The pattern of species turnover resulting from stochastic population dynamics: The model and field data

The model of random population dynamics in a sampling site returns geometric distribution of longevities of continuous presence (=persistence) and Poisson distribution of the presence–absence transitions. This discrete-time stochastic process describes the presence–absence pattern observed in the beetles surveyed 6 years on Mount Carmel, Israel. Homogeneous pools of species mostly on the Families rank, exhibit the predicted by the model patterns. Conformity to an ergodic hypothesis is the criterion of ecological homogeneity. This criterion assumes the equivalence of short-term behavior of entire pool and long-term behavior of any species from this pool. The pool of all 801 species of Order Coleoptera does not match the model. Thus a taxon of an arbitrary rank may not be considered a priory as a unit of ecological study. Determined from field data parameters of the model are biased and magnitude of the bias depends on longevity of the survey. Parameter of distribution depends also on species tolerance, which is the level adaptation of given species to given environment in given time interval. Random process of species turnover may be considered as a game of species to gain their presence against deteriorative fluctuations of environmental conditions.     

上海市能源消费碳排放分析

根据联合国政府间气候变化专门委员会(IPCC)2006年版碳排放计算指南中的计算公式和碳排放系数缺省值,计算了上海市1994─2006年能源消费碳排放量. 结果表明:1994年以来碳排放量逐年增加,碳排放强度不断下降,由1994年的2.51 t/(104元)降到2006年的1.07 t/(104元). 通过比较2005年上海与全国以及主要经济大国间的碳排放量、碳排放强度和人均碳排放量发现,上海市能源消费碳排放量占全国的3.5%;碳排放强度低于全国和全球水平,但比英国、德国、日本高;人均碳排放量为2.7 t/a,是全国和全球平均水平的2倍多,低于美国、澳大利亚和加拿大. 从能源利用效率、经济增长方式、能源结构以及经济结构等角度分析了碳排放强度下降的原因,其中能源结构调整引起的平均碳排放系数下降和第三产业比重上升是主要原因.      

沈阳市多介质环境铅污染研究

系统研究了沈阳市大气、土壤、灰尘、加杨叶和儿童血铅等多介质环境中Pb的污染特征.结果表明,沈阳市区铅暴露普遍,各环境介质铅污染较严重.铅浓度空间分异大,从市中心到郊区铅污染由重到轻,局部污染十分严重,已经形成4个高浓度中心.儿童血铅有明显的性别差异.大气铅浓度日变化呈双峰型,季节变化是冬>春>秋>夏,年变化呈下降趋势.土壤、灰尘、加杨叶介质中的铅浓度重心相距较近, 且都远离几何中心.儿童血铅与大气铅相关性最大,其次是土壤和灰尘.实行无铅汽油之后,大气铅污染有了很大改善,但是土壤和灰尘中的铅容易以扬尘的方式再次进入大气,成为二次污染源.     

成都市“温、郫、都”生态示范区的战略地位与示范意义

成都市“温、郫、都”生态示范区是全国第一批生态示范区域之一。该示范区是“天府之国”的一个缩影,有优越的区位优势和突出的战略地位,生态示范区代表区域发展新的战略思维和发展模式。     

西部大开发中的生物多样性的保护

全球的生物物种在急剧减少,而此情景也呈现于我国的西部在,在机遇与挑战同在的西部大开发过程中如何切实效保护生物多样性,无疑已成为我们必须关注和思考的问题。本文从生物多样性的内涵、生物多样性的价值、生物多样性的丧失及保护生物多样性的必要性及对策等方面,论述笔者对预防、保护、恢复生物多样性的几点思考,但愿能引起广大社会的关注和支持。     

德阳市旅游特色及其开发对策

以德阳市旅游资源为研究对象,进行了旅游资源评价,并剖析了旅游产业发展过程中出现的问题,提出了具体对策。     

西部大开发与重庆市旅游业的可持续发展

重庆具有发展旅游业得天独厚的区位条件,而西部大开发进一步从交通环境、经济基础、市场开拓和生态保护几个方面为重庆旅游提供了良好的外部条件;但目前重庆的旅游业发展面临着严重的挑战。从战略方向和形象策划、客源定位、旅游产品的深层次开发、旅游基础设施的建设和旅游服务体系的完善、旅游管理和旅游人才的教育以及发展生态旅游几个方面,提出了重庆旅游业可持续发展的战略方向和战略对策。     

赤壁市生态旅游资源特色与开发

赤壁生态旅游资源丰富,特色鲜明,类型齐全,具有较大的开发价值。通过对赤壁市开发条件、开发力和客源市场的分析,作者指出了该市开发旅游资源的巨大前景,提出了建立七种不同类型生态旅游区的构想。     

重庆市耕地资源可持续利用研究

分析了重庆市耕地资源利用现状、利用中存在的主要问题及其产生的原因 ,提出了重庆市耕地资源可持续利用的相应对策。     

AFTER THE 1993 FLOOD: A WATER AND SURFICIAL BED SEDIMENT QUALITY SCENARIO ON THE ILLINOIS AND UPPER MISSISSIPPI RWERS1

ABSTRACT: Effects of the 1993 flood on river water and sediment quality were investigated using historical data and data collected from the Illinois River and Upper Mississippi River in a post‐flood period. Overall the post‐flood results showed systematic reductions and individual changes in the water and sediment constituents. The reductions in sediment metals and nutrients were most obvious at the Keokuk and Lock and Dam 26 stations. By analyzing and comparing the physical changes to the changes in water and sediment constituents at each station, it was found that physical processes such as sediment entrainment and, more importantly, the removal of fine sediment to be the main causes for the reduced concentrations in sediment constituents. On the other hand, sediment redistribution and associated secondary contamination could have caused the emergence of several water and sediment constituents that were undetected before the flood.