We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of ric...We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of richness, diversity and density of understory vegetation of logged sites. A factorial experiment was conducted in the mixed conifer forest of Gidakom in Western Bhutan. Levels of the logging treatment included small(0.15 – 0.24 ha), medium(0.25 – 0.35 ha) and large(0.36 – 1.31 ha) gaps. The grazing treatment included grazed(primarily by cattle) and ungrazed(where herbivores were excluded by a fence) plots nested within each gap. Data were collected from 12 gaps(4 replicates at each level of logging) using the point intercept method. Shannon Weaver Diversity and Margalef's indices were used to estimate species diversity and describe species richness, respectively. Soil samples were analyzed for pH and nutrients. The interaction effect of logging and grazing was significant(p≤0.001) only on species diversity. Relative to ungrazed areas, species diversity was significantly higher(0.01≤p≤0.05) in medium grazed gaps. Under grazed conditions, soil P was negatively correlated with gap size and species diversity. While species diversity was positivelycorrelated(0.01≤p≤0.05) with soil N in grazed plots species richness was positively correlated(0.001≤p≤0.01) with soil N in ungrazed plots. Relative density of Yushania microphylla and Carex nubigena were higher under ungrazed conditions. Our study suggests that the combined effect of cattle grazing and logging results in higher species diversity of understory vegetation in medium and grazed gaps in mixed conifer forests of Bhutan,whereas increase or decrease in relative density of major species is determined primarily by the independent effects of grazing and logging. From management perspective, forest managers must refrain from creating large gaps to avoid loss of nutrients(mainly P and N), which may eventually affect tree regeneration. Managers intending to maintain understory vegetation diversity must consider the combined effects of grazing and logging, ensuring low to moderate grazing pressure.展开更多
Inequality in distribution has become an issue of public concern in China. Incomes of the Chinese people have grown year after year ever since the reform and opening era began in the late 1970s. Meanwhile, the income ...Inequality in distribution has become an issue of public concern in China. Incomes of the Chinese people have grown year after year ever since the reform and opening era began in the late 1970s. Meanwhile, the income gap between urban and rural residents has widened constantly, from 1.8:1 in the mid-1980s to 3.2:1 in 2003. In a report entitled Analysis and Forecast of China's Social Conditions 2004-2005, experts with the Chinese Academy of Social Sciences listed the widening income gaps as the second most serious of the six problems China is facing. The report notes that such gaps have kept widening not only between individual workers in the same profession but also between workers in different industries and regions. In view of this, the national economic work conference held in early January called for effort to improve the order of income distribution and readjust the distribution of national wealth in an appropriate manner. How to view the problem of inequality in distribution as we see now? How the divide of the rich and the poor affects the improvement of human rights? What should be done to narrow the gap between the rich and the poor? We have dis- cussed these questions with two leading social scientists in China, Sun Guohua, pro- fessor of law at the Renmin University of China and Prof. Hu Angang of Qinghua University, a noted expert in study of the conditions in China.展开更多
贫者日贫,富者日富。这是一个普遍存在于许多国家的现象。自1977年以来,美国老百姓的税后年收入的差距也日益扩大,到了1999年贫富之间的差距达到了创记录的程度。 据统计,美国的高收入者约占其总人口的1％,约270万人。自1977年以来,他...贫者日贫,富者日富。这是一个普遍存在于许多国家的现象。自1977年以来,美国老百姓的税后年收入的差距也日益扩大,到了1999年贫富之间的差距达到了创记录的程度。 据统计,美国的高收入者约占其总人口的1％,约270万人。自1977年以来,他们的收入增加了一倍多,其1999年的预计收入可达51万美元;而占总人口20％的最低收入者,其1999年的预计收入仅为8,800美元。前者是后者的近60倍！ 下面的换算更形象地说明了美国贫富收入之悬殊: …the after-tax income share of the richest 2.7 million people in 1999matched that of the bottom 38 percent of the population,embracing about 100million people. 本文透露的一个重要信息是:美国贫富收入之所以如此悬殊的原因在于: …increased global trade,innovations in technology and weaker laborunions.展开更多
