Resistance & Resilience
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Sage grouse and many other species rely on a range of mesic habitats—including riparian areas, wet meadows, alfalfa fields, and productive rangelands—to sustain their populations. Landscapes with the greatest uncertainty in mesic abundance and distribution support the fewest grouse.
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The historical management of agroecological systems, such as California’s rangelands, have received criticism for a singular focus on agricultural production goals, while society has shifting expectations to the supply of multiple ecosystem services from these working landscapes. The sustainability and the multiple benefits derived from these complex social-ecological systems is increasingly threatened by weed invasion, extreme disturbance, urban development, and the impacts of a rapidly changing and increasingly variable climate. California’s grasslands, oak savannas, and oak woodlands are among the most invaded ecosystems in the world. Weed eradication efforts are rarely combined with seeding on these landscapes despite support for the inclusion of the practice in a weed management program. Depending on seed mix choice, cost and long-term uncertainty, especially for native seed, is an impediment to adoption by land managers. We investigated four seeding mixes (forage annual, native perennial, exotic perennial, and exotic-native perennial) to evaluate how these treatments resist rein-vasion and support the delivery of simultaneous multiple ecosystem services (invasion resistance, native richness, nitrogen fixing plants, pollinator food sources, plant community diversity, forage quality, and productivity). We found the increase of exotic and native perennial cover will drive resistance to an invading weedy summer flowering forb Centaurea solstitialis but provides a mixed response to resisting invasive annual grasses. The resistance to invasion is coupled with little tradeoff in forage productivity and quality and gains in plant diversity and native cover.
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In this study, we used longer-term data to evaluate the relationships among soil climate conditions, perennial herbaceous cover, and cheatgrass cover following fuel management treatments across the environmental gradients that characterize sagebrush ecosystems in the Great Basin. Both prescribed fire and mechanical treatments increased soil water availability on woodland sites and perennial herbaceous cover on some woodland and sagebrush sites. Prescribed fire also slightly increased soil temperatures and especially increased cheatgrass cover compared to no treatment and mechanical treatments on most sites. Non-metric dimensional scaling ordination and decision tree partition analysis indicated that sites with warmer late springs and warmer and wetter falls had higher cover of cheatgrass. Sites with wetter winters and early springs (March-April) had higher cover of perennial herbs. Our findings suggest that site resistance to cheatgrass after fire and fuel control treatments decreases with a warmer and drier climate. This emphasizes the need for management actions to maintain and enhance perennial herb cover, such as implementing appropriate grazing management, and revegetating sites that have low abundance of perennial herbs in conjunction with fuel control treatments.
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In sagebrush ecosystems invasion of annual exotics and expansion of pinyon and juniper are altering fire regimes and resulting in large-scale ecosystem transformations. Management treatments aim to increase resilience to disturbance and enhance resistance to invasive species by reducing woody fuels and increasing native perennial herbaceous species. This study used Sagebrush Steppe Treatment Evaluation Project data to test predictions on effects of fire vs. mechanical treatments on resilience and resistance for three site types. Warm (mesic) WY Shrub and WY PJ sites had lower resistance to annual exotics than cool (frigid to cool frigid) Mtn PJ sites. In WY shrub, fire and sagebrush mowing had similar effects on shrub cover and, thus, on perennial native herbaceous and exotic cover. In WY PJ and Mtn PJ, effects were greater for fire than cut-and-leave treatments and with high tree cover in general because most woody vegetation was removed increasing resources for other functional groups. In WY shrub, about 20% pretreatment perennial native herb cover was necessary to prevent increases in exotics after treatment. Cooler and moister WY PJ and especially Mtn PJ were more resistant to annual exotics, but perennial native herb cover was still required for site recovery. We use our results to develop state and transition models that illustrate how resilience and resistance influence vegetation dynamics and management options.
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On the Ground Emerging applications of ecosystem resilience and resistance concepts in sagebrush ecosystems allow managers to better predict and mitigate impacts of wildfire and invasive annual grasses. Widely available soil survey information can be harnessed to spatially depict and evaluate relative resilience and resistance from regional to site scales. New products and tools illustrate how managers can use soils data to inform rapid risk assessments, determine appropriate management strategies, and prioritize resources to maintain and restore functioning sagebrush ecosystems.
