Download or read book Spatial and Temporal Variation in Biomass Accumulation in Southern California Chaparral written by Kellie Ann Uyeda and published by . This book was released on 2015 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wildfires are a common occurrence in chaparral shrublands, and post-fire patterns of biomass accumulation are important for understanding ecosystem productivity and fuel available for future fires. In this research, I examine patterns of biomass accumulation in southern California chaparral shrublands at early and late stages of post-fire recovery using a combination of detailed field work and remote sensing. Using field measurements of a site with adjacent stands of varying ages and high spatial resolution imagery, I examine patterns of species composition and associated levels of biomass to characterize long-term patterns in biomass accumulation. I also evaluate the potential for utilizing shrub growth ring widths to track annual biomass accumulation in the first decade of post-fire recovery, and test for the relationship between biomass and spatial variation in factors related to the energy and water balance. In addition, I examine the potential for extending the use of shrub growth rings to track biomass across larger spatial extents using satellite-based growth metrics. The study of stands of varying ages reveals that biomass shows substantial variation even within stands of the same age, and that species composition is different in younger stands of chaparral compared to the more mature stands. In the study of growth rings, I find that while measuring growth rings widths is a valuable method for tracking biomass accumulation in the first decade following a fire, there is no apparent relationship between biomass and factors related to the energy and water balance. Annual biomass growth, as estimated from shrub growth ring widths, shows a promising relationship with satellite-based metrics of annual growth, indicating the potential for further study of the relationship over larger spatial extents.

Download or read book Spatial and Temporal Variation in Biomass Accumulation in Southern California Chaparral written by and published by . This book was released on 2014 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wildfires are a common occurrence in chaparral shrublands, and post-fire patterns of biomass accumulation are important for understanding ecosystem productivity and fuel available for future fires. In this research, I examine patterns of biomass accumulation in southern California chaparral shrublands at early and late stages of post-fire recovery using a combination of detailed field work and remote sensing. Using field measurements of a site with adjacent stands of varying ages and high spatial resolution imagery, I examine patterns of species composition and associated levels of biomass to characterize long-term patterns in biomass accumulation. I also evaluate the potential for utilizing shrub growth ring widths to track annual biomass accumulation in the first decade of post-fire recovery, and test for the relationship between biomass and spatial variation in factors related to the energy and water balance. In addition, I examine the potential for extending the use of shrub growth rings to track biomass across larger spatial extents using satellite-based growth metrics. The study of stands of varying ages reveals that biomass shows substantial variation even within stands of the same age, and that species composition is different in younger stands of chaparral compared to the more mature stands. In the study of growth rings, I find that while measuring growth rings widths is a valuable method for tracking biomass accumulation in the first decade following a fire, there is no apparent relationship between biomass and factors related to the energy and water balance. Annual biomass growth, as estimated from shrub growth ring widths, shows a promising relationship with satellite-based metrics of annual growth, indicating the potential for further study of the relationship over larger spatial extents.

Download or read book Valuing Chaparral written by Emma C. Underwood and published by Springer. This book was released on 2018-04-09 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chaparral shrubland ecosystems are an iconic feature of the California landscape, and a highly biodiverse yet highly flammable backdrop to some of the fastest growing urban areas in the United States. Chaparral-type ecosystems are a common element of all of the world’s Mediterranean-type climate regions – of which California is one – yet there is little public appreciation of the intrinsic value and the ecosystem services that these landscapes provide. Valuing Chaparral is a compendium of contributions from experts in chaparral ecology and management, with a focus on the human relationship with chaparral ecosystems. Chapters cover a wide variety of subjects, ranging from biodiversity to ecosystem services like water provision, erosion control, carbon sequestration and recreation; from the history of human interactions with chaparral to current education and conservation efforts; and from chaparral restoration and management to scenarios of the future under changing climate, land use, and human population. Valuing Chaparral will be of interest to resource managers, the research community, policy makers, and the public who live and work in the chaparral dominated landscapes of California and other Mediterranean-type climate regions.

