Research and Publications
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Cows were fitted with VF collars (calves not collared) that use Global Positioning System positioning to contain cattle inside fuel break boundaries and record animal locations at 5-min intervals. End-of-trial forage utilization was 48.5% ± 3.7% and 5.5% ± 0.7% for areas inside and outside of the fuel break, respectively. Daily percentage of cattle locations inside the fuel break was initially > 94% but declined to approximately 75% by the end of the trial. Percentage daily locations of dry cows and cow/calf pairs inside the fuel break was 98.5% ± 0.5% and 80.6% ± 1.1%, respectively (P < 0.001). Our data suggest virtual fencing can be a highly effective method of concentrating grazing to reduce herbaceous fuel biomass within linear fuel breaks. Efficacy of this method could be substantially impacted by use of dry versus cow/calf pairs.
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We found the predicted positive relationship between mesic habitat availability and sage-grouse productivity, but annual precipitation explained additional variation in productivity even after accounting for mesic habitat availability. Hence, precipitation and drought may drive sage-grouse productivity via more than one mechanism acting on multiple demographic rates. Productivity was also limited by exotic annual grass invasion and conifer encroachment. Mesic habitat availability was a function of topographic relief, mean elevation, annual mean snow water equivalent, and winter temperatures, indicating that snowpack recharges the late summer mesic resources that support sage-grouse productivity. Management actions focused on maintaining and restoring mesic resources and drought resilient habitats, limiting the spread of exotic annual grasses, and reversing conifer encroachment should support future sage-grouse recruitment and help mitigate the effects of climate change.
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Our findings suggest that all deserts exhibited vulnerability to increasing fire disturbance because relatively low soil seed densities may not provide enough propagules for revegetation. Therefore, seeding of these communities may be especially important. In the cold deserts, this susceptibility was further evidenced by the fact that aboveground community composition in fire-affected areas was significantly different from the nearby unburned community even 30 years after fire and burned communities were associated with non-native species. That said, native species did exist in seed banks of burned sites and some taxa, like Sporobolus sp., occurred in high densities. Therefore, caution may be needed when using herbicide treatments to control exotic species as there may be unintended consequences of decreasing desirable species. In contrast, our warm desert sites exhibited less change in terms of seed densities, species richness and aboveground community composition following fire. In the face of more frequent fires, the lack of shrub seeds in the seed bank of all deserts was notable and we found no evidence of greater seed densities or unique species assemblages associated with shrub microsites.
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We tested the effects of site environmental variables (elevation, mean annual precipitation, heat load, and clay content) and management choices (seed source and planting date) on germination favorability and barrier occurrence (mean) and variability (coefficient of variation). Seedling exposure to barriers was strongly linked to management decisions in addition to site mean precipitation and elevation. Later fall plantings and seed sources with slower germination (lower mean germination favorability) were less likely to encounter freezing and drought barriers. These results suggest that management actions can play a role comparable to site environmental variables in reducing exposure of vulnerable seedlings to adverse weather conditions and subsequent effects on restoration outcomes.
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High severity wildfires led to the greatest decrease in cover for all plant functional types, while low severity wildfires caused the least decrease in the functional type cover in most cases, though some variations existed. Furthermore, the impacts of wildfires on vegetation cover were greater in woody (SHR and TREE) types than in herbaceous (AFG and PFG) types. Significant negative correlation existed between percent changes in AFG and PFG cover and SPEI indicating higher prefire soil moisture conditions likely increased fine fuel loads and led to a larger decrease in AFG and PFG cover following wildfires. Significant positive correlation existed between percent changes in SHR and TREE cover and SPEI indicating drier prefire conditions resulted in larger decreases in SHR and TREE cover following wildfires.
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We evaluated seeding bitterbrush (Purshia tridentata) after wildfire in former western juniper (Juniperus occidentalis ssp. occidentalis) canopy compared with interspace microsites at six locations for 3 yr post seeding. Bitterbrush abundance was 3.6-fold greater in former canopy compared with interspace microsites after 3 yr. Bitterbrush height was 1.5 to 2.5-fold greater in former canopy compared with interspace microsites. The first year after fire, exotic annual grass cover was 15.6-fold greater in interspace compared with canopy microsites. Abundance and cover of other herbaceous vegetation were generally also greater in the interspace. Exotic annual grass and native bunchgrass abundance increased substantially over time in former canopy microsites, suggesting abundant resource availability. Less herbaceous competition and presumably greater resource availability in former canopies probably resulted in greater success of seeded bitterbrush. These results suggest that capitalizing on spatial variability in environments can be used to increase restoration efficiency. After fire in western juniper−encroached rangelands, former juniper canopy microsites are a favorable environment for establishment and growth of seeded bitterbrush and could be targeted for restoration efforts to improve efficiency.
