Download or read book Effects of Nitrogen Deposition on the Carbon Allocation and Nutrient Concentration of Southern California Vegetation written by Shelley Lawrence and published by . This book was released on 2015 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal sage scrub and chaparral vegetation of Southern California have become fragmented due to a loss of habitat over the past several decades, which has been caused by several contributing factors such as agriculture, urbanization, increased fire frequency and intensity. Although nitrogen deposition has also been found to be a contributing factor to the loss of coastal sage scrub (CSS) and chaparral habitats in previous studies, the mechanism for these effects not been examined. Leaf tissue from existing field plots, fertilized with nitrogen since 2003, was analyzed for carbon allocation patterns and nutrient retention on a seasonal and annual basis from 2006, 2008 and 2010. Nitrogen fertilization did not have an effect on carbon allocation to cellulose, holocellulose or lignin fractions of leaf tissue in CSS California sagebrush (Artemisia californica) or chaparral chamise (Adenostoma fasciculatum) shrubs. However, it was found that seasonal and interannual variation in soluble carbon were highest in both species, but without any N treatment interaction. It was also found that year and season did have a significant effect on carbon allocation, and these temporal variations were correlated with precipitation rates and nutrient availability. The lack of nitrogen effect in the soluble carbon, holocellulose and lignin fractions suggests these avenues of carbon allocation are linked to life history traits that are specific to each species such as drought tolerance, woodiness, and maturation.
Download or read book Nitrogen Deposition and Its Effects on the Soils Vegetation and Fire Risk in Southern California Deserts written by Leela Ellen Rao and published by . This book was released on 2008 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidant Air Pollution Impacts in the Montane Forests of Southern California written by Paul R. Miller and published by Springer. This book was released on 1999 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the 1950s, the pines native to the San Bernardino Mountains in Southern California have shown symptoms of decline that have proven to result from exposure to ozone, a major plant-damaging gas in photochemical oxidant air pollution. Because of their proximity to major urban areas, the San Bernardino Mountains have served as a natural laboratory for studying effects of oxidant and acidic air pollution on a mixed-conifer forest. This volume presents a body of research conducted over more than thirty years, including an intensive interdisciplinary five-year study begun in 1991. Chapters include studies of the relationships of biogeography and climate to the region's air pollution, the chemical and physiological mechanisms of ozone injury, as well as the impacts of nitrogen-containing pollutants and natural stresses on polluted forests. The synthesis of such long-term studies provides insights into the combined influences of pollutants on ecosystem function in forested regions with Mediterranean-type climates.
Download or read book The Effects of Nitrogen Deposition on Plant Community Dynamics in a Heterogeneous Savanna Landscape written by Elise M. Tulloss and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Urbanization and agricultural intensification in California has increased N emissions and, consequently, deposition to adjacent oak savanna landscapes. The total amount and chemical form of this deposition varies across the landscape at multiple spatial scales and through time. At a coarse scale, there is a non-linear gradient in N deposition across the California oak savanna region such that savanna sites closest to sources of N emissions receive greater deposition than sites in more remote areas. At a fine scale within savanna sites, a strong research foundation in oak woodland systems has described heterogeneity in soil resources created by the existence of oak canopies. This phenomenon, termed islands of fertility, is a net result of enhanced nutrient inputs and retention facilitated by the tree, with nitrogen deposition being recently suggested as a primary cause of enhanced inputs. The interaction between the regional-scale gradient of N deposition, the local-scale island of fertility, and the seasonal variability of N deposition results in heterogeneous soil N resources. Nitrogen availability is greatest beneath oaks and at sites on the high end of the regional gradient and during seasonal pulses of N deposition associated with precipitation events. These heterogeneous soil N resources play a critical role in structuring plant communities under current and increased N deposition. The aim of this dissertation was to investigate how N deposition varies at multiple scales depending on specific landscape drivers, such as site context and vegetation structure, and tease apart the effect of that heterogeneous N deposition on native and exotic competitive dynamics relative to multiple controlling factors. I quantified a gradient of N deposition across 6 oak savanna sites in north-central California. At the regional scale, sites closer to pollutant emissions received greater N deposition and sites in remote areas received less. At the local, within-site scale, the oak canopy was a hotspot of higher N deposition. The magnitude of the hotspot effect beneath oaks was not constant across the regional gradient, but rather oaks at the high end of the regional gradient received proportionally more N deposition than oaks at the low end of the gradient. This finding emphasized the importance of landscape context to within-site dynamics. The N deposition gradient was complex because several other soil and climate variables co-varied. Subsequent research was designed to experimentally tease apart the relative effect of N deposition on plant community dynamics from other factors that varied across this complex gradient, including soil type, which varied across the regional scale, and light availability, which varied between canopy and open areas at the local scale. A greenhouse experiment examined competitive interactions among native and exotic grasses in response to N fertilization, soil type, and light availability. Native and exotic grasses were both most sensitive to N deposition during the period of rapid vegetative growth in early spring. Invasive exotic grass was not becoming competitively dominant under increased N. Overall, N increased plant biomass, height, and seed mass altering the outcome of species interactions in a few cases, and thus, was important not as a single driving factor, but rather in the context of the other environmental factors I manipulated. This result indicated that N deposition must be considered together with the complex suite of environmental factors to predict effects to plant communities. In advancing our understanding of landscape and ecosystem ecology, the dissertation research highlighted the importance of landscape context and complex interactions among spatially and temporally heterogeneous factors in influencing dynamics within wildlands.