Download or read book Interpretation and Implications of Variability in Ecological Systems written by Robert Klinger and published by Frontiers Media SA. This book was released on 2024-07-22 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous hypotheses have been proposed to explain the dynamics in abundance of individual species, how species interact, how communities assemble, and how interactions between biotic and abiotic processes shape ecosystem stability. Many if not most of these hypotheses find some degree of support, but often only within relatively narrow spatial and temporal ranges. This is because conditions vary over time and from place to place, and so the strength and extent of processes that were the focus of a given a hypothesis become altered by other forces. Ecologists have confronted variability from two perspectives; conceptual and statistical. Conceptually, spatial and temporal variability are now recognized as being scale dependent and hierarchical. Statistically, there are many models that ecologists readily use that account for the hierarchical and scale-dependence of variability present in many datasets. But linking the two perspectives into a meaningful understanding of what variability means in real systems has been much less successful. For example, it is common to see studies where the fixed effects of a generalized linear mixed model are reported, but very often random effects are completely ignored or, at best, given scant attention. The likelihood of this being a significant problem increases greatly in what are rapidly becoming more common studies that utilize datasets spanning long temporal and/or large spatial scales, or when extreme and often unpredictable events (gray and black swans) occur.

Download or read book Uncoupling Impacts of Drought and Short interval Fire on Chaparral in Southern California Using Time sequential Landsat Imagery written by and published by . This book was released on 2019 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: errestrial vegetation growth, climate variation, and fire activity have been strongly coupled since the advent of vascular plants approximately 420 million years before present. Rises in anthropogenic land cover transformation, invasive species propagation, carbon emission, and artificial sources of fire ignition in recent centuries have greatly affected terrestrial plant communities. The populous, semi-arid region of southern California is marked by heightened fire activity and extreme drought episodes in recent decades. Contemporary regimes (spatial-temporal patterns) of fire and drought may exceed historical ranges of variability and thus threaten native plant communities, which may have adapted to quite different disturbance regimes. Postfire recovery of southern California shrub species (chaparral) may be impeded by fires that recur at short intervals or by severe drought. Evaluating the response of chaparral to compound fire-drought effects is key in conservation planning under projected climate, land use, and fire regime scenarios. Time-sequential remote sensing based on Landsat satellite imagery is a useful way to characterize shrub cover change over regional extents and several decades, and may provide a broader perspective than much of the ecological and biogeographic literature, which is mostly based on field studies. Landscape-scale variations of shrub type, soil reflectance, and terrain may introduce spatial bias into signals of change in fractional shrub cover (FSC) based on spectral vegetation indices (SVIs), including Normalized Difference Vegetation Index (NDVI). Chapter 2 evaluates these potential error sources in the application of postfire recovery assessment based on Landsat image series. Chapter 2 is based on three chaparral landscapes having internally-varied postfire recovery trajectories, and involves a cross-stratification variable-control approach. Results show that differences in shrub type linked to biomass variations can significantly influence linear NDVI-FSC relations, and such effects are accentuated in postfire recovery metrics based on NDVI difference. Minor effects due to soil spectral reflectance differences were observed at one site, but no significant effect of terrain illumination variability was found. Insights from Chapter 2 guided the methodologies of Chapters 3 and 4, which evaluate regional-scale influences of repeated fire and of drought on chaparral recovery, respectively. A regional map of change in FSC between the periods 1984–1989 and 2014–2018 was derived by transforming Landsat NDVI trajectories into calibrated estimates of FSC within 49 manually-delineated portions of the regional chaparral community, based on detailed shrub cover maps derived from high spatial resolution aerial imagery. Postfire recovery patterns were evaluated in 246 areas which burned in the period 1985–2008 and represent varied numbers of burns (one to three) and fire return intervals (1 to 23 years). Fire-return interval was not significantly related to recovery, except at sites that had burned three times within 25 years. Mean precipitation, soil hydrologic properties, and chaparral community type were significant predictors of recovery in the region. Limited postfire recovery was most acute in transmontane ecotonal chamise sites bounding the Colorado Desert. Chapter 4 addresses the influence of drought on postfire chaparral recovery in montane, cismontane and transmontane areas of southern California (deemed as climate zones). I evaluated drought based on summer (June–August) and wet-season (November–May) aggregates of precipitation, Palmer Drought Severity Index (PDSI) and climatic water deficit (CWD), in years preceding and following fire events. Only prefire drought was significant in postfire recovery of montane chaparral. Drought before and in the first and second wet seasons after fire were significant controls on recovery in the other climate zones. High-elevation transmontane chamise sites most impacted by drought (with spatially variable recovery patterns) were selected to evaluate landscape-level predictors of recovery. Elevation, soil permeability, chaparral community type, and FSC-normalized Landsat Visible Atmospherically-Resistant Index (VARI) were significant predictors of landscape-scale variation of recovery under drought impact (R2 = 0.53). Based on twelve proximal (once-burned) chaparral stands that exhibited varied recoveries, I found that high CWD in immediate-postfire and several prefire wet seasons explained ~42 percent of recovery variation. The results of this work suggest that drought effects on resprouting vigor or fire intensity are limiting factors of postfire chaparral recovery in southern California. This dissertation represents the most temporally- and spatially-extensive assessment of postfire chaparral recovery yet conducted, providing insights (regarding the importance of drought versus frequent fire in recovery) which may help to inform land management and conservation efforts in the region. This work has also advanced the technical application of time-sequential satellite imagery and spatial analysis in the study of ecological change, and may segue to greater advancements in vegetation monitoring and ecological theory.

