How do invasive species affect wildfire behavior?

Invasive species significantly influence wildfire behavior by introducing new fuel types and increasing fuel loads. Many invasive plants can grow rapidly and in densely packed formations, which can lead to an increase in the amount and variety of combustible materials available for wildfire ignition and spread. These species often displace native vegetation, which may be better adapted to the local ecosystem and may not carry fire as readily.

The presence of invasive species can alter the fire regime in an area by changing the timing, intensity, and frequency of wildfires. For example, species like cheatgrass are known to provide a continuous layer of fine fuel that dries out quickly and becomes highly flammable, leading to more frequent and intense fires. This shift in fuel composition not only affects the spread of fires but can also have ecological consequences that impact local habitats and wildlife.

In contrast, reducing fuel loads, having no impact on wildfire behavior, or creating barriers to fire spread do not accurately reflect the role invasive species play in wildfires. Invasive species tend to exacerbate fire risks rather than mitigate them; therefore, their introduction can lead to more severe wildfires and challenge fire management efforts.