Land-Use Type as a Driver of Large Wildfire Occurrence in the U.S. Great Plains
Victoria M. Donovan, Carissa L. Wonkka, David A. Wedin, Dirac Twidwell
Abstract
Wildfire activity has surged in North America’s temperate grassland biome. Like many biomes, this system has undergone drastic land-use change over the last century; however, how various land-use types contribute to wildfire patterns in grassland systems is unclear. We determine if certain land-use types have a greater propensity for large wildfire in the U.S. Great Plains and how this changes given the percentage of land covered by a given land-use type. Almost 90% of the area burned in the Great Plains occurred in woody and grassland land-use types. Although grassland comprised the greatest area burned by large wildfires, woody vegetation burned disproportionately more than any other land-use type in the Great Plains. Wildfires were more likely to occur when woody vegetation composed greater than 20% of the landscape. Wildfires were unlikely to occur in croplands, pasture/hay fields, and developed areas. Although these patterns varied by region, wildfire was most likely to occur in woody vegetation and/or grassland in 13 of 14 ecoregions we assessed. Because woody vegetation is more conducive to extreme wildfire behaviour than other land-use types in the Great Plains, woody encroachment could pose a large risk for increasing wildfire exposure. Regional planning could leverage differential wildfire activity across land-uses to devise targeted approaches that decrease human exposure in a system prone to fire.