Download or read book The Impact of Spatial and Temporal Variability in California Vernal Pool Landscapes written by Julia Shoshana Hruska Michaels and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As global biodiversity loss continues to accelerate at an unprecedented rate, the maintenance of diversity at regional and local scales is a key target in restoration and land management. In order to protect these threatened ecosystems, it is fundamental to understand the patterns and underlying processes that shape this biodiversity. For example, we know that biodiversity is not distributed equally across the landscape, but rather, many species exist in small patches or diversity 'hotspots' distributed across larger ecosystems. These patches can contain only a few species each, but high variation between them can add up to a great deal of diversity at the landscape level. Species diversity and the patterns of species distribution are likely to be sensitive to managed disturbance regimes, such as livestock grazing, and temporal variability in environmental conditions, such as the timing and amount of rainfall within a given season. In this dissertation, I investigate how these multiple layers of spatial and temporal heterogeneity interact to produce patterns of biodiversity in California vernal pools, or seasonally flooded depressions within grasslands. Vernal pools are among the Californian bioregion's most important and critically threatened reservoirs of endemic plant diversity. In Chapter 1, I examine how long-term livestock grazing affects the distribution of plant diversity within and between vernal pools, and whether grazing-related changes in species distribution at the local scale may lead to changes in diversity at the landscape scale. In Chapter 2, I aim to understand whether the reintroduction of livestock to vernal pools that have been under long-term grazing exclusion has similar effects as continuous grazing, and also explore the potential grazing-related mechanisms driving these community changes. In Chapter 3, I aim to identify the aspects of vernal pool hydrology that are most biologically relevant for sensitive plant and animal taxa, specifically temporal variation in pool water depth, and determine which sampling methods best capture this variability. Together, the findings of this dissertation help to increase our understanding of how patterns of biodiversity respond to disturbance and environmental variation, and provide insight into the management of these highly heterogeneous landscapes.

Download or read book Variability of Giant Kelp Forests in Southern California written by Kyle Christopher Cavanaugh and published by . This book was released on 2011 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal ecosystems are structured by a complex interplay of forcing processes that operate across a variety of scales. However, it is often difficult to monitor these dynamic systems over large geographic areas and long time periods. Thus, there are significant gaps in our understanding of how the relative roles of important coastal ecosystem forcing processes vary in space and time. Here, I developed novel methods for estimating the biomass of giant kelp from satellite imagery, which allowed me to examine kelp biomass dynamics on spatial scales ranging from meters to 1000s of km and temporal scales ranging from months to decades. I combined this satellite biomass data with diver surveys of kelp biomass to describe the relationship between plot (40 m), forest (& sim;1 km), and regional (& sim;60 km) scale changes in kelp biomass along the Santa Barbara mainland coast. I then compared changes in kelp biomass across the entire Santa Barbara Channel with environmental and climatic data and found substantial spatial and temporal heterogeneity in the controls of giant kelp biomass dynamics. Finally, I evaluated the relative roles of spatial metapopulation and local environmental controls on giant kelp extinction/colonization dynamics and resilience. Many coastal ecosystems are well studied at the local scale, but long-term, large-scale studies of these systems provide valuable insight into the spatial and temporal generality of local results.

Download or read book The Ecology of Natural Disturbance and Patch Dynamics written by Steward T.A. Pickett and published by Elsevier. This book was released on 2013-10-22 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecologists are aware of the importance of natural dynamics in ecosystems. Historically, the focus has been on the development in succession of equilibrium communities, which has generated an understanding of the composition and functioning of ecosystems. Recently, many have focused on the processes of disturbances and the evolutionary significance of such events. This shifted emphasis has inspired studies in diverse systems. The phrase "patch dynamics" (Thompson, 1978) describes their common focus. The Ecology of Natural Disturbance and Patch Dynamics brings together the findings and ideas of those studying varied systems, presenting a synthesis of diverse individual contributions.

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 Ecology Abstracts written by and published by . This book was released on 1989 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: Indexes journal articles in ecology and environmental science. Nearly 700 journals are indexed in full or in part, and the database indexes literature published from 1982 to the present. Coverage includes habitats, food chains, erosion, land reclamation, resource and ecosystems management, modeling, climate, water resources, soil, and pollution.

