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Beth Pratt has spent her career protecting Los Angeles’ mountain lions, which roam an area currently engulfed by wildfires. These apex predators, also known as cougars or pumas, share a scrubby landscape with lavish private homes and a dense network of roads. When major fires take out huge areas of open space, their options are limited.
“This is the LA area – these mountain lions can’t move into the Kardashians’ back yard,” says Pratt, California executive director for the National Wildlife Federation. “My heart is very heavy right now,” she says.
The chaparral vegetation, which covers about 10% of the state of California, creates one of the most flammable landscapes in the world. It is characterised by grasslands, shrubs and short woody species designed to come back to life after the planet’s most intense wildfires.
In LA, wealthy suburbs sprawl into these habitats, and roads and development block the animals’ ability to flee elsewhere. If they haven’t already died in the flames or from smoke inhalation, they may starve over the coming days and weeks, as the land is transformed from a vibrant ecosystem into scorched earth. “Areas that did provide food, shelter, habitat, are being taken out of commission,” says Pratt.
The impact of the wildfires will “reverberate throughout all life”, she says. Human losses have been devastating, with 88,000 people told to evacuate their homes as the death toll rises to 25, and the effects will also ripple through the non-human world. Worst affected are endangered species with a limited range, and species that can’t flee the flames. Biologists are particularly concerned about threatened red-legged frogs, which were reintroduced into some streams in the Santa Monica mountains in 2014. The Woolsey fire in 2018 was followed by mudslides which wiped out much of the habitat, and scientists are waiting to see what the damage will be this time. The habitat of California newts has also been severely affected during these latest fires.
Reptiles and snakes are likely to be killed. Mammals might escape, but could struggle to set up elsewhere or find food while the ecosystem recovers. Birds are likely to survive, unless they are nesting or looking after young.
Although the landscape looks devastated, within the coming weeks nature should start to re-emerge as fresh shoots start appearing from the soil and wildlife returns.
“It looks like Armageddon now,” says Prof Stefan Doerr from Swansea University, who is co-editor-in-chief of the International Journal of Wildland Fire. However, new life is waiting in the wings. Even in raging fires, life an inch under the surface of the soil can stay relatively cool, so seeds can often survive and later germinate. “The chaparral ecosystem in California is actually a fire-adapted ecosystem, thus burning maintains its biodiversity,” says Doerr.
He says the shrub vegetation will probably take about 10 years to recover, depending on rainfall in the coming years. Grasses could start to sprout within weeks of the first rain.
Fire records suggest the landscape is adapted to high-intensity burning every 30 to 100 years. “This is one of the most flammable ecosystems on the planet. This may sound very strange, but from a longer-term ecological perspective, as such, these fires may not be particularly damaging,” Doerr says.
He says that at specific locations the fire may seem extremely damaging to the ecosystem in the short term, but at a large scale, highly destructive fires can “rejuvenate this ecosystem”.
Prof Rory Hadden, chair of fire science at the University of Edinburgh, agrees. “The nature part of the story often gets lost in this. Everyone sees these as bad things, but actually, wildfires are necessary in some parts of the world to have healthy, vibrant and diverse ecosystems.”
Because these fires have been so intense, the area is unlikely to burn in such a way for 20 years or more – all the fuel has been used up, Hadden says. “They are kind of a reset on the ecosystem.”
Research shows, however, that California’s ecosystems are increasingly threatened by human population growth, expanding urban areas, warming temperatures and droughts lasting multiple years.
In recent times, low-severity fires have been happening more frequently in many California shrub ecosystems, mainly due to human ignitions and severe weather conditions. Some locations have burned up to six times in the past 30 years. “This has actually degraded this ecosystem in something that is untypical,” says Doerr. From a purely ecological perspective, he says, “some people would say that, actually, what we’ve been lacking is a high-severity fire”.
Conditions are particularly extreme this time, and this is likely to have been exacerbated by “climate swings”, says Hadden. Fires grew quickly and there was a lot of vegetation to burn because last year was a wet year, which then dried out during the drought. Officials flagged that the Santa Ana winds were particularly dangerous because there had been no rainfall for months, with high levels of plant material creating a “recipe for fire”.
By Monday, the Palisades fire had burned about 23,000 acres (nine hectares), the Eaton fire 14,000 acres, and the Hurst fire 800 acres. The August complex fire in 2020 was more than 25 times bigger.
In the coming weeks, ash from the wildfire should provide protection to the soil and nutrients for plants to regrow. But Imma Oliveras Menor, a researcher in disturbance ecology at the University of Oxford, says that although these ecosystems have strategies to survive after intense wildfires, the severity of this one could inhibit this process.
“The main danger is that the intensity of the fires has killed the below-ground organs of the plants and thus killed them. Another plausible scenario is that the intensity of the fires has caused severe damage to the soil structure,” she says. If landscapes are highly denuded by fire and then there is heavy rainfall or high winds, this can lead to soil erosion, landslides and water contamination. It is impossible to assess the damage while the fires are still raging, she says.
When the embers have finished burning, Pratt will be keeping an eye on what wildlife returns to the area, and whether mountain lions will have been able to hold on elsewhere. “The habitat will come back, of course, but it may come back differently,” she says.
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