Utah professor discovers extinction of ancient herbivores fueled wildfires. Here’s why that matters.

This story is part of The Salt Lake Tribune’s ongoing commitment to identify solutions to Utah’s biggest challenges through the work of the Innovation Lab.

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Walking through the back corridors of the University of Utah’s Natural History Museum, Tyler Faith can’t look at the wooden crates without thinking about Raiders of the Lost Ark.

“After bones, crates are my favorite thing,” Faith said. As curator of archaeology for the museum, a professor in the anthropology department, and a guy who gets to study giant sloths and saber-toothed cats all day, Faith lives every 8-year-old’s dream job(s).

“I guess I just never grew up.”

His work is usually firmly planted in the past, but recent research conducted with colleagues at Yale and in South Africa may have deep importance for our future.

Despite its name, the ice age saw its fair share of wildfires, particularly towards the end.

Humans were partly to blame, as was likely a catastrophic comet that burned some 10% of the earth’s surface almost 13,000 years ago. But Faith and his colleagues found another surprising culprit: the disappearance of large grazers.

“As these ancient giants became extinct, there was nothing left to keep grasses under control,” Faith said, standing in front of a few of Utah’s own long-gone ice age behemoths: the short-faced bear, the mammoth, and the ancient bison. “Instead of mammoths and mastodons, fire became the ultimate herbivore.”

Faith’s research offers five key lessons as we face a new age of climate change.

Lesson 1: Grazers or wildfire, something will eat the grass

Faith’s work adds to studies where researchers fenced off an area of savannah grassland to see what happens when herbivores are closed off.

“Not surprisingly,” Faith said, “exclude herbivores and vegetation grows and becomes fuel for fires.”

The new study looks at charcoal records from 410 sites around the globe and compares them with the extinction of large grazers between 50,000 to 6,000 years ago. The researchers found that continents that saw greater loss of large grazers (North & South America) saw a greater uptick in wildfires.

Looking at the full scale of Earth’s history, fire and herbivores have acted to control grasses and vegetation.

“It’s a balance,” Faith said, “but if you take out one, the other is going to take its place.”

Lesson 2: Wild herbivores are declining worldwide

Wildlife populations are declining across the globe.

“Look around,” Faith said, “you don’t see bison roaming around. Outside of farms and national parks, animal populations are on the decline.”

Faith said this can be seen on the scale of millennia and on the scale of decades: “We’ve seen real population declines in our lifetime. In the geologic time scale that’s less than nothing.”

Lesson 3: Pleistocene Park probably isn’t the answer

In September, Colossal Bioscience went public with their effort to resurrect (de-extinct) the woolly mammoth and reintroduce them to Siberia.

Colossal, oddly enough, is a private company. Their website boldly proclaims, “We have the DNA,the technology and the leading experts in the field. Next, we will have the woolly mammoth. Alive again.”

There are arguments for what is known as “rewilding” – reintroducing missing species into ecosystems as was done with the reintroduction of wolves in certain areas. Faith notes that it might make sense to introduce some comparable species to replace North America’s missing large grazers, “but ecological systems are so complex, and every little change comes with a cascade of consequences, that we have to be cautious.”

Faith uses cheatgrass, which serves as fuel for most of Utah’s valley and foothill fires, as an example. “Mammoths could take care of cheatgrass for us, maybe.”

But that is a big maybe. Some past research has suggested that grazing cattle could help prevent cheatgrass fires, but a more recent study shows cattle grazing as a spreader of cheatgrass.

Faith hopes to see experiments come out of the team’s research, some testing of ideas, but done with all due caution.

Lesson 4: We should rethink wild lands management

Faith sees thousands of years of evidence supporting the idea that wildfire prevention through fire suppression is a flawed approach.

“Extinction killed off large herbivores, vegetation grew, fire took over the job of controlling vegetation,” he said. “If you continually suppress wildfires, the same thing happens – biomass builds up, you get more and more fuel and you’ve got a formula for mega-fires like we keep seeing in the west.”

Lesson 5: Humans are part of the system

“People say just take out the human component and everything will be fine, but that gets depressing because the human footprint is everywhere,” Faith said.

Faith sees accepting our role in the ecological system as critical to making change: “Once you get over that mental hurdle and accept we’re part of the system, it’s empowering. … We have a lot of studying to do, but if we better accept and understand our role, we can start to make positive change.”