水利血防工程中生态抑螺护岸设计与应用初探

传统的水利血防工程采用硬质护岸形式,极大程度地影响了河道生物多样性。依托某水利血防工程,在对河道附近水位站潮位资料统计排频的基础上,给出了常规硬质护岸的设计方案。结合植物抑螺理念,设计出一种生态型的抑螺护岸。并将不同抑螺植物组合设置成三个生态抑螺护岸试验段。通过现场调查比较,硬质护岸和生态抑螺护岸都能起到灭螺效果,相对于硬质护岸河流景观单一化,生态抑螺护岸更贴近自然,三个生态护岸试验区中,以密毛酸模叶蓼为挺水植物,以益母草为草本植物的实验段植物存活率更高。     

Life under ice in the perennial ice‐covered Lake Glubokoe in Summer (East Antarctica)

This study focuses on hydrological and biotic variables in Lake Glubokoe, which is located in Thala Hills of Enderby Land (East Antarctica). Water and sediment samples and physical measurements were collected once a week in the austral summer (19 December 2010 – 6 February 2011). This lake exhibits perennial ice cover that reached a thickness of 2.5–2.7 m during the study period. A very low concentration of planktonic chlorophyll‐a (0.06–0.45 μg L^?1) was measured in the lake, indicating its ultra‐oligotrophic status. The water was poorly populated by algae and metazoans, especially in upper waters below ice cover to a depth of 2 m. Small planktonic organisms (2–5 μm) were observed throughout the study period, but larger organisms (>8 μm) such as the cyanobacteria Planktolyngbya limnetica occurred only during the warmest period (January). Only few individuals of metazoans (rotifers) were found in planktonic samples. Due to deep light penetration (10–15% of incoming active solar radiation reached the depth of 30 m), thick cyanobacterial mats (30 cm) cover all the bottom surface (grey silts) in the lake. Abundant benthic biota associated with these mats was found (up to 1000 ind. m^?2). Among the benthic metazoans, bdelloid rotifers and tardigrades were the dominating taxa. The results of this study suggest a typical ecological feature of most subglacial lakes in East Antarctica is that metazoans are very poor in the pelagic zone, preferring instead to occupy an area near the lake bottom because of a favourable constant temperature of 4 °C, good level of dissolved oxygen and available food resources as the bacterial detritus.     

"平垸行洪、退田还湖"对血吸虫病扩散的影响及对策研究

血吸虫病是一种严重危害人民健康、影响社会经济发展的传染性疾病,钉螺是血吸虫的唯一中间宿主.1998年洪水后实施的"平垸行洪、退田还湖"措施对于钉螺和血吸虫病的扩散有着重要的影响.总结影响钉螺和血吸虫病扩散的因素,并对典型"平垸行洪、退田还湖"后钉螺和血吸虫病变化情况进行调查研究,结果表明,认识某一区域钉螺和血吸虫病扩散...     

LINKING RIVER MANAGEMENT TO SPECIES CONSERVATION USING DYNAMIC LANDSCAPE‐SCALE MODELS

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape‐scale changes in species distributions in response to water management decisions. We present a framework and methods for integrating hydrology, geographic context and metapopulation processes to simulate effects of changes in streamflow on fish occupancy dynamics across a landscape of interconnected stream segments. We illustrate this approach using a 482 km² catchment in the southeastern US supporting 50 or more stream fish species. A spatially distributed, deterministic and physically based hydrologic model is used to simulate daily streamflow for sub‐basins composing the catchment. We use geographic data to characterize stream segments with respect to channel size, confinement, position and connectedness within the stream network. Simulated streamflow dynamics are then applied to model fish metapopulation dynamics in stream segments, using hypothesized effects of streamflow magnitude and variability on population processes, conditioned by channel characteristics. The resulting time series simulate spatially explicit, annual changes in species occurrences or assemblage metrics (e.g. species richness) across the catchment as outcomes of management scenarios. Sensitivity analyses using alternative, plausible links between streamflow components and metapopulation processes, or allowing for alternative modes of fish dispersal, demonstrate large effects of ecological uncertainty on model outcomes and highlight needed research and monitoring. Nonetheless, with uncertainties explicitly acknowledged, dynamic, landscape‐scale simulations may prove useful for quantitatively comparing river management alternatives with respect to species conservation. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

BENCHMARKING RIVER HABITAT IMPROVEMENT

River ecosystems have witnessed a long history of human pressure, particularly the disruption of freshwater fish populations. The awareness of this situation has led to many habitat improvement projects, with a variable degree of success. In natural situations, fish populations co‐inhabit throughout the hydrological cycle with different degrees of adequacy, and the sequence of favourable and unfavourable conditions dictates abiotic constraints and biotic interactions that shape the final biological assemblages. We postulate that a part of unsuccessful restoration results is related to insufficient closeness to the natural habitat conditions of the river type that is to be restored, including the naturally adverse periods. We used the river2d model to predict habitat availability as weighted usable area (WUA) at a degraded site that is to be restored, for two native Mediterranean species and their life stages—the Southwestern nase Iberochondrostoma almacai and the Arade chub Squalius aradensis. We then analysed the yearly evolution of the natural WUA at a nearby reference site. Overall, the reference site exhibited the longest periods during which the WUA was continuously lower than the chosen WUA thresholds for each of the four bioperiods. Considerable divergences from natural habitat availability values can be seen for the spawning, rearing and growth bioperiods. Restoration outcomes can result in appreciable deviations—favourable or unfavourable to fish populations—from the WUA occurring under natural conditions over the course of the year. Restoration should therefore take account of local hydraulic and habitat patterns that govern population dynamics and result in the final fish assemblage. Copyright © 2011 John Wiley & Sons, Ltd.     