Download or read book Ecosystems of California written by Harold Mooney and published by Univ of California Press. This book was released on 2016-01-19 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.
Download or read book The California Nitrogen Assessment written by Thomas P. Tomich and published by Univ of California Press. This book was released on 2016-06-14 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Collaborating Institutions: Agricultural Sustainability Institute at UC Davis, UC ANR Sustainable Agriculture Research and Education Program, UC ANR Kearney Foundation of Soil Science, UC ANR Agricultural Issues Center, UC ANR California Institute for Water Resources, Water Science and Policy Center at UC Riverside."
Download or read book Responses of Nitrifying Microbes in Southern California Native Plant Communities to Additions of Nitrogen written by Robert R. Mustard and published by . This book was released on 2008 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Resource Allocation written by Fakhri A. Bazzaz and published by Elsevier. This book was released on 1997-07-23 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant Resource Allocation is an exploration of the latest insights into the theory and functioning of plant resource allocation. An international team of physiological ecologists has prepared chapters devoted to the fundamental topics of resource allocation. - Comprehensive coverage of all aspects of resource allocation in plants - All contributors are leaders in their respective fields
Download or read book Global Energy Assessment written by Thomas B. Johansson and published by Cambridge University Press. This book was released on 2012-08-27 with total page 1885 pages. Available in PDF, EPUB and Kindle. Book excerpt: Independent, scientifically based, integrated, policy-relevant analysis of current and emerging energy issues for specialists and policymakers in academia, industry, government.
Download or read book Clean Coastal Waters written by National Research Council and published by National Academies Press. This book was released on 2000-08-17 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental problems in coastal ecosystems can sometimes be attributed to excess nutrients flowing from upstream watersheds into estuarine settings. This nutrient over-enrichment can result in toxic algal blooms, shellfish poisoning, coral reef destruction, and other harmful outcomes. All U.S. coasts show signs of nutrient over-enrichment, and scientists predict worsening problems in the years ahead. Clean Coastal Waters explains technical aspects of nutrient over-enrichment and proposes both immediate local action by coastal managers and a longer-term national strategy incorporating policy design, classification of affected sites, law and regulation, coordination, and communication. Highlighting the Gulf of Mexico's "Dead Zone," the Pfiesteria outbreak in a tributary of Chesapeake Bay, and other cases, the book explains how nutrients work in the environment, why nitrogen is important, how enrichment turns into over-enrichment, and why some environments are especially susceptible. Economic as well as ecological impacts are examined. In addressing abatement strategies, the committee discusses the importance of monitoring sites, developing useful models of over-enrichment, and setting water quality goals. The book also reviews voluntary programs, mandatory controls, tax incentives, and other policy options for reducing the flow of nutrients from agricultural operations and other sources.
Download or read book Nitrogen Deposition Along a California Freeway and Impacts on Central Valley Grassland Species written by John Theodore Rusmore and published by . This book was released on 2004 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acidic Deposition State of Science and Technology written by and published by . This book was released on 1991 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nitrogen Deposition and Soil Microorganisms of Artemisia Californica and Exotic Grasses in Southern California written by Concepción Sigüenza and published by . This book was released on 2000 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Impact of Nitrogen Deposition on Natural and Semi Natural Ecosystems written by S.J. Langan and published by Springer Science & Business Media. This book was released on 1999-07-31 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an up-to-date synthesis of the understanding of the interaction between the emission of nitrogen, its deposition and impact on the most important components of natural and semi-natural ecosystems. The work consists of contributions from internationally renowned research scientists. Individual chapters deal with the factors and processes related to nitrogen deposition and soils, non-forest vegetation communities, forest ecosystems, and surface waters. The assessment of these impacts is discussed in terms of setting critical loads. The book is aimed at researchers, advanced course students and policy makers/advisors involved with aspects of the impact of air pollution.
