Download or read book The Effects of Climate Change and Nitrogen Deposition on the Sierran Mixed conifer Understory Plant Community written by Matthew David Hurteau and published by . This book was released on 2007 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Initial Response of a Sierran Mixed conifer Understory Community to Burning and Thinning Restoration Treatments written by Rebecca Bewley Wayman and published by . This book was released on 2005 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of nitrogen deposition on ecosystems above and belowground written by Hui Wang and published by Frontiers Media SA. This book was released on 2023-03-09 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Atmospheric Nitrogen Deposition to Global Forests written by Enzai Du and published by Elsevier. This book was released on 2023-10-22 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric Nitrogen Deposition in Global Forests: Spatial Variation, Impacts, and Management Implications provides the most comprehensive knowledge on spatial variation and ecological impacts of reactive nitrogen deposition in global forests, as well as forest management options to mitigate the negative impacts. Written and edited by international experts in the field, this book synthesizes recent research developments and insights in monitoring and modeling nitrogen deposition in global forests. The book also assesses ecological impacts of enhanced nitrogen deposition on forest structure and function and responses of forest ecosystems to decreasing nitrogen deposition in regions such as the European Union and North America. Finally, the book reviews indicators and thresholds for nitrogen saturation in global forests and analyzes remediation options to reduce impacts of excess nitrogen deposition. This is an important resource for researchers in forestry and biodiversity conservation, as well as graduate students, policymakers and others who want to understand environmental issues of reactive nitrogen deposition in global forests. Offers a systematic view of the ecological impacts of enhanced nitrogen deposition Provides the most comprehensive knowledge on spatial variation and the ecological impacts of reactive nitrogen deposition in global forests Presents expert research and findings on forest management options to remediate negative impacts
Download or read book Photochemical Oxidant Air Pollution Effects on a Mixed Conifer Forest written by R. N. Kickert and published by . This book was released on 1980 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: EPA contract 68-03-2442 provided support for three years of the studies to determine the chronic effects of photochemical oxidant air pollutants on a western mixed conifer forest ecosystem. This report deals with the year 1976-77 and is the final publication on EPA contract 68-03-2442. Computer simulation programs have been written for some of the subsections. Subsystems which received greatest attention during this study were: major tree species response to oxidant dose, tree population dynamics, tree growth, moisture dynamics, soil chemical and physical properties, tree mortality relative to disease, insects and other factors, epidemiology of forest tree pathogens with emphasis on Fomes annosus, cone and seed production, tree seedling establishment, litter production and litter decomposition relative to microfloral decomposer populations.
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 Impacts of Nitrogen Deposition and Climate Change on Plant Species Diversity written by Stephan Roos and published by . This book was released on 2015 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predicting the effects of atmospheric nitrogen deposition in conifer stands written by B A. Emmett and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The NITREX project, which encompasses seven ecosystem-scale experiments in coniferous forests at the plot or catchment level in northwestern Europe, investigates the effect of atmospheric nitrogen (N) deposition in coniferous forests. The common factor in all of the experiments is the experimentally controlled change in N input over a period of 4-5 years. Results indicate that the status and dynamics of the forest floor are key components in determining the response of forests to altered N inputs. An empirical relationship between the carbon-nitrogen (CIN) ratio of the forest floor and retention of incoming N provides a simply measured tool through which the likely timing and consequences of changes in atmospheric N deposition for fresh waters may be predicted. In the terrestrial ecosystem, a 50% increase in tree growth is observed following the experimental reduction of N and sulfur inputs in a highly N-saturated site, illustrating the damaging effects of acidifying pollutants to tree health in so me locations. Few biotic responses to the experimental treatments were observed in other NITREX sites, but the rapid response of water quality to changes in N deposition, and the link to acidification in sensitive areas, highlight the need for N-emission controls, irrespective of the long-term effects on tree health. The observed changes in ecosystem function in response to the experimental treatments have been considered within the framework of the current critical-load approach and thus contribute to the formulation of environmental policy.
Download or read book Regeneration in Mixed Conifer Shelterwood Cuttings in the Cascade Range of Eastern Oregon written by Kenneth W. Seidel and published by . This book was released on 1979 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soil Water Availability in an Arizona Mixed Conifer Clearcutting written by Robert S. Embry and published by . This book was released on 1971 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical Responses to Atmospheric Nitrogen Deposition in Subalpine Ecosystems of the Cascades written by Justin Paul Poinsatte and published by . This book was released on 2017 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: We examined the influence of snow regime on subalpine ecosystem C and N cycling at Mount Rainier under ambient conditions and in climate change scenarios. Timing of snow release influenced ecosystem C and N storage and loss. Climate change may reduce snow accumulation by up to 80% at Mount Rainier by 2050. Snowpack loss may enhance ecosystem C and N accumulation during the growing season and increase winter N leaching.
Download or read book Regeneration in Mixed Conifer Clearcuts in the Cascade Range and the Blue Mountains of Eastern Oregon written by Kenneth W. Seidel and published by . This book was released on 1979 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure Composition and Sampling Characteristics of Old growth Mixed Conifer Forests of the Western Sierra Nevada written by Carmia Suzannah Feldman and published by . This book was released on 2000 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photochemical Oxidant Air Pollution Effects on a Mixed Conifer Forest written by R. N. Kickert and published by . This book was released on 1980 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: EPA contract 68-03-2442 provided support for three years of the studies to determine the chronic effects of photochemical oxidant air pollutants on a western mixed conifer forest ecosystem. This report deals with the year 1976-77 and is the final publication on EPA contract 68-03-2442. Computer simulation programs have been written for some of the subsections. Subsystems which received greatest attention during this study were: major tree species response to oxidant dose, tree population dynamics, tree growth, moisture dynamics, soil chemical and physical properties, tree mortality relative to disease, insects and other factors, epidemiology of forest tree pathogens with emphasis on Fomes annosus, cone and seed production, tree seedling establishment, litter production and litter decomposition relative to microfloral decomposer populations.
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 Ecosystem Level Alterations in Soil Nutrient Cycling written by and published by . This book was released on 1996 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
