Effects of hydrologic regulation on icefish population dynamics,assemblage structure and fishery yield in Lake Nanyi,China

Stock dynamics and demographic parameters of a family of annual icefishes (Salangidae) were investigated in Lake Nanyi in eastern China before and after construction of irrigation infrastructure. After hydroregulation, two of four icefish species, a migratory species (Hemisalanx brachyrostralis) and a previously rare species (Neosalanx tangkahkeii) were absent from survey samples. The relative abundance of the remained icefish stocks changed greatly. The spring and autumn stocks of N. taihuensis increased from 9.9% and 1.7% to 74.8% and 4.8%, respectively, and N. oligodontis decreased from 84.8% to 20.4%. Total icefish density (CPUE) and yield doubled under the new hydrologic regime. Average adult body size and absolute fecundity of the three persistent icefish stocks decreased, and this could have resulted from slower rates of growth and development of larvae and juveniles in response to greater density of icefishes overall and more intense competition for planktonic food resources during summer and fall.     

基于GSM远程水文监测软件的研制*

 利用GSM引擎模块，结合单片机系统和串口，通过Visual Basic编写程序代码，实现数据的无线传输，开发远程水文监测软件。分析了该系统存在的功能限制并提出了改进系统。     

主要森林植被土壤及枯落物水分蒸发量动态研究

运用固定标准地观测的方法,对辽东山区几种主要森林植被落叶松幼龄林、落叶松中龄林、红松幼龄林、红松中龄林、柞树林、杂木林土壤的枯落物水分蒸发量进行测量。试验表明单位面积上落叶松幼龄林的平均日蒸发量最小,农田的日蒸发量较大。影响单位面积蒸发量的主要因子为地表枯落物量,同时蒸发量又与郁闭度呈弱负相关,地表至20 cm表层土壤的水分蒸发量占总蒸发量的绝大部分,而20 cm以下的土壤失水很少,红松林的土壤水分在20 cm以上的土层有上下交流的现象,而农田的水分上下交流活跃带可深达25 cm。根据布兰尼—尼里德尔公式推算出了辽宁省实验林场邻域范围内的年土壤和枯落物水分蒸发量,表明蒸发量的月份间差异显著,蒸发量冬季较小而在夏季很大。     

Long‐term plant community changes in managed fens in Ohio,USA

• 1. Long‐term studies are necessary to describe effects of restoration efforts on plant communities and invasive species in North American fen communities. In 1986, 1999 and 2000, wetland plant communities and abiotic factors were sampled in two fens in Ohio that were actively managed as a state nature preserve since 1986. The correlation between plant species and environmental conditions was examined in 1986 to 2000, and changes in woody plant cover were measured on aerial photographs from 1938 to 1997 to analyse long‐term effects of management practices.
• 2. 142 vascular plant species and 32 bryophyte taxa were found in these rich fens, including 13 rare (i.e. state‐listed as endangered, threatened or potentially threatened) and 14 alien species. TWINSPAN analyses identified nine plant community types, and species distributions were correlated with several abiotic factors (groundwater depth, pH, soil organic content, distance from wetland edge and depth of peat). Communities along the wetland edge in deep peat had higher richness, more woody species, more alien species and fewer rare species than communities in areas near sources of flowing groundwater with more marl and less peat.
• 3. There was little change in species richness, evenness, and Shannon's diversity from 1986 to 2000. However, plant species assemblages changed during the study, and changes were different in unmanipulated transects compared with those where habitat managers removed invasive woody plants. An aerial photograph analysis indicated that woody plant cover increased by about 1% each year during 1938 to 1997 despite current management efforts to remove invasive trees and shrubs. Additional strategies should be directed toward reducing shrub encroachment and invasive species while promoting rare species.

Copyright © 2007 John Wiley & Sons, Ltd.     

利用带水河水文泥沙监测资料分析水土保持综合效益

如何定量地分析水土保持综合治理所取得的成效,从而更好地指导水土保持工作,在我国南方是值得长期研究的课题.湖北省恩施州水土保持试验监测站于1985年开始实施带水河流域综合治理,1996年建立水文泥沙观测站,监测相关水文泥沙数据.通过统计分析10 a来的监测资料,定量地评价了该区综合治理所取得的效益.     

Monitoring suspended sediments and associated chemical constituents in urban environments: lessons from the city of Atlanta, Georgia, USA Water Quality Monitoring Program

Background, aim, and scope  The City of Atlanta, Georgia (COA) is part of the ninth largest metropolitan area in the USA and one of the fastest growing (e.g., >24% between 2000 and 2007). Since 2003, the US Geological Survey has been operating an extensive long-term water-quantity and water-quality monitoring network for the COA. The experience gained in operating this network has provided insights into the challenges as well as some solutions associated with determining urban effects on water quality, especially in terms of estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients. Discussion and findings  The majority (>90%) of the annual fluxes of suspended sediment and discharge (>60%) from the COA occur in conjunction with stormflow. Typically, stormflow averages ≤20% of the year. Normally, annual flux calculations employ a daily time-step; however, due to the “flashy” nature of the COA’s streams, this approach can produce substantial underestimates (from 25% to 64%). Greater accuracy requires time-steps as short as every 2 to 3 h. The annual fluxes of ≥75% of trace elements (e.g., Cu, Pb, Zn), major elements (e.g., Fe, Al), and total P occur in association with suspended sediment; in turn, ≥90% of the transport of these constituents occurs in conjunction with stormflow. With the possible exception of nitrogen, baseflow sediment-associated and both baseflow and stormflow dissolved contributions represent relatively insignificant portions of the total annual load; hence, nonpoint (diffuse) sources are the dominant contributors to the fluxes of almost all of these constituents.     

天山中段北麓盐渍化现状与成因

运用遥感影像目视解译和计算机自动分类的手段,分析了中天山北麓盐渍化土的分布范围与程度,结合地貌、水文、植被、人类活动等因素,对盐渍化成因进行了初步讨论.     

国内外森林水文研究现状和进展

基于国内外近几十年森林水文学的研究成果,在简要介绍森林水文研究历史的基础上,概述了森林对降水、蒸发散、径流、泥沙和水质的影响等方面的最新研究进展.从国内外的研究成果看,森林植被在涵养水源、调节径流、减少径流泥沙、改善水质等方面具有重要作用,但由于研究方法、研究尺度、森林生态系统本身的复杂性等原因,各地森林水文效应具有较大差异.因此,今后森林水文研究工作必须加强水文过程物理机制研究,对于分析评价不同地带、尺度、类型的森林水文效应具有重要意义.     

小流域森林水文监测管理信息系统(FHMMIS)的设计与开发

介绍了以GIS软件ArcView GIS 3.2a为开发平台,设计与开发张家冲小流城水土保持站森林水文监测管理信息系统(FHMMIS)的过程,重点介绍了三维地形的实现、飞行鸟瞰、监测数据管理、空间复合查询及多媒体链接等设计与开发的问题。该系统能满足水土保持站在森林水文研究管理方面的需求,可以应用于小流域水土保持站森林水文监测管理。