Download or read book Wet thermal Time and Plant Available Water in the Seedbeds and Root Zones Across the Sagebrush Steppe Ecosystem of the Great Basin written by Nathan Lyle Cline and published by . This book was released on 2014 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Drivers of Plant Community Dynamics in Sagebrush Steppe Ecosystems written by Michael D. Reisner and published by . This book was released on 2011 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems' resilience to disturbance and invasion by Bromus tectorum (cheatgrass). The role of the foundational shrub Artemisia as a driver of herbaceous community structure and dynamics during this degradation process is poorly understood. Many of the individual factors driving B. tectorum invasions are well documented. However a predictive understanding of the relative importance of complex, interacting factors in the causal network of simultaneously occurring processes determining invasibility has proven elusive. I examined these issues at the landscape level across 75 sites capturing a range of soil and landscape properties and cattle grazing levels similar to those found across the Great Basin. Cumulative cattle herbivory stress levels were a predominant component of both the overlapping heat and water stress gradients driving the structure of Artemisia interactions with herbaceous species. Consistent with the stress gradient hypothesis, Artemisia facilitation of herbaceous species was most frequent and strongest at the highest stress levels, and competition was most frequent and strongest at the lowest stress levels. The two species with the highest competitive response abilities, Elymus elymoides and Poa secunda, showed the strongest facilitation at the upper limits of their stress tolerances. The structure of Artemisia interactions with the invasive B. tectorum was strikingly different than those with native bunchgrasses. Artemisia interactions with native bunchgrasses shifted from competition to facilitation with increasing heat, water, and herbivory stress, but its interactions remained competitive with B. tectorum along the entire stress gradient. Shifts in the structure of interactions between Artemisia and native bunchgrasses were associated with both an increase and decrease in community compositional and functional stability. I report the first evidence of native species facilitation decreasing community invasibility. Artemisia facilitation increased native bunchgrass composition, which reduced the magnitude of B. tectorum invasion in under-shrub compared to interspace communities. This decreased invasibility did not translate into lower invasibility at the community level because of the limited spatial scale over which such facilitation occurs. Artemisia facilitation increased community compositional and functional stability at intermediate stress levels but decreased community stability at high stress levels. Facilitation became a destabilizing force when native bunchgrass species became "obligate" beneficiaries, i.e. strongly dependent on Artemisia facilitation for their continued persistence in the community. Structural equation modeling assessed the structure of the causal network and relative importance of factors and processes predicted to drive community invasibility. The linchpin of ecosystem invasibility was the size of and connectivity between basal gaps in perennial vegetation, driven by shifts in the structure and spatial aggregation of the native bunchgrass community. Landscape orientation and soil physical properties determined inherent risk to invasion. Resident bunchgrass and biological soil crust communities provided biotic resistance to invasion by reducing the size of and connectivity between basal gaps and thereby limiting available resources and reducing safe sites for B. tectorum establishment. High levels of cattle grazing reduced ecosystem resilience by reducing native bunchgrass and biological soil crust abundance and altering bunchgrass community composition and facilitated B. tectorum invasion. Conserving and restoring resilience and resistance of these imperiled ecosystems will require reducing cumulative stress levels. As global climate change increases heat and water stress, reducing cumulative cattle grazing intensities by altering utilization rates and/or seasons of use may be the only effective means of accomplishing these goals.

Download or read book Plant Responses to Environmental Heterogeneity in Great Basin Sagebrush Steppe written by Sarah C. Barga and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emerging Seed Enhancements to Reduce the Risk of Sagebrush Post fire Seeding Failure written by Ryan Scott Call and published by . This book was released on 2018 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sagebrush (Artemisia spp.) steppe is undergoing rapid ecological change. The degradation of sagebrush steppe rangelands has resulted in the listing of more than 350 animals and plants as species of conservation concern. In addition, there has been a decrease in recreational values, reduced forage production, degraded water resources, and an increase in fire frequency. In the sagebrush steppe, success rates for seeding sagebrush after wildfire are notoriously low. Not only are sagebrush seeds hard to sow due to their small size and associated flower parts, but seedlings are exposed to numerous stresses that lowers their survivability. To improve sowing efficiency and reduce the associated stresses to seedling development we use seed enhancement technologies. In Chapter 1, we explain how a rotary seed coater can be used to agglomerate and apply enhancements to Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis) seed. Using a mix of compost and clay we used a rotary seed coater to create small uniform agglomerates that allowed for enhancements to be applied to the seed. Our study demonstrated that agglomerates have no negative effects on seed germination and increased the overall flow of seed. In Chapter 2, we analyzed the addition of the plant hormone abscisic acid (ABA) in seed coatings. This hormone may delay seed germination and allow seedlings to avoid mortality due to over-winter freezing. We determined effects of different concentrations of ABA on total germination and timing of germination. Using a wet-thermal accumulation model, we estimated germination timing of seeds using soil temperature and water potential data for six different sites in the Great Basin. These models illustrate the variation in germination timing across the Great Basin. From our results we proposed the idea of using ABA to create a bet- hedging strategy in seed mixes to increase the probability that some seeds would germinate when conditions are favorable for seedling success.