洞庭湖区淡水渔业发展现状和制约因素分析——以湖南南县为例

南县是湖南省高效渔业先进县,也是洞庭湖淡水渔业县的典型代表。改革以来,南县淡水渔业得到了快速发展。本文结合实际调研与历史数据,分析了南县淡水渔业发展情况,并从产业链环节分析了存在的问题,提出了加强养殖环节基础设施建设支持力度、加强技术培训、加快水产品批发市场和信息渠道建设、发展水产加工业、培育社会化服务组织、落实池塘使用权证等相关政策建议。     

钉螺起动流速试验研究

 阐述了钉螺起动流速试验研究成果。由于钉螺对河床具有吸附作用，因而钉螺起动可概括为三种不同起动状态：第一种为定床有吸附力起动，起动流速在１．０ｍ／ｓ以上；第二种为动床有吸附力起动，起动流速约在０．３～０．４ｍ／ｓ之间；第三种为无吸附力起动，起动流速在０．１４～０．１９ｍ／ｓ之间。钉螺无吸附力起动可利用钉螺起动流速公式计算。     

大庆水库冰表面温度特征及其在冰工程实践应用方法探讨

根据冰面热平衡方程并以大庆红旗泡水库冰面观测的气温、太阳辐射、风速、相对湿度、冰厚数据以及水库附近安达气象站记录的云量、湿度和海平面气压数据,求解了2009/2010年度冬季的冰表面温度,并分析了冰表面温度特征及其同太阳辐射之间的关系、同气温、风速之间的响应关系。在此基础上,就传统考虑的抗冰工程设计所需的设计冰表面温度进行了评估;就日益增加的安全用冰工程设计所需冰表面温度取值也给予定量讨论;对气候变化下的冰内和冰下水体生态适应问题所需的冰面温度日内变化速率和开河期冰凌爆破所需冰表面温度的取值也进行探索。尽管受国际气象资料观测规定的限制,历史资料的应用存在利用接近观测时刻资料的事实,但仍然期望这些分析和讨论能够推动科学地、更广阔地应用冰表面温度。     

Determining the Efficacy of a Submersible in situ Fluorometric Device for Cyanobacteria Monitoring Coalesced with Total Suspended Solids Characteristic of Lowland Reservoirs

The purpose of this study was to ascertain the effect of turbid water on a fluourometric device designed to detect phycocyanin and chlorophyll a in cyanobacteria cells in vivo. Cell densities corresponding to the Blue Green Algae Alert levels endorsed by the Australian National Health and Medical Research Council and adopted by numerous water resource managers were coalesced with a range of total suspended solids at defined gradients characteristic of lowland freshwater ecosystems. The parameters of interest were phycocyanin and chlorophyll a. Microcystis aeruginosa was the experimental organism used to establish cell densities consistent with the three‐stage alert level framework. We found phycocyanin to be an effective measure for detecting M. aeruginosa at concentrations prescribed within the cyanobacterial alert levels (Green, Amber and Red) in turbid waters up to 200 Nephelometric Turbidity Units. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of damming a large lowland river on chironomids and fish assessed with the (multiplicative partitioning of) true/Hill biodiversity measure

The impact of a large lowland temperate zone reservoir on chironomid and fish biodiversity was investigated in the same upstream (U) and downstream (D) sites on the same sampling occasions in spring and autumn of several post‐impoundment years. The true/Hill N1 diversity measure was used to construct diversity models of the impact, and partitioning of N1 to reveal the importance of ecological gradients. N1 is unique in being decomposable among multiple levels and easily comparable across ecosystems and animal groups. Chironomids were more diverse than fish in all community sets owing to their probably lower mobility, lower interspecific competition, opportunistic character and much shorter life spans than those of fish. Fish exerted consumption pressure on chironomids upstream by foraging mostly on benthic insects, but not downstream where they fed on microcrustaceans of reservoir origin or on epiphytic fauna (mainly Chironomidae). The reservoir impact on chironomids decreased their diversity in U and increased in D, while much the opposite was true in fish. In D in macroinvertebrates, the impact consisted in advancing over time intensification of seasonal development of submersed macrophytes, while in D in fish in a few species escaping from the reservoir after their populational explosions each year. Partitioning of diversity revealed that the spatial (upstream–downstream) gradient was the strongest factor of diversity change in chironomids as compared with season, and age of the impoundment. No gradient was dominant in fish. Comparisons of observed data with a null model testified to very strong intraspecific aggregation in both chironomids and fish. Copyright © 2010 John Wiley & Sons, Ltd.