Author: Roger LongPublisher:
ISBN:
Category :
Languages : en
Pages : 59
Book Description
Nitrogen Dynamics in the Sagebrush Steppe
Author: Roger LongThe Effects of Change in Timing and Amounts of Precipitation on Vegetation Dynamics and Nitrogen Mineralization in a Sagebrush-steppe Ecosystem
Author: Amy N. MorrisPublisher:
ISBN:
Category : Nitrification
Languages : en
Pages : 196
Book Description
The Role of Fire and Nitrogen on Plant Invasion Into the Sagebrush Steppe
Author: Erin GoergenSeed and Soil Dynamics in Shrubland Ecosystems
Author: Ann L. HildPublisher:
ISBN:
Category : Germination
Languages : en
Pages : 240
Book Description
Biological Soil Crusts: Structure, Function, and Management
Author: Jayne BelnapPublisher: Springer Science & Business Media
ISBN: 3642564755
Category : Science
Languages : en
Pages : 496
Book Description
In arid lands, where vegetation is sparse or absent, the open ground is not bare but generally covered by a community of small, highly specialized organisms. Cyanobacteria, algae, microfungi, lichens, and bryophytes aggregate soil particles to form a coherent skin - the biological soil crust. It stabilizes and protects the soil surface from erosion by wind and water, influences water runoff and infiltration, and contributes nitrogen and carbon to desert soils. Soil surface disturbance, such as heavy livestock grazing, human trampling or off-road vehicles, breaks up the fragile soil crust, thus compromising its stability, structure, and productivity. This book is the first synthesis of the biology of soil crusts and their importance as an ecosystem component. Composition and functioning of different soil-crust types are discussed, and case studies are used to show the impact of crusts on landscape hydrology, soil stability, nutrient cycles, and land management.
Soil Community Dynamics in Sagebrush and Cheatgrass-invaded Ecosystems of the Northern Great Basin
Author: Nicole M. DeCrappeoPublisher:
ISBN:
Category : Cheatgrass brome
Languages : en
Pages : 276
Book Description
Sagebrush steppe ecosystems in the Great Basin have become increasingly threatened by the proliferation of cheatgrass (Bromus tectorum L.), an invasive annual grass. Diverse sagebrush and perennial bunchgrass landscapes can be converted to homogenous cheatgrass grasslands mainly through the effects of fire. Although the consequences of this conversion are well understood in the context of plant community dynamics, information on changes to soil communities has not been well documented. I characterized soil surface, microbial, and nematode community dynamics in sagebrush steppe and cheatgrass-invaded areas across the northern Great Basin. I also examined how restoration treatments, such as seeding with a low impact rangeland drill and applying herbicide or sugar to plots, affected soil communities. Soil community functional diversity and structure were alike at sites where soil pH and percent bare ground were similar. Rangeland drill seeding and associated human trampling decreased biological soil crust cover at sites with high proportions of cyanobacteria. Herbicide treatments had little effect on soil communities, but addition of sugar to plots increased carbohydrate utilization and fungal biomass of cheatgrass- invaded soils. In studying paired intact and cheatgrass-invaded sagebrush plots, I found that microbial functional diversity and community composition were different in sagebrush, bunchgrass, cheatgrass, and interspace soils. Fungal biomass and species richness were highest under sagebrush and decreased under cheatgrass. To examine how soil community shifts might affect ecosystem processes, I investigated the contribution of fungi to inorganic nitrogen (N) mineralization in sagebrush and cheatgrass rhizospheres. Results from a 15N pool dilution experiment modified with the fungal protein synthesis inhibitor cycloheximide showed that gross and net N cycling rates did not differ between control sagebrush and cheatgrass soils and that fungi were important for gross NH4+ production and consumption in both soil types. However, net nitrification increased in sagebrush soils after 24 h, suggesting that when organic matter decomposition by fungi ceased bacteria became carbon limited and could no longer assimilate NH4+. These studies demonstrate that cheatgrass invasion into sagebrush steppe ecosystems can bring about significant changes to soil communities and that these changes may have repercussions for ecosystem functioning in the northern Great Basin.
Distribution of Total Carbon, Total Nitrogen, and Nitrogen Mineralization Pools Following Shrub Removal and Nitrogen Additions in Sagebrush Steppe
Author: Heather Ann BechtoldPublisher:
ISBN:
Category : Big sagebrush
Languages : en
Pages : 126
Book Description
Concentrations of total N and C were 39% higher below shrub canopies. Seven years after shrubs were removed, soil N and C concentrations remained higher in areas where shrubs previously were than in open interspace areas. Because nitrogen is a limiting resource for plant growth, persistence of resource islands may facilitate shrub re-establishment patterns after disturbances that removed shrubs.
Ground Cover Dynamics in a Sagebrush Steppe Community
Author: Bruce P. Van HaverenPublisher:
ISBN:
Category : Ground cover plants
Languages : en
Pages : 2
Book Description
Long-term Vegetation Dynamics and Post-fire Establishment Patterns of Sagebrush Steppe
Author: Elizabeth C. ColketPublisher:
ISBN:
Category : Big sagebrush
Languages : en
Pages : 288
Book Description
Ecology of the Shortgrass Steppe
Author: W. K. LauenrothPublisher: Oxford University Press
ISBN: 0199722803
Category : Science
Languages : en
Pages : 537
Book Description
Ecology of the Shortgrass Steppe: A Long-Term Perspective summarizes and synthesizes more than sixty years of research that has been conducted throughout the shortgrass region in North America. The shortgrass steppe was an important focus of the International Biological Program's Grassland Biome project, which ran from the late 1960s until the mid-1970s. The work conducted by the Grassland Biome project was preceded by almost forty years of research by U.S. Department of Agriculture researchers-primarily from the Agricultural Research Service-and was followed by the Shortgrass Steppe Long-Term Ecological Research project. This volume is an enormously rich source of data and insight into the structure and function of a semiarid grassland.