基金support of the Government of Austria with funds routed through the sterreischer Austauschdienst(OeAD)
文摘We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of richness, diversity and density of understory vegetation of logged sites. A factorial experiment was conducted in the mixed conifer forest of Gidakom in Western Bhutan. Levels of the logging treatment included small(0.15 – 0.24 ha), medium(0.25 – 0.35 ha) and large(0.36 – 1.31 ha) gaps. The grazing treatment included grazed(primarily by cattle) and ungrazed(where herbivores were excluded by a fence) plots nested within each gap. Data were collected from 12 gaps(4 replicates at each level of logging) using the point intercept method. Shannon Weaver Diversity and Margalef's indices were used to estimate species diversity and describe species richness, respectively. Soil samples were analyzed for pH and nutrients. The interaction effect of logging and grazing was significant(p≤0.001) only on species diversity. Relative to ungrazed areas, species diversity was significantly higher(0.01≤p≤0.05) in medium grazed gaps. Under grazed conditions, soil P was negatively correlated with gap size and species diversity. While species diversity was positivelycorrelated(0.01≤p≤0.05) with soil N in grazed plots species richness was positively correlated(0.001≤p≤0.01) with soil N in ungrazed plots. Relative density of Yushania microphylla and Carex nubigena were higher under ungrazed conditions. Our study suggests that the combined effect of cattle grazing and logging results in higher species diversity of understory vegetation in medium and grazed gaps in mixed conifer forests of Bhutan,whereas increase or decrease in relative density of major species is determined primarily by the independent effects of grazing and logging. From management perspective, forest managers must refrain from creating large gaps to avoid loss of nutrients(mainly P and N), which may eventually affect tree regeneration. Managers intending to maintain understory vegetation diversity must consider the combined effects of grazing and logging, ensuring low to moderate grazing pressure.
文摘Inequality in distribution has become an issue of public concern in China. Incomes of the Chinese people have grown year after year ever since the reform and opening era began in the late 1970s. Meanwhile, the income gap between urban and rural residents has widened constantly, from 1.8:1 in the mid-1980s to 3.2:1 in 2003. In a report entitled Analysis and Forecast of China's Social Conditions 2004-2005, experts with the Chinese Academy of Social Sciences listed the widening income gaps as the second most serious of the six problems China is facing. The report notes that such gaps have kept widening not only between individual workers in the same profession but also between workers in different industries and regions. In view of this, the national economic work conference held in early January called for effort to improve the order of income distribution and readjust the distribution of national wealth in an appropriate manner. How to view the problem of inequality in distribution as we see now? How the divide of the rich and the poor affects the improvement of human rights? What should be done to narrow the gap between the rich and the poor? We have dis- cussed these questions with two leading social scientists in China, Sun Guohua, pro- fessor of law at the Renmin University of China and Prof. Hu Angang of Qinghua University, a noted expert in study of the conditions in China.
文摘贫者日贫,富者日富。这是一个普遍存在于许多国家的现象。自1977年以来,美国老百姓的税后年收入的差距也日益扩大,到了1999年贫富之间的差距达到了创记录的程度。 据统计,美国的高收入者约占其总人口的1％,约270万人。自1977年以来,他们的收入增加了一倍多,其1999年的预计收入可达51万美元;而占总人口20％的最低收入者,其1999年的预计收入仅为8,800美元。前者是后者的近60倍！ 下面的换算更形象地说明了美国贫富收入之悬殊: …the after-tax income share of the richest 2.7 million people in 1999matched that of the bottom 38 percent of the population,embracing about 100million people. 本文透露的一个重要信息是:美国贫富收入之所以如此悬殊的原因在于: …increased global trade,innovations in technology and weaker laborunions.
