Fires alter wildlife’s food, water, and shelter forcing animals to either adjust or find new homes. In an intense fire the complex humus layer on the forest floor gets charred, depleting nutrients and causing soils to repel water. Erosion is greater and the compromised soil produces less nutritious food for the animals.
Despite the hit it has taken, nature starts healing. In the spring broad-leaved plants such as Rocky Mt maple, dogwood, willow, and aspen sprout from their roots and flowers like fireweed get established. Their leaves begin to shade the ash-covered slopes and cool the soil. This helps protect small mammals from predators whose burrow openings had been exposed by the fire.
Other species that benefit from the regrowth on the newly exposed slopes are insects and small birds that come for the pollen, nectar, and seeds produced by the shrubs and flowers. The leaves and twigs attract browsers such as deer, elk, and moose and their predators eventually follow. A species of beetles fire fighters call "fire beetles" can sense fire’s heat from miles away and come to dine on the dead trees. And then, or course, there are those species – ourselves included – who fatten up on the morel mushrooms that are so plentiful after a fire!
Lodgepole pines seeds germinate en masse after fires and their baby trees soon create more diversity in the deciduous regrowth, which in turn supports more species.
Animals such as the pine marten and wolverine that depend upon continuous older forest habitat and canopy cover take a hit when the canopy has burned. Wolverines also suffer because snow melts earlier when the canopy is lost. And fish get stressed because water temperatures increase when streamside vegetation is burned and the higher erosion rates add silt to the streams.
And then there’s the bears that have been visiting firefighters on the fire line. Even without a fire, bears are particularly stressed at this time of year because they need to fatten up for the winter. Hyperphagia is the term for it, and if their food is burned and their denning site is exposed bears have that much more work to do in order to survive. No wonder they are on the prowl.
The healing process after an intense fire is slow. It rebuilds in its own time, not ours. As these hotter fires continue to burn the landscape we must learn to regard nature needs above our own. That’s the only way we can turn this ship around.
Wildlife has evolved with fires over the eons. Though wildfire certainly takes its toll, not as many animals die as one might expect. However, more animals die if fires occur early in the season when babies are still being cared for or if fires are severe, as so many are today.
Raptors, like eagles and hawks, have keen eyesight and acute hearing, so are forewarned of fire before most other species. They easily escape the flames and also take advantage of the opportunity to prey on animals such as rodents, small mammals, and insects fleeing from the fire.
Birds’ respiratory systems pump far more oxygen than ours do, so smoke inhalation as well as deposition of toxins takes a greater toll. Smaller songbirds fly lower than raptors so they are far more vulnerable to dying from smoke inhalation.
Large animals such as bear, deer, mountain lions, and wolves generally survive fires by staying ahead of the flames, but can succumb to smoke inhalation or burning if the fire is erratic or fast moving.
The rodents that don’t get picked off by predators or that don’t panic and run into the flames, can survive fire’s heat by taking refuge in their burrows. As long as they get at least four inches below the surface and their tunnels have several openings they won’t asphyxiate.
If snakes aren’t molting they can slither away or take cover in a burrow. Turtles hide out in burrows and amphibians dig down into the muck and wait it out.
Some coping methods that don’t have good outcomes are the insect species that are drawn to fire’s warmth and therefore incinerated en masse. However, this creates a feast for many other species. Small mammals such as squirrels and porcupines that tend to flee into the treetops for safety also don’t fare well.
As our fires subside, the plants and animals will carry on. Their habitat has completely changed and they will either benefit from that change or will move on. More about that in my next post...
Smoke. More smoke. Ridiculous amounts of smoke. That has been what we in Seeley Lake have been breathing and looking through since July 24th. We know the smoke is impacting our health, but how is it impacting the trees and plants?
Plants breath and photosynthesis through openings called stomata. When wildfire smoke fills the air, plants reduce the size of their stomata, which means that just like us, they can’t breath as well, and their ability to photosynthesize is reduced. So yes, they’re stressed. And yes, they want the smoke to go just as much as we do.
Studies have shown that conifers, like Douglas fir, recover more quickly from smoke exposure than do broad-leaved plants, like Rocky Mountain maple. Researchers speculate this is because conifers have evolved to resist fire with their thick bark rather than succumb and re-sprout like many deciduous plants. Persisting means the conifers must quickly get back to the business of living once the fires and smoke have passed.
Plants divide their energies between photosynthesizing and creating their own chemical compounds that deter insects, pathogens, and some herbivores from eating them. On a good note, fires temporarily reduce the amount of insects and pathogens that eat plants so after a fire, plants can spend more energy growing. And according to researcher, Amina Khan, when fire has burned out the forest canopy, causing sunlight to pass through the charred ground at a different angle, chemicals in the smoke make the surviving plants more receptive to the altered light, causing them to grow thicker, tougher stems, which makes them more likely to survive.
I am impressed to discover that plants possess such refined and complex adaptive abilities and that they have evolved to respond positively to smoke's messages. It gives me hope that they will find ways to persist in our rapidly changing environment.