The increase in warmer and drier climates predicted to occur under climate change scenarios has led many scientists to also predict a global increase in the number of wildfires.
But a new study in the May issue of Ecological Monographs shows that in some cases, changes in the types of plants growing in an area could override the effects of climate change on wildfire frequency.
Philip Higuera of Montana State University and his colleagues show that although changing temperatures and moisture levels set the stage for changes in wildfire frequency, they can often be trumped by changes in the distribution and abundance of plants. Vegetation plays a major role in determining the flammability of an ecosystem, he says, potentially dampening or amplifying the impacts that climate change has on fire frequencies.
"Climate is only one control of fire regimes, and if you only considered climate when predicting fire under climate-change scenarios, you would have a good chance of being wrong," he says. "You wouldn't be wrong if vegetation didn't change, but the greater the probability that vegetation will change, the more important it becomes when predicting future fire regimes."
Higuera and his colleagues examined historical fire frequency in northern Alaska by analyzing sediments at the bottom of lakes. Using meter-long samples, called sediment cores, Higuera and his colleagues measured changes in the abundance of preserved plant parts, such as pollen, to determine the types of vegetation that dominated the landscape during different time periods in the past. Like rings in a tree, different layers of sediment represent different times in the past.
The researchers used radiocarbon dating to determine the sediment's age, which dates as far back as 15,000 years. They then measured charcoal deposits in the sediment to determine fire frequency during time periods dominated by different vegetation. Finally, they compared their findings to known historical climate changes.
In many cases, the authors discovered, changes in climate were less important than changes in vegetation in determining wildfire frequency. Despite a transition from a cool, dry climate to a warm, dry climate about 10,500 years ago, for example, the researchers found a sharp decline in the frequency of fires. Their sediment cores from that time period revealed a vegetation change from flammable shrubs to fire-resistant deciduous trees, a trend which Higuera thinks was enough to offset the direct effects of climate on fire frequencies.
"In this case, a warmer climate was likely more favorable for fire occurrence, but the development of deciduous trees on the landscape offset this direct climatic effect. Consequently, we see very little fire," Higuera says.
Similarly, during the development of the modern spruce-dominated forest about 5000 years ago, temperatures cooled and moisture levels increased, which – considered alone – would create unfavorable conditions for frequent fires. Despite this change, the authors observed an increase in fire frequency, a pattern they attribute to the high flammability of the dense coniferous forests.
Higuera thinks this research has implications for predictions of modern-day changes in fire regimes based on climate change. These findings, Higuera says, emphasize that predicting future wildfire frequency shouldn't hinge on the direct impacts of climate change alone.
"Climate affects vegetation, vegetation affects fire, and both fire and vegetation respond to climate change," he says. "Most importantly, our work emphasizes the need to consider the multiple drivers of fire regimes when anticipating their response to climate change."
To access high-resolution images associated with this release, contact Christine Buckley at firstname.lastname@example.org.
The Ecological Society of America is the world's largest professional organization of ecologists, representing 10,000 scientists in the United States and around the globe. Since its founding in 1915, ESA has promoted the responsible application of ecological principles to the solution of environmental problems through ESA reports, journals, research, and expert testimony to Congress. ESA publishes four journals and convenes an annual scientific conference.
When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Ecology, The Environment and Conservation
24.05.2018 | Medical Engineering
24.05.2018 | Physics and Astronomy