Wildland Fire

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.

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.

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.

This updated protocol is based on the National Wildfire Coordinating Group (NWCG)’s 2017 “Guide to Preventing Aquatic Invasive Species Transport by Wildland Fire Operations” (PMS 444). The intent of this NRCG guide is to provide a more prescriptive protocol intended for a fire management audience, and to increase compliance and consistency of best management practices related to preventing AIS. The protocol applies to both ground operations and aviation and is mandatory in the Northern Rockies region. This protocol is demonstrated via a “How to Guide,” which includes detailed instructions for ordering, set up, and assembly of AIS decontamination stations; options for products/equipment based on site specific conditions; and best management practices for drafting water, which can prevent the risk of most AIS being transported or spread via wildland fire equipment. Fire management agencies in the west are taking the threat of AIS seriously and have committed to decreasing the possible risk of introduction and spread by fire management personnel.
See also: Invasive Species Subcommittee which provides national leadership in the prevention of invasive species transport by wildland fire mobile equipment and related vehicles.

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.

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.