The importance of riparian subtropical lucidophyllous forest to odonate conservation

1. Glossy, broad‐leaved, evergreen (lucidophyllous) forests are found mainly in humid subtropical regions of East Asia and are recognized as a biodiverse biome harbouring numerous endemic species. To date, however, few studies have considered the conservation importance of rivers draining these unique environments. In this study, lotic Odonata were used as indicators to examine factors affecting riparian forest–stream linkages in a lucidophyllous forest in south‐western Japan.
2. Lotic odonates of 10 species, including seven endemic species, and their habitats were studied along 30 stream reaches with varying environmental characteristics.
3. Odonate species richness was greatest in shadier reaches as well as in heterogeneous locations in larger streams. In contrast, larger streams modified by channel enlargement for flood control had few or no odonate species.
4. Protecting larger streams with less human impact and streams in dense riparian forest are the best options for conserving lotic odonates and their habitats in this globally unique forest type.

     

Food resources and cyprinid diet in permanent and temporary Mediterranean rivers with natural and regulated flow

This study addresses the differences in food availability, diet and feeding activity of the Iberian barbel, between permanent and temporary nonregulated rivers, and the effect of flow regulation on feeding parameters. A total of 267 adult barbels were seasonally collected in four nonregulated and regulated rivers from permanent and temporary basins, and their gut content was analysed. Locally available food sources were evaluated across sites and seasons. Barbels from the permanent nonregulated river exhibit a more variable and diversified diet in which invertebrates assumed a large importance, especially during high flows. Barbels from the temporary nonregulated river presented a more uniform diet composed of plant material and detritus, particularly in drought seasons. Flow regulation affected different flow components in both systems, but the effects on food resources and barbels' diet were similar, resulting in an intra‐annual stabilisation of resource availability and fish diet, with a higher consumption of plants and detritus. Changes in fish diet and feeding activity in both nonregulated and regulated rivers were strongly associated with the seasonal variability of streamflow components, particularly between low‐ and high‐flow periods, and with the reduction in flow variability in the case of dam regulation. Results from this study can be used to improve guidelines for flow requirement implementation.     

北运河水生态系统服务功能价值评估

提出北运河水生态系统服务功能分类及评估方法,采用2007年相关调查统计资料,对北运河水生态系统服务功能价值进行估算.得出2007年北运河水生态系统服务平均总价值41.08亿元,其中,直接服务价值占24.03％,间接服务价值占75.97％,为当地政府在北运河水生态方面的管理和开发利用提供决策依据。     

Woody species composition,diversity and structure of riparian forests of four watercourses types in Burkina Faso

Riparian forests are classified as endangered ecosystems in general,particularly in sahelian countries like Burkina Faso because of human-induced alterations and civil engineering works.The modification of this important habitat is continuing,with little attention being paid to the ecological or human consequences of these changes.The objective of this study is to describe the variation of woody species diversity and dynamic in riparian forests on different type of watercourse banks along phytogeographical gradient in Burkina Faso.All woody species were systematically measured in 90 sample plots with sides of 50 m × 20 m.Density,dominance,frequency and species and family importance values were computed to characterize the species composition.Different diver-sity indices were calculated to examine the heterogeneity of riparian forests.A total of 196 species representing 139 genera and 51 families were recorded in the overall riparian forests.The species richness of individuals with dbh ≥ 5cm increased significantly from the North to the South along the phytogeographical gradient and varied significantly between the different types of riparian forests.Similarity in tree species composition between riparian forests was low,which indicates high beta diversity and reflects differences in habitat conditions and topography.The structural characteristics varied significantly along the phyto-geographical gradient and between the different types of riparian forests.The diameter class distribution of trees in all riparian forests showed a reverse "J" shaped curve except riparian forest of stream indicating vegetation dominated by juvenile individuals.Considering the ecological importance of riparian forest,there is a need to delineate and classify them along watercourses throughout the country.     

Monitoring fish stocks in relation to acidification in Norwegian watersheds

The Norwegian Monitoring Programme for Long-Range Transported Air Pollutants started in 1980. The biological part of this programme includes besides invertebrate studies in streams, (i) fish community status in lakes by means of interviews, test-fishing in lakes by using standard gill-net series, recruitment studies of brown trout in inland streams, and juvenile stock assess and monitoring of fish kills in salmon rivers. Damaged fish stocks are recognized within a land area of 51,500 km² in southern Norway and 30 km² in northern Norway. At least 6,000 lake-dwelling fish stocks have either been lost or are at various stages of reduction. Brown trout (Salmo trutta) is the most widespread and abundant species of fish in Norwegian watersheds, and is also most severe affected by acidification. More recently, there are some indications of an increase in the abundance of brown trout in some areas. However, analysis of age structure in lakes, and fry densities in streams in such areas revealed large annual variations in recruitment rate, which indicates unstable water chemical conditions. Atlantic salmon (Salmo salar) is virtually extinct in 25 rivers in southernmost, southwestern and western Norway.     

