Article / Book
The book, Exotic brome-grasses in arid and semiarid ecosystems of the western US: causes, consequences, and management implications, is presented in several chapters.
Access is provided for the following chapters -
Chapter 1 - Introduction: Exotic annual Bromus in the western USA
Chapter 2 - Exotic annual Bromus invasions: comparisons among species and ecoregions in the western US
Chapter 3 - Ecosystem impacts of exotic annual invaders in the genus Bromus
Chapter 7 - Community ecology of fungal pathogens on Bromus tectorum
Chapter 8 - Soil moisture and biogeochemical factors influence the distribution of annual Bromus species
Chapter 9 - Bromus response to climate and projected changes with climate change
Chapter 10 - Plant community resistance to invasion by Bromus species: The roles of community attributes, Bromus interactions with plant communities, and Bromus traits
Chapter 11 - Land uses, fire, and invasion: Exotic annual Bromus and human dimensions
Chapter 12 - Assessing restoration and management needs for ecosystems invaded by exotic annual Bromus species
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This study reviewed published studies on reburns in fire-adapted ecosystems of the world, including temperate forests of North America, semi-arid forests and rangelands, tropical and subtropical forests, grasslands and savannas, and Mediterranean ecosystems. To date, research on reburns is unevenly distributed across the world with a relative abundance of literature in Australia, Europe and North America and a scarcity of studies in Africa, Asia and South America. This review highlights the complex role of repeated fires in modifying vegetation and fuels, and patterns of subsequent wildfires. In fire-prone ecosystems, the return of fire is inevitable, and legacies of past fires, or their absence, often dictate the characteristics of subsequent fires.
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Our results demonstrated that the important predictors from Lidar-derived metrics had a strong correlation with field-measured biomass in the Random Forests (RF) regression models. The Stepwise Multiple Regression (SMR) results were similar but slightly better than RF. Overall, both RF and SMR methods explained more than 74% of the variance in biomass, with the most important Lidar variables being associated with vegetation structure and statistical measures of this structure (e.g., standard deviation of height was a strong predictor of biomass). Using our model results, we developed spatially-explicit Lidar estimates of total and shrub biomass across our study site in the Great Basin, U.S.A., for monitoring and planning in this imperiled ecosystem.
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Models explained much of the variability between predictions and manual measurements, and yet it is expected that future applications could produce even better results by reducing some of the methodological sources of error that we encountered. Our work demonstrates how terrestrial laser scanning (TLS) can be used efficiently to extend manual measurement of vegetation characteristics from small to large plots in grasslands and shrublands, with potential application to other similarly structured ecosystems. Our method shows that vegetation structural characteristics can be modeled without classifying and delineating individual plants, a challenging and time-consuming step common in previous methods applying TLS to vegetation inventory. Improving application of TLS to studies of shrub-steppe ecosystems will serve immediate management needs by enhancing vegetation inventories, environmental modeling studies, and the ability to train broader datasets collected from air and space.
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This study provides the first time series estimates of PM2.5 smoke costs across mortality and several morbidity measures for the Western US over 2005–2015. This time period includes smoke from several megafires and includes years of record-breaking acres burned. Smoke costs are estimated using a benefits transfer protocol developed for contexts when original health data are not available. The novelty of our protocol is that it synthesizes the literature on choices faced by researchers when conducting a smoke cost benefit transfer. On average, wildfire smoke in the Western US creates $165 million in annual morbidity and mortality health costs.
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This study identifies a broader set of objectives, decisions and constraints to be integrated into the next generation operational research models. Including these changes would support evaluation of a suite of response options and the efficient resource packages necessary to achieve response objectives, aiding decision maker’s ability to minimize responder exposure while reducing the social, ecological and economic impacts of wildfires. Researchers follow with a proposed framework for expanding current large fire decision support systems, and conclude by briefly highlighting critical research needs and organizational changes necessary to create and implement these tools and overcome the negative consequences of positive feedbacks derived from historical and current wildfire management policies and strategies.
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This study compared resultant travel rates to LiDAR-derived estimates of slope, vegetation density and ground surface roughness using linear mixed effects modelling to quantify the relationships between these landscape conditions and travel rates. The best-fit model revealed significant negative relationships between travel rates and each of the three landscape conditions, suggesting that, in order of decreasing magnitude, as density, slope and roughness increase, travel rates decrease. Model coefficients were used to map travel impedance within the study area using LiDAR data, which enabled mapping the most efficient routes from fire crew locations to safety zones and provided an estimate of travel time.
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The Fire Science Core Curriculum – Promoting Awareness, Understanding, and Respect of Fire through Knowledge of the Science is designed to teach the basics of fire to non-fire-professional community members, including instructors and landowners, such as ranchers and farmers. The goal is to reduce risk and fire hazard through education and understanding.
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This analysis found that season, plant composition, and ungulate assemblage may all influence dietary competition between wild horses and other large ungulate sharing western North American rangelands; however, the low and nonsignificant heterogeneity values at alpha 0.01 for cattle:horse effect size comparisons suggest that cattle and horses respond to regional and seasonal variation similarly—a result not observed for other ungulate:horse comparisons. Our meta-analysis provides a robust data set for evaluations of diet composition for wild horses, livestock, and wildlife, whereas no empirical studies have assessed all species together.
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Collectively, these results provide clear evidence that local sage-grouse distributions and demographic rates are influenced by pinyon-juniper, especially in habitats with higher primary productivity but relatively low and seemingly benign tree cover. Such areas may function as ecological traps that convey attractive resources but adversely affect population vital rates. To increase sage-grouse survival, our model predictions support reducing actual pinyon-juniper cover as low as 1.5%, which is lower than the published target of 4.0%. These results may represent effects of pinyon-juniper cover in areas with similar ecological conditions to those of the Bi-State Distinct Population Segment, where populations occur at relatively high elevations and pinyon-juniper is abundant and widespread.