生态保护红线刚性约束下水利工程前期工作实践与探索

以天津市某水库综合治理工程为例,分析工程实施对陆生生态系统、生产力和生物量、景观多样性以及水生生态系统的影响,为管理者对区域生态红线管控提供了可靠的技术依据。分析结果显示:在生态保护红线的刚性约束下,采取以20世纪80年代该区域植物多样性分布为参照,栽植多种陆生及水生植物,做到了"功能不降低、性质不改变、环境不破坏、面积不减少"保护目标。     

拉鲁湿地水文特征年际变化趋势分析

自20世纪60年代以来,拉鲁湿地面积不断萎缩,干化、退化现象十分严重。20世纪90年代以来,湿地的保护受到了越来越广泛的重视,湿地的退化得到了有效遏制。选取拉鲁湿地作为研究对象,在收集的相关资料基础上,采用线性倾向估计法、m-k法对拉鲁湿地水文特征年际变化趋势进行了统计、分析,有助于为拉鲁湿地的水文研究打下基础。     

巴尔喀什湖流域径流变化特征分析

通过对巴尔喀什流域主要代表站20世纪50年代以来气温、降水、径流的年际变化过程分析表明,20世纪50年代以来,流域气温呈增加趋势,降水、径流总体呈减少趋势,且减少趋势一直持续至20世纪90年代。从减少幅度来看,径流减少幅度远大于降水,说明巴尔喀什湖20世纪70年代低水位过程是在流域降水等气候因素和人类开发利用水资源等综合影响下造成的。     

全面实施流域综合规划 有效推进绿色珠江建设——《珠江流域综合规划》解读

<正>新中国成立以来,党中央、国务院高度重视珠江流域综合规划编制工作,20世纪90年代国务院批复的珠江流域综合利用规划对珠江流域治理开发与保护工作起到了十分有效的指导作用。进入21世纪以后,珠江水利委员会(以下简称"珠江委")在科学发展观和可持续发展治水思路的指导下,总结多年治江实践,分析珠江     

新疆北部气候变化及其对水资源的影响分析

利用新疆北部地区5个气象站1951~2006年月平均气温及月降水总量资料,用高桥浩一郎公式计算了新疆北部地区区域平均蒸发量及水资源总量。分析了近56年来新疆北部地区气候变化及水资源变化趋势,以及气候变化对水资源的影响。通过分析初步得出结论:①新疆北部地区气温从20世纪60年代以来基本上呈上升趋势,90年代以来气温明显高于平均值,为正距平;新疆北部地区降水自20世纪80年代初期开始出现增加趋势,90年代以后,降水持续增加,并且高于平均值;60年代中期至80年代末期,蒸发比平均值偏少,自80年代末期以来蒸发高于平均值,为高值期。②水资源总量自20世纪80年代初期至今呈增加趋势,90年代以来呈现出正距平。③降水与水资源总量之间存在明显正相关。在此基础上建立了降水变化对水资源总量影响的统计评估模型。     

太湖五里湖水生植物群落演替及其驱动因素

根据2003~2005年的调查和前人研究资料,分析了五里湖水生植物群落的演替过程和驱动因素。得出以下结论:①五里湖水生植物群落的演替过程可划分为3个阶段:20世纪70年代以前是漫长的群落演替阶段,50年代以前,大型水生植物生长茂盛,盖度高、生活型丰富;20世纪70年代至2002年,是水生植物群落的退化消失阶段,浮游植物剧增,大型水生植物迅速消失,小河道和湖边池塘等浅水环境成为水生植物的最后避难所。2002年至目前,水生植物群落恢复阶段,示范工程区内水生植物生长茂盛,工程区外岸边浅水区水生植物有了自然恢复的迹象。②随着围垦活动、水质、底质和鱼类的变化,水生植物群落发生了相应的变化,水生植物是在与其它生态因子的相互耦合作用过程中逐渐退化消失的,是在人类干扰下多种因素综合作用的结果,多种正反馈过程加速了这一过程。     

九龙河流域水文气象因子演变趋势分析

通过收集整理九龙河流域水文气象监测站点实测监测的气温、降水、蒸发、径流等系列资料,应用数理统计方法分析了流域水文气象因子演变趋势,得出流域气温自20世纪90年代以来持续升高,降水量自1983年以来持续小幅减少,流域为半湿润区,径流量自20世纪80年代以来线性大幅减少等结论。为流域综合治理、经济社会建设、水资源管理提供技术支撑。     

