Xem 1-20 trên 688 kết quả Ecosystems
  • Tham khảo sách 'insect ecology an ecosystem approach', nông - lâm - ngư, nông nghiệp phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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  • The planet is a marvelous place: a place with blue skies, wild storms, deep lakes, and rich and diverse ecosystems. The tides ebb and flow, baby animals are born in the spring, and tropical rain forests harbor an astonishing array of life. The Earth sustains living things and provides humans with the resources to maintain a bountiful way of life: water, soil, and nutrients to grow food, and the mineral and energy resources to build and fuel modern society, among many other things.

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  • Cùng nắm kiến thức trong bài giảng "Hệ sinh thái Ecosystem" thông qua việc tìm hiểu các nội dung sau: các phần cơ bản của môi trường trái đất, sinh quyển và sinh đới, hệ sinh thái và quan hệ giữa các nhân tố sinh thái, sự chuyển hóa vật chất trong hệ sinh thái, dòng năng lượng và năng suất sinh học của hệ sinh thái, sự phát triển và tiến hóa của các hệ sinh thái, sự tăng trưởng và tự điều chỉnh các quần thể sinh vật, tác động của con người đến hệ sinh thái.

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  • Pacific Regional Fishery Management Council and represents the first step in an incremental and collaborative approach to implement ecosystem approaches to fishery management in the Pacific Remote Island Areas (PRIA) of Baker Island, Johnston Island, Jarvis Island, Johnston Atoll, Kingman Reef, Wake Island and Palmyra Atoll.

    pdf232p lulanphuong 20-03-2012 51 11   Download

  • Compared to other ecosystems, wetlands have received an exceptional amount of attention. Wetlands are valuable as sources, sink and transformers of a multitude of chemical, biological and genetic materials. They stabilize water supplies, clean polluted waters, protect shorelines, and recharge groundwater aquifers. They have increasingly become recognized for their unique ecological functions in the environment and are the focus of increased research by scientists and study programs by schools, communities, and nature centers.

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  • Why did I decide to write this book? As an undergraduate student I could not make up my mind whether I wanted to be a zoologist or a botanist, so I decided to adopt ecology, in its broadest sense, as my area of interest. This led me to think about interactions among organisms and to try to look at ecosystems from a holistic, rather than from an autecological, point of view. As someone with little formal training in mycology, my interest in fungi started during my doctoral research, especially when attending university-wide lectures by C. T. Ingold, given at the University of London.

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  • Plant species that invade an alien area and outgrow the native vegetation, establishing and increasing their own territory, often lead to negative economic, environmental, and social impacts. Even native species can behave like invasive species by their exponential spread. Similarly, not all non-native species are invasive. Many alien invasive species, however, do threaten the health and integrity of our terrestrial and aquatic ecosystems.

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  • Human activities are affecting the global environment in myriad ways, with numerous direct and indirect effects on ecosystems. The climate and atmospheric composition of Earth are changing rapidly. Humans have directly modified half of the ice-free terrestrial surface and use 40% of terrestrial production. Our actions are causing the sixth major extinction event in the history of life on Earth and are radically modifying the interactions among forests, fields, streams, and oceans.

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  • This book addresses the significant environmental changes experienced by high latitude and high altitude ecosystems at the beginning of the 21st century. Increased temperatures and precipitation, reduction in sea ice and glacier ice, the increased levels of UV-radiation and the long-range transported contaminants in arctic and alpine regions are stress factors that challenge terrestrial and aquatic ecosystems.

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  • Ecosystems provide a wide variety of marketable goods, fish and lumber being two familiar examples. However, society is increasingly recognizing the myriad functions—the observable manifestations of ecosystem processes such as nutrient recycling, regulation of climate, and maintenance of biodiversity— that they provide, without which human civilizations could not thrive. Derived from the physical, biological, and chemical processes at work in natural ecosystems, these functions are seldom experienced directly by users of the resource.

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  • Challenges to sustaining the productivity of oceanic and coastal fisheries have become more critical and complex as these fisheries reach the upper limits to ocean harvests. In addition, it is now clear that we are managing interactive and dynamic food webs rather than sets of independent single-species populations.

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  • This collection of papers reflects the diversity of concepts, methods, and case studies that address the challenge of Managing for Healthy Ecosystems as holistic environmental management in the context of health, integrity, and sustainability. Ecosystem health embodies the capacity of ecosystems to function without impairment, while management concerns the assessment of ecosystem conditions relative to social goals and adoption of interventions to achieve designated goals.

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  • The late Neogene (the period between − 14 and − 2.4 Ma) is one of the most interesting phases in understand the present conWguration of terrestrial ecosystems. It was during this time that the change took place from the middle Miocene dominant subtropical forests that stretched across southern Europe and western Asia to a more open but still wooded biotope that now prevails in warm–temperate areas. This change in vegetation, which strongly aVected the composition of mammalian faunas, seems to be linked to the rapid spread of grasses around 8–10 Ma ago....

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  • The Current State and Trends assessment presents the findings of the Condition and Trends Working Group of the Millennium Ecosystem Assessment. This volume documents the current condition and recent trends of the world’s ecosystems, the services they provide, and associated human well-being around the year 2000. Its primary goal is to provide decision-makers, ecosystem managers, and other potential users with objective information and analyses of historical trends and dynamics of the interaction between ecosystem change and human well-being.

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  • The idea for this book stems from a meeting sponsored by the European Union, organized by N. van Breemen, and held in Doorweerth at the end of 1991. At this meeting a large number of European scientists discussed the different issues related to the accumulation and decomposition of organic matter in terrestrial ecosystems. One of the objectives was to gather scientists from various disciplines (biologists, chemists, ecologists, agriculturalists) to pool their different disciplinary approaches and come up with a common perspective for future research on soil organic matter.

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  • Tham khảo sách 'humic substances in terrestrial ecosystems', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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  • The history and development of the longleaf pine (Pinus palustris Mill.) ecosystem in the southeastern United States has intrigued natural resource professionals, researchers, and the general public for many decades. Prior to European settlement, longleaf pine forests were one of the most extensive ecosystems in North America. Most recent estimates suggest that only about 2.2% of the original area remains today, making it one of the most threatened ecosystems in North America.

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  • Forest ecosystems cover large parts of the terrestrial land surface and are major components of the terrestrial carbon (C) cycle. Most important, forest ecosystems accumulate organic compounds with long C residence times in vegetation, detritus and, in particular, the soil by the process of C sequestration. Trees, the major components of forests, absorb large amounts of atmospheric carbon dioxide (CO2) by photosynthesis, and forests return an almost equal amount to the atmosphere by auto- and heterotrophic respiration.

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  • This project has its origins in a conference on ecosystem services that Gretchen Daily of the Stanford Biology Department, Geoff Heal of the Columbia Business School, and Peter Raven, Director of the Missouri Botanical Gardens, organized at the Gardens in 1998. Having become intrigued by the concept of ecosystem services, which at the time was still relatively new even within ecological economics, the three of us eagerly attended and immediately noticed that, besides J. B., only one other lawyer was present in the audience of more than a hundred.

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  • Overharvesting has led to severe reductions in the abundance and range of nearly every large vertebrate species that humans have ever found worth pursuing. These megafaunal reductions, dating in some cases from first contact with early peoples (Martin 1973), are widely known. In contrast, remarkably little is known about the ecological consequences of megafaunal extirpations. Whales and whaling are part of that legacy. Most people know that large whales have been depleted, but little thought has been given to how the depletions may have influenced ocean ecosystems.

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