Download or read book 1990 Integrated Assessment Report written by and published by . This book was released on 1991 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Response to Stress written by John D. Tenhunen and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is dedicated to international cooperation, understanding and peace. It is the end result of several years of cooperative work between scientists of three countries: the United States, Germany, and Portugal. The work presented, however, draws from a much broader base, hopefully achieving the objective of NATO Advanced Research Workshops, which have been established to allow and stimulate the exchange of new ideas and the synthesis of information by scientists of NATO countries. The tasks of the workshop were several; to review established methodologies that have provided insight into ecosystem function and adaptations of plants in mediterranean climate zones; to examine new methodologies that have recently been applied in ecological studies and have provided new types of information; to summarize recent studies in mediterranean regions of plant water relations, photosynthesis and production, mineral nutrition, plant growth and development, and response to fire; to stimulate in particular an exchange of information among scientists of European Mediterranean countries; and to discuss means by which all of these objectives might be even more effectively achieved in the future through cooperative international research efforts. This variety of themes is clearly evident in the layout of the book. Held in Sesimbra, Portugal in October of 1985, the workshop took place in a ..
Download or read book The Effects of Chronic Nitrogen Deposition on the Ectomycorrhizal Community Structure and Function of a Forest Ecosystem with a Mediterranean Climate written by Benjamin A. Waitman and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, I examine how environment-altering anthropogenic disturbances affect the relationship between plants and beneficial soil microbes. Many disturbances change key aspects of the soil environment, directly affecting both plants and soil microbes, and potentially altering plant-microbe interactions. I use a combination of field and greenhouse experiments to compare plant-soil microbe interactions across different levels of environmental disturbance. In Chapter I and II, I used a well-known pollution gradient across montane forests in Southern California to examine how nitrogen (N) deposition alters the structure and function of ectomycorrhizal fungi in forests with a Mediterranean climate. Many studies have identified strong effects of anthropogenic nitrogen deposition on the community composition of ectomycorrhizal fungi in boreal and temperate forest soils. These ecosystems are typically N limited, and it is not clear whether N deposition has similar effects on ectomycorrhizal communities in less productive ecosystems where N may be colimiting to plant productivity along with other resources. I tested the effects of N deposition on ectomycorrhizal communities within forests receiving a range of N deposition in the San Bernardino National Forest of Southern California, where tree growth during the growing season is typically limited by water availability. To determine the effects of N deposition on ectomycorrhizal communities, I sampled both the ectomycorrhizae colonizing the root tips of ponderosa pine and present as fungal hyphae, collectively referred to as mycelium. Ectomycorrhizal fungi present in these samples were identified using PCR based molecular methods. In addition, I tested whether N deposition alters functional traits of ectomycorrhizal communities by assaying the production of a suite of extracellular enzymes that target a range of organic soil nutrients. For enzyme assays, I used ectomycorrhizal colonized root tips collected from forest stands across the N deposition gradient during both dry and wet seasons. Ectomycorrhizal community composition was correlated with N deposition for both colonized root tip and mycelium samples. In addition, mycelium abundance was negatively correlated with soil nitrate concentration. However, the function of ectomycorrhizal communities was not strongly affected by N deposition in this study, and N deposition was much less important to EMF enzyme production than seasonal effects. I found that enzyme production was consistent in most seasons across the N deposition gradient for enzymes that target organic nitrogen sources, organic phosphorus, and recalcitrant carbon sources. Only the production of glycoside hydrolyzing enzymes were positively correlated with N deposition, and only during the wettest sampling period in December. These results confirm that N deposition is changing ectomycorrhizal communities and abundance, even in dry forests where conditions may reduce the relative importance of nitrogen nutrition for forest trees. However, the change in community composition does not appear to result in a change in the capacity of EMF communities to produce extracellular enzymes. In Chapter III, I evaluate the effects of multiple mechanisms of plant soil feedbacks in exotic and native grasses using a greenhouse study in which soil microbial communities, soil organic matter distribution, and nitrification rates were manipulated. Both exotic and native grasses exhibited evidence of negative plant soil feedback, but the results were much stronger in native grasses. In addition, different mechanisms of plant soil feedback were important for exotic and native grasses. Mixing soil profiles, a treatment that redistributed soil resources throughout the soil column, caused exotic grasses to grow significantly more deep roots. As exotic grasses tend to concentrate roots and soil resources in upper soil layers, this result may indicate potential negative feedback under field conditions. Native grass biomass responded positively to sterilization and reduced nitrification. That different feedback mechanisms were important in explaining the plant soil feedback between co-occurring species highlights the value of testing multiple feedback mechanisms and underscores the diversity of changes that exotic species may have on the soil environment.