Want to beef-up your library? You can request the following resources in hard copy from Génie (listed in order of most recent publication date). You can also add them to your electronic library, just follow the links for downloads.
Fire patterns in piñon and juniper land cover types in the Semiarid Western United States from 1984 through 2013, 2018. RMRS-GTR-372
Restoration handbook for sagebrush steppe ecosystems with emphasis on greater sage-grouse habitat—Part 3. Site level restoration decisions, 2018. USGS Circular 1426
Science framework for conservation and restoration of the sagebrush biome: Linking the Department of the Interior’s Integrated Rangeland Fire Management Strategy to long-term strategic conservation actions, 2017. RMRS-GTR-360
Pocket Guide to Sagebrush Birds, reprint, 2017. A partnership between Rocky Mountain Bird Observatory and PRBO Conservation Science
Pocket Guide to Sagebrush, reprint, 2017. Made possible by USU, NRCS, USFS, BLM, PRBO Conservation Science, NDOW, GBFSE
Ecohydrologic impacts of rangeland fire on runoff and erosion: A literature synthesis, 2016. RMRS-GTR-351
Using resilience and resistance concepts to manage threats to sagebrush ecosystems, Gunnison sage-grouse, and Greater sage-grouse in their eastern range: A strategic multi-scale approach, 2016. RMRS-GTR-356
A field guide for rapid assessment of post-wildfire recovery potential in sagebrush and pinon-juniper ecosystems in the Great Basin: Evaluating resilience to disturbance and resistance to invasive annual grasses and predicting vegetation response, 2015. RMRS-GTR-338
A review of fire effects on vegetation and soils in the Great Basin Region: Response and site characteristics, 2013. RMRS-GTR-308
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In this study, we use freely available, satellite remote sensing to explore changes in vegetation productivity(normalized difference vegetation index) of three distinct, low-tech, riparian and wet meadow restoration projects. Case studies are presented that range in geographic location (Colorado, Oregon, and Nevada), restoration practice (Zeedyk structures,beaver dam analogs, and grazing management), and time since implementation. Restoration practices resulted in increased vegetation productivity of up to 25% and increased annual persistence of productive vegetation. Improvements in productivity with time since restoration suggest that elevated resilience may further enhance wildlife habitat and increase forage production.Long-term, documented outcomes of conservation are rare; we hope our findings empower practitioners to further monitor and explore the use of low-tech methods for restoration of ecohydrologic processes at meaningful spatial scales.
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In this study cut bolts of Great Basin bristlecone pine and two susceptible host tree species, limber (P. flexilis) and lodgepole (P. contorta) pines were infested with adult mountain pine beetles and compared offspring performance. To investigate the potential for variation in offspring performance among mountain pine beetles from different areas, we tested beetles from geographically-separated populations within and outside the current range of Great Basin bristlecone pine. Although mountain pine beetles constructed galleries and laid viable eggs in all three tree species, extremely few offspring emerged from Great Basin bristlecone pine, regardless of the beetle population. Our observed low offspring performance in Great Basin bristlecone pine corresponds with previously documented low mountain pine beetle attack preference. A low preference-low performance relationship suggests that Great Basin bristlecone pine resistance to mountain pine beetle is likely to be retained through climate-driven high-elevation mountain pine beetle outbreaks.
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This interactive map and database highlights aspen research as it relates to regions in primarily North America.
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USGS scientists Lea Condon and David Pyke tested the idea that biotic communities mediate the effects of disturbances such as fire and grazing on site resistance by using structural equation modeling to test relationships between disturbance events, the biotic community, and resistance to cheatgrass invasion. Increased site resistance following fire was associated with higher bunchgrass cover and recovery of bunchgrasses and mosses with time since fire. Fire reduced near-term site resistance to cheatgrass on actively grazed rangelands, and evidence of grazing was more pronounced on burned sites and was positively correlated with cheatgrass cover. Independent of fire, grazing impacts resulted in reduced site resistance to cheatgrass, suggesting that grazing management that enhances plant and biocrust communities will also enhance site resistance.