Burning Questions: Discovering the Roles of Fire, Fuel, and Fauna

By Cosette Reeves

Every summer, smoke from nearby wildfires blankets Salt Lake Valley, clouding Utah’s iconic mountains. While it’s easy to view fire as the enemy here, it has been a natural and essential part of the Earth’s system for hundreds of millions of years, playing a vital role in maintaining the health of our landscapes. Scientists around the globe are working hard to uncover the complex interplay between wildfire, climate change, herbivore loss, and human activity to help us understand how these factors interact and how we can help better foster the health and resilience of our natural world. 

NHMU’s News from Our Scientists exhibit features a new story every six months highlighting the work of Museum scientists.

The Natural History Museum of Utah (NHMU) is showcasing a new story in its rotating News from Our Scientists exhibit, exploring the pivotal roles wildfire and herbivores play in shaping our world. This fascinating exhibit, brought to life by NHMU’s dedicated Exhibits Team, highlights the work of NHMU Chief Curator and Curator of Paleontology Dr. Tyler Faith, NHMU Curator of Botany Dr. Mitchell Power, and University of Utah undergraduate intern Eliana Massey. Based on research led by Dr. Faith and funded by the National Science Foundation (NSF), the exhibit offers an engaging look at some of the world’s most transformative forces.   

Grasslands, which cover a significant portion of the planet, are the most flammable ecosystems on Earth. Grasses not only serve as fuel for fires but also regenerate quickly, allowing the same areas to burn annually. However, grazing herbivores can diminish the amount of available fuel and, therefore, help moderate wildfire activity. While it is well understood that grazers influence fire frequency on small spatial scales, Dr. Faith and his collaborators aimed to explore the impact of grazers on continental scales. After gathering an extensive paleo record of fossil and environmental data across the globe, they discovered a strong correlation between herbivore extinction and increased wildfire activity, demonstrating the critical role grazers play in regulating wildfires across entire continents.   

Building on this discovery, the team dug deeper and analyzed records spanning the past 12,000 years in Africa to better understand how climate change influences wildfire patterns. This relationship proved to be more complex than it might initially seem. In arid environments where the amount of fuel is a limiting factor, long-term increases in rainfall due to climate change promote plant growth, enhancing fuel loads and leading to greater fire activity. Yet, in wetter environments, the limiting factor shifts to fuel moisture, and increased rainfall leaves fuels too wet to burn. This means the potential of fire is not simply determined by changes in fuel load alone but by the delicate balance between fuel availability and fuel moisture. After refining this model, the team applied it to wildfire records across Africa and found strong evidence supporting the relationship between climate change and the frequency of wildfires.

With these insights in hand, the team shifted their focus to quantifying how much of the available fuel herbivores consume and, consequently, the extent to which herbivore extinction—driven by climate change and human activity—impacts wildfire patterns today. Throughout the last year, they have meticulously combed through literature from the past century to find as many observations as possible on vegetation consumed by grazers, aiming to use this data to develop a more reliable model for such calculations. While other scientists’ efforts on this have heavily relied on both experimental and theoretical work, neither approach has proven to be entirely adequate for large-scale generalizations.

This project is still underway, but Dr. Faith began collaborating with others at NHMU to share his findings with the public. After taking Dr. Faith’s Intro to Museum Collections class at the University of Utah and expressing interest in the project, Eliana Massey was offered an internship to work side by side with Dr. Faith and help design the exhibit on this work. Eliana, who has been involved with the Museum in various capacities, described this opportunity as particularly fulfilling. “It was a unique and cool internship—it’s not very often that you get to see a project from the beginning to the end, especially at such a large Museum,” she explained. She played a key role in nearly every aspect of this exhibit, including the fascinating process of extracting a lake sediment core—a valuable paleoenvironmental proxy—for display. 

NHMU’s Exhibits Team assists with the extraction of a sediment core under the guidance of Dr. Mitchell Power.

Sediment cores provide an extraordinary window into the past, preserving a wealth of information about the natural history of the area. Within, we can find layers of charcoal derived from wildfire, pollen from nearby vegetation, and spores from fungi found only in herbivore dung to give us a detailed view of what the local landscape looked like and how it changed over time. Using the core, scientists can build an age-depth model, dating the sediment layers by every 5 – 10 centimeters to construct a detailed timeline of environmental history, making this an invaluable tool for scientists and a strong addition to the exhibit’s story. Dr. Power, who has extensive experience in extracting sediment cores, led the research team and several members of NHMU’s Exhibits Team on a field trip to Tony Grove Lake in Logan Canyon. Together, they used specialized equipment to successfully extract two usable cores with thousands of years’ worth of sediment record. 

Members of NHMU's exhibits team carefully preserve a lake core for display.

Although Dr. Power is well-versed in extracting sediment cores for study, maintaining them for display presented a new yet crucial challenge—how do you showcase a meter-long column of mud? Asked by colleagues on several occasions to find a way to do so, Dr. Power set out to develop a method to stabilize the cores and safeguard them from mold and other environmental damage. This effort involved close collaboration with NHMU’s Exhibits Team, particularly Assistant Exhibit Developer Casey Clifford, who conducted extensive research on potential display methods. The team ultimately chose an epoxy substrate, carefully piping in a mixture of acetone and Paraloid (a thermoplastic resin) in a series of steps to solidify and reinforce the core. This innovative method marks the first time the scientific community has successfully prepared a sediment core for display, and it’s now featured here at the Museum as of December 10, 2024. Dr. Faith proudly remarked, “We are the leading edge of embedding mud with epoxy.”

This project exemplifies NHMU’s innovative and collaborative approach to science and storytelling, highlighting the momentum museum research can bring to the global scientific community.