Download or read book Cross scale effects of biological soil crusts on runoff generation and water erosion in semiarid ecosystems Field data and model approach written by Emilio Rodríguez Caballero and published by Universidad Almería. This book was released on 2014-11-06 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: CD-ROM Water availability is one of the main limiting factors that control ecosystem functions and productivity in semiarid regions. Vegetation of these regions usually presents a patchy distribution where sparse plant cover is interspersed over a bare soil. During the few rainfall events, runoff is generated in non-vegetated areas and redistributed towards vegetation, which act as surface obstruction for water, sediments and nutrients. Thus, non-vegetated areas are more susceptible to water erosion processes. Non-vegetated areas from semiarid ecosystems around the world, are often covered by Biological Soil Crusts (BSCs). BSCs result from an intimate association between soil particles and cyanobacteria, algae, microfungi, lichens and bryophytes. These communities live within, or immediately on top of, the uppermost millimeters of soil, influencing soil surface properties involved in infiltration, runoff generation and water erosion. Several papers have demonstrated that BSCs are one of the most important soil stabilizing factors in drylands. There are, however, contradictory results on the role that BSCs play in regulating soil water fluxes. Some studies point BSCs as runoff sources that may increase downslope erosion or on the contrary may represent an additional supply of water for downslope vegetation allowing its survival. The impact of this additional runoff should be evaluated at less detailed scales than the patch and to analyze all interactions in terms of water, sediments and nutrients between areas covered by BSCs and vegetated patches in order to establish the real effects of BSCs on both runoff and erosion. Also, to correctly predict the impact of future climate changes or antropic disturbances on hydrological behavior and water erosion in systems dominated by BSCs their effects should be included on spatially distributed runoff and erosion models. Until now, the influence of BSCs on these processes has been addressed almost exclusively at patch scale, despite the fact some authors have pointed the need of upscaling their effects, and even more their influence on runoff generation and water erosion was never considered in spatially implicit medelling. The goal of this thesis is to determine BSC effects on runoff and water erosion from plot to catchment scale in a typical semiarid ecosystem. To achieve this objective, first direct and indirect effects of BSCs at patch scale must be clearly defined under natural rainfall conditions to solve the controversy about BSCs effects on runoff generation. To know the direct and indirect relationships among soil surface characteristics, BSC cover and type, topography, rainfall characteristics (duration, amount and intensity) and runoff, structural equation models (SEM) were applied. Our results reveal the critical importance of BSCs on runoff and water erosion. Both processes in biologically crusted areas are directly controlled by crust type and cover. BSCs also modified some soil surface properties involved in runoff generation and water erosion, such as microtopography, surface stability or water repellency. The final interaction of both, direct and indirect BSCs effects, determine the hydrological behavior of these surfaces under natural rainfall conditions. Moreover, the final effect of BSCs on runoff generation is strongly driven by rainfall properties, which determined the set of complex interactions among BSCs, type and developmental stage and soil surface properties: on one hand, during low intensity rains, BSC-induced microtopography increases the amount of surface micro-depressions, which act as temporal water sinks, reducing the connectivity among source areas, delaying runoff initiation and reducing runoff rates; on the other hand, during intense rainfall events, BSCs type and water repellency are the main factors determining runoff generation. When the effects of BSCs are analyzed at coarser scales, including all interactions among BSCs and vegetated areas on a whole catchment, our results reveal the importance of the interactions between areas with BSCs and areas with vegetation on runoff generation and water erosion. We show the capacity of vegetated areas to retain runoff waters generated by upslope biologically crusted areas as an important driver for the hydrological and erosional response at catchment scale. However, the capability of vegetated areas to trap and retain water and sediments is limited and can be exceeded during high magnitude events, increasing catchment connectivity, as well as runoff and water erosion at the catchment outlet. Even during high-magnitude events, when the runoff generated in BSC areas reaches the channel network, the local protection provided by BSCs also affects downslope areas and the catchment response. These results confirm that BSCs must be included in runoff and soil erosion models to obtain reliable predictions of the spatial pattern of runoff and water erosion in catchments with abundant BSCs. In order to correctly introduce the effects of BSCs in these models, it is necessary to have an accurate spatial characterization of BSCs. It is shown that a spectral mixture analysis is required for the precise characterization of the complex spatial distribution of BSCs, due to the intrinsic spatial heterogeneity of semiarid ecosystems and to the spectral similarities among BSCs, dry vegetation and bare soil. Due to the methodological and practical application problems of spectral mixture analysis when it is applied to spectrally complex areas or when some surface elements only appear in specific areas of the image, we needed to develop a novel methodology for BSCs classification and quantification (lichen and cyanobacteria-dominated CBS), based on hyperspectral images. Support vector machine classification was applied for spectral and ecological classification of homogenous areas to solve the mentioned problems inherent to spatial heterogeneity. Inmediately afterwards, spectral mixture analysis (SMA) was applied to each SVM class to quantify the proportion of each type of surface cover within each pixel. Relative abundance images obtained with this methodology achieve a relatively high accuracy for different types of BSCs, and have demonstrated to be an adequate source of spatially distributed information, to correctly characterize surface properties in biologically crusted drylands systems. Moreover, to have the spatial distribution of type and abundance of BSCs allows to increase the accuracy of modeled runoff and erosion. Thus, when BSCs effects are not included in the LISEM model, an important increase in modeled water erosion was observed in areas where BSCs was not considered.