Download or read book Shifts in Plant Functional Types Have Time dependent and Regionally Variable Impacts on Dryland Ecosystem Water Balance written by John B. Bradford and published by . This book was released on 2014 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1. Terrestrial vegetation influences hydrologic cycling. In water-limited, dryland ecosystems, altered ecohydrology as a consequence of vegetation change can impact vegetation structure, ecological functioning and ecosystem services. Shrub steppe ecosystems dominated by big sagebrush (Artemisia tridentata) are widespread across western North America, and provide a range of ecosystem services. While sagebrush abundance in these ecosystems has been altered over the past century, and changes are likely to continue, the ecohydrological consequences of sagebrush removal and reestablishment remain unclear. 2. To characterize the immediate and medium-term patterns of water cycling and availability following sagebrush plant community alteration, we applied the SOILWAT ecosystem water balance model to 898 sites across the distribution of sagebrush ecosystems, representing the three primary sagebrush ecosystem types: sagebrush shrublands, sagebrush steppe and montane sagebrush. At each site, we examined three vegetation conditions representing intact sagebrush, recently disturbed sagebrush and recovered but grass-dominated vegetation. 3. Transition from shrub to grass dominance decreased precipitation interception and transpiration and increased soil evaporation and deep drainage. Relative to intact sagebrush vegetation, simulated soils in the herbaceous vegetation phases typically had drier surface layers and wetter deep layers. 4. Our simulations suggested that alterations in ecosystem water balance may be most pronounced in vegetation representing recently disturbed conditions (herbaceous vegetation with low biomass) and only modest in conditions representing recovered, but still grass-dominated vegetation. Furthermore, the ecohydrological impact of simulated sagebrush removal depended on climate; while short-term changes in water balance were greatest in wet areas represented by the montane sagebrush ecosystem type, medium-term impacts were greatest in dry areas of sagebrush shrublands and sagebrush steppe. 5. Synthesis. This study provides a novel, regional-scale assessment of how plant functional type transitions may impact ecosystem water balance in sagebrush-dominated ecosystems of North America. Results illustrate that the ecohydrological consequences of changing vegetation depend strongly on climate and suggest that decreasing woody plant abundance may have only limited impact on evapotranspiration and water yield.

Download or read book Big Sagebrush written by Bruce Leigh Welch and published by . This book was released on 2005 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pioneers traveling along the Oregon Trail from western Nebraska, through Wyoming and southern Idaho and into eastern Oregon, referred to their travel as an 800 mile journey through a sea of sagebrush, mainly big sagebrush ( Artemisia tridentata). Today approximately 50 percent of the sagebrush sea has given way to agriculture, cities and towns, and other human developments. What remains is further fragmented by range management practices, creeping expansion of woodlands, alien weed species, and the historic view that big sagebrush is a worthless plant. Two ideas are promoted in this report: (1) big sagebrush is a nursing mother to a host of organisms that range from microscopic fungi to large mammals, and (2) many range management practices applied to big sagebrush ecosystems are not science based.

