Download or read book Quantifying the Effects of Spatial Environmental Variation and Soil Microbes on Plant Community Dynamics written by Gaurav Sunil Kandlikar and published by . This book was released on 2020 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the processes that determine the diversity and dynamics of plant communities is a longstanding challenge in ecology. Many studies have inferred the role of demographic processes by studying patterns of functional trait variation in natural communities, but studies explicitly linking such functional trait differences to demographic processes are lacking. There has also been a growing realization that the dynamics of plant communities are also influenced by the composition of the soil microbial community, but despite hundreds of empirical studies, predicting the influence of soil microbes on the diversity and dynamics of natural plant communities remains a challenge. In my dissertation I couple ecological theory with field and greenhouse experiments to build a more complete and generalizable understanding of the processes that control plant biodiversity. In Chapter One, I ask whether community-wide shifts in three key plant functional traits across an environmental gradient reflect variation in the trait-performance relationship across the landscape. To address this question I coupled observational data of variation in plant composition and functional with experimental data on species performance across the same landscape. I asked whether observed trait-environment interactions in the experimental data match observed patterns of trait variation. I found that shifts in community-weighted mean traits generally reflect the direction of trait-environment interactions. But on the whole, the interactions we found were weak, and by themselves might not be sufficient to explain community-wide shifts. This supports the value of plant functional traits for predicting species responses to environmental variation, and highlights a need for more detailed evaluation of how trait-performance relationships change across environments to improve such predictions. Chapters Two and Three focus on how soil microbes can influence diversity in plant communities. Chapter Two begins with a re-analysis of a classic framework that has been extensively used to study how feedbacks between plants and soil microbes can influence species coexistence. A great deal of existing theoretical and empirical work has shown that soil microbes can promote plant coexistence when they generate stabilizing feedback loops, or can drive exclusion when they generate destabilizing feedback loops. I applied insights from modern coexistence theory to show that existing work has largely neglected another avenue by which plant-soil feedbacks can mediate plant coexistence, by driving average fitness differences between plants. This chapter also extends classic models of plant-soil feedback to include more biological detail to show how the effects of plant-soil feedback on plant coexistence depends critically on how plants interact with each other through other processes like resource competition. In the final chapter of my dissertation, I applied the insights from Chapter Two to ask how plant-soil feedbacks influence diversity in southern California annual grassland communities. I conducted a greenhouse experiment to quantify microbially mediated stabilization and fitness differences among fifteen pairs of annual plants. We found that soil microbes frequently generate negative frequency-dependent dynamics that stabilize plant interactions, but they simultaneously generate large average fitness differences between species. The net result is that if the plant species are otherwise competitively equivalent, soil microbes would often drive exclusion among the focal species. This work illustrates the importance of quantifying microbially mediated fitness differences, and points to important avenues for future studies on how soil microbes shape plant diversity.
Download or read book Quantifying the Effects of Spatial Environmental Variation on Dynamics of Natural Plant Populations written by Anna Louise Warwick Sears and published by . This book was released on 2004 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spatial Distribution of Microbes in the Environment written by Rima Franklin and published by Springer Science & Business Media. This book was released on 2007-09-04 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume highlights recent advances that have contributed to our understanding of spatial patterns and scale issues in microbial ecology. The book brings together research conducted at a range of spatial scales (from μm to km) and in a variety of different types of environments. These topics are addressed in a quantitative manner, and a primer on statistical methods is included. In soil ecosystems, both bacteria and fungi are discussed.
Download or read book Aboveground Belowground Linkages written by Richard D. Bardgett and published by Oxford University Press. This book was released on 2010-07-29 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aboveground-Belowground Linkages provides the most up-to-date and comprehensive synthesis of recent advances in our understanding of the roles that interactions between aboveground and belowground communities play in regulating the structure and function of terrestrial ecosystems, and their responses to global change. It charts the historical development of this field of ecology and evaluates what can be learned from the recent proliferation of studies on the ecological and biogeochemical significance of aboveground-belowground linkages. The book is structured around four key topics: biotic interactions in the soil; plant community effects; the role of aboveground consumers; and the influence of species gains and losses. A concluding chapter draws together this information and identifies a number of cross-cutting themes, including consideration of aboveground-belowground feedbacks that occur at different spatial and temporal scales, the consequences of these feedbacks for ecosystem processes, and how aboveground-belowground interactions link to human-induced global change.