关于河岸护坡形式应用的探讨

20世纪90年代以来,德国、美国等纷纷大规模拆除了以前人工在河床上铺设的硬质材料,以维护河岸的自然生态性。保持河道的自然环境对保护动植物资源、保护水质、防止水资源流失发挥极为重要的作用。我国经济发达地区的河岸护坡形式已经从单一的实用性向结合生态环保、景观亲水方向转变,但大部分地区由于受经济、自然条件约束,传统的硬质化护坡仍在广泛应用。     

汾河流域气候变化及其对径流影响探讨

在分析汾河径流量变化趋势、20世纪70年代以来断流气候背景,以及气温、降水变化与径流趋势联系和80年代中期以来气候变化特点基础上,建立了河津站天然年径流量计算公式,探讨了气候变化对径流的影响。结果表明:①自20世纪50、60年代丰水期之后径流量总体呈递减趋势;②20世纪70年代以来汾河水量偏枯和断流趋势发展乃是以北半球增暖效应为背景;③20世纪80年代中期以来气候较前期变化有气温升高、尤其冬季最甚,降水减少、特别是汛期及夏、秋季最显著之特点;④气候变化引起径流量平均每年减少5.67亿m3(24.9%),其中气温影响8.6%,降水影响16.3%。因此,汾河流域气候变化及其对径流的影响较为显著。     

水生植物对湖泊生态系统的影响

结合国内外富营养化湖泊治理经验,总结了水生植物对湖泊生态系统的影响,特别是对污染水体的修复机理以及应用水生植物修复湖泊时要注意的问题.对水生植物净化水体中营养盐的机理,影响去除水中氮、磷的因素进行了分析研究.水生植物对水体具有净化作用,但腐烂的植物也会对水体造成二次污染,应及时采取措施.水生植物还具有吸收重金属、抑制藻类生长、保护生物多样性等作用,分别对水生植物的这些作用进行了分析总结.     

Composition of the seed bank in drawdown areas of Navigation Pool 8 of the Upper Mississippi River

In an effort to enhance aquatic plant production and habitat diversity on the Upper Mississippi River (UMR), resource managers considered water level reduction as a management tool to increase the area of emergent and submersed aquatic vegetation by natural seed germination. To quantify the availability of seed, we assessed the potential seed bank of selected areas of Navigation Pool 8 of the UMR from substrate samples collected in spring 2000. We tested these samples for viable seed content under four hydrologic conditions: dry, moist, shallow flooded and submerged. Forty‐seven species were identified in the seed bank, including 27 obligate wetland, 10 facultative wetland and 7 upland species. Dominant taxa within the seed bank included Sagittaria spp., Lindernia dubia, Zosterella dubia, Cyperus spp., Eragrostis spp. and Leersia oryzoides. Of the four hydrologic treatments, moist substrates had the greatest species diversity and were the most productive, yielding an average density of 1420 seedlings m^?2. Emergent and submersed aquatic species were widely distributed, each type occurring in more than 90% of the samples. Timing of seedling germination varied among species and has implications for scheduling drawdowns to promote establishment of desired species. Seed bank results were correlated with the vegetation response on substrates exposed during a reduction of water levels of Pool 8 during summer 2001. Experimentally determining the composition and viability of seed banks from drawdown areas provides information useful in predicting the types of vegetation that may develop on exposed substrates. Further, these findings provide resource managers a better understanding of the potential for achieving desired vegetation response through water level reductions. Published in 2008 by John Wiley & Sons, Ltd.     

An investigation of marginal habitat and macrophyte community enhancement on the River Torne,UK

During floodbank raising work as part of a major capital flood defence scheme on the River Torne between 1985 and 1990, selected reaches of the main trapezoidal channel were enhanced. By winning spoil from the channel margins and from borrow pits in the floodplain, a more varied marginal zone was created which maximised the potential habitat for wetland plant communities and their associated fauna. Enhancement comprised bank re‐profiling to create narrow wetland shelves (berms), shallow bays, channel margins of varying shape and depth and linear still ponds from the borrow pits. The 1990 planting programme comprised 11 macrophyte species and a total of 7740 individual plants. This paper reports on an initial study to evaluate the marginal habitat enhancements on the River Torne 5 years after completion of the project. Lack of pre‐scheme data necessitated a space‐time substitution; enhanced river margins were compared with neighbouring reaches that had undergone conventional floodbank repair and remained as trapezoidal channel sections planted with a standard, low maintenance seed mix. Marginal vegetation was surveyed and supported by measurements of the physical habitat at 10 enhanced and 10 conventionally‐engineered reaches. The macrophyte surveys and the results from the cluster analysis and polar ordination indicate that enhanced and conventionally‐engineered reaches are floristically distinct and that the enhanced reaches have a more varied macrophyte community. The results from the Mann–Whitney U‐tests show that enhanced reaches have significantly higher values of wetland species diversity and equitability, percentage of wetland species, bank width and soil moisture and significantly lower bank angles. However, the correlation and linear regression analyses did not show any strong associations between the physical habitat and plant parameters. Copyright © 2000 John Wiley & Sons, Ltd.     

