933 resultados para global services


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Studies of experimental grassland communities have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change. Here we analyse diversity-stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.

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Increasing scrutiny from the wider community is contributing to a shift towards the delivery and operation of major projects that meets and maintains the sustainability priorities of the community. This is especially significant for large economic projects which have a global track record of social benefit shortfalls, cost overruns, and underestimation of risks. Major industrial and infrastructure projects that cost more than US$1 billion are typically called mega-projects. Globally, investment in mega-projects has exceeded $10 trillion in the last ten years. With so many projects in the pipeline -and many taking place in emerging economies – the effectiveness of the sustainability decision making process is particularly important. The purpose of this paper is to examine how the existing sustainability decision making processes and strategies address the potential challenges facing communities affected by mega-projects. It highlights issues with current operational level approaches to social sustainability assessment at the project level, and argues that to improve accountability and transparency of project outcomes, positive externalities that flow from goods and services provided by the social and cultural systems of the community must be incorporated into decision making.

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In this age of electronic money transactions, the opportunities for electronic crime expanded at the same rate as ever expanding rise of on-line services. With world becoming a global village, crime over the internet transcends no boundaries, borders or jurisdictions. This paper critically examines the available literature on spam, and the control measures available to control spam. This study is followed by the literature overview related to mobility of devices and how the application of mobile technologies as communication medium has impacted the handling of spam. The conclusion of this literature review with proposed direction of study is summarized.