Download or read book Badlands Dynamics in a Context of Global Change written by Estela Nadal-Romero and published by Elsevier. This book was released on 2018-08-06 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Badlands Dynamics in the Context of Global Change presents the newest ideas concerning badland formation and relates them to the larger context of global change. The book provides an overview of badland landforms and covers a variety of interdisciplinary topics, such as runoff generation, erosion processes and rates, the potential for modeling badland systems, and emerging technologies in research. It is an ideal resource for geomorphologists, physical geographers and soil scientists interested in this terrain and how it relates to land degradation in other environments. - Provides a global understanding of the complex dynamics of badlands through geology, geomorphology and soil science - Covers critical material properties for badlands development based on current knowledge and new data - Includes vegetation dynamics in different badlands systems and their relationship with geomorphology dynamics
Download or read book Biological Soil Crusts An Organizing Principle in Drylands written by Bettina Weber and published by Springer. This book was released on 2016-05-21 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes our current understanding of biological soil crusts (biocrusts), which are omnipresent in dryland regions. Since they cover the soil surface, they influence, or even control, all surface exchange processes. Being one of the oldest terrestrial communities, biocrusts comprise a high diversity of cyanobacteria, algae, lichens and bryophytes together with uncounted bacteria, and fungi. The authors show that biocrusts are an integral part of dryland ecosystems, stabilizing soils, influencing plant germination and growth, and playing a key role in carbon, nitrogen and water cycling. Initial attempts have been made to use biocrusts as models in ecological theory. On the other hand, biocrusts are endangered by local disruptions and global change, highlighting the need for enhanced recovery methods. This book offers a comprehensive overview of the fascinating field of biocrust research, making it indispensable not only for scientists in this area, but also for land managers, policy makers, and anyone interested in the environment.
Download or read book Rangeland Systems written by David D. Briske and published by Springer. This book was released on 2017-04-12 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY-NC 2.5 license. This book provides an unprecedented synthesis of the current status of scientific and management knowledge regarding global rangelands and the major challenges that confront them. It has been organized around three major themes. The first summarizes the conceptual advances that have occurred in the rangeland profession. The second addresses the implications of these conceptual advances to management and policy. The third assesses several major challenges confronting global rangelands in the 21st century. This book will compliment applied range management textbooks by describing the conceptual foundation on which the rangeland profession is based. It has been written to be accessible to a broad audience, including ecosystem managers, educators, students and policy makers. The content is founded on the collective experience, knowledge and commitment of 80 authors who have worked in rangelands throughout the world. Their collective contributions indicate that a more comprehensive framework is necessary to address the complex challenges confronting global rangelands. Rangelands represent adaptive social-ecological systems, in which societal values, organizations and capacities are of equal importance to, and interact with, those of ecological processes. A more comprehensive framework for rangeland systems may enable management agencies, and educational, research and policy making organizations to more effectively assess complex problems and develop appropriate solutions.
Download or read book Effects of urban development on stream ecosystems in nine metropolitan study areas across the United States written by James F. Coles and published by . This book was released on 2012 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Riparian Areas written by National Research Council and published by National Academies Press. This book was released on 2002-10-10 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Download or read book Arid Land Ecosystems Volume 1 written by R. A. Perry and published by CUP Archive. This book was released on 1979-03-08 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive account of arid-land ecosystems will be of importance to university teachers and professional ecologists throughout the world.