Stimulating a Great Lakes coastal wetland seed bank using portable cofferdams: implications for habitat rehabilitation

Coastal wetland seed banks exposed by low lake levels or through management actions fuel the reestablishment of emergent plant assemblages (i.e., wetland habitat) critical to Great Lakes aquatic biota. This project explored the effectiveness of using portable, water-filled cofferdams as a management tool to promote the natural growth of emergent vegetation from the seed bank in a Lake Erie coastal wetland. A series of dams stretching approximately 450 m was installed temporarily to isolate hydrologically a 10-ha corner of the Crane Creek wetland complex from Lake Erie. The test area was dewatered in 2004 to mimic a low-water year, and vegetation sampling characterized the wetland seed bank response at low, middle, and high elevations in areas open to and protected from bird and mammal herbivory. The nearly two-month drawdown stimulated a rapid seed-bank-driven response by 45 plant taxa. Herbivory had little effect on plant species richness, regardless of the location along an elevation gradient. Inundation contributed to the replacement of immature emergent plant species with submersed aquatic species after the dams failed and were removed prematurely. This study revealed a number of important issues that must be considered for effective long-term implementation of portable cofferdam technology to stimulate wetland seed banks, including duration of dewatering, product size, source of clean water, replacement of damaged dams, and regular maintenance. This technology is a potentially important tool in the arsenal used by resource managers seeking to rehabilitate the functions and values of Great Lakes coastal wetland habitats.     

Secondary seed dispersal in hydro‐fluctuation belts and its influence on the soil seed bank

The completion of the Three Gorges project altered the water level fluctuations from “summer submersion and winter exposure” to “summer exposure and winter submersion.” The reverse seasonal flooding has dramatically changed both the time and duration of exposure and submergence of reservoir banks. Secondary seed dispersal by water is the primary method of dispersal in hydro‐fluctuation belts. This study conducted field sampling and germination experiments to evaluate the effects of reverse seasonal flooding on species composition, diversity, and density of the secondary seed dispersal system and the soil seed bank, and their changes with elevation, in the Xiangzi River. The results indicate that that the secondary seed dispersal system and soil seed bank were associated with 42 and 50 plant species, respectively, and their average seed densities were 1,876.27 and 7,322.18 seeds/m², respectively. The quantity of seeds from secondary seed dispersal accounted for 20.40% of the soil seed bank. The species life‐form composition of both consisted mainly of annual and perennial grasses. Among these grasses, the dominant species in the secondary seed dispersal system were Cynodon dactylon and Paspalum distichum, whereas the dominant species in the soil seed bank were Solanum nigrum and Rumex dentatus. Due to the effects of reverse seasonal water level fluctuations, the species composition and quantity of the soil seed bank and secondary seed dispersal system largely exhibited similar spatial distribution characteristics, but some differences were observed. The species quantity, species diversity index, and seed density in the soil seed bank were the highest in the middle section of the hydro‐fluctuation belt, followed by the top section and then the bottom section. Conversely, the species quantity, species diversity index, and seed density in the secondary seed dispersal system were highest at the top section, followed by the middle section and then the bottom section.     

东太湖不同人为干扰程度区域植物多样性研究

水产养殖等人为活动会影响水生植被群落结构、群落动态和生物多样性。为具体分析人为活动对水生植被群落的影响,2013~2014年,在东太湖人工干扰严重的网围养殖区和人工干扰较轻的非养殖区选取11个样点进行了8次实地采样分析。分析结果表明,东太湖现有双子叶植物16科21属23种,主要有3种植物群落类;在人为干扰严重的围栏养殖区域,植物多样性较轻度人为干扰的湖区有明显下降;但植物多样性在2010年退渔还湖后较2002~2008年有较为明显的提高。     

含淹没植物的水流阻力试验研究

河道中存在水生植物会改变水流阻力,在大多数情况下会导致水位抬高,降低河道的泄洪能力。然而,水生植物的存在对河道治理、边滩保护、水质净化等起积极作用。为了探索河道中水生植物对水流阻力的影响,在实验室水槽中进行了不同密度的流淹没刚性植物水流试验,观测了沿程的水位变化,计算了水面坡降,基于试验资料分析了雷诺数、植物密度对糙率系数的影响,并建立拖曳力同植物水流特征粗糙度对数关系表达式,丰富了植物条件下明渠流动的试验观测资料数据库。     

