A fish-based typology of small temperate rivers in the northeastern lowlands of Germany

Fish assemblage data from 69 brooks and small streams were analysed to derive a fish-based typology of small lowland streams in the “Central Plains” ecoregion of northeastern Germany. Altogether 32 native, 1 non-native fish species and 2 lamprey species were detected in the lowland rivers studied. Species number and diversity varied significantly according to mean summer water temperatures and size of the watercourses. Summer-cold brooks contained on average 3-5 species, brooks with higher summer temperatures 5-8 species and small lowland rivers around 10-14 species. Small lowland brooks contained a significantly higher number of fish species when they flowed into or out of lakes: typically around 8-12.In the northeastern German lowlands the following three different river types were distinguished according to their fish assemblages: (1) The “lowland trout brook”, where brown trout (Salmo trutta L.) are reference species and accompanied by stone loach (Barbatula barbatula (L.)), brook lamprey (Lampetra planeri (Bloch)), three-spined stickleback (Gasterosteus aculeatus L.), ten-spined stickleback (Pungitius pungitius (L.)) and gudgeon (Gobio gobio (L.)); (2) The “perch- and roach-dominated lowland brook”, where perch (Perca fluviatilis L.) and roach (Rutilus rutilus (L.)) are reference species, accompanied by pike (Esox lucius L.), three-spined stickleback and gudgeon; and (3) The “lowland lake connected brook” inhabited by higher numbers of fish species, with higher proportions of cyprinid fishes, and higher proportions of limnophilic fish. Apart from perch and roach, bleak (Alburnus alburnus (L.)), common bream (Abramis brama (L.)), silver bream (Blicca bjoerkna (L.)) and rudd (Scardinius erythrophthalmus (L.)) also occurred frequently.Further two observed fish-based types were not considered: The potential stone loach-dominated brook was not sufficiently represented in this study to be verified, and the stickleback brook was considered to represent degradation of lowland trout brooks.The correspondence between the fish-based typology and the morphology-based German stream typology was rather weak and requires further investigation.     

Osculating and Superosculating Intermediate Orbits and their Applications

A method of construction of intermediate orbits for approximating the real motion of celestial bodies in the initial part of trajectory is proposed. The method is based on introducing a fictitious attracting centre with a time-variable gravitational parameter. The variation of thisparameter is assumed to obey the Eddington–Jeans mass-variationlaw. New classes of orbits having first-, second-, and third-order tangency to the perturbed trajectory at the initial instant of time are constructed. For planar motion, the tangency increases by one or two orders. The constructed intermediate orbits approximate the perturbed motion better than the osculating Keplerian orbit and analogous orbits of otherauthors. The applications of the orbits constructed in Encke's methodfor special perturbations and in the procedure for predicting themotion in which the perturbed trajectory is represented by a sequenceof short arcs of the intermediate orbits are suggested.The use of the constructed orbits is especially advantageous in the investigation of motion under the action of large perturbations.     

Influence of bed heterogeneity and habitat type on macroinvertebrate uptake in peri-urban streams

The role of geomorphic structure, referred to as physical heterogeneity, and its influence upon the colonization of habitat by macroinvertebrates was analysed in the peri-urban, Twin Streams Catchment, in West Auckland, New Zealand. Using a cross-scalar approach, 4 riffle-run assemblages were analysed in each of 2 River Styles (a confined, low sinuosity, gravel bed river and a partly confined, low sinuosity, bedrock, cobble, and gravel bed river). Each of these 8 locations comprised 2 distinct sampling areas; the upstream zone had a more heterogeneous river bed with a high diversity of physical features and flow, whilst the downstream area had a more homogeneous structure. Microhabitat features sampled at each site included streambed material, bank margins, fine grained organic debris, wood, and boulders. Habitat mosaics and their associated macroinvertebrate relationships followed a semi-predictable but interrupted pattern, supporting the view that river systems are a patchy discontinuum. Homogeneous zones were more frequently characterised by higher proportions of Trichoptera than heterogeneous zones, whilst heterogeneous zones were frequently characterised by Plecoptera and Ephemeroptera. Diversity was maximised when the species pools from heterogeneous and homogeneous sites were combined for any given site. Functional habitats influenced macroinvertebrate assemblages in non-linear and complex ways. Wood and organic debris habitats were associated with high diversity, abundance, and sensitive species whereas streambed habitat was usually associated with low diversity. A diverse range of physical zones that approximates the 'natural range of behaviour' for the given type of stream was considered to provide a more effective platform for rehabilitation planning than emphasising heterogeneity of physical structure in its own right.     