Download or read book Permafrost Soils written by Rosa Margesin and published by Springer Science & Business Media. This book was released on 2008-10-31 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the Earth’s biosphere is characterized by low temperatures. Vast areas (>20%) of the soil ecosystem are permanently frozen or are unfrozen for only a few weeks in summer. Permafrost regions occur at high latitudes and also at high ele- tions; a significant part of the global permafrost area is represented by mountains. Permafrost soils are of global interest, since a significant increase in temperature is predicted for polar regions. Global warming will have a great impact on these soils, especially in northern regions, since they contain large amounts of organic carbon and act as carbon sinks, and a temperature increase will result in a release of carbon into the atmosphere. Additionally, the intensified release of the clima- relevant tracer gas methane represents a potential environmental harzard. Significant numbers of viable microorganisms, including bacteria, archaea, p- totrophic cyanobacteria and green algae, fungi and protozoa, are present in per- frost, and the characteristics of these microorganisms reflect the unique and extreme conditions of the permafrost environment. Remarkably, these microorg- isms have been reported to be metabolically active at subzero temperatures, even down to ?20°C.
Download or read book Population Dynamics in Variable Environments written by Shripad Tuljapurkar and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demography relates observable facts about individuals to the dynamics of populations. If the dynamics are linear and do not change over time, the classical theory of Lotka (1907) and Leslie (1945) is the central tool of demography. This book addresses the situation when the assumption of constancy is dropped. In many practical situations, a population will display unpredictable variation over time in its vital rates, which must then be described in statistical terms. Most of this book is concerned with the theory of populations which are subject to random temporal changes in their vital rates, although other kinds of variation (e. g. , cyclical) are also dealt with. The central questions are: how does temporal variation work its way into a population's future, and how does it affect our interpretation of a population's past. The results here are directed at demographers of humans and at popula tion biologists. The uneven mathematical level is dictated by the material, but the book should be accessible to readers interested in population the ory. (Readers looking for background or prerequisites will find much of it in Hal Caswell's Matrix population models: construction, analysis, and in terpretation (Sinauer 1989) ). This book is in essence a progress report and is deliberately brief; I hope that it is not mystifying. I have not attempted to be complete about either the history or the subject, although most sig nificant results and methods are presented.
Download or read book Methods in Soil Biology written by Franz Schinner and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: In terrestrial ecosystems, soil microorganisms and soil animals are essential for litter degradation, soil formation and the availability of nutrients and trace elements. The measurement of biological soil parameters allows a rapid evaluation of the effects of chemical and physical influences due to pollutants or soil management. This book introduces a number of well proved methods for the analysis of carbon, nitrogen, phosphorus and sulfur cycles. It focuses further on the determination of the number and biomass of microorganisms, algae and animals in the soil. Particular emphasis is placed on the comprehensible and complete description of the experimental procedures.
Download or read book Biogeochemistry of Wetlands written by K. Ramesh Reddy and published by CRC Press. This book was released on 2022-09-10 with total page 926 pages. Available in PDF, EPUB and Kindle. Book excerpt: The globally important nature of wetland ecosystems has led to their increased protection and restoration as well as their use in engineered systems. Underpinning the beneficial functions of wetlands are a unique suite of physical, chemical, and biological processes that regulate elemental cycling in soils and the water column. This book provides an in-depth coverage of these wetland biogeochemical processes related to the cycling of macroelements including carbon, nitrogen, phosphorus, and sulfur, secondary and trace elements, and toxic organic compounds. In this synthesis, the authors combine more than 100 years of experience studying wetlands and biogeochemistry to look inside the black box of elemental transformations in wetland ecosystems. This new edition is updated throughout to include more topics and provide an integrated view of the coupled nature of biogeochemical cycles in wetland systems. The influence of the elemental cycles is discussed at a range of scales in the context of environmental change including climate, sea level rise, and water quality. Frequent examples of key methods and major case studies are also included to help the reader extend the basic theories for application in their own system. Some of the major topics discussed are: Flooded soil and sediment characteristics Aerobic-anaerobic interfaces Redox chemistry in flooded soil and sediment systems Anaerobic microbial metabolism Plant adaptations to reducing conditions Regulators of organic matter decomposition and accretion Major nutrient sources and sinks Greenhouse gas production and emission Elemental flux processes Remediation of contaminated soils and sediments Coupled C-N-P-S processes Consequences of environmental change in wetlands# The book provides the foundation for a basic understanding of key biogeochemical processes and its applications to solve real world problems. It is detailed, but also assists the reader with box inserts, artfully designed diagrams, and summary tables all supported by numerous current references. This book is an excellent resource for senior undergraduates and graduate students studying ecosystem biogeochemistry with a focus in wetlands and aquatic systems.
