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During the past two decades, there has been a gradual change of emphasis in ecological studies directed at unravelling the complexity of natural communities. Initially, the population approach was used, where interest lay in the way individual populations change and in the identification of factors af fecting these changes. A good understanding of the dynamics of single populations is now emerging, but this has not been a very fruitful approach at the community level. In the natural world, few species can be treated as isolated populations, as most single species are the interacting parts of multispecies systems. This has led to a community approach, involving the study of interrelationships between species within com munities and investigation of the actual organization of natural communities as a whole. The formalization of a number of new concepts and ideas has evolved from this approach, including niche theory, resource allocation, guild structure, limiting similarity, niche width and overlap etc. , which, until fairly recently, have been examined mainly from a theoretical point of view. However, a wealth of field data is gradually being added to the literature, especially from the general areas of island biogeography and resource partitioning amongst closely related species. Community structure embodies patterns of resource allocation and spatial and temporal abundance of species of the community, as well a. '1 community level properties such as trophic levels, succession, nutrient cycling etc.
This introduction to basic concepts of biodiversity-sampling outlines standardized field methods for macroalgae and seagrass communities developed by NaGISA (Natural Geography in Shore Areas), a project operating under the international Census of Marine Life. NaGISA promotes simple standardized protocols and focuses on widespread nearshore habitats. This book, written by premier coastal ecologists and taxonomists, provides a text for field courses, a manual for coastal managers, and a reference guide for researchers studying biodiversity or preparing species inventories.
The United States is among the wealthiest nations in the world, but it is far from the healthiest. Although life expectancy and survival rates in the United States have improved dramatically over the past century, Americans live shorter lives and experience more injuries and illnesses than people in other high-income countries. The U.S. health disadvantage cannot be attributed solely to the adverse health status of racial or ethnic minorities or poor people: even highly advantaged Americans are in worse health than their counterparts in other, "peer" countries. In light of the new and growing evidence about the U.S. health disadvantage, the National Institutes of Health asked the National Research Council (NRC) and the Institute of Medicine (IOM) to convene a panel of experts to study the issue. The Panel on Understanding Cross-National Health Differences Among High-Income Countries examined whether the U.S. health disadvantage exists across the life span, considered potential explanations, and assessed the larger implications of the findings. U.S. Health in International Perspective presents detailed evidence on the issue, explores the possible explanations for the shorter and less healthy lives of Americans than those of people in comparable countries, and recommends actions by both government and nongovernment agencies and organizations to address the U.S. health disadvantage.
This much revised and expanded edition provides a valuable and detailed summary of the many uses of diatoms in a wide range of applications in the environmental and earth sciences. Particular emphasis is placed on the use of diatoms in analysing ecological problems related to climate change, acidification, eutrophication, and other pollution issues. The chapters are divided into sections for easy reference, with separate sections covering indicators in different aquatic environments. A final section explores diatom use in other fields of study such as forensics, oil and gas exploration, nanotechnology, and archaeology. Sixteen new chapters have been added since the first edition, including introductory chapters on diatom biology and the numerical approaches used by diatomists. The extensive glossary has also been expanded and now includes over 1,000 detailed entries, which will help non-specialists to use the book effectively.
In the United States, some populations suffer from far greater disparities in health than others. Those disparities are caused not only by fundamental differences in health status across segments of the population, but also because of inequities in factors that impact health status, so-called determinants of health. Only part of an individual's health status depends on his or her behavior and choice; community-wide problems like poverty, unemployment, poor education, inadequate housing, poor public transportation, interpersonal violence, and decaying neighborhoods also contribute to health inequities, as well as the historic and ongoing interplay of structures, policies, and norms that shape lives. When these factors are not optimal in a community, it does not mean they are intractable: such inequities can be mitigated by social policies that can shape health in powerful ways. Communities in Action: Pathways to Health Equity seeks to delineate the causes of and the solutions to health inequities in the United States. This report focuses on what communities can do to promote health equity, what actions are needed by the many and varied stakeholders that are part of communities or support them, as well as the root causes and structural barriers that need to be overcome.
Insect Ecology: An Ecosystem Approach, Fifth Edition provides the most updated and comprehensive knowledge of the diversity of insect responses to environmental changes and their effects on ecosystem properties and services. Written by an expert in the field, this book addresses ways in which insect morphology, physiology and behavior tailor their adaptation to particular environmental conditions, how those adaptations affect their responses to environmental changes, and how their responses affect ecosystem properties and the ecosystem services on which humans depend for survival. This edition also addresses recent reports of global declines in insect abundance and how these declines could affect human interests. Insect Ecology: An Ecosystem Approach, Fifth Edition is an important resource for researchers, entomologists, ecologists, pest managers and conservationists who want to understand insect ecology and to manage insects in ways that sustain the delivery of ecosystem services. Graduate and advanced undergraduate students may also find this as a useful resource for entomology and specifically insect ecology courses. The only insect ecology text that emphasizes insect effects on ecosystem properties and services, as well as evolutionary adaptations to environmental conditions Includes new material on long-term trends in insect abundance, addressing the so-called “insect apocalypse Offers crucial updates on mechanisms by which insects affect, and potentially regulate, ecosystem structure and function Applies ecological principles to improved management of insects for the sustainable delivery of ecosystem services