Download or read book Intraspecific Variation in Plant plant Interactions and Belowground Zone of Influence of Big Sagebrush Artemisia Tridentata written by Andrii Zaiats and published by . This book was released on 2019 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Post-fire restoration of degraded sagebrush ecosystems over large areas of the Great Basin is challenging, in part due to unpredictable outcomes. Low rates of restoration success are attributed to increasing frequencies of wildfires, biological invasions, and climate variability. Quantifying restoration outcomes by accounting for sources of biotic and abiotic variability will improve restoration as a predictive science. One source of biotic variability is neighbor interactions, which can regulate demographic parameters of coexisting species and are an important determinant of community structure, ecosystem functions, and population dynamics. Our objective was to quantify how intraspecific variability in big sagebrush, Artemisia tridentata, including three subspecies and two ploidy levels, is related to subspecies' reaction to conspecific neighbor presence. Neighbor interactions can alter population growth rate via competition or facilitation depending on specific environmental conditions. Using a long-term common garden experiment, we developed spatially-explicit hierarchical models to quantify the effects of size-structured crowding on plant growth and survival. We found that neighbor interactions can vary significantly over time and space, and tend to be more pronounced under wetter and cooler climate conditions. We further tested if water availability, one of the major limiting factors in arid ecosystems, can underlie competitive interactions in a common garden, including density dependence. We used a deuterium-tracer experiment to quantify belowground zone of influence and crowding effect on plant water uptake. The results suggest that intraspecific variability in lateral root extent may be linked to subspecies identity and ploidy level. We did not find strong evidence that neighbor presence and size can alter water uptake from a shallow soil horizon, potentially suggesting size-independent partitioning of water resources between neighboring plants. We further hypothesize that variability in root architecture may reflect an axis for ecohydrological niche segregation contributing to the process of plant coexistence and evolution in heterogeneous landscapes. Our study complements previous knowledge of belowground processes in big sagebrush populations, including patterns of resource acquisition, and indicates promising avenues for further research of the ecology and evolution of this species. The results highlight how local plant-plant interactions can be a source of variation in common garden experiments, which are used to evaluate adaptive capacity and seed transfer zone development for A. tridentata populations. Potential applications of our work include planting density recommendations for big sagebrush in applied and experimental contexts, and provide mechanistic understanding of intraspecific diversification and ecological tradeoffs related to local adaptations."--Boise State University ScholarWorks.

Download or read book Guide for Quantifying Post treatment Fuels in the Sagebrush Steppe and Juniper Woodlands of the Great Basin written by Andrea Stebleton and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Invasive species and woodland encroachment have caused extensive changes in the fire regimes of sagebrush steppe over the past 150 years. Land managers and resource specialists of the Great Basin are increasingly required to implement vegetation treatments to maintain habitat, reduce fire risk and restore landscapes to a more desirable state. Often it is difficult to measure treatment effectiveness because gathering pre- and post-treatment data is time-consuming and costly. In two years of post-treatment sampling across six Great Basin states, researchers from the Sagebrush Steppe Treatment and Evaluation Project (SageSTEP) measured the vegetation response to prescribed fire, tree mastication and cutting, shrub mowing, and herbicide application. Treated plots were compared to untreated control plots.

Download or read book Shrub steppe Balance and Change in a Semi arid Terrestrial Ecosystem written by William Howard Rickard and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shrub steppe written by and published by . This book was released on 1988 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fire Effects Guide written by and published by . This book was released on 1994 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plant soil Feedbacks and Invasion in Sagebrush Steppe Ecosystems written by Rachel Oglevie Jones and published by . This book was released on 2014 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Invasion by non-native species is a serious ecological threat and the susceptibility of ecosystems to invasion is often highly correlated with soil resource availability. Understanding the role of plant-soil feedbacks in invaded ecosystems could provide insight into community successional trajectories following invasion and could improve our ability to manage these systems to restore native diversity. My dissertation examined how plant-soil feedbacks and resource availability influence the success of both cheatgrass and native species with three interrelated studies. In a large-scale observational study, I evaluated plant community characteristics as well as soil and plant nutrients associated with progressive cheatgrass invasion in a broadly distributed sagebrush ecological site type. I found that although many nutrient pools did not differ among levels of invasion, soil ammonium (NH4+) was negatively affected by increases in cheatgrass cover. Also, cheatgrass nutrient content did not differ across sites indicating that cheatgrass may alter plant available soil nutrients to the detriment of competitors while maintaining its own nutritional content via high nutrient use efficiency and/or soil mining. I also conducted a field experiment to provide a more mechanistic understanding of the role of disturbance on nutrient availability and invasion and to address potential management approaches. I evaluated the effects of 4-5 years of repeated burning, in combination with litter removal and post-fire seeding, on nutrient dynamics and plant responses. Results from my field experiment indicated that repeated burning is unlikely to decrease soil N availability in cheatgrass-dominated systems due to cool fire temperatures that do not volatilize biomass N and strong effects of weather on plant growth and soil processes. Repeated burning and litter removal, however, did have negative effects on litter biomass and C and N contents which negatively influenced cheatgrass biomass, density and reproduction. In addition, post-fire seeding with common wheat decreased cheatgrass abundance, likely due to competition. Integrated restoration approaches that decrease litter biomass and seed banks and increase competitive interactions may be more effective at reducing annual grasses and establishing desirable perennial species than approaches aimed at reducing soil nutrients. Together, the observational and experimental components of my dissertation indicate that plant-soil feedbacks in arid sagebrush shrublands are complex and that understanding these feedbacks requires both spatial and temporal variability in sampling. Furthermore, the results from these studies provide valuable information on techniques that could facilitate the restoration of cheatgrass-dominated systems to more diverse plant communities.

