Resistance & Resilience
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In mountain big sagebrush associations, simulations of prescribed burn fuel treatments indicated that treatments were economically efficient in ecosystems dominated by sagebrush or in the early to mid-phases of pinyon-juniper expansion when compared to expected suppression costs. For low sagebrush, mechanical fuel treatments were not economically efficient, mainly due to higher associated costs. For black sagebrush, mechanical fuel treatments led to increased suppression costs in three of six potential treatment settings largely due to increases in surface fuels and fire behavior.
While wildfire suppression cost savings were the primary benefit, economic benefits included enhanced wildlife habitat, water availability, livestock grazing, and recreational opportunities. This research suggests that if land managers consider treatment costs along with specific sagebrush associations and their resilience and resistance levels, they can plan more effective and efficient fuel treatments.
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In a collaborative effort with Dixie National Forest, Sarah Barga, a research botanist with the Rocky Mountain Research Station, outlines a project focused on building ecosystem resilience and resistance in Utah’s Pine Valley Ranger District. A team of specialists from the National Forest system, Utah State University, and Rocky Mountain Research station are examining the roles of invasive species, local vegetation, and fire history in managing this key landscape. The project launched in 2024 with initial ground truthing surveys to build out localized strategies to support the recovery of native understory plants resistant to invasives like cheatgrass and resilient to wildfire. The work underscores the significance of adapting efforts at the local level and the role of partnerships in integrating knowledge into future planning for improved management outcomes.
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We investigated the relationship between aspen regeneration and site moisture availability potential using ecosystem type as a proxy. We hypothesized that aspen stands growing along perennial-flowing streams would support higher aspen regeneration densities than upland aspen stands. We compared stand structure, groundcover composition, and regeneration densities of nine riparian aspen stands with nine paired upland aspen stands in the Caribou-Targhee National Forest. Aspen regeneration densities were significantly higher in the riparian aspen stands (845. 3 + 318.7 stems ha-1) compared to the upland aspen stands (249.1 + 74.1 stems ha-1) for regeneration shorter than one meter (p = 0.0391). Riparian stands also exhibited significantly higher forb (p< 0.001) and graminoid (p < 0.001) cover compared to upland aspen stands, suggesting that riparian sites provided higher site moisture availability. We suggest that riparian areas may provide refugia for aspen in the future considering projections of increased incidence of acute drought.
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This guide identifies seven primary components that largely determine the outcomes of vegetation treatments to reduce fuels and maintain or increase resilience to disturbance and resistance to invasive annual plants. The components are (1) characteristics of the ecological type, (2) current, pre-treatment vegetation, (3) disturbance and management history, (4) fuel characteristics and appropriate treatments, (4) treatment severity and ecological response, (6) seeding considerations, and (7) post-treatment monitoring and management. Key questions and a set of tools are provided to assess the components. The guide provides information to (1) evaluate resilience and resistance for potential treatment areas, (2) determine likely effects of treatments on fuels, fire behavior, and ecological response, and (3) select appropriate treatments, including the need to seed. An evaluation score sheet is included for assessing relative resilience and resistance and seeding needs. The Pine Valley Ranger District of the Dixie National Forest, part of a USDA Forest Service “Wildfire Crisis Landscape,” is used as a case study. Maps and data summaries included for the district are dominant shrubland and pinyon-juniper ecological types, burn probabilities, cover of the invasive annual, cheatgrass, proxy soil temperature and moisture regimes, relative resilience and resistance, pinyon-juniper stand characteristics, and habit for mule deer and pinyon jay.
Workshop information and registration.
The Bureau of Land Management and U.S. Forest Service will host a public workshop to present information and gather feedback on a range of topics regarding the science and management of pinyon and juniper woodlands, particularly mature and old-growth forests.
The workshop will occur May 8, 1-5 p.m. and May 9, 9 a.m.-5 p.m., 2024, at the Nugget Casino Resort, 1100 Nugget Ave., Sparks, NV, 89431. This event is part of BLM’s ongoing public comment period on pinyon and juniper woodlands, during which interested parties may also submit comments regarding management and conservation of pinyon and juniper ecosystems. Please see more information on how to comment below.
