Author: Sarah C. BargaPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Plant Responses to Environmental Heterogeneity in Great Basin Sagebrush Steppe
Recovery of Soil Properties, Sagebrush Steppe Community Structure, and Environmental Heterogeneity Following Drastic Disturbance and Reclamation
Author: Caley K. GaschPublisher:
ISBN: 9781303631375
Category : Restoration ecology
Languages : en
Pages : 93
Book Description
The objective of this research was to investigate vegetation and soil property structure in sagebrush steppe ecosystems as they recover from drastic disturbance, particularly in assessing the variability of properties across space. On reclaimed pipelines, I collected vegetation data and analyzed soil for organic carbon, total nitrogen, microbial community structure, moisture, salinity, and alkalinity. Using a Bayesian hierarchical mixed model, I quantified soil properties with posterior predictive distributions to compare reclaimed areas with the reference areas. The variance of most soil properties was affected by disturbance, and not always accompanied by a shift in the mean. Distributions for soil properties in reclaimed areas became more similar to those of undisturbed reference areas as recovery time increased. I then explored the differences in sampling designs, analysis, and inference gained from spatial and non-spatial soil data. I also conducted side-by-side analyses of each data type for a reclaimed area and an undisturbed area. The analysis of random data revealed differences in soil property averages between treatments. These differences were also apparent in the geostatistical analysis, which also provided information about the spatial structure in soil properties at the scale of individual plant effects (10 cm - 10 m). The third project expanded the assessment in both space and time, by including reclaimed pipelines that spanned 55 years, and by sampling at a scale up to 100 meters. I used Bayesian geostatistical models to quantify the correlation structure and to create surface predictions for measured properties. The reclaimed areas maintained uniform grass cover with low diversity and shrub establishment, while the responses of soil properties to disturbance and reclamation were variable. All three modeling approaches indicated that soil properties closely associated with vegetation experienced reduced variability and homogenization across space following disturbance. Soil abiotic properties appeared to be affected by the physical effects of disturbance, but were not associated with homogenization. Development of belowground heterogeneity was possibly delayed by the slow recovery of the plant community, particularly the shrub component. This research illustrates some long lasting ecological consequences of disturbance in sagebrush steppe and emphasizes the need for establishing shrubs in reclaimed sagebrush steppe.
Big Sagebrush
Author: Bruce Leigh WelchPublisher:
ISBN:
Category : Big sagebrush
Languages : en
Pages : 220
Book Description
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.
Shrub-steppe
Author: Pacific Northwest LaboratoryPublisher: Elsevier Publishing Company
ISBN:
Category : Science
Languages : en
Pages : 292
Book Description
Owing to man-made intervention, the shrub-steppe now represents a rapidly disappearing landscape in the arid regions of North America. This book represents a systems-level study of ecological variables affecting water balance, and responses to perturbation. The study focused on a very large, protected, landscape unit, comprising a natural watershed'' area located in the semi-arid western United States. Long-term and concurrent data sets were established with a view towards establishing system-level responses to manipulative interventions, and natural perturbations like wildfire. These data sets were established for micrometeorology, climatology, mineral cycling in soils, nutrient and mineral pathways in springs and streams, vegetational dynamics, and population changes on the site. In synthesizing nearly twenty years of data, the more interesting ecosystem level responses concerned vegetational recovery and water balance. For instance, the synthesis uniquely demonstrates the interaction of biotic and non-biotic factors and their integrated effect on regional water balance.
Wet-thermal Time and Plant Available Water in the Seedbeds and Root Zones Across the Sagebrush Steppe Ecosystem of the Great Basin
Author: Nathan Lyle ClinePublisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 139
Book Description
Exotic Brome-Grasses in Arid and Semiarid Ecosystems of the Western US
Author: Matthew J. GerminoPublisher: Springer
ISBN: 3319249304
Category : Technology & Engineering
Languages : en
Pages : 475
Book Description
Invasions by exotic grasses, particularly annuals, rank among the most extensive and intensive ways that humans are contributing to the transformation of the earth’s surface. The problem is particularly notable with a suite of exotic grasses in the Bromus genus in the arid and semiarid regions that dominate the western United States, which extend from the dry basins near the Sierra and Cascade Ranges across the Intermountain Region and Rockies to about 105° longitude. This genus includes approximately 150 species that have a wide range of invasive and non-invasive tendencies in their home ranges and in North America. Bromus species that became invasive upon introduction to North America in the late 1800’s, such as Bromus tectorum and B. rubens, have since became the dominant cover on millions of hectares. Here, millenia of ecosystem development led to landscapes that would otherwise be dominated by perennial shrubs, herbs, and biotic soil crusts that were able to persist in spite of variable and scarce precipitation. This native ecosystem resilience is increasingly coveted by land owners and managers as more hectares lose their resistance to Bromus grasses and similar exotics and as climate, land use, and disturbance-regime changes are also superimposed. Managers are increasingly challenged to glean basic services from these ecosystems as they become invaded. Exotic annual grasses reduce wildlife and livestock carrying capacity and increase the frequency and extent of wildfi res and associated soil erosion. This book uses a unique ecoregional and multidisciplinary approach to evaluate the invasiveness, impacts, and management of the large Bromus genus. Students, researchers, and practitioners interested in Bromus specifically and invasive exotics in general will benefit from the depth of knowledge summarized in the book.
Additive Partitioning Reveals Spatial Patterns of Plant Species Diversity in a Sagebrush Steppe
Author: Anne-Marie HoskinsonPublisher:
ISBN:
Category :
Languages : en
Pages : 228
Book Description
Habitat Threats in the Sagebrush Ecosystem
Author: David S. DobkinPublisher:
ISBN:
Category : Habitat conservation
Languages : en
Pages : 340
Book Description
This book is about the status and future of the sagebrush ecosystem and its dependent species. The ecosystem is not healthy and is diminishing due to the many and various human land uses. Maintaining the ecosystem will require monumental changes in management and those changes must address all land uses in an integrated, holistic manner to be effective. The two major obstacles are a lack of needed resources, both funds and land use direction, and the attempt to stop the loss and degradation of sagebrush habitats while lacking essential research information on which to base effective strategies.
American Journal of Botany
Author: Plant-soil Feedbacks and Invasion in Sagebrush Steppe Ecosystems
Author: Rachel Oglevie JonesPublisher:
ISBN:
Category : Electronic books
Languages : en
Pages : 318
Book Description
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.