Download or read book The Effects of Neighboring Vegetation and Soil Moisture on Establishment of Mountain Big Sagebrush Artemisia Tridentata Ssp Vaseyana Seedlings After Fire in Sagebrush Steppe written by Katherine M. DiCristina and published by . This book was released on 2004 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the growing season of 2003, patterns of establishment of Artemisia tridentata ssp. vaseyana were observed after fire in a sagebrush steppe ecosystem in southeastern Idaho. It was examined how A. t. vaseyana seedling establishment was affected by neighboring vegetation and how these effects were modulated by 1) identity (functional group) and proximity of neighboring vegetation, 2) time since burning, and 3) water availability. Manipulative experiments were conducted to further isolate how identity and water affect competitive interactions between seedlings and neighbors and so that the causal relationships between herbs and seedlings could be better substantiated. Patterns of establishment for A. t. vaseyana were detected in addition to interactions between A. t. vaseyana and neighboring herbs that appeared to be modulated by water. Therefore, in the growing season of 2004, it was observed how neighboring herbs and seasonal soil drying affected carbon assimilation and competitive responses of A. t. vaseyana seedlings. This research contributes to land management decisions in sagebrush steppe ecosystems.

Download or read book Restoring Western Ranges and Wildlands written by Stephen B. Monsen and published by . This book was released on 2004 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial and Temporal Controls on Population and Flux Processes in Steppe Ecosystems written by Kusum Naithani and published by . This book was released on 2009 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth and Water Relations of Mountain Big Sagebrush on Reclaimed Mine Soils in Southwestern Wyoming written by Alan T. Carpenter and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mined-land reclamation practices in shrub-steppe ecosystems can be augmented by planting seedlings of locally dominant shrubs, e.g., mountain big sagebrush. Dispersion pattern could affect sagebrush performance by influencing amounts of windborne snow, soil and litter which accumulate around shrubs and by influencing water withdrawal by roots. Mountain big sagebrush seedlings were planted in plots on a reclaimed coal strip mine in two dispersion patterns: singly and in clumps of four at the same overall density. Performance of mountain big sagebrush was monitored during two growing seasons. Measures included plant survival, end-of-growing season aboveground biomass, leaf water potential components, soil water potential, twig and ephemeral leaf survival and reproductive allocation. Most measures of performance were similar for single and clumped plants. However, single plants had a greater twig elongation rate than clumped plants, and roots of plants in clumps removed less soil water to 50 cm than roots of single plants. In order for shrub dispersion pattern to affect plant performance via differential snow, soil or litter accumulation, the plants would have to respond to the added resources, probably water and nitrogen. An experiment was conducted to test if a small extra increment of water and nitrogen would affect mountain big sagebrush plants. The same plant performance indices listed above were monitored. The added water and nitrogen, either alone or in combination, had no effect except on reproduction. In 1983, there was a significant water* fertilizer interaction observed for some of the reproductive metrics, while in 1984 there was a significant water effect. While a significant main effect of nitrogen was expected under the prevailing wet conditions, the large reservoir of soil nitrogen evidently provided sufficient nitrogen. Reproduction was more sensitive to added water and nitrogen resources than was vegetative growth. The nearly equal performance of mountain big sagebrush in the two dispersion patterns may have resulted from several factors. Water availability to the experimental shrubs was very high throughout the study due to abnormally heavy precipitation and to removal of weeds from the plots. During drier years, dispersion pattern may have greater influence on the shrubs.

Download or read book Pilbara Seed Atlas and Field Guide written by Todd Erickson and published by CSIRO PUBLISHING. This book was released on 2016-04-01 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Pilbara region in Australia’s arid northwest is rich in flora that is suited to extreme temperatures and boom and bust cycles of moisture availability. It is also a region important for its natural resources. In places where mining activities have finished and the land is under management for ecological restoration, there is increasing demand for information about native plant communities and the biology of their seeds. Pilbara Seed Atlas and Field Guide is the first book to combine plant identification with robust, scientific criteria for cost-effective seed-based rehabilitation. It describes 103 regional plant taxa and provides guidelines for effective collection, cleaning, storage and germination of their seeds. It addresses issues such as timing of collection, quality and viability of seed, and dormancy release, which are essential for successful restoration programs. With photographs to portray the subtle differences and unique features of each species’ biology, this book will be of great use to practitioners in the field, including environmental consultants, rehabilitation companies, commercial seed collectors and government authorities, as well as naturalists and people interested in growing the Pilbara’s remarkable plants.