A University of Wisconsin ecologist said at this week’s Wednesday Nite @ the Lab that climate change can broadly affect ecosystems across the country, including forests like Yellowstone National Park.
Landscape ecologist Monica Turner conducts research in Yellowstone National Park, where she studies how the landscape has transitioned since fires ravaged the park in 1988 and 2016.
“I think we all probably agree that our national parks are national treasures. These are very special places that preserve our national heritage,” Turner said. “This region is one of the largest intact landscapes on earth.”
Turner said an exceptionally dry and windy summer caused major fires in 1988, and likened those conditions to recent ones in California, which caused fire outbreaks last year. She said fire suppression — refusing to set infrequent, ecologically safe fires for forest management — did not cause the fires, only the dry conditions.
Turner said fires aren’t new to Yellowstone. She said infrequent, “stand-replacing” fires, which she said help renew some of the forestry, are historically common. She also said big, severe fires are a relatively modern occurrence.
“The fires were really, really big. They started in late June — there was no rain, no precipitation in June, July or August,” Turner said. “It was really shocking to everyone in the country, and certainly the managers and the scientists.”
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Turner said forest fires tend to create a “patchwork quilt” of burned down areas of forest alternating with healthier areas.
She studied some of these patterns, along with their vegetative growth. Her first major fire research began in 1989, after the 1988 fires ravaged over 800,000 acres of Yellowstone.
Her team found vegetation rebounded quickly after the 1988 fires — even many of the native plants. By 1989, the next summer, seedlings began to sprout. Lodgepole pines, one of the most common trees, rebounded especially quickly. Turner said now, after 25 years, it’s hard to even tell how damaging the fire was, since the lodgepole pines have grown quickly and the old, surviving trees have fallen.
“We were really surprised by how quickly the vegetation recovered,” Turner said.
Turner said this means native plants and animals have adapted well to infrequent, high-severity fires. But she said climate change changes the game — warmer temperatures, regularly earlier snowmelt and longer fire seasons cause more large fires and more area burned.
Turner’s team conducted a study on the resilience of Yellowstone to see whether or not the forests are adapting to climate change. Using models, she projected a warmer, drier climate causing more fires.
“Can our forests recover the way we’ve seen them recover in the past?” Turner asked.
Atmospheric scientist Michael Notaro has conducted research on increasing temperatures in Yellowstone, and he’s found the average park temperature has risen 2.5 degrees Celsius on average in the past few decades.
Turner said there are several solutions to explore. She said some of the most important measures to take are conducting long term studies and experiments, comparing the effects of past fires to more recent fires and using computer models to predict the future. She also said to focus on tree regeneration as the most important factor for ecosystem recovery.
“You can’t recover a forest if the trees don’t establish,” Turner said.
The 2016 fires ended up burning many of Turner’s research plots, so in 2017 she mounted a field campaign to study the effects of this fire. She found some effects common for a simple stand replacing fire, but she also found extremely high burn severity, where all the trees and logs had been consumed.
Her team found, compared to 1988, 77% less trees regenerated, and because many of the trees surrounding the burned area were immature still, fewer seeds were available in the burned area.
Using a modeling software called iLand, Turner’s team explored several climate scenarios which simulated fires. One projected a 35% decline in trees. Now, she’s continuing to study these models and examine potential forest responses.
“If 35% of the forest goes away, what will it be? Will it be grasslands, will it be meadows?” Turner asked.
Turner said this field of study is entering a new frontier, and nobody knows exactly how plant and wildlife species will adapt to changing climate.
