A conservation paradox in the Great Basin—Altering sagebrush landscapes with fuel breaks to reduce habitat loss from wildfire

Abstract

Interactions between fire and nonnative, annual plant species (that is, "the grass/fire cycle") represent one of the greatest threats to sagebrush (Artemisia spp.) ecosystems and associated wildlife, including the greater sage-grouse (Centrocercus urophasianus). In 2015, U.S. Department of the Interior called for a "science-based strategy to reduce the threat of large-scale rangeland fire to habitat for the greater sage-grouse and the sagebrush-steppe ecosystem." An associated guidance document, the "Integrated Rangeland Fire Management Strategy Actionable Science Plan," identified fuel breaks as high priority areas for scientific research. Fuel breaks are intended to reduce fire size and frequency, and potentially they can compartmentalize wildfire spatial distribution in a landscape. Fuel breaks are designed to reduce flame length, fireline intensity, and rates of fire spread in order to enhance firefighter access, improve response times, and provide safe and strategic anchor points for wildland fire-fighting activities. To accomplish these objectives, fuel breaks disrupt fuel continuity, reduce fuel accumulation, and (or) increase plants with high moisture content through the removal or modification of vegetation in strategically placed strips or blocks of land. Fuel breaks are being newly constructed, enhanced, or proposed across large areas of the Great Basin to reduce wildfire risk and to protect remaining sagebrush ecosystems (including greater sagegrouse habitat). These projects are likely to result in thousands of linear miles of fuel breaks that will have direct ecological effects across hundreds of thousands of acres through habitat loss and conversion. These projects may also affect millions of acres indirectly because of edge effects and habitat fragmentation created by networks of fuel breaks. Hence, land managers are often faced with a potentially paradoxical situation: the need to substantially alter sagebrush habitats with fuel breaks to ultimately reduce a greater threat of their destruction from wildfire. However, there is relatively little published science that directly addresses the ability of fuel breaks to influence fire behavior in dryland landscapes or that addresses the potential ecological effects of the construction and maintenance of fuel breaks on sagebrush ecosystems and associated wildlife species. This report is intended to provide an initial assessment of both the potential effectiveness of fuel breaks and their ecological costs and benefits. To provide this assessment, we examined prior studies on fuel breaks and other scientific evidence to address three crucial questions: (1) How effective are fuel breaks in reducing or slowing the spread of wildfire in arid and semi-arid shrubland 1 U.S. Geological Survey. 2 U.S. Forest Service. 2 ecosystems? (2) How do fuel breaks affect sagebrush plant communities? (3) What are the effects of fuel breaks on the greater sage-grouse, other sagebrush obligates, and sagebrush-associated wildlife species? We also provide an overview of recent f...

The ecological uncertainty of wildfire fuel breaks: examples from the sagebrush steppe

“…However, most of these records are relatively recent (post‐2012) and often incomplete (eg many fuel breaks remain unmapped), and the required “yes/no” responses often lack ancillary information to describe exactly how treatments affected fire behavior or aided suppression (Shinneman et al . ). Additionally, underreporting of fuel break failure may be problematic, as suggested by a cursory analysis in southwestern Idaho documenting breaches of fuel breaks by recent (2012–2016) fires (Shinneman et al .…”

“…; Shinneman et al . ), and require regular maintenance (eg blading, mowing, herbicides) to avoid undesirable shifts in vegetation and fuels. The overall effect of fuel breaks on wildlife species diversity in sagebrush ecosystems is largely unknown but likely depends on factors such as treatment type and timing, plant community response, and wildlife species’ resource and life‐history needs (Beck et al .…”

“…Despite the potential for fuel breaks to help reduce unwanted wildfire (Figure ), scientific research on their ecological effects as well as their effectiveness (ie to restrain wildfire) is scarce for many ecosystems (Shinneman et al . ). Many scientists and resource managers are therefore concerned that the ecological costs associated with fuel breaks may outweigh any potential benefits (eg Keeley ).…”

“…However, the thousands of kilometers of new fuel breaks being proposed could more than double the length and area already occupied by fuel breaks in the region (Shinneman et al . ). If fully implemented, this may be one of the largest fuel break networks in the world that is ostensibly designed to help conserve an imperiled ecosystem.…”

“…There are an estimated ≥10,000 linear kilometers of fuel breaks already in the Great Basin, occupying approximately 130,000 ha (Shinneman et al . ). Priority future fuel breaks proposed by the US Bureau of Land Management could more than double these numbers, although implementation will undergo further agency planning and review, and includes both new fuel break construction as well as maintenance and enhancement of existing ones.…”