Balch, Jennifer: University of Colorado, Boulder (Project Lead)
Abatzoglou, John: University of Idaho (Co-Investigator)
Bradley, Bethany: University of Massachusetts, Amherst (Co-Investigator)
Project Funding:
2014 - 2017
NRA: 2013 NASA: Terrestrial Ecology
Funded by NASA
Abstract:
Invasive grasses are increasing fire activity globally, yet the mechanisms driving the
initiation and perpetuation of these novel fire regimes remain largely unknown. Our
proposed work will compare how short-term climate, long-term climate and land use
interact with land cover across the intermountain west to alter the probability and
behavior of fires. Climate interactions with wildfires in forested lands of the western
U.S. are well studied, with forest fires generally promoted by short-term drought and
warmer temperatures which lead to fuel desiccation and increased flammability. Fires in
arid ecosystems dominated by invasive cheatgrass (Bromus tectorum) are thought to be
largely driven by long-term moisture availability, which increases fuel biomass and
cover. However, at a regional scale, this association has not been empirically tested
despite ongoing concern about cheatgrass fires, which we have shown to be larger, faster
spreading and more frequent than fires in native land cover. Current predictive models of
fire risk, based on climatic conditions that drive forest fires, are insufficient for predicting
fires in the intermountain west because they neglect both the presence of cheatgrass and
the unique climatic and land use conditions that influence cheatgrass fires.
This research will address: How do climate and land use influence fire likelihood and
behavior in native and invaded ecosystems across the intermountain west? Using novel
techniques that we have developed to detect cheatgrass and derive fire regime metrics
from remote sensing data, we will explore this major question. We hypothesize that
cheatgrass fires will be related primarily to coupled extreme wet-dry climate conditions
and strongly associated with human ignitions, compared with native forest fires. Burn
probability and fire behavior will be derived from the MODIS burned area and active fire
products. Regional meteorological and land use maps will be used to assess climate and
land use. A regional, updated map of cheatgrass will be created from MODIS time series
to differentiate invaded land cover. Using these spatial layers, we will develop an
integrated model framework that predicts burn probability and fire behavior based on
short-term climate, long-term climate, land cover, and proximity to land use. This
analysis will: i) assess fire dynamics in the intermountain west in relation to preceding
climate conditions and proximity to anthropogenic ignition sources; and ii) model current
and mid-century fire risk in ecosystems and developed areas across the western U.S
under future climate change and land use scenarios.
A predictive framework for understanding how climate and land use interact with land
cover to promote fires will improve assessments of vulnerability of intermountain west
terrestrial ecosystems to global and regional environmental change. We will integrate
Earth observations from satellites into statistical models to create spatial predictions of
wildfire vulnerability. These analyses are critically needed given that cheatgrass doubles
the likelihood of fire and played a prominent role in the largest fire events in the
intermountain west during the last decade. Assessing the relative influence of climate and
anthropogenic drivers will also provide insights into how the cheatgrass-fire cycle can be
prevented or reversed. While climate-induced shifts in fire activity have already been
observed and predicted in forest ecosystems, little is known about how invasive grass
fuels will concurrently change fire activity on regional to global scales. Our study will
provide new mechanistic insights and foundational methods to characterize and quantify
the current and future influence of feedbacks between climate, land use, and invasive
grasses on native fire regimes.
Publications:
Abatzoglou, J. T., Balch, J. K., Bradley, B. A., Kolden, C. A. 2018. Human-related ignitions concurrent with high winds promote large wildfires across the USA. International Journal of Wildland Fire. 27(6), 377. DOI: 10.1071/WF17149
Abatzoglou, J. T., Kolden, C. A., Balch, J. K., Bradley, B. A. 2016. Controls on interannual variability in lightning-caused fire activity in the western US. Environmental Research Letters. 11(4), 045005. DOI: 10.1088/1748-9326/11/4/045005
Abatzoglou, J. T., Williams, A. P. 2016. Impact of anthropogenic climate change on wildfire across western US forests. Proceedings of the National Academy of Sciences. 113(42), 11770-11775. DOI: 10.1073/pnas.1607171113
Balch, J. K., Bradley, B. A., Abatzoglou, J. T., Nagy, R. C., Fusco, E. J., Mahood, A. L. 2017. Human-started wildfires expand the fire niche across the United States. Proceedings of the National Academy of Sciences. 114(11), 2946-2951. DOI: 10.1073/pnas.1617394114
Fusco, E. J., Abatzoglou, J. T., Balch, J. K., Finn, J. T., Bradley, B. A. 2016. Quantifying the human influence on fire ignition across the western USA. Ecological Applications. 26(8), 2390-2401. DOI: 10.1002/eap.1395
Williams, A. P., Abatzoglou, J. T. 2016. Recent Advances and Remaining Uncertainties in Resolving Past and Future Climate Effects on Global Fire Activity. Current Climate Change Reports. 2(1), 1-14. DOI: 10.1007/s40641-016-0031-0
2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- Introduced annual grass increases regional fire activity across the arid western USA (1980–2009)
-- (Jennifer Balch, Bethany Bradley, Carla D'Antonio, Jose Gomez-Dans)
[abstract]
- Lightning Ignited Fires over the Western United States
-- (John Abatzoglou, Bethany Bradley, Emily Fusco, Jennifer Balch)
[abstract]
- Quantifying human influence on fire ignitions across the western U.S.
-- (Emily Fusco, John Abatzoglou, Jennifer Balch, Bethany Bradley)
[abstract]
More details may be found in the following project profile(s):