Ability of a species and/or its habitat to recover from stresses and disturbances. Resilient ecosystems have the capacity to reorganize and regain their fundamental structure, processes, and functioning when altered by stressors like invasive species and disturbances like improper livestock grazing and altered fire regimes. Species resilience is closely linked to ecosystem resilience and refers to the ability of a species to recover from stressors and disturbances.
Capacity of an ecosystem to retain its fundamental structure, processes and functioning (or remain largely unchanged) despite stresses, disturbances, or invasive species. Resistant ecosystems have the capacity to retain their fundamental structure, processes, and functioning when exposed to stressors, disturbances, or invasive species. Resistance to invasion by nonnative plants is increasingly important in sagebrush ecosystems; it is a function of the abiotic and biotic attributes and ecological processes of an ecosystem that limit the population growth of an invading species.
In this video, Jeanne Chambers explains how the concepts of Resilience and Resistance help managers make better decisions on management objectives.
Informing Wildfire and Fuels Management Strategies
to Conserve Sage-Grouse
Vegetation and fuels management projects are important for the conservation, maintenance, and restoration of sagebrush landscapes. Resilience and resistance concepts provide a science-based background that can inform strategic placement of fuels treatments, augment effective fire operations, and inform allocation of scarce assets during periods of heightened fire activity across the Interior West. Collectively, fuels management includes vegetation projects that mitigate wildfire risk, improve resilience to disturbance, and restore habitat, as well as habitat protection projects (actions intended to protect intact sage-grouse habitat):
- Mechanical treatments are typically applied to reduce fuel loading or to change species composition consistent with land management objectives.
- Prescribed burning is used to improve habitat conditions or create fuel conditions that reduce negative impacts from wildfire.
- Chemical and seeding treatments are conducted to reduce invasive species, and to shift species composition to native or more fire resistant species.
Managers are designing management activities that reflect the unique ecosystem responses that occur across environmental gradients. Resilience and resistance concepts are especially relevant for evaluating tradeoffs related to current ecological conditions, rates of recovery, and possible ecological consequences of different fire management activities. For example, prioritizing initial attack efforts based on ecological types and their resilience and resistance at fire locations is one application of resilience and resistance concepts. Also, fire prevention efforts can be focused on intact, high quality habitats with inherently low resilience and resistance where human ignitions have commonly occurred.
Fuels management projects are often applied on a landscape scale to:
- Constrain or minimize fire spread;
- Alter species composition;
- Reduce fire intensity, severity, or effects;
- Create fuel breaks or anchor points that augment fire management efforts;
- Improve wildlife habitat;
- Create resilient landscapes; and
- Restore habitats or vegetation conditions.
These activities are selectively used based on the projected ecosystem response, anticipated fire patterns, and probability of success. For example, in areas that are difficult to restore due to low to moderate resilience, fuel treatments can be placed to minimize fire spread and conserve sagebrush habitat. In cooler and moister areas with moderate to high resilience and resistance, mechanical or prescribed fire treatments may be appropriate to prevent conifer expansion and dominance.
Given projected climate change and longer fire seasons across the western U.S., fuels management represents a proactive approach for modifying large fire trends and maintaining desired vegetation patterns. Fire operations and fuels management programs contribute to a strategic, landscape approach when coupled with data that illustrate the likelihood of fire occurrence, potential fire behavior, and risk assessments. In tandem with resilience and resistance concepts, these data can further inform fire operations and fuels management decisions.
Proactive fuels management practices differ in the eastern vs. western portion of the sagebrush biome. For example, roadside linear fuel breaks are seldom used in the east, but are more commonly used in the west. Also, while conifer expansion in the western range is largely pinyon and juniper species, expanding conifers in the eastern range include limber pine (Pinus flexilis), Douglas fir (Pseudotsuga menziesii), and ponderosa pine (Pinus ponderosa).
Mechanical treatments of expanding conifers, which include mastication and chainsaw treatments, are increasingly used in the eastern and western parts of the sagebrush biome to retain sagebrush cover. Prescribed burning is a fuels management tool which is selectively and cautiously applied, typically to:
- Reduce downed woody fuels resulting from mechanical treatments;
- Treat expanding conifers;
- Convert conifer woodlands to shrub-steppe;
- Create age class and structural diversity within sagebrush communities; and
- Restore riparian systems through multi-phased treatments.
Managers are cognizant of the tradeoffs related to sagebrush removal through burning, and apply this tool in consultation with wildlife managers and in consideration of site conditions. Additional fuels management practices include monitoring and treating areas with invasive annual grass populations with herbicides and seedings where insufficient perennial grasses and forbs exist for recovery, and installing fuels breaks, which can complement fire suppression effectiveness.
The tools and data presented here can be used by fire and fuels managers, in cooperation with resource managers, to inform strategies for fire operations and fuels management related to suppression responses, treatment planning, and post-fire management. Post-fire rehabilitation is a cross-cutting effort involving disciplines such as range, wildlife, fire, and fuels management. Managers apply knowledge of seed zones, resilience and resistance, and ecological sites to inform rehabilitation strategies.
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