The Sponge City Hypothesis: does it hold water?

The notion of sponge cities has attracted considerable attention in the media, in the policy arena, and in academia. It rests on the notion that some regional centres ‘soak up’ population and business from a ‘pool’ of surrounding areas, thereby appearing as ‘oases’ of growth in areas of population decline. Specifically, the notion of sponge cities rests on two premises and a deduction: some large towns and provincial cities are growing; surroundings areas are losing population; therefore, the growth results from the relocation of people from outlying farms and smaller towns to the nearby growing centres. Despite its popularity, the notion has largely gone untested. Investigation of migration trends in Dubbo and Tamworth (New South Wales, Australia), frequently cited as sponge cities, over the period 1986–2001 shows that the reality is much more complex than the simple metaphor suggests. The contribution made by the ‘pool’ to the growth of the regional ‘sponges’ is relatively minor. This calls into question the value of the notion of a sponge city—and the use of metaphors in social science more generally.     

城市湿地景观格局演变及湿地恢复重建研究

城市湿地景观格局演变的驱动力及生态效应研究具有重要的意义,目前研究主要集中在城市湿地景观格局及其组分的动态变化,在驱动力和恢复重建等方面的研究则是案例较多、归纳总结和机制研究相对薄弱。本文分析了形成当前研究现状的原因并提出了今后研究的方向,包括发展能够反映生态过程的景观格局指数、归纳城市湿地景观演变的驱动机制、总结湿地恢复与重建的目的与目标、建立完善的湿地恢复成效评估标准、加强城市湿地景观规划设计研究及城市湿地景观结构设计机理研究。     

晋城市数字测震台网简介

晋城市数字测震台网为山西省地市级建成的第一个数字测震台网。介绍了晋城市数字测震台网的建设目的、建设背景、仪器性能、软件功能及实际监测速报能力,对存在的问题进行了探讨,以对其他地市同类台网建设起到参考和借鉴作用。     

塔里木盆地西南缘侏罗纪含煤岩系聚煤规律

通过对塔里木西南缘含煤盆地侏罗系内沉积物的厚度，岩相，沉积相及其组合分带特征研究，结合岩石（层）结构，构造，矿物成份，古生物，垂直层序以及空间形态等成因标志，进行沉积相分析，总结了含煤盆地古地理类型属于内陆山间盆地型的山间湖盆亚型，聚煤规律为富煤,带，即相当于煤层聚集带，富煤中心与凹陷中心一致，煤层累计厚度与地层厚度呈正相关关系，另一规律是砂泥岩比值低的地区即为成煤有利地带，累计厚度与砂泥岩比值呈负相关关系。     

MapGIS气象专题产品配色方案制作的研究

GIS作为一门重要的空间信息技术,在越来越多的气象信息系统建设中发挥了重要作用.本文针对气象不同专题产品的图饰样式,做出了对图例、标题、图框等点线面GIS文件的编辑,保存的样式文件(.XML)可在Web上发布,并可生成配色配置文件(.XML).使用MapGIS平台基础SDK与组件库,利用数据中心易搭建思想,将数据中心功能仓库中的各个组件按需要按类型组合成一个大的功能模块,多个功能模块组成系统的主体框架,并说明了后台配置管理系统的总体技术架构.在其基础之上实现空间地理信息数据可视化管理、配色方案管理、工作空间编辑、图例编辑、标题图框编辑等一系列桌面GIS应用.