How Animals Are Coping with California’s Wildfires

Right now, dozens of wildfires^[1]
are raging across the world. Earlier this month, blazes broke out
in Greece^[2], and consistent heat and
drought conditions this summer have set the table for fires in
Sweden,
Norway, Finland, Spain, and England^[3]. In North America,
states like California, Oregon, and Alaska have reported
persistent, deadly blazes that have already charred millions of
acres of land this year alone.

Currently, wildfires in Northern
California are leaving a trail of destruction. The Carr
Fire^[4] in Redding, which is
about 160 miles north of Sacramento, has
claimed several lives^[5]
and destroyed hundreds of buildings. But for some wildlife species
that have evolved to live with fire, the scenario is not so
dire.

In these regions, “wildlife have a
long-standing relationship with fire,” ecosystem ecologist Mazeika
Sullivan^[6] of the Ohio State
University said in a previous interview. “Fire is a natural part of
these landscapes.”

Many animals have some ability to escape
the heat. Birds may fly away, mammals can run, and amphibians and
other small creatures burrow into the ground, hide out in logs, or
take cover under rocks. And other animals, including large ones
like elk, will take refuge in streams and lakes.

Gabriel d’Eustachio, a bush firefighter
in Australia, said in 2014 that he has witnessed a mass-movement of
small invertebrates fleeing from blazes. “You get overrun by this
wave of creepy crawlies walking ahead of the fire,” he says. (See
video: “Fighting
Wildfires^[7].”)

“In those short-term situations,” such as
when creatures flee from flames, says Sullivan, “there’s always
winners and losers.”

A moderate level of fire in areas where
it naturally occurs may also increase the “patchiness” of forests
and create a wider variety of micro-habitats, from open meadows to
re-growing forest, research shows. Having a diversity of biomes
supports
multiple species of animals^[8]
and the ecosystem as a
whole^[9].

Scientists don’t have any good estimates
on the number of animals that die in wildfires each year. But there
are no documented cases of fires—even the really severe ones—wiping
out entire populations or species. (Watch: “Fish
Skin Bandages Help Burned Bears and Cougar Heal^[10]”)

Of course, some animals do die in the smoke and fire—those that
can’t run fast enough or find shelter. Young and small animals are
particularly at risk. And some of their strategies for escape might
not work—a koala’s natural instinct to crawl up into a tree, for
example, may leave it trapped. (See “Koala
Rescued From Australia Fires^[11].”)

Heat can kill too—even organisms buried deep in the ground, such
as fungi. Jane
Smith^[12], a mycologist with the
U.S. Forest Service in Corvallis, Oregon, has measured temperatures
as high as 1,292 degrees Fahrenheit beneath logs burning in a
wildfire, and 212 degrees Fahrenheit a full two inches below the
surface.

The California wildfires are affecting more than just organic
life. Particularly high temperatures are forming new clouds, called
pyrocumulus clouds^[13]. Usually created out of
volcanic eruptions, pyrocumulus clouds are quickly formed when heat
burns moisture out of vegetation, which latches on to smoke
particles and condenses as they rise. These dark gray giants are
filled with smoke and ash, and can be nearly five miles high.

Wild areas like forests and prairies naturally grow and change
in composition over time. A year-old forest will have a different
set of plants and animals living in it than a forest that’s 40
years old. A disturbance like a wildfire can serve as a sort of
reset button, letting an old forest be born again, says Patricia Kennedy^[14], a wildlife biologist
at Oregon State University in Union. And “a lot of species require
that reset.” (See National Geographic’s wildfire
pictures^[15].)

Exactly what happens after a fire occurs depends on the
landscape, the severity of the fire, and the species involved. But
the event always sparks a succession of changes as plants,
microbes, fungi, and other organisms recolonize the burned land. As
trees and plants age, light and other features change—and the
composition of creatures in the area changes in response.

Streams and other water bodies that flow through a burned area
can also change. Water flow, turbidity, chemistry, and structure
can be altered. Fish may temporarily move away. And there can be
short-term die-offs among aquatic invertebrates, which can affect
animals on land.

“The water and the land,” says Sullivan, “are highly
connected.”

Many species actually require fire as a part of their life
history. Heat from the flames can stimulate some fungi, like morel
mushrooms, to release spores. Certain plants will seed only after a
blaze. Without fire, those organisms can’t reproduce—and anything
that depends on them will be affected. (Related: “Why
These Birds Carry Flames In Their Beaks^[16]”)

So, although fire can have unexpectedly positive outcomes for
some species, too many blazes are bad for most. Since the early
1970s, the wildfire season in the western U.S. has grown from
about
five to more than seven months^[17]. Climate change drives
up temperatures, causing the snow atop mountains to melt, and
making forests deprived of that moisture more susceptible to
burning.

As Kennedy says, fire is a bad thing when it happens in your
backyard. But to an extent, it can be a healthy event for a
forest—and for at least some of the animals that live there.