Research and Publications
View article.
Study results suggest that weather is a primary driver of resource orders over the course of extended attack efforts on large fires. Incident Management Teams (IMTs) synthesize information about weather, fuels, and order resources based on expected fire growth rather than simply reacting to observed fire growth. Analysis shows that incident management teams are generally forward-looking and respond to expected rather than recently observed weather-driven fire behavior. These results may have important implications for forecasting resource needs and costs in a changing climate
View article.
This study estimates biome‐wide mesic resource productivity from 1984 to 2016 using remote sensing to identify patterns of food availability influencing selective pressures on sage‐grouse. We linked productivity to abiotic factors to examine effects of seasonal drought across time, space, and land tenure, with findings partitioned along gradients of ecosystem water balance within Great Basin, Rocky Mountains and Great Plains regions. Precipitation was the driver of mesic resource abundance explaining ≥70% of variance in drought‐limited vegetative productivity. Spatiotemporal shifts in mesic abundance were apparent given biome‐wide climatic trends that reduced precipitation below three‐quarters of normal in 20% of years. Drought sensitivity structured grouse populations wherein landscapes with the greatest uncertainty in mesic abundance and distribution supported the fewest grouse. Privately owned lands encompassed 40% of sage‐grouse range, but contained a disproportional 68% of mesic resources. Regional drought sensitivity identified herein acted as ecological minimums to influence differences in landscape carrying capacity across sage‐grouse range. Our model depictions likely reflect a new normal in water scarcity that could compound impacts of demographic bottlenecks in Great Basin and Great Plains. We conclude that long‐term population maintenance depends on a diversity of drought resistant mesic resources that offset climate driven variability in vegetative productivity. We recommend a holistic public–private lands approach to mesic restoration to offset a deepening risk of water scarcity.
View article.
This study quantified which reptile species may benefit from the protection of intact sage‐grouse habitat and which may be affected by recent (since about 1990) habitat restoration actions targeting sage‐grouse. Of 190 reptile species in the United States and Canadian provinces where greater sage‐grouse occur, 70 (37%) occur within the range of the bird. Of these 70 species, about a third (11 snake and 11 lizard species) have >10% of their distribution area within the sage‐grouse range. Land cover similarity indices revealed that 14 of the 22 species (8 snake and 6 lizard species) had relatively similar land cover associations to those of sage‐grouse, suggesting greater potential to be protected under the sage‐grouse conservation umbrella and greater potential to be affected, either positively or negatively, by habitat management actions intended for sage‐grouse. Conversely, the remaining 8 species are less likely to be protected because of less overlap with sage‐grouse habitat and thus uncertain effects of sage‐grouse habitat management actions. Our analyses of treatment databases indicated that from 1990 to 2014 there were at least 6,400 treatments implemented on public land that covered approximately 4 million ha within the range of the sage‐grouse and, of that, >1.5 million ha were intended to at least partially benefit sage‐grouse. Whereas our results suggest that conservation of intact sagebrush vegetation communities could benefit ≥14 reptiles, a greater number than previously estimated, additional research on each species’ response to habitat restoration actions is needed to assess broader claims of multi‐taxa benefits when it comes to manipulative sage‐grouse habitat management.
View article.
Screening is a strategy for detecting undesirable change prior to manifestation of symptoms or adverse effects. Although the well-recognized utility of screening makes it commonplace in medicine, it has yet to be implemented in ecosystem management. Ecosystem management is in an era of diagnosis and treatment of undesirable change, and as a result, remains more reactive than proactive and unable to effectively deal with today’s plethora of non-stationary conditions. In this paper, we introduce spatial imaging-based screening to ecology. We link advancements in spatial resilience theory, data, and technological and computational capabilities and power to detect regime shifts (i.e., vegetation state transitions) that are known to be detrimental to human well-being and ecosystem service delivery. With a state-of-the-art landcover dataset and freely available, cloud-based, geospatial computing platform, we screen for spatial signals of the three most iconic vegetation transitions studied in western USA rangelands: (1) erosion and desertification; (2) woody encroachment; and (3) annual exotic grass invasion. For a series of locations that differ in ecological complexity and geographic extent, we answer the following questions: (1) Which regime shift is expected or of greatest concern? (2) Can we detect a signal associated with the expected regime shift? (3) If detected, is the signal transient or persistent over time? (4) If detected and persistent, is the transition signal stationary or non-stationary over time? (5) What other signals do we detect? Our approach reveals a powerful and flexible methodology, whereby professionals can use spatial imaging to verify the occurrence of alternative vegetation regimes, image the spatial boundaries separating regimes, track the magnitude and direction of regime shift signals, differentiate persistent and stationary transition signals that warrant continued screening from more concerning persistent and non-stationary transition signals, and leverage disciplinary strength and resources for more targeted diagnostic testing (e.g., inventory and monitoring) and treatment (e.g., management) of regime shifts. While the rapid screening approach used here can continue to be implemented and refined for rangelands, it has broader implications and can be adapted to other ecological systems to revolutionize the information space needed to better manage critical transitions in nature.
Access summary and report.
