Journeys in America: The Grand Canyon, the mountain lion and wildlife corridors

It is impossible to grasp the scale of the Grand Canyon as you stand at one of the vantage points looking out. At about 433km long, and on average 18km wide, it is visible from space. But the Canyon itself is only one part of the National Park that surrounds it. The vast majority of the 4930 km² park is home to an array of wildlife. This includes the mountain lion.

One of the impressive aspects of America’s National Park Service is the emphasis placed on education. There are a range of programmes available for children, offering them a chance to learn about the environment that surrounds them. For the adults, there are talks on a variety of topics. When we visited the Grand Canyon, we went along to listen to an excellent talk: ‘God of Hunters: The Mountain Lion’ which was presented by one of the rangers at the park. The expectation was to learn more about the animal, yet this went well beyond that. From understanding the interaction of humans and nature, through to appreciating the beauty that is the mountain lion, I walked away feeling both informed and excited to learn more about the merging of nature and civilisation.

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First, some quick facts. The mountain lion is known by a multitude of names. You have heard of pumas, cougars and panthers as well? They are all the same animal: Puma concolor. The San Diego zoo website has a good summary about the mountain lion which is well worth a read. Perhaps most striking is its jumping stats. They can jump 5.5m from the ground into a tree, and they can jump 6.1m up or down a hillside. Yep, 6.1m – the height of many two story buildings.

The mountain lion is a striking predator, but the risk to humans is actually pretty minimal. For the most part, they simply stay away from humans where possible. Where the natural habitat has been impacted, there can be more interaction with people and their livestock. Unfortunately, there are fatal attacks on humans – normally children or lone adults – but the numbers are minimal. In a study of mountain lions in the Grand Canyon, they found that there was little evidence of the mountain lions venturing into the areas where humans were most prevalent. Instead, the cats stayed in the shadows and hunted elsewhere in the expansive park. Learning how to share the space is important; whilst there was a drive to eradicate the mountain lion, it is now understood that they play a crucial role in the North American ecosystem.

Two biologists from Oregon State University, William Ripple and Robert Beschta, study the impact of predators on the ecosystem. One of the intriguing aspects of their research for me is the demonstration of how removing predators can have unforeseen consequences lower down the food chain. In a study of Zion and Yosemite national parks, they found that the scarcity of predators (in this case the mountain lion) led to an increase in deer population. The consequence: a substantial decrease in biodiversity. This can be seen in the case of Zion Canyon, where the biologists report that:

Increases in human visitors in Zion Canyon apparently reduced cougar (Puma concolor) densities, which subsequently led to higher mule deer (Odocoileus hemionus) densities, higher browsing intensities and reduced recruitment of riparian cottonwood trees (Populus fremon- tii), increased bank erosion, and reductions in both terrestrial and aquatic species abundance.

That is, ecological change comes not only from changes at the bottom (where humans impact natural food sources etc), but can also be a result of altering the top of the food chain. Predators, such as the mountain lion in America, play an important role in maintaining ecological balance. Through continuing to understand them, we can learn how to live side by side with them.

So, the question looms over how to work with the mountain lion so that they can continue their role in ecosystem, whilst also reducing the fatal encounters with humans. One of the intriguing ideas presented at the ranger talk we attended was the concept of wildlife corridors. A big challenge for wild animals is the human alteration of the environment. When humans encroach into what has been a hunting ground for centuries, the consequences can be dire for the animals who called that home, and ultimately humans as well. Finding a middle ground allows for conserved space for the likes of the mountain lion to call home. There are large swaths of land that has been deemed public space in the United States and, as a result, conservation efforts have been able to reestablish populations of animals who were once struggling to maintain numbers. The mountain lion is not considered to be a threatened species, a result of a change of human ideas around the cat – from pest to an important part of the ecological system. (Also of note, mountain lions are a self regulating species – they are a cannibalistic animal, with older males in particular committing acts of infanticide. Their preference for isolation and large spaces means that they will control the population spread effectively.) However, there is still work to be done in ensuring their continued place within the ever-changing landscape.

The next stage is supporting the migratory patterns of animals throughout the American continent. Borrowing from ideas successfully implemented in Europe and Canada, there is a move towards implementing wildlife corridors. These allow for the safe passage of animals across major highways – which benefits both animals and humans through a reduction in collisions.

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A wildlife overpass on the Trans-Canada Highway in Banff National Park, British Columbia. The Park is a leader in highway mitigation, part of a 30-year-old initiative that has installed 44 crossing structures. Credit, Adam Ford, Highwaywilding.org

On our drive east, we were lucky enough to see a newly established wildlife crossing in action in Colorado. A long length of fence has been installed along both sides of the roadside, helping to corral animals into tunnels and over bridges – avoiding cars along a notorious stretch of road. It’s working too, within days the animals were safely crossing over or under the road.

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Wildlife crossing (credit: Colorado Parks & Wildlife)

One of the big disadvantages of this approach is the cost. Someone needs to be able to pay for these, and in a country with an awful lot of roads it is going to be astronomical to attempt to instigate wholesale change overnight. However, with ongoing discussion about the importance of improving the American infrastructure, there is surely space to consider the environmental impact alongside upgrades. Allowing space for American wildlife alongside the development of the American infrastructure will ultimately benefit everyone.

If you are interested, you can donate to the program (I’m not sure how this works outside of the US) to support these beautiful animals in the Grand Canyon. Details here.

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2 thoughts on “Journeys in America: The Grand Canyon, the mountain lion and wildlife corridors

  1. It’s great to see so much work is being done for the natural world. Certainly different problems from what we face in New Zealand but just as important. Thanks Anna

    Like

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