凤眼莲在城市重污染河道修复中的应用

外港河是秦淮河重要支流,长期以来遭受严重污染。2006年4月份起对外港河进行了综合生态治理。在前期清淤和截污的基础上,7月份开始引种凤眼莲。在上游排污口附近和外港河河口段分别设置的4个生态区以及河面上布设的水面载体内全面放养以凤眼莲为主的浮水植物。经过5个多月的初步治理,外港河水体透明度从40 cm以下提高到120 cm左右,COD下降了70.4％,TSS、TN和NH₃-N分别下降了39.6％、49.7％和21.8％。结果证明,凤眼莲在净化严重污染的河道方面起到了良好的效果,引种凤眼莲治理城市重污染河道是切实可行的;此外,用PVC管设计制作的水面载体来放养浮水植物可以点缀水面环境,美化城市河道景观。     

恢复生态学的理论基础、关键技术与应用前景

从群落自然演替的理论出发,指出生态系统的退化并不是不可逆的。恢复生态学阐述了在被破坏的生态系统自然演替的过程中,可以通过人为手段加以调控,改变演替的方向和速度,缩短生态恢复的时间过程的理论。作者指出生态恢复并不一定恢复原状,而是根据自然和社会条件恢复或重建生态系统的结构和功能,并使之达到自维持状态。生物种类及其生长介质的丧失或改变是影响生态恢复的主要障碍,因此,提出选择适合植物种类改造介质和利用物理、化学方法直接改良介质等生态恢复的关键技术。根据我国现实的环境、社会、经济情况提出生态恢复工程技术产业化的问题,并列举了详细数据和成功的范例     

遮光对亚热带山地大泥炭藓(Sphagnum palustre L.)生长及维管植物控制效果的影响

控制亚热带山地泥炭藓湿地中维管植物的生长可以帮助泥炭藓湿地快速恢复.以亚热带山地大泥炭藓(Sphagnum palustre L.)为研究对象,采用人工覆盖遮光网控制遮光率,探究遮光对大泥炭藓生长及维管植物控制效果的影响.结果显示:(1)大泥炭藓的生长状态方面,在无遮光下及遮光处理下,随着遮光率的增加,大泥炭藓的头状枝...     

山地小微湿地生态修复探讨 ——以梁平区猎神村梯塘小微湿地为例

小微湿地是乡村景观的组成部分,是乡村重要的水土基础设施.湿地的功能已经得到广泛认同,但过去多关注大面积成片分布的沼泽、湖泊、滨海湿地及大型河流湿地等,而对于那些数量众多、分散分布的小型和微型湿地却缺少关注.2018年10月,《湿地公约》第十三届缔约方大会通过了中国政府提交的《小微湿地保护与管理决议草案》,小微湿地的保护...     

Initial Adjustments Within a New River Channel: Interactions Between Fluvial Processes, Colonizing Vegetation, and Bank Profile Development

A conceptual model of the morphological development of the riparian margins of newly cut river channels is presented, suggesting early feedbacks between vegetation growth and bank form. To test the model, observations of long and cross profiles, bank sediment and seed deposition, and bank vegetation development were collected over the first 2 years of river flows through a reach of the River Cole, West Midlands, UK. The newly created channel had a sinuous planform and varying asymmetric trapezoidal cross section in sympathy with the planform. No imposed bedforms or bank reseeding were included in the design. Over the 2 years, development of bedforms was rapid, with bed sediment sorting and bank profile adjustment occurring more steadily and progressively. Six classes of bank profile were identified by the end of the study period, illustrating close associations with sediment aggradation, vegetation colonization, and growth patterns. Vegetation colonization of the banks was seeded predominantly from local sources during the summer and from hydrochory (transport by the river) during the winter. Colonizing vegetation on the riverbanks appeared to act as a significant propagule source by the second summer and as an increasingly important roughness element, trapping both propagules and sediment, within the second year and providing early feedback into bank evolution. As a result, the time required for riparian margin development in the conceptual model was found to be considerably longer than observed in the study river. In addition, the role of surface wash/bank failure in modifying the bank profile and transporting seeds onto the upper bank face during the first year of bank development was found to be important in initiating rapid bank vegetation colonization and surface stabilization. This set of processes had not been incorporated in the initial conceptual model. In relation to channel restoration, this research illustrates that in small temperate rivers of modest energy the provision of an initial, sinuous corridor is sufficient to induce rapid development of fluvial features and vegetation cover without the need to construct bed forms or to seed the banks.     

