More Grasses More Fires: Invasive grasses increase fire occurrence and frequency across US ecoregions
Written by Berlin Nelson, edited by Emily Fusco
Summary
Wildfire risk is projected to increase with climate change, including in the Northeast U.S. Though their effects in the Northeast region are understudied, worsening invasions of non-native grasses may be another important piece of the puzzle in understanding fire regimes. Invasive grasses impact wildfires by providing flammable fuels that can ignite easily and by providing continuous connection between fuel sources. Compared to trees and shrubs, grasses also tend to regrow quickly after a fire, resulting in more flammable fuels and potential for an area to burn again in a short time frame.
Fusco et al. found eight grass species significantly raise the rate of fire occurrence, including two species that are currently widespread invasives in the Mid-Atlantic region. One of these species, stiltgrass (Microstegium vimineum), invades forest understories and creates a flammable layer of thatch. The other species, maiden grass (Miscanthus sinensis) is a large ornamental grass that is commonly planted across the Northeast (and is prohibited from sale in Massachusetts, New Jersey, and New York). Regional fire risk is already increasing due to more extreme droughts driven by climate change. Managing wildfire risk in the region will be increasingly important as climate change and flammable invasive grass species increase wildfire potential in the Northeast.
Take Home Points
Invasive grasses change fire regimes by providing fuel, increasing fuel continuity, increasing the range of conditions suitable for fire, and regrowing quickly.
Two invasive grass species that have been linked to increased wildfire risk are becoming more common in the Northeast.
Management Implications
Managing current grass invasions and preventing future introduction of fire promoting invasive grass species is an important piece of managing wildfire risk.
Managing invasive grasses will be key for mitigating the ecological and economic consequences of wildfire
Keywords
Impact study, terrestrial plant, fire, Miscanthus sinensis, Microstegium vimineum