Montana climate matters: impacts on wildlife in the treasure state

by Dr. Frank Lance Craighead, Bozeman

Ecologists understand that each species occupies a ‘niche’ in the environment where the right living conditions (defined by temperature and moisture), resources (including food, water, and shelter), and lack of competition from other species allow populations to survive and reproduce. Plants grow where conditions are right, and animals depend upon plant communities to provide food and shelter.

A niche is a ‘space’ in the world that a species has adapted to over its whole history. Grizzly bears now mostly live in the mountains where they find what they need and are not killed by humans. Mule deer live in forests but are being driven out of open habitats by white-tailed deer, which outcompete them. Pikas live in high alpine habitats that remain cool during summer, have sufficient snow to insulate them from severe winter cold, and offer mountain meadows where they can find food. 

For most of my time on earth, life has been good for the wildlife in Montana, but things are rapidly changing for them. Climate scientists, as well as most of the public, understand that the climate is warming much faster than normal because of increased greenhouse gas emissions.  Human actions are the main cause of the problem. We are changing the climate faster than species can adapt, and that includes us.

As higher primates, we also have a niche we occupy. Our early ancestors on the African savannah lived where they would not freeze at night and had water and food. As we developed technologies like clothing, weapons, and fire, our niche expanded and we spread out across the planet. Today our technologies allow us to live virtually anywhere, supported by buildings, insulation, agriculture, food storage, fossil fuels, and medical technologies. Our expanding niche has diminished the living space for other species, often to the point of extinction. Now, in addition to taking away the physical space needed by other species, we are shrinking the climate space they need.

As temperatures increase in Montana and reliable sources of water shift in time and space, wildlife need to move in search of the conditions that they require. In general, as it heats up, animal species will move up in elevation or north in latitude to keep pace with the shifting location of their niche. To do this, however, is becoming more difficult.

As summers get hotter and drier in Montana, wildlife will become increasingly uncomfortable in their present location. Eventually, they may shift their range to mountain tops where it’s cooler. Unfortunately, in those places there is little to eat, forcing them back to lower elevations to suffer the heat. This is the plight of pikas, already living at the upper limit of plant life. Pikas die if air temperatures get above 80 degrees F for long, and they freeze to death if snow doesn’t form a blanket over their burrows.

Most wildlife are not aware that far to the north—perhaps hundreds of miles away—it is cooler. They are aware, though, that conditions are getting too hot where they live. Water sources are drying up, and food plants are disappearing. And so, they move. Perhaps they see a distant mountain, or the wind brings them the scent of forest or water or food, or they move randomly. Animals moving farther north are likely to find better conditions. However, moving in any direction is a difficult and risky business, because people, roadways, and occupied landscapes block their path and endanger their lives.

In coming years with warming conditions, we will see wildlife in unusual, unhealthy places, just trying to find a place to survive.