Sagebrush
Visit ANREP 2020 Conference website.
The Association of Natural Resource Extension Professionals (ANREP) conference theme was: Place-Based and Future-Focused: Fulfilling the Land Grant Mission in an Evolving Landscape. It was held virtually May 23-26, 2021.
The conference offers abundant opportunities for professional growth and development. Presentations, field tours, workshops, poster displays and informal networking provide a variety of options for skill building, knowledge sharing, collaboration and idea generation in a welcoming atmosphere.
This study determined average songbird density in areas of high and low probability of sage‐grouse occurrence. Sagebrush cover at intermediate scales was an important predictor for all species, and ground cover was important for all species except sage thrashers. Areas with a higher probability of sage‐grouse occurrence also contained higher densities of Brewer’s sparrows, green‐tailed towhees, and sage thrashers, but predicted sagebrush sparrow densities were lower in these areas. In northwest Colorado, sage‐grouse may be an effective umbrella for Brewer’s sparrows, green‐tailed towhees, and sage thrashers, but sage‐grouse habitat does not appear to capture areas that support high sagebrush sparrow densities. A multi‐species focus may be the best management and conservation strategy for several species of concern, especially those with conflicting habitat requirements.
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For this study, we used big sagebrush (Artemisia tridentata) as a model species to explore whether including human‐induced factors improves the fit of the species distribution models (SDM). Models including fire attributes and restoration treatments performed better than those including only climate and topographic variables. Number of fires and fire occurrence had the strongest relative effects on big sagebrush occurrence and cover, respectively. The models predicted that the probability of big sagebrush occurrence decreases by 1.2% (95% CI: −6.9%, 0.6%) when one fire occurs and cover decreases by 44.7% (95% CI: −47.9%, −41.3%) if at least one fire occurred over the 36 year period of record. Restoration practices increased the probability of big sagebrush occurrence but had minimal effect on cover. Our results demonstrate the potential value of including disturbance and land management along with climate in models to predict species distributions.
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In this study, we evaluated associations between soil properties and gradients in sagebrush canopy structure in stands that had successfully reestablished after fire and subsequent seeding treatments. Using a dataset collected across the Great Basin, USA, of sagebrush stands that had burned and reestablished between 1986 and 2013, we tested soil depth and texture, soil surface classification, biological soil crusts plus mean historical precipitation, solar heatload, and fire history as modeling variables to explore gradients in sagebrush canopy structure growth in terms of cover, height, and density. Deeper soils were associated with greater sagebrush canopy structure development in terms of plant density and percent cover, coarser textured soils were associated with greater sagebrush cover and density, and more clayey soils were typically associated with greater height. Biological crust presence was also positively associated with enhanced sagebrush canopy growth, but adding more demographically or morphologically explicit descriptions of biocrust communities did not improve explanatory power. Increasing heatload had a negative effect on sagebrush canopy structure growth, and increased mean annual precipitation was only associated with greater sagebrush height. Given that conservation and restoration of the sagebrush steppe ecosystems has become a priority for land managers, the associations we identify between gradients in post‐fire sagebrush canopy structure growth and field‐identifiable soil characteristics may improve planning of land treatments for sagebrush restoration and the understanding of semi‐arid ecosystem functioning and post‐disturbance dynamics.
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The apparent failure of ecosystems to recover from increasingly widespread disturbance is a global concern. Despite growing focus on factors inhibiting resilience and restoration, we still know very little about how demographic and population processes influence recovery. Using inverse and forward demographic modelling of 531 post‐fire sagebrush populations across the western US, we show that demographic processes during recovery from seeds do not initially lead to population growth but rather to years of population decline, low density, and risk of extirpation after disturbance and restoration, even at sites with potential to support long‐term, stable populations. Changes in population structure, and resulting transient population dynamics, lead to a > 50% decline in population growth rate after disturbance and significant reductions in population density. Our results indicate that demographic processes influence the recovery of ecosystems from disturbance and that demographic analyses can be used by resource managers to anticipate ecological transformation risk.
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This study assessed causal relationships between conifer encroachment and sagebrush restoration (conifer removal and seeding native plants) on small mammal communities over 11 yr using a Before-After-Control–Impact design. Sagebrush habitat supported an additional small mammal species, twice the biomass, and nearly three times higher densities than conifer-encroached habitat. Sagebrush restoration increased shrub cover, decreased tree cover, and density but failed to increase native herbaceous plant density. Restoration caused a large increase in the non-native, invasive annual cheatgrass. Counter to prediction, small mammal diversity did not increase in response to sagebrush restoration, but restoration maintained small mammal density in the face of ongoing conifer encroachment. Piñon mice, woodland specialists with highest densities in conifer-encroached habitat, were negatively affected by sagebrush restoration. Increasing cheatgrass due to sagebrush restoration may not negatively impact small mammal diversity, provided cheatgrass density and cover do not progress to a monoculture and native vegetation is maintained. The consequences of conifer encroachment, a long-term, slow-acting impact, far outweigh the impacts of sagebrush restoration, a short-term, high-intensity impact, on small mammal diversity. Given the ecological importance of small mammals, maintenance of small mammal density is a desirable outcome for sagebrush restoration.
Webinar recording.
The Science Framework for Conservation and Restoration of the Sagebrush Biome is a two-part volume on managing sagebrush ecosystems in the West that was developed by an extensive interagency team of scientists and managers. An overview of using the concepts of resilience to disturbance (ability to recover) and resistance to invasive annual grasses across three geographic scales (sagebrush biome, ecoregions, and local sites) to prioritize conservation and restoration actions is provided.
The webinar discusses how to use the Science Framework in management planning efforts, focusing on considerations like monitoring and adaptive management, climate adaptation, wildfire and vegetation management, nonnative invasive plant management, application of National Seed Strategy concepts, livestock grazing management, and wild horse and burro considerations.
Michele Crist, BLM National Interagency Fire Center, and Jeanne Chambers, USFS Rocky Mountain Research Station, present.
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Study findings include:
- From 2011-2017, the extent of conifer cover in sagebrush country decreased by 1.6%. Human management efforts are responsible for 2/3 of the total reduction; the other 1/3 is due to wildfires.
- Previous estimates suggest that conifer cover in sagebrush country is growing by 0.4%-1.5% annually, which means that our efforts are keeping pace with conifer encroachment but that more needs to be done.
- Public/private partnerships are successfully reducing conifers in highly targeted priority watersheds, such as in northwest Utah.
- The maps also show that woodlands are still expanding into many sagebrush landscapes. Continued partnership efforts are needed to strategically conserve priority shrublands.
The dataset provides a spatially explicit estimate of 2019 herbaceous annual percent cover predicted on May 1st with an emphasis on annual grasses. The estimate is based on the mean output of two regression-tree models. For one model, we include, as an independent variable amongst other independent variables, a dataset that is the mean of 17-years of annual herbaceous percent cover.