Download or read book Bibliography of Agriculture written by and published by . This book was released on 1983 with total page 2330 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 Fire and Climatic Change in Temperate Ecosystems of the Western Americas written by Thomas T. Veblen and published by Springer Science & Business Media. This book was released on 2006-05-10 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both fire and climatic variability have monumental impacts on the dynamics of temperate ecosystems. These impacts can sometimes be extreme or devastating as seen in recent El Nino/La Nina cycles and in uncontrolled fire occurrences. This volume brings together research conducted in western North and South America, areas of a great deal of collaborative work on the influence of people and climate change on fire regimes. In order to give perspective to patterns of change over time, it emphasizes the integration of paleoecological studies with studies of modern ecosystems. Data from a range of spatial scales, from individual plants to communities and ecosystems to landscape and regional levels, are included. Contributions come from fire ecology, paleoecology, biogeography, paleoclimatology, landscape and ecosystem ecology, ecological modeling, forest management, plant community ecology and plant morphology. The book gives a synthetic overview of methods, data and simulation models for evaluating fire regime processes in forests, shrublands and woodlands and assembles case studies of fire, climate and land use histories. The unique approach of this book gives researchers the benefits of a north-south comparison as well as the integration of paleoecological histories, current ecosystem dynamics and modeling of future changes.

Download or read book Environment Abstracts Annual written by and published by . This book was released on 1992 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This database encompasses all aspects of the impact of people and technology on the environment and the effectiveness of remedial policies and technologies, featuring more than 950 journals published in the U.S. and abroad. The database also covers conference papers and proceedings, special reports from international agencies, non-governmental organizations, universities, associations and private corporations. Other materials selectively indexed include significant monographs, government studies and newsletters.

Download or read book Ecological Foundations for Fire Management in North American Forest and Shrubland Ecosystems written by J. E. Keeley and published by DIANE Publishing. This book was released on 2011-05 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides an ecological foundation for mgmt. of the diverse ecosystems and fire regimes of N. America, based on scientific principles of fire interactions with vegetation, fuels, and biophysical processes. Detailed discussion of six ecosystems ¿ ponderosa pine forest (western N. America), chaparral (Calif.), boreal forest (Alaska and Canada), Great Basin sagebrush (inter-mountain West), pine and pine-hardwood forests (Southern Appalachian Mountains), and longleaf pine (Southeastern U.S.) ¿ illustrates the complexity of fire regimes and that fire mgmt. requires a clear regional focus that recognizes where conflicts might exist between fire hazard reduction and resource needs. Illustrations. This is a print on demand report.

Download or read book Conference Papers Index written by and published by . This book was released on 1985 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monthly. Papers presented at recent meeting held all over the world by scientific, technical, engineering and medical groups. Sources are meeting programs and abstract publications, as well as questionnaires. Arranged under 17 subject sections, 7 of direct interest to the life scientist. Full programs of meetings listed under sections. Entry gives citation number, paper title, name, mailing address, and any ordering number assigned. Quarterly and annual indexes to subjects, authors, and programs (not available in monthly issues).

Download or read book Ecological Foundations for Fire Management in North American Forest and Shrubland Ecosystems written by and published by . This book was released on 2009 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This synthesis provides an ecological foundation for management of the diverse ecosystems and fire regimes of North America, based on scientific principles of fire interactions with vegetation, fuels, and biophysical processes. Although a large amount of scientific data on fire exists, most of those data have been collected at small spatial and temporal scales. Thus, it is challenging to develop consistent science-based plans for large spatial and temporal scales where most fire management and planning occur. Understanding the regional geographic context of fire regimes is critical for developing appropriate and sustainable management strategies and policy. The degree to which human intervention has modified fire frequency, intensity, and severity varies greatly among different ecosystems, and must be considered when planning to alter fuel loads or implement restorative treatments. Detailed discussion of six ecosystems--ponderosa pine forest (western North America), chaparral (California), boreal forest (Alaska and Canada), Great Basin sagebrush (intermountain West), pine and pine-hardwood forests (Southern Appalachian Mountains), and longleaf pine (Southeastern United States)-- illustrates the complexity of fire regimes and that fire management requires a clear regional focus that recognizes where conflicts might exist between fire hazard reduction and resource needs. In some systems, such as ponderosa pine, treatments are usually compatible with both fuel reduction and resource needs, whereas in others, such as chaparral, the potential exists for conflicts that need to be closely evaluated. Managing fire regimes in a changing climate and social environment requires a strong scientific basis for developing fire management and policy.