Colonisation of terrestrial vegetation in an intermittent river: Diversity responses to seasonal drying

Intermittent rivers are dynamic ecosystems that experience a predictable or unpredictable loss of surface water and are characterised by changing lotic, lentic (ponding) and dry habitats. Plant communities colonising dry channels during the desiccation stage can be diverse, abundant and differ in their tolerances to water availability and habitat conditions. This study examines the colonisation of terrestrial vegetation in two intermittent rivers in the United Kingdom, and whether terrestrial plant taxonomic richness and functional diversity increase during the dry phase. Six reaches were surveyed for terrestrial plants during the dry phase over a standard 100 m length every month from April to October 2021. We found the channel and bank taxonomic richness increased with drying duration. Functional traits of vegetation height, clonality, clonality richness and Ellenberg's value of light moisture also increased with stream desiccation. Bed sediment conditions (the proportion of sand and gravel) and the 12-month antecedent percentage of zero flow days were the key drivers of plant community composition. We believe plant propagules from the riparian zone and channel vegetation on topographic high points in the channel aided plant colonisation of the riverbed once flow ceased. Past research may have underestimated the biodiversity value of intermittent rivers by failing to include the ecological importance of plants during the dry phase. Information on plant diversity of the dry phase is important to determine the overall biodiversity of intermittent rivers for their long-term conservation and management.     

我国湖泊存在的生态问题

随着社会经济的不断发展,我国湖泊普遍存在着湖泊圈围,库容减少;湖泊违法采砂、违章取土,屡禁不止;护岸裁弯取直,流态单一;直立式硬化河坡,植物多样性缺失;硬化湖岸,景色单调;过度建设生态湿地,舍本逐末;不当养殖水生物,易造成生态灾难;湖泊富营养化严重,污染治理治标不治本等问题。这些行为严重影响了湖泊的水环境、水生态、水旅游的发展,甚至危及近岸海洋生态系统生存、繁衍,呈现亚健康、不健康状态,威胁了近海湖泊的可持续发展。应该加强法制教育,加强涉水工作者的水环境意识,建设亲水湖岸;减少水污染,减少末端治理。     

鄱阳湖区堤防植物多样性特征与土壤种子库密度的关系

以鄱阳湖区重点堤防作为研究对象,采用线路踏查、样方调查和种子萌发相结合的方法,研究不同加固土料堤防地上植物多样性特征与土壤种子库密度的关系。结果表明:湖区重点堤防高等植物共计106种,隶属于38科,89属,以草本植物为主,禾本科、菊科和大戟科为优势科;不同加固土料堤防植物多样性指数与土壤种子库密度以水稻土最高,其次是建筑垃圾,山地黏土最低;不同植草模式下0~10 cm土层的土壤种子库密度以自然修复模式最大,其次是假俭草植草模式,以狗牙根植草模式最小;土壤种子库密度与地上植物种数、Simpson指数、Shannon-weiner指数和Pielou群落均匀度指数呈显著正相关,与地上植被密度、重要值呈极显著正相关,但与Margalef丰富度指数无显著相关性。因此,堤防土壤种子库密度与地上植物多样性特征之间具有较强的相互作用关系,研究成果对于鄱阳湖区重点堤防的除险加固与管理维护具有重要意义。     

Comparison of summer zoobenthic communities in four habitats of a floodplain impoundment:1975 and 1990

The diversity, evenness, similarity, standing crop and abundance of benthic macroinvertebrates in Navigation Pool 8 of the upper Mississippi River were compared in 1975 and 1990. Macroinvertebrates were collected in midsummer from four habitats: marsh, bay, open water and side channel. These habitat types accounted for 64% of the total habitat area in the impoundment. The community structure changed in all four habitats; the percentage similarities between 1975 and 1990 were lowest in open water (19%), intermediate in bays (44%) and side channels (50%) and highest in marshes (62%). Macroinvertebrate diversity and evenness were not significantly different between 1975 and 1990. The standing crop decreased in all habitat types. The abundance decreased in all habitats except bays between 1975 and 1990. The greatest changes in standing crop and community composition occurred in bays and open water. Because the bays and open water habitat comprise 55% of the total area, it is possible that these declines may signal degradation of the aquatic habitat in the entire reservoir. Changes in macroinvertebrate community structure and standing crop may have been due to unstable sediment conditions caused by erosion of islands, resuspension of sediments and loss of aquatic macrophytes and depth.