河岸芦苇、茭白和香蒲植物带处理受污染河水中试研究

利用中试规模的河岸植物带(芦苇、茭白、香蒲)及无植物空白带对受污染河水进行处理,并对它们处理结果进行比较.结果表明,3种植物均能强化污染物的去除.其中芦苇带效果最好,它在整个运行期间对COD、NH₄⁺-N和TP的去除效果分别为43.7%、79.5%和75.2%.对出水溶解氧与水温进行了考察,结果表明植物带水体的溶解氧变化比无植物带小,水温比无植物带低.其中,芦苇带水的溶解氧最高,香蒲带水温和溶解氧最低.芦苇、茭白、香蒲带对河水中污染物的去除和改善水环境条件等方面表现了不同的特点,在河岸带修复时应尽可能保证水生植物的多样性.     

河岸混合植物带处理受污染河水中试研究

利用2种混合植物带(香根草+沉水植物、湿生植物+香蒲+芦苇)对受污染河水进行中试研究,并与无植物空白带进行了对比.结果表明,混合植物带对污染物的降解效果优于无植物空白带,其中香根草+沉水植物带效果最好,它在整个运行期间对COD、NH₄⁺-N和TP的去除率分别为43.5%、71.1%和69.3%.对出水溶解氧及水温进行了考察,结果表明混合植物带水域中水的溶解氧比无植物带稳定,且在夏季水温低于无植物带水域的水温.说明在河道修复中植物带对平衡河岸带环境条件、改善河流局部小气候有重要作用.     

生态恢复对退化河岸植物群落的作用 ——以重庆九龙外滩河岸带生态恢复为例

河岸带是陆地生态系统与水生生态系统之间的过渡地带,受人类干扰的威胁较大.长江是流经重庆都市区的主要河流,主城区两江四岸部分河岸硬化,河岸生态功能退化或丧失,生物多样性降低.本文以重庆主城区九龙外滩的河岸带为研究区域,通过调查,采用Ward最小方差法对植物群落类型进行划分,比较了生态恢复区域和自然区域的植物群落特征及优势...     

ANADROMOUS SALMONID RECOVERY IN THE UMATILLA RWER BASIN,OREGON: A CASE STUDY1

ABSTRACT: The Umatilla River Basin Fisheries Restoration Plan was initiated in the early 1980s to mitigate salmonid losses caused by hydroelectric development and habitat degradation. The objectives are to enhance the abundance of endemic steelhead and reintroduce extirpated chinook and coho salmon. The project prompted collaborative effort among federal, state, and tribal agencies, and local water users. It has incorporated habitat restoration, flow enhancement, fish passage improvements, and population supplementation through artificial production. Water exchanges have successfully increased minimum flows during spring and fall migration. While flows remain depressed compared to historic conditions, there is potential for improved habitat, passage, and homing. The mean adult‐to‐adult return rate of hatchery‐reared steelhead exceeded replacement and that of the naturally‐spawning population. Although the smolt‐to‐adult survival rates of hatchery‐reared fish fluctuate, salmonid escapement has increased in recent years, permitting steelhead and spring chinook harvest. Enumeration of potential spawners and observed redds reveals an increase in natural production of all supplemented species. Comparison of hatchery‐reared and naturally‐spawning steelhead populations revealed differences in life history characteristics (in age composition and sex ratios) though run timing and genetic stock compositions of the two components of the populations have not differed. Sustained monitoring is needed to determine benefits of integrating habitat restoration and artificial production in restoring salmonid populations.     

GRASS VERSUS TREES: MANAGING RIPARIAN AREAS TO BENEFIT STREAMS OF CENTRAL NORTH AMERICA1

ABSTRACT: Forestation of riparian areas has long been promoted to restore stream ecosystems degraded by agriculture in central North America. Although trees and shrubs in the riparian zone can provide many benefits to streams, grassy or herbaceous riparian vegetation can also provide benefits and may be more appropriate in some situations. Here we review some of the positive and negative implications of grassy versus wooded riparian zones and discuss potential management outcomes. Compared to wooded areas, grassy riparian areas result in stream reaches with different patterns of bank stability, erosion, channel morphology, cover for fish, terrestrial runoff, hydrology, water temperature, organic matter inputs, primary production, aquatic macroinvertebrates, and fish. Of particular relevance in agricultural regions, grassy riparian areas may be more effective in reducing bank erosion and trapping suspended sediments than wooded areas. Maintenance of grassy riparian vegetation usually requires active management (e.g., mowing, burning, herbicide treatments, and grazing), as successional processes will tend ultimately to favor woody vegetation. Riparian agricultural practices that promote a dense, healthy, grassy turf, such as certain types of intensively managed livestock grazing, have potential to restore degraded stream ecosystems.