Download or read book Grand Challenges in Environmental Sciences written by National Research Council and published by National Academies Press. This book was released on 2001-05-24 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientists have long sought to unravel the fundamental mysteries of the land, life, water, and air that surround us. But as the consequences of humanity's impact on the planet become increasingly evident, governments are realizing the critical importance of understanding these environmental systemsâ€"and investing billions of dollars in research to do so. To identify high-priority environmental science projects, Grand Challenges in Environmental Sciences explores the most important areas of research for the next generation. The book's goal is not to list the world's biggest environmental problems. Rather it is to determine areas of opportunity thatâ€"with a concerted investmentâ€"could yield significant new findings. Nominations for environmental science's "grand" challenges were solicited from thousands of scientists worldwide. Based on their responses, eight major areas of focus were identifiedâ€"areas that offer the potential for a major scientific breakthrough of practical importance to humankind, and that are feasible if given major new funding. The book further pinpoints four areas for immediate action and investment.
Download or read book Root Ecology written by Hans de Kroon and published by Springer Science & Business Media. This book was released on 2003-05-21 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the course of evolution, a great variety of root systems have learned to overcome the many physical, biochemical and biological problems brought about by soil. This development has made them a fascinating object of scientific study. This volume gives an overview of how roots have adapted to the soil environment and which roles they play in the soil ecosystem. The text describes the form and function of roots, their temporal and spatial distribution, and their turnover rate in various ecosystems. Subsequently, a physiological background is provided for basic functions, such as carbon acquisition, water and solute movement, and for their responses to three major abiotic stresses, i.e. hard soil structure, drought and flooding. The volume concludes with the interactions of roots with other organisms of the complex soil ecosystem, including symbiosis, competition, and the function of roots as a food source.
Download or read book Microbial Communities written by Heribert Insam and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on decomposer communities of terrestrial ecosystems for a long time has focussed on microbial biomass and gross turnover parameters. Recently, more and more attempts are made to look beyond the biomass, and more specifically determine functions and populations on a smaller scale-in time and space. A multitude of techniques is being improved and developed. Garland and Mills (1991) triggered a series of publications on substrate utilization tests in the field of microbial ecology. Despite several promising results for different applications in different laboratories, many problems concerning the assay and the interpretation of results became evident. After individual discussions on the approach with colleagues from various laboratories we started to plan a workshop on the matter. The response on our first circular was extraordinary, and instead of a small workshop it became a meeting with almost 150 participants. The meeting was named 'Substrate use for characterization of microbial communities in terrestrial ecosystems' (SUBMECO) and was held in Innsbruck, Austria, from Oct. 16-18, 1996. The very focussed scope attracted enthusiastic advocates of the approach, and also serious critics. Some of the topics concerned improvements of current inoculation and incubation techniques, ranging from sample pre-treatment, inoculum density and incubation temperature to statistical data handling. New methods for calculating microbial diversity were proposed, as well as bootstrap methods that allow statistics with many variables on a relatively low number of replicates.
