fences, and to go further to codify this practice. Los Angeles County code prohibits fencing in wildlife-sensitive areas. Teton County, WY requires that all fencing comply with wildlife-friendly design standards, and Pitkin County, CO strictly prohibits mesh or woven wire fencing.
With growing awareness around biodiversity along with how essential movement and migration is to wildlife population survival, more fencing is being built to consider migration routes and corridors. Communities can begin to reintegrate wildlife consciousness into property management through integrating the principle of permeability into fencing across the country.