The Rocky Mountains

The Rocky Mountains form a nearly continuous chain across the western part of North America, sweeping down from Alaska through Canada and the western third of the United States. They are more than 4 800 kilometers long. The Rocky Mountains as they stand today began to form around 80 million years ago. One of the plates that make up the Earth’s crust, the Pacific oceanic plate, began sliding underneath the North American plate. It slid under at a shallow angle, gradually pushing up a broad and long belt of mountains over a thousand kilometers from where the plates first collided.

Since then, the Rockies have been shaped from beneath by more plate movement, as well as from above, by wind and rain. Large sheets of ice that slide down the mountainside, glaciers, have also worn down the mountains, creating their dramatic peaks and valleys. The highest peak is Mount Elbert in Colorado at 4 400 metres. Ecologists divide the Rocky Mountains into three main zones, based on what kind of species can survive there. In the montane zone, below about 2 700 metres, a wide variety of trees thrive, including aspen and lodgepole pine.

This is the warmest zone. It gets little snow, even in winter. Mule deer wander among the trees and muskrats and beavers live in the streams and lakes. Cross into the subalpine zone, and we find the hardier Engelmann spruce and subalpine fir. Here you might spot a snowshoe hare, or hear northern goshawks overhead.

As we climb further up the subalpine, the temperature gradually drops and more snow falls. The forest thins out and the trees are smaller. When the last trees give way to an open landscape at around 3 500 metres, we arrive in the alpine zone. Only sturdy wildflowers, like the alpine phlox, can survive the cold temperatures and frequent strong winds here. They provide grazing grounds for yellow-bellied marmot and bighorn sheep.

Humans have lived in the Rocky Mountains for perhaps as long as 12 000 years. For most of this time, they were home to the Kootenai, the Shoshone, the Hopi and many other indigenous peoples. In 1540, Spanish explorer Francisco Coronado marches into the region with a group of soldiers, missionaries, and slaves. Other Europeans follow. They bring with them new diseases, and they destroy the habitats of the bison that the Indigenous peoples hunt.

Fewer and fewer Indigenous people live in the Mountains. In the 1800s, fur traders and gold miners arrive. New railway lines make it easier to reach the Mountains. Tents and camps become ranches and farms, trading posts become towns. All this human activity threatens the natural environment of the Rockies.

Forests cleared for buildings leave animals with no habitats; pesticides from farms poison birds. People worry that the Rockies will lose their natural beauty. In the early 1900s, the Canadian and US governments set aside large areas of the Rockies as National Parks, where human activity is restricted. They include Jasper, Banff, and Yoho in Canada, and the vast Rocky Mountain National Park in the USA. In many of these parks, wildlife populations are tracked.

Trees are planted to reforest large areas. Government and private organisations work together to buy more land and preserve it for conservation. Today, the natural beauty of the Rockies and especially its National Parks, draws millions of visitors each year to hike, camp, canoe, or mountain climb. With sustained efforts to protect the Rocky Mountains’ natural environment, plants, animals, and humans can continue to co-exist on these ancient slopes.