Download or read book Soil Protists written by Stefan Geisen and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2015-10-13 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Protists are by far the most diverse and abundant eukaryotes in soils. Nevertheless, very little is known about individual representatives, the diversity and community composition and ecological functioning of these important organisms. For instance, soil protists are commonly lumped into a single functional unit, i.e. bacterivores. This work tackles missing knowledge gaps on soil protists and common misconceptions using multi-methodological approaches including cultivation, microcosm experiments and environmental sequencing. In a first part, several new species and genera of amoeboid protists are described showing their immense unknown diversity. In the second part, the enormous complexity of soil protists communities is highlighted using cultivation- and sequence-based approaches. In the third part, the present of diverse mycophagous and nematophagous protists are shown in functional studies on cultivated taxa and their environmental importance supported by sequence-based approaches. This work is just a start for a promising future of soil Protistology that is likely to find other important roles of these diverse organisms.
Download or read book The Unified Neutral Theory of Biodiversity and Biogeography written by Stephen P. Hubbell and published by Princeton University Press. This book was released on 2011-06-27 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite its supreme importance and the threat of its global crash, biodiversity remains poorly understood both empirically and theoretically. This ambitious book presents a new, general neutral theory to explain the origin, maintenance, and loss of biodiversity in a biogeographic context. Until now biogeography (the study of the geographic distribution of species) and biodiversity (the study of species richness and relative species abundance) have had largely disjunct intellectual histories. In this book, Stephen Hubbell develops a formal mathematical theory that unifies these two fields. When a speciation process is incorporated into Robert H. MacArthur and Edward O. Wilson's now classical theory of island biogeography, the generalized theory predicts the existence of a universal, dimensionless biodiversity number. In the theory, this fundamental biodiversity number, together with the migration or dispersal rate, completely determines the steady-state distribution of species richness and relative species abundance on local to large geographic spatial scales and short-term to evolutionary time scales. Although neutral, Hubbell's theory is nevertheless able to generate many nonobvious, testable, and remarkably accurate quantitative predictions about biodiversity and biogeography. In many ways Hubbell's theory is the ecological analog to the neutral theory of genetic drift in genetics. The unified neutral theory of biogeography and biodiversity should stimulate research in new theoretical and empirical directions by ecologists, evolutionary biologists, and biogeographers.
Download or read book The Nature of Plant Communities written by J. Bastow Wilson and published by Cambridge University Press. This book was released on 2019-03-21 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive review of the role of species interactions in the process of plant community assembly.
Download or read book The Herbaceous Layer in Forests of Eastern North America written by Frank Gilliam and published by Oxford University Press. This book was released on 2014-04 with total page 689 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most comprehensive existing volume of multidisciplinary research by top ecologists on the herbaceous layer of forests.
Download or read book Modern Soil Microbiology Second Edition written by Jan Dirk van Elsas and published by CRC Press. This book was released on 2006-12-21 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the ten years since the publication of Modern Soil Microbiology, the study of soil microbiology has significantly changed, both in the understanding of the diversity and function of soil microbial communities and in research methods. Ideal for students in a variety of disciplines, this second edition provides a cutting-edge examination of a fascinating discipline that encompasses ecology, physiology, genetics, molecular biology, and biotechnology, and makes use of biochemical and biophysical approaches. The chapters cover topics ranging from the fundamental to the applied and describe the use of advanced methods that have provided a great thrust to the discipline of soil microbiology. Using the latest molecular analyses, they integrate principles of soil microbiology with novel insights into the physiology of soil microorganisms. The authors discuss the soil and rhizosphere as habitats for microorganisms, then go on to describe the different microbial groups, their adaptive responses, and their respective processes in interactive and functional terms. The book highlights a range of applied aspects of soil microbiology, including the nature of disease-suppressive soils, the use of biological control agents, biopesticides and bioremediation agents, and the need for correct statistics and experimentation in the analyses of the data obtained from soil systems.
Download or read book Measuring Plant Diversity written by Thomas J. Stohlgren and published by OUP USA. This book was released on 2007 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is a thorough presentation and critique of the sampling approaches, designs and field techniques for measuring plant diversity. Ecologists interested in assessing landscapes and ecosystems must measure biomass, cover, and the density or frequency of various key species. Recently, sampling designs for measuring species richness and diversity, patterns of plant diversity, species-environment relationships, and species distributions have become finer-grained, as it has become increasingly important to accurately map and assess rare species for conservation. This book lays out the range of current methods for mapping and measuring species diversity, for field ecologists, resource managers, conservation biologists, and students, as a tool kit for future field measurements of plant diversity.
