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This state-of-knowledge review of information on relationships between wildland fire and nonnative invasive plants can assist fire managers and other land managers concerned with prevention, detection, and eradication or control of nonnative invasive plants. The 16 chapters in this volume synthesize ecological and botanical principles regarding relationships between wildland fire and nonnative invasive plants, identify the nonnative invasive species currently of greatest concern in major bioregions of the United States, and describe emerging fire-invasive issues in each bioregion and throughout the nation. This volume can help increase understanding of plant invasions and fire and can be used in fire management and ecosystem-based management planning.

Provides a collation of best available research literature, research gaps, and a summary of published researchfor wildland fire and invasive species issues. NISC staff searched Google Scholar, USGS publications warehouse, USDA, FS TreeSearch, and AGRICOLA using keywords “invasive species”, “invasive species and fire”, “invasive species and wildfire” from 2000 to 2024. Most of the existing research explores the relationship between invasive plants, particularly grass species, and wildfire risk, fire regimes, impacts to native plant communities, and loss of wildlife habitats. These are living documents and will be updated on a regular basis.

Across the Pacific, wildfire poses a major threat to biological and cultural resources, and the threat is only predicted to become larger with climate change. In this talk, graduate students Kevin Faccenda and Kelsey Brock discuss a new tool and methodology for predicting the fire risk of invasive species before they enter a region so that management efforts can be focused on the highest risk incipient species.

This tool uses data collected from the primary literature as well as a machine learning model trained on expert survey data to predict fire risk. Their team examined this risk in a spatial context by modeling the distribution of multiple invasive plants and climatic conditions that promote wildfire across the main Hawaiian Islands. Models were created based on current-day climate conditions as well potential conditions at the end of the century to under climate change.

Invasive grass species can alter fire regimes, converting native terrestrial ecosystems into non-native, grass-dominated landscapes, creating a self-reinforcing cycle of increasing fire activity and flammable grass expansion. Analyses of this phenomenon tend to focus on the ecology and geography of the grass–fire cycle independent of human activities. Yet people introduce non-native grasses to new landscapes (eg via agriculture), facilitate their spread (eg via road networks), and are a primary source of ignition (eg via debris burning). We propose a new framework for this phenomenon that explicitly recognizes the important role of anthropogenic activities in the human–grass–fire cycle. We review links between land use and invasive species as well as ignitions, with a particular focus on the spatial and temporal co-occurrences of these activities to show that these two drivers of wildfires are inextricable. Finally, management strategies that could mitigate impacts are discussed.

Citation: Fusco EJ, et al. 2021. The human–grass–fire cycle: how people and invasives co-occur to drive fire regimes. Frontiers in Ecology and the Environment. 20(2): 117-126.

In a study recently published in the journal Ecology, "Long-term drought promotes invasive species by reducing wildfire severity," University of California, Irvine scientists uncover the intricate dance between drought, wildfires and invasive species in Southern California’s coastal sage scrub ecosystems.  Titled “Long-term drought promotes invasive species by reducing wildfire severity,” the research, led by Sarah Kimball, Ph.D., director of the Center for Environmental Biology at UCI, sheds light on the critical interplay of these factors and its profound implications for ecosystem health.

Seed banks can provide insight into a forest’s past and give land managers valuable information to help them plan for the forest’s future. For example, knowing which species may germinate after future fires is valuable, especially when nonnative invasive species in the seed bank could proliferate quickly following disturbances.

In this study, researchers analyzed the species composition of buried seeds and extant vegetation present in areas that have faced differing fire conditions over many years on the Monongahela National Forest in West Virginia.

New research from The University of Western Australia has shed light on why some invasive plants make a better comeback after a fire, outstripping native species in the race for resources.

This policy resolution addresses the management of forest and rangelands in coordination with federal agencies and addresses issues including wildland fire, invasive spaces, and collaborative efforts.

WGA resolutions are in effect for three years and then expire or are renewed. See all current WGA Policy Resolutions.

The National Cohesive Wildland Fire Management Strategy is a collaborative process with active involvement of all levels of government and non-governmental organizations, as well as the public, to seek national, all-lands solutions to wildland fire management issues.

Invasive cheatgrass, reviled by Western ranchers and conservationists, has long since earned a reputation as a firestarter, making wildfires worse and more common. Same with climate change: It's well understood that climate warming is making western wildfires worse. But it’s not just cheatgrass anymore, or just a warming West: a new analysis finds at least seven other non-native grasses can increase wildfire risk in places across the country, some doubling or even tripling the likelihood of fires in grass-invaded areas.

Images of this year’s most devastating wildfires across the West have shown forests of ponderosa, spruce and lodgepole engulfed in flames. Fires on grasslands and rangelands may not capture as much coverage, but can be just as landscape-altering as forest fires. Plus, they can spread more rapidly, and in some cases, cause more damage than fires in forested areas. Across the West, the increasing prevalence of invasive plants, and the growing influence of climate change, is changing the relationship between vast rangelands, drought, and wildfire.

Scientists have long warned that Hawaii’s cover of nonnative shrubs is kindling waiting to burn.
See also: Additional Invasive Species related articles

Learn how the U.S. government is responding to the Hawaii wildfires affecting Maui and the Big Island.

Cattle grazing on a nearly half mile wide targeted strip of cheatgrass near Beowawe, Nevada, created a firebreak that helped limit a rangeland fire to just 54 acres this past August compared to rangeland fires that more commonly race across thousands of acres of the Great Basin. This "targeted grazing" firebreak and eight others are part of an evaluation project being managed by the Agricultural Research Service (ARS), partnering with other federal, state and local agencies and local cattle ranchers in Idaho, Nevada and Oregon. These demonstration sites are being studied so the concept's efficacy and environmental impacts can be uniformly evaluated and compared.

Cheatgrass, also known as downy brome, is an invasive annual that dominates more than 100 million acres of the Great Basin in the western U.S. Germinating each winter, cheatgrass grows furiously in spring and dies in early summer, leaving the range carpeted in golden dry tinder. The Great Basin now has the nation's highest wildfire risk, and rangeland fires are outpacing forest fires when it comes to acreage destroyed.

Fire management can help maintain natural habitats, increase forage for wildlife, reduce fuel loads that might otherwise lead to catastrophic wildfire, and maintain natural succession. Today, there is an emerging challenge that fire managers need to be aware of: invasive plants. Fire management activities can create ideal opportunities for invasions by nonnative plants, potentially undermining the benefits of fire management actions. This manual provides practical guidelines that fire managers should consider with respect to invasive plants.

Fire-friendly grasses have invaded new habitats around the world. Five species (cheatgrass, cogon grass, gamba grass, molasses grass, and buffelgrass) are considered among the most problematic grasses, threatening to transform entire ecosystems.

New geographic strategies provide the landscape context needed for effective management of invasive annual grasses in sagebrush country. Identifying and proactively defending intact rangeland cores from annual grass invasion is a top priority for management. Minimizing vulnerability of rangeland cores to annual grass conversion includes reducing exposure to annual grass seed sources, improving resilience and resistance by promoting perennial plants, and building capacity of communities and partnerships to adapt to changing conditions and respond to the problem with appropriate actions in a timely manner.

Citation: Maestas JD, et al. 2022. Defend the core: maintaining intact rangelands by reducing vulnerability to invasive annual grasses. Rangelands. 000: 1-6.