نتایج جستجو برای: forest ecosystems
تعداد نتایج: 144986 فیلتر نتایج به سال:
Global or regional environmental changes in climate or land use have been increasingly implied in shifts in boundaries (ecotones) between adjacent ecosystems such as beech or oak-dominated forests and forest-steppe ecotones that frequently co-occur near the southern range limits of deciduous forest biome in Europe. Yet, our ability to detect changes in biological communities across these ecosys...
Carbon (C) storage for all the components, especially dead mass and soil organic carbon, was rarely reported and remained uncertainty in China's forest ecosystems. This study used field-measured data published between 2004 and 2014 to estimate C storage by three forest type classifications and three spatial interpolations and assessed the uncertainty in C storage resulting from different integr...
Ecosystem analysis has established nutrient cycling as an important area of ecology involving biological, chemical, and geological interactions. Studying the flow of elements through ecosystems provides us with a tool for understanding the functioning of ecosystems. For example, if an ecosystem component has a rapid flux of elements through it, or if it stores large amounts of an element, that ...
without doubt is one important aspects of sustainable forest management the continuing forest regeneration. identify and determine is effective dispersal and distribution pattern of regeneration patches in various types of forest and its evolution, in maintaining biodiversity in natural ecosystems. purpose was chosen of gorazbon district kheyrod forest for study, all patches regeneration were l...
Terrestrial vegetation plays a major role in regulating the global carbon cycle and in turn the climate of the Earth system. It is believed that the North America forest ecosystems are a net sink for anthropogenic carbon. However, significant uncertainties exist in quantifying this claim. Inaccurate and incomplete characterization of forest vegetation is among the main causes to these uncertain...
Why a Special World Heritage Focus on Forests? Forest ecosystems hold the vast majority of the world's terrestrial species. Ironically, these same ecosystems are under the greatest chronic pressure from human activities. The most important threat comes from permanent conversion to non-forest uses – typically agriculture. The FAO (2005A) calculates that since 1990, an average of neary 12.3 milli...
The conversion of tropical forest ecosystems to agro-pastoral ecosystems and other land uses continues unabated in Latin America. The present document constitutes a comparative study in which the degree of forest fragmentation through a 23-year period (between 1973 and 1996) was evaluated in two areas located within the same ecological region, but in two different countries (Colombia and Ecuado...
The last decade has seen a dramatic shift in the focus of nitrogen cycling research in forest ecosystems. Concerns over nitrogen deficiencies and effects of removal in harvest have given way to concerns over excess nitrogen availability and the potential for forest decline and surface water pollution. Driving this paradigm shift is the increase in atmospheric deposition of nitrogen to forests d...
The belowground soil prokaryotic community plays a cardinal role in sustaining the stability and functions of forest ecosystems. Yet, the nature of how soil prokaryotic diversity co-varies with aboveground plant diversity along a latitudinal gradient remains elusive. By establishing three hundred 400-m(2) quadrats from tropical rainforest to boreal forest in a large-scale parallel study on both...
Protected areas in Thailand were first established 40 years ago. The total area of existing protected areas covers 18.2% of the country's land area and the Class 1 Watershed, another form of protection, encompasses 18.1%. The government of Thailand intends to increase protected area systems to 25% of the country in 2006 and 30% in 2016. There are always questions arising about how much is enoug...
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