The primary objective of this study was to explore the application of a dynamic global vegetation model (DGVM), the Ecosystem Demography (EDv2.2), to understand vegetation dynamics and ecosystem productivity in varying climate and fire scenarios. Most vegetation models do not represent sagebrush’s physical and physiological functions. Thus, we developed a sagebrush plant functional type (PFT) to use in modeling. Associated with this, the researchers performed a series of analyses and evaluations of the sagebrush and in the context of scenarios under natural (undisturbed) and disturbed (fire) environments.
- Results indicate that a number of sagebrush parameters are most sensitive to how productive the plant is (in our model). These include specific leaf area (SLA), stomatal slope, fine root turnover rate, cuticular conductance, and maximum carboxylation rate. These findings allow future sagebrush modeling efforts to further refine these parameters in different environments.
- The researchers comparisons between model runs and field data from Reynold Creek Experimental Watershed (RCEW), show good agreement. Improvements are needed to refine the model with additional PFTs representative of a range of elevations in the Great Basin.
- The researchers fire scenario modeling suggested that fire substantially reduced shrub gross primary production (GPP) and it took several decades before it was restored to pre-fire conditions. Grass GPP, however, responded more quickly in post-fire conditions. While these processes are representative of field observations and other studies, additional PFTs and improvement in fire routines in the model will provide for a better prognosis of future ecosystem dynamics of the sagebrush-steppe.
Visit the new PJ website maintained by Rick Miller.
View the complete pinyon-juniper synthesis
View fact sheet on pinyon-juniper ecology
View fact sheet on pinyon-juniper history
View fact sheet on pinyon-juniper ecohydrology
View fact sheet on pinyon-juniper management and restoration
This synthesis reviews current knowledge of pinyon and juniper ecosystems, in both persistent and newly expanded woodlands, for managers, researchers, and the interested public. We draw from a large volume of research papers to centralize information on these semiarid woodlands. The first section includes a general description of both the Great Basin and northern Colorado Plateau. The ecology section covers woodland and species life histories, biology, and ecology and includes a detailed discussion of climate and the potential consequences of climate change specific to the Great Basin and Colorado Plateau. The history section discusses 20,000 years of woodland dynamics and geographic differences among woodland disturbance regimes and resilience. The ecohydrology section discusses hydrologic processes in woodlands that influence soil conservation and loss; water capture, storage, and release; and the effect that woodland structure and composition have on these processes. The final section, restoration and management, covers the history of woodland management, the different methods used, the advantages and disadvantages of different vegetation treatments, and posttreatment vegetation responses. We also discuss successes and failures and key components that determine project outcomes important for consideration when restoring ecosystem function, integrity, and resilience.
Access article.
We analyzed the relationship between predicted housing exposure to wildfire and local self-assessment of community competence to mitigate wildfire risks in 60 communities in the western US. Results generally demonstrate that (1) the number of sources of wildfire risk influences local housing exposure to wildfire, and (2) perceived community-competence is associated with predicted exposure to wildfire. We suggest that investments in ongoing updates to community risk planning and efforts to build multi-jurisdictional risk management networks may help to leverage existing capacity, especially in moderate capacity communities. The analysis improves the social-ecological understanding of wildfire risks and highlights potential causal linkages between community capacity and wildfire exposure.
View article.
Using a sample of 722 large fires from the western United States, we observe whether a fire interacted with a previous fire, the percent area of fires burned by previous fires, and the percent perimeter overlap with previous fires. Fires that interact with previous fires are likely to be larger and have lower total expenditures on average. Conditional on a fire encountering a previous fire, a greater extent of interaction with previous fires is associated with reduced fire size but higher expenditures, although the expenditure effect is small and imprecisely estimated. Subsequent analysis suggests that fires that interact with previous fires may be systematically different from other fires along several dimensions. We do not find evidence that interactions with previous fires reduce suppression expenditures for subsequent fires. Results suggest that previous fires may allow suppression opportunities that otherwise might not exist, possibly reducing fire size but increasing total expenditures.
View paper.
It is sometimes assumed the sparse and low statured vegetation in arid systems would limit the effectiveness of two remote-sensing derived indices of burn severity: the difference Normalised Burn Ratio (dNBR) and relativised difference Normalised Burn Ratio (RdNBR). We compared the relationship that dNBR, RdNBR and a ground-based index of burn severity (the Composite Burn Index, CBI) had with woody cover and woody density 1 year after burning in five fires that occurred in the Mojave Desert during 2005. Statistically, dNBR and RdNBR were both effective measures of severity in all three elevation zones; woody cover and density had steep exponential declines as the values of each remote-sensing index increased. We found though that dNBR was more ecologically interpretable than RdNBR and will likely be of most relevance in the Mojave Desert.
View article.
Drawing from literature on natural hazard vulnerability, disaster recovery, and wildfire ecology, this paper proposes a linked social-ecological model of community recovery and adaptation after disaster. The model contends that changes during post-wildfire recovery shape a community’s vulnerability to the next wildfire event. While other studies have highlighted linked social-ecological dynamics that influence pre-fire vulnerability, few studies have explored social-ecological feedbacks in post-fire recovery. This model contributes to interdisciplinary social science research on wildfires and to scholarship on community recovery by integrating hazard vulnerability reduction with recovery in a cyclical framework. Furthermore, it is adaptable to a variety of hazards beyond wildfire. The model provides a basis for future empirical work examining the nature and effectiveness of recovery efforts aimed at long-term vulnerability reduction.