Anthropogenic and lightning‐started fires are becoming larger and more frequent over a longer season length in the U.S.A.

Global Ecology and Biogeography - Tập 29 Số 4 - Trang 668-681 - 2020
Megan E. Cattau1,2, Carol A. Wessman1,3,4, Adam L. Mahood5,1, Jennifer K. Balch5,1
1Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado
2Human-Environment Systems, Boise State University, Boise, Idaho
3Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado
4Environmental Studies, University of Colorado, Boulder, Colorado
5Department of Geography, University of Colorado, Boulder, Colorado

Tóm tắt

AbstractAimOver the past several decades, wildfires have become larger, more frequent, and/or more severe in many areas. Simultaneously, anthropogenic ignitions are steadily growing. We have little understanding of how increasing anthropogenic ignitions are changing modern fire regimes.LocationConterminous United States.Time period1984–2016.Major taxa studiedVegetation.MethodsWe aggregated fire radiative power (FRP)‐based fire intensity, event size, burned area, frequency, season length, and ignition type data from > 1.8 million government records and remote sensing data at a 50‐km resolution. We evaluated the relationship between fire physical characteristics and ignition type to determine if and how modern U.S.A. fire regimes are changing sensu stricto given increased anthropogenic ignitions, and how those patterns vary over space and time.ResultsAt a national scale, wildfires occur over longer fire seasons (17% increase) and have become larger (78%) and more frequent (12%), but not necessarily more intense. Further, human ignitions have increased 9% proportionally. The proportion of human ignitions has a negative relationship with fire size and FRP and a positive relationship with fire frequency and season length. Areas dominated by lightning ignitions experience fires that are 2.4 times more intense and 9.2 times larger. Areas dominated by human ignitions experience fires that are twice as frequent and have a fire season that is 2.4 times longer. The effect of human ignitions on fire characteristics varies regionally. Ecoregions in the eastern U.S.A. and in some parts of the coastal western U.S.A. have no areas dominated by lightning ignitions. For the remaining ecoregions, more intense and larger fires are associated with lightning ignitions, and longer season lengths are associated with human ignitions.Main conclusionsIncreasing anthropogenic ignitions – in tandem with climate and land cover change – are contributing to a ‘new normal’ of fire activity across continental scales.

Từ khóa


Tài liệu tham khảo

10.3390/fire1020023

10.1073/pnas.1617394114

10.3390/fire1010017

10.1071/WF15083

10.1071/WF07022

10.5849/forsci.14-164

10.1179/1947461X13Z.00000000010

10.1139/x2012-147

10.1002/2014GL059576

10.1890/ES11-00271.1

10.4996/fireecology.0301003

10.1002/2013GL059086

10.1016/j.rse.2018.10.028

10.1016/S0034-4257(03)00184-6

10.1071/WF08104

Grala K., 2017, Impact of human factors on wildfire occurrence in Mississippi, United States, Forest Sector Trade, 81, 38

Groemping U., 2006, Relative importance for linear regression in R: The package relaimpo, Journal of Statistical Software, 17, 1

Harball E., 2015, Firefighters face risky “new normal” in wildfire behavior, Climatewire. E & E News

10.1016/j.rse.2017.06.027

10.1071/WF12087

10.1016/j.foreco.2009.10.024

10.1007/978-3-319-19809-5_8

10.1046/j.1365-2699.2002.00676.x

10.1071/WF07049

10.1016/j.foreco.2012.10.020

10.4236/oje.2018.812038

10.1016/j.foreco.2012.06.049

10.1016/j.jfe.2004.08.001

10.1073/pnas.0500880102

10.1371/journal.pone.0153589

10.1071/WF11115

10.5194/bg-10-247-2013

10.1002/sim.1545

Muggeo V. M. R., 2008, segmented: An R package to fit regression models with broken‐line relationships, R News Website

Nagy R. C., 2018, Human‐related ignitions increase the number of large wildfires across U.S. ecoregions, Fire, 1

National Interagency Fire Center (NIFC). (2018).Total Wildland Fires and Acres (1926‐2018). Retrieved fromhttps://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html

10.1126/science.aab2356

10.1111/j.1467-8306.1987.tb00149.x

Omernik J. M., 1995, Biological assessment and criteria: Tools for water resource planning and decision making, 49

10.1007/s00267-003-5197-2

Parisien M. A., 2016, The spatially varying influence of humans on fire probability in North America, Environmental Research Letters, 11

10.1088/1748-9326/11/3/035002

10.1071/WF15039

Pinheiro J., 2018, nlme: Linear and nonlinear mixed effects models (R package version 3.1‐137)

10.2737/SRS-GTR-171

10.1890/04-1413

Rasker R., 2015, Resolving the increasing risk from wildfires in the American West, The Solutions Journal, 6, 55

R Core Team, 2018, R: A language and environment for statistical computing

10.1016/S0304-3800(01)00483-5

Rossi J. L., 2018, Encyclopedia of wildfires and wildland‐urban interface (WUI) fires

10.1890/120329

10.1073/pnas.1617464114

10.5194/essd-6-1-2014

Short K. C., 2017, Spatial wildfire occurrence data for the United States, 1992–2013

10.1002/ecs2.2222

10.1071/WF04006

10.1016/j.ecolecon.2010.06.009

10.1073/pnas.1713885114

10.1073/pnas.1609775113

10.1016/j.landurbplan.2007.06.002

10.1007/s00477-011-0461-0

Van Lear D. H., 2002, Proceedings: The role of fire for nongame wildlife management and community restoration: Traditional uses and new directions, 2

10.1016/j.rse.2017.06.025

Vives R., 2017, Southern California’s fire devastation is “the new normal,” Gov. Brown says, Los Angeles Times

10.1098/rstb.2015.0178

10.1126/science.1128834

10.1029/2005JD006318

10.1086/662675

Thông tin
Thông tin xuất bản

Global Ecology and Biogeography

Tập 29 Số 4

668-681

Thông tin tác giả