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We evaluated plant community succession following prescribed fire on Artemisia arbuscula var. arbuscula (low sagebrush) steppe in southeastern Oregon. Treatments were “prescribed burned” (burn; fall 2012) and “unburned” (control) low sagebrush a steppe, and the study design was a randomized complete block with 4 replicates per treatment. Herbaceous yield and vegetation canopy cover and density were compared between treatments (2012–2020). Fire practically eliminated low sagebrush and there was no recruitment of new plants in the first 8 years after burning. Herbaceous yield in the burn treatment was about double the control for most of the postfire period. Native perennial grasses and forbs constituted 94% to 96% and Bromus tectorum L. (cheatgrass) 0.2% to 2% of total herbaceous yield in the control. In the burn treatment, perennial grasses and forbs constituted 83% to 87%, native annual forbs 2% to 5%, and cheatgrass 3% to 9% of total herbaceous yield. Despite an increase in cheatgrass, the burned low sagebrush sites were dominated by herbaceous perennial grasses and forbs and exhibited high levels of resilience and resistance. After prescribed fire, for the study sites and comparable low sagebrush associations, weed control or seeding are not necessary to recover the native herbaceous community. However, the results in our study are for low-severity prescribed fire in intact low sagebrush plant communities. Higher-severity fire, as might occur with wildfire, and in low sagebrush communities having greater prefire invasive weed composition should not be assumed to develop similarly high levels of community resilience and resistance.
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In 2006, we initiated fuel reduction treatments (prescribed fire, mowing, and herbicide applications [tebuthiuron and imazapic]) in six Artemisia tridentata ssp. wyomingensis communities. We evaluated long-term effects of these fuel treatments on: (1) magnitude and longevity of fuel reduction; (2) Greater sage-grouse habitat characteristics; and (3) ecological resilience and resistance to invasive annual grasses. Responses were analyzed using repeated-measures linear mixed models. Response variables included plant biomass, cover, density and height, distances between perennial plants, and exposed soil cover. Prescribed fire produced the greatest reduction in woody fuel over time. Mowing initially reduced woody biomass, which recovered by year 10. Tebuthiuron did not significantly reduce woody biomass compared to controls. All woody fuel treatments reduced sagebrush cover to below 15% (recommended minimum for Greater Sage-grouse habitat), but only prescribed fire reduced cover to below controls. Median mowed sagebrush height remained above the recommended 30 cm. Cheatgrass (Bromus tectorum) cover increased to above the recommended maximum of 10% across all treatments and controls. Ecological resilience to woody fuel treatments was lowest with fire and greatest with mowing. Low resilience over the 10 posttreatment years was identified by: (1) poor perennial plant recovery posttreatment with sustained reductions in cover and density of some perennial plant species; (2) sustained reductions in lichen and moss cover; and (3) increases in cheatgrass cover. Although 10 years is insufficient to conclusively describe final ecological responses to fuel treatments, mowing woody fuels has the greatest potential to reduce woody fuel, minimize shrub mortality and soil disturbance, maintain lichens and mosses, and minimize long-term negative impacts on greater sage-grouse habitat. However, maintaining ecological resilience and resistance to invasion may be threatened by increases in cheatgrass cover, which are occurring regionally.
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Scientists in and beyond academia face considerable challenges to effectively sharing science, including lack of time and training, systemic disincentives, and the complexity of the modern media/attention landscape. Considering these constraints, 3 achievable shifts in mindset and practice can substantively enhance science communication efforts. Here, we provide evidence-based and experientially informed advice on how to center shared values, articulate science communication goals, and leverage the power of stories to advance our communication goals in connection with the values we share with our stakeholders. In addition to a discussion of relevant, foundational principles in science communication, we provide actionable recommendations and tools scientists can immediately use to articulate their values, identify shared values between stakeholders, set science communication goals, and use storytelling as a means of building and reinforcing relationships around shared values, thereby working productively to achieve those goals
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Assessing the geomorphic sensitivity of streams and the ecological resilience of riparian ecosystems provides the basis for understanding how they have responded to disturbances and management actions and how they are expected to respond in the future.
A collaborative group of managers and scientists led by Jeanne Chambers, research ecologist and senior scientist (emeritus) with the USDA Forest Service Rocky Mountain Research Station, and geomorphologist Jerry Miller, a professor of environmental science at Western Carolina University, developed a multiscale approach to help land managers rapidly assess watersheds and categorize them based on resilience and sensitivity to disturbance. The project was built on the long-term work of Chambers and her collaborators on Great Basin riparian ecosystems.