Download or read book Ecosystems and Human Well being written by Joseph Alcamo and published by . This book was released on 2003 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystems and Human Well-Being is the first product of the Millennium Ecosystem Assessment, a four-year international work program designed to meet the needs of decisionmakers for scientific information on the links between ecosystem change and human well-being. The book offers an overview of the project, describing the conceptual framework that is being used, defining its scope, and providing a baseline of understanding that all participants need to move forward. The Millennium Assessment focuses on how humans have altered ecosystems, and how changes in ecosystem services have affected human well-being, how ecosystem changes may affect people in future decades, and what types of responses can be adopted at local, national, or global scales to improve ecosystem management and thereby contribute to human well-being and poverty alleviation. The program was launched by United National Secretary-General Kofi Annan in June 2001, and the primary assessment reports will be released by Island Press in 2005. Leading scientists from more than 100 nations are conducting the assessment, which can aid countries, regions, or companies by: providing a clear, scientific picture of the current sta
Download or read book Hillslope Hydrology written by M. J. Kirkby and published by John Wiley & Sons. This book was released on 1978 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete guide to the behavior of water on graded land Hillslope Hydrology provides a comprehensive introduction to the behavior of water on a slope. Describing the fates of precipitation, the mechanics of runoff, and the calculations involved in assessment, this book clarifies the complex interplay of soils, sediment, subsurface flow, overland flow, saturation, erosion, and more. An ideal resource for graduate students of Earth science, environmental science, civil engineering, architecture, landscape management, and related fields, this informative guide provides the essential information needed to work effectively with graded land or predict outcomes of precipitation.
Download or read book The Regional Impacts of Climate Change written by Intergovernmental Panel on Climate Change. Working Group II. and published by Cambridge University Press. This book was released on 1998 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cambridge, UK : Cambridge University Press, 1998.
Download or read book Modeling and Practice of Erosion and Sediment Transport under Change written by Mohamed Meddi and published by MDPI. This book was released on 2019-09-17 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate and anthropogenic changes impact the conditions of erosion and sediment transport in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes in natural areas, as well as in cultivated areas, and, sometimes, in degraded areas and desertified landscapes. These anthropogenized landscapes are more sensitive to erosion. On the other hand, the increase in the number of dams in watersheds traps a great portion of sediment fluxes, which do not reach the sea in the same amount, nor at the same quality, with consequences on coastal geomorphodynamics. This book is dedicated to studies on sediment fluxes from continental areas to coastal areas, as well as observation, modeling, and impact analysis at different scales from watershed slopes to the outputs of large river basins. This book is concentrated on a number of keywords: “erosion” and “sediment transport”, “model” and “practice”, and “change”. The keywords are briefly discussed with respect to the relevant literature. The contributions in this book address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.
Download or read book Banded Vegetation Patterning in Arid and Semiarid Environments written by David J. Tongway and published by Springer Science & Business Media. This book was released on 2001-06-15 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerial photography has revealed the striking, widespread phenomenon of repeating patterns of vegetation in more arid areas of the world. Two interdependent phases, bands of dense and sparse vegetation, alternate in the landscape. This volume synthesizes half a century's accumulated knowledge of both theoretical and applied landscape function from a variety of these regions. It covers structure, dynamics, and methods of study, as well as disturbances to these landscapes and relevant management issues. Various chapters discuss the role of modeling in answering questions about the origins and complex processes of banded landscapes.
Download or read book Predicting Soil Erosion by Water written by Kenneth G. Renard and published by . This book was released on 1997 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction and history; Rainfall-runoff erosivity factor (R); Soil erodibility factor (K); Slope length and steepness factors (LS); Cover-management factor (C); Support practice factor (P); RUSLE user guide; Coversion to SI metric system; Calculation of EI from recording-raingage records; Estimating random roughness in the field; Parameter values for major agricultural crops and tillage operations.
Download or read book Biological Soil Crusts Structure Function and Management written by Jayne Belnap and published by Springer Science & Business Media. This book was released on 2013-12-01 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Rainfall Interception by Chaparral in California written by E. L. Hamilton and published by . This book was released on 1949 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mediterranean region under climate change written by Collectif and published by IRD Éditions. This book was released on 2018-11-19 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines.
Download or read book Encyclopedia of Agrophysics written by Jan Gliński and published by Springer Science & Business Media. This book was released on 2011-06-07 with total page 1075 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Encyclopedia of Agrophysics will provide up-to-date information on the physical properties and processes affecting the quality of the environment and plant production. It will be a "first-up" volume which will nicely complement the recently published Encyclopedia of Soil Science, (November 2007) which was published in the same series. In a single authoritative volume a collection of about 250 informative articles and ca 400 glossary terms covering all aspects of agrophysics will be presented. The authors will be renowned specialists in various aspects in agrophysics from a wide variety of countries. Agrophysics is important both for research and practical use not only in agriculture, but also in areas like environmental science, land reclamation, food processing etc. Agrophysics is a relatively new interdisciplinary field closely related to Agrochemistry, Agrobiology, Agroclimatology and Agroecology. Nowadays it has been fully accepted as an agricultural and environmental discipline. As such this Encyclopedia volume will be an indispensable working tool for scientists and practitioners from different disciplines, like agriculture, soil science, geosciences, environmental science, geography, and engineering.
