Over the summer of 2023, wildfires ravaged the Canadian wilderness. The season was a stark reminder of the effects of climate change, and impacted many lives directly. People in the path were forced to evacuate, and an unlucky few lost their homes. Smoke was cast far and wide from these fires, choking people abroad for weeks, not to mention further exacerbating carbon emissions.
While we spent much of our attention and care on the human lives close to these forests, the animals that lived in them were among the most affected. The direct impacts are obvious. Animals too slow to flee a burning area, include the young, were lost. Those that were mobile still had to navigate a chaotic environment where they could still succumb to heat exhaustion or smoke inhalation. Once free of a dangerous area, these animals had to establish themselves in a foreign landscape, competing with native populations and other refugees for resources. Others attempted to return to their home territory to find it largely devoid of necessities, namely a large forest canopy for cover from predators and for feeding.
Species of all shapes and sizes have adapted to meet many of the challenges of wildfires, but that has depended on historically consistent scales. Beetles feed on charred trees, which in turn feed returning birds. Between four and 12 years later, a forest can return to a state that can support large mammals like elk and deer, which can in turn attract natural predators. However, evolution has yet to account for the wildfires that have been caused by climate change.
One factor of this new breed of natural disaster is the area burned. Canadian wildfires during the summer of 2023 destroyed 18.5 million hectares, soundly beating out the previous record of 7.1 million. We're still learning how wildlife will adapt to this scale of unprecedented habitat loss. One study shows that spotted owls and black-backed woodpeckers, who typically thrive in post-fire environments, aren't able to cope following large-scale fires. These pyroadapted species still require some patches of vegetation left; when large swathes of land are burned, original inhabitants, however well-adapted to fire, are unlikely to return.
Generally wildfires will clear surface vegetation and return nutrients to the soil, but not burn hot enough to destroy seeds and the microbiome below the surface. These are necessary building blocks of a new forest, but Canada's wildfires this year burned deeper as well as wider. More intense fires are able to work their way into the soil where they can continue to burn long after the surface fires are done. Some can even last through an entire winter only to resurface in the spring. These subterranean fires impede the regrowth of habitats needed by wildlife. In the case of limber pine, the absence of the Clark nutcracker severely impedes regrowth rates due to its role in spreading seeds. Some tree species like jack pine actually depend on fires to spread their seeds, but even then, their regeneration is hampered by high-severity fires.
While we're still reeling from last year's fire season and bracing for the next, there's a lot of worthwhile ongoing research on wildlife impacts. Here are a few groups digging into the problem:
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