Workshop information and registration
Topics for the workshop will include classifying the various pinyon and juniper systems and understanding their geographic and population dynamics, methods for assessing woodland conditions, values associated with old-growth pinyon and juniper woodlands, management objectives and effectiveness, and opportunities for increasing climate resilience. Participants will have opportunities to engage and interact on a range of topics.
To attend the event, individuals are required to reserve a spot. This is a two-day workshop, but you must register for both days to attend. To attend on May 8, please register through the eventbrite portal for day one. To attend on May 9, please register through the eventbrite portal for day two.
Webinar recording.
In this LANDFIRE Office Hour, USFS, RMRS Quantitative Ecologist, Jessi Brown discusses how dryland ecosystems are facing threats from invasive species and altered fire patterns, risking shifts to less desirable states. Prioritizing areas for management can be achieved by considering ecological resilience and resistance to invasives, alongside LANDFIRE’s Biophysical Settings (BpS) data. This aids in assessing ecosystem status and choosing suitable management approaches in the sagebrush biome. Scroll down for more resources!
Webinar recording.
Webinar sessions will be half presentation and half question and answer. All presenters are scientists at the Rocky Mountain Research Station.
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Sagebrush shrublands in the Great Basin, USA, are experiencing widespread increases in wildfire size and area burned resulting in new policies and funding to implement fuel treatments. However, we lack the spatial data needed to optimize the types and locations of fuel treatments across large landscapes and mitigate fire risk. To address this, we developed treatment response groups (TRGs)—sagebrush and pinyon-juniper vegetation associations that differ in resilience to fire and resistance to annual grass invasion (R&R) and thus responses to fuel treatments.
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The sagebrush biome is a dryland region in the western United States experiencing rapid transformations to novel ecological states. Threat-based approaches for managing anthropogenic and ecosystem threats have recently become prominent, but successfully mitigating threats depends on the ecological resilience of ecosystems. We used a spatially explicit approach for prioritizing management actions that combined a threat-based model with models of resilience to disturbance and resistance to annual grass invasion. The threat-based model assessed geographic patterns in sagebrush ecological integrity (SEI) to identify core sagebrush, growth opportunity, and other rangeland areas. The resilience and resistance model identified ecologically relevant climate and soil water availability indicators from process-based ecohydrological models. The SEI areas and resilience and resistance indicators were consistent – the resilience and resistance indicators showed generally positive relationships with the SEI areas. They also were complementary – SEI areas provided information on intact sagebrush areas and threats, while resilience and resistance provided information on responses to disturbances and management actions. The SEI index and resilience and resistance indicators provide the basis for prioritizing conservation and restoration actions and determining appropriate strategies. The difficulty and time required to conserve or restore SEI areas increase as threats increases and resilience and resistance decrease.
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Using biophysical predictors and patterns of burn severity from 1180 recent fire events, we mapped the locations of potential fire refugia across upland conifer forests in the southwestern United States (US) (99,428 km2 of forest area), a region that is highly vulnerable to fire-driven transformation. We found that low pre-fire forest cover, flat slopes or topographic concavities, moderate weather conditions, spring-season burning, and areas affected by low-to moderate-severity fire within the previous 15 years were most-commonly associated with refugia. Based on current (i.e., 2021) conditions, we predicted that 67.6% and 18.1% of conifer forests in our study area would contain refugia under moderate and extreme fire weather, respectively. However, potential refugia were 36.4% (moderate weather) and 31.2% (extreme weather) more common across forests that experienced recent fires, supporting the increased use of prescribed and resource objective fires during moderate weather conditions to promote fire-resistant landscapes. When overlaid with models of tree recruitment, 23.2% (moderate weather) and 6.4% (extreme weather) of forests were classified as refugia with a high potential to support post-fire recruitment in the surrounding landscape. These locations may be disproportionately valuable for ecosystem sustainability, providing habitat for fire-sensitive species and maintaining forest persistence in an increasingly fire-prone world.