Epilithic biofilm as a key factor for small‐scale river fisheries on Caribbean islands

Abstract Numerous freshwater species are consumed or exploited through artisanal fisheries in the rivers of the islands of Guadeloupe, French West Indies. Autochthonous production of organic matter is limited in these flowing rivers and is mainly represented by scarce filamentous green algae and an abundant epilithic biofilm growing on wet stones in the river bed. Stable isotope analysis was used to quantify the relative importance of biofilm and other riverine allochthonous and autochthonous food sources in the diet of tropical shrimps (Palaemonidae, Atyidae and Xiphocarididae) and fishes (Gobiidae and Eleotridae) consumed by the local people. The epilithic biofilm was exploited by most species, constituted an important source of autochthonous carbon and was an important source of organic matter production at the base of freshwater food webs in Caribbean rivers. Biofilm percentages in the diet reached 32% for molluscs, 85% for atyid shrimps, 29% for xiphocaridid shrimps, 14% for palaemonid shrimps and 13% for fish. Assessment of biofilm in nine rivers showed that blue and red cyanobacteria were quantitatively dominant with a moderately rich diatom flora. These results address the interactions between river biofilm and Caribbean freshwater fauna where trophic links between consumers and their potential resources have poorly been documented.     

国内河流反应器的水质净化情况研究进展

运用河流反应器的概念,将河流反应器划分为水环境、水建筑物和河流生态系统3个部分,讨论了河流反应器各组成部分在污染河流治理中的作用和研究进展,阐明了各治理方法的现有理论成果和取得的实际效果,也指出了各理论亟待解决的问题,对未来受污染河流的治理工作有一定的借鉴意义。     

西北干旱区典型绿洲盐生植被群落特征及多样性研究

本文以西北干旱区典型绿洲-渭干河-库车河三角洲为主要研究区域,运用数量生态学的方法对盐生植被群落特征及物种多样性进行了分析.结果表明:以梭棱为单优势种的群落Ⅳ具有最高的优势度指数(C)和最低的丰富度指数(R)、多样性指数(H')和均匀度指数(E),群落结构最为简单;以骆驼刺为优势种和梭棱为主要伴生种的群落Ⅱ具有较高的多样性指数和均匀度指数,但优势度指教较低,结构相对稳定;而以柽柳和梭梭为共优势种的群落Ⅰ具有最高的物种丰富度和中等水平的优势度指数、多样性指数和均匀度指数,群落中物种数较多,群落结构较为复杂;以芦苇和骆驼剌为共优势种的群落Ⅵ,其物种丰富度指数和物种多样性指数,物种优势度指数和物种均匀度指数水平居中;以柽柳为主要优势种的群落Ⅲ和Ⅴ,其物种丰富度指数、优势度指数、多样性指教和均匀度指数则属于中等偏上水平,群落结构稳定.     

珠江上游水资源配置及持续利用对策研究

 珠江流域在云南省境内部分是该省重要的工农业经济区,地区生产总值、工业增加值分别占全省的30.1%,42.7%,它们和人均GDP都是全省水平的1.5倍。已基本形成以蓄水工程为主、引提水等为辅的供水结构,但人均水资源量不足,现状南盘江及主要支流部分河段水质为Ⅴ类水体,高原湖泊水环境质量不容乐观。以MIKE BASIN为技术平台,通过水资源节约保护、高效利用,进行供需水预测、合理配置研究。并就影响水资源持续利用的主要问题如节约用水、水资源保护、应对突发性水污染事件、应对气候变化及极端气候事件、建立河流生态补偿机制等进行了探讨。     

The role of the UK conservation agencies in protecting river flows

Abstract An outline is given of the scale and nature of special wildlife designations in the UK river network, the general approach of the UK conservation agencies to their evaluation and management, and the specific way in which impacts of river flows are handled. The need for a holistic ecological and biodiversity view of water resource impacts on river systems is stressed, within which the specific needs of individual species, such as Atlantic salmon, Salmo salar L., can be framed. An approach founded on the provision of a natural flow regime within a natural physical channel not only provides the most suitable conditions for characteristic riverine wildlife to flourish but also provides the best local defence against global climate change. Arguments are made for a future focus on the generic evidence base for flow targets and its strengthening through strategic and demonstrably fit‐for‐purpose research. The practical constraints to an approach based on protection of the natural flow regime are discussed. Ultimately, transparent separation and consideration of what river ecosystems really need, and what can realistically be provided, is the key to shared ownership of the water resource dilemma.