长江口3个不同生态系的浮游植物群落

初步研究表明 ,长江口及邻近海域存在 3个不同的生态系 ,与以盐度划分的水团 (长江河口水、长江冲淡水、外海水 )基本一致 ,每个生态系包含 1个浮游植物群落。 1997～ 2 0 0 0年的 7个航次调查中共鉴定出浮游植物 393种 ,其中大部分为硅藻。长江口的浮游植物基本可归为 5个类群 :淡水类群、河口半咸水类群、近岸低盐性类群、外海高盐类群、海洋广布性类群。它们自西向东在 3个生态系中有明显的分布格局 ,并且随着长江径流量的变化而摆动和变化。根据栖息水域的盐度浮游植物可分为 3个群落 :河口群落、冲淡水低盐群落、外海高盐群落。     

Adaptive Strategies at the Ecosystem Level: Examples from Two Benthic Marine Systems

Abstract. Adaptive strategies on the ecosystem level are demonstrated using the properties of systems (community biomass, trophic level energy transfer). Development of stabilizing storages versus rapid turnover and energy transfer through the grazing food chain versus detritus food chain are shown to be adaptive processes leading towards an optimal performance of the system. A model of incorporation and processing of information in ecosystems is proposed which contains the essential features of evolution. The persistence of "interspecific altruism" is discussed.     

ISLANDS AS PLACES OF BEING AND BELONGING*

ABSTRACT. Islands, traditionally important units of research and analysis in ethnographic research, have come to be viewed as a problematic unit of analysis, as anthropologists have realized the close integration of island societies within the wider world. This article argues that islands are still useful and fruitful foci of research, if their particular character is explored from an islandic point of view. Through life‐story interviews conducted in three large, dispersed families of Caribbean origin, the article demonstrates that islands may be usefully conceptualized as sociocultural constructs that constitute important anchoring points as well as sources of identification for migrants and their descendants.     

PROPRIETARY RESIDENTIAL COMMUNITIES IN THE UNITED STATES

ABSTRACT. Proprietary residential communities constitute a major component in the evolving geography of urban America. In many metropolitan regions, proprietary residential communities or common‐interest developments, and associated forms of urban management, have emerged as the dominant form of residential development. Critical discourse on these communities and their residential community/homeowner associations has focused principally on the negative consequences for urban social and political life. It is argued here that many critical assessments are grounded in an idealistic view of contemporary society and an outdated conceptualization of citizenship. This article is intended to reenergize debate on these developments through a realist interpretation of the benefits and disbenefits of a form of residential development destined to exercise a major influence on the sociospatial structure of U.S. metropolitan areas in the early twenty‐first century.     

北京西部山区传统村落保护与旅游开发利用——以门头沟区为例

北京西部山区保留有许多传统村落,这些传统村落经过历史的积淀而具有典型的地域特征和深厚的文化底蕴,成为京西独特的景观旅游资源。伴随北京市山区发展的新战略,许多村落将进行搬迁,搬迁后的村落和其他传统村落一起成为北京市山区一个亟待解决的课题。根据北京门头沟传统村落的类型和特征,探讨京西山区传统村落保护体系和机制的基础上,探讨了传统村落旅游开发利用的模式和途径。     

基于村落尺度的丘陵山区人口分布特征与规律——以甘肃天水为例

在以农业生产为主的丘陵山地,人口分布具有明显的分散性和差异性。基于村落尺度分析人口分布更接近实际。位于秦岭山地向黄土丘陵区过渡的天水地区,从市域、县域、乡镇到村落,随着分辨尺度的缩小,人口空间分布上的疏密不均现象越突出,变异系数迅速扩大。在7 915个由城镇、村落和居民点构成的斑块上,面积在1.0~10 hm2范围的较小斑块占84.7%,表明分散的、小规模的村落仍是人口分布的主要形式。用非线性函数分析人口密度与村落用地比例、单位面积上的斑块数量、斑块大小的关系,可以较好地揭示人口分布上的一些特征和规律。天水人口分布在地域上明显地表现为河谷高密度区、丘陵中密度区、山地低密度区三种类型,反映人口分布特征的劳作半径和村落间距离在三种类型中都有显著差异。     

Rural Restructuring and the Changing Geography of Competitive Sport

The geography of sport has received relatively little attention from those interested in processes of rural social and economic change. This is despite the important role that sport plays in the structure of rural communities and regions. In addition to the obvious health benefits associated with physical activity, sport contributes to community identity and provides opportunities for social interaction. There is, however, considerable evidence to suggest that processes of restructuring are having direct impacts on sport in rural areas. Drawing on a case study from rural Western Australia, this paper argues that economic adjustment in the farming and business sectors, service withdrawal, and population decline are just some of the changes undermining the viability of sporting clubs in rural areas. We suggest that while sporting clubs have tended to be resilient in the face of restructuring, it is also clear that one of the outcomes is a changing geography of sport in declining rural areas.     

山地农村社会经济缓慢发展的实证分析--以河南省上河村为例

通过实证调查,山地农村社会经济发展呈下滑态势,指出:人力资源外流、兼业弱化、农户投入减少且偏向生活投资、农民负担日渐加重等是山地农村社会经济缓慢发展的主要原因,提高山地农村社会经济发展的主要措施包括:大力发展山地农村的文化教育,发挥当地的林业优势,积极有效引导劳动力合理流动,增加农民收入渠道,加强农村市场建设,切实减轻农民负担等。