【作者】 黎璇；

【导师】 袁兴中；

【作者基本信息】 重庆大学 ， 环境工程， 2009， 硕士

【摘要】 在经济高速发展区域,面临的突出问题之一就是河流生态系统的退化。如何对河流进行有效的管理和恢复,就需要合适的管理工具,以便抓住所有关键的生态组分,而河流生境就可以作为这样的工具。因为在河流生态系统中,一个完整的河流生境纵向上包含了从上游水源地到河口,横向上分为了泛滥平原、河槽和水体3个区域,能为多种水生生物提供适宜的栖息地。通过对山地河流生境的生态学研究,不仅丰富了河流分类系统,而且对于河流生态环境及生物多样性的保护具有重要的现实意义和应用价值。本文以开县澎溪河为研究对象,在对山地河流的河溪等级结构分析的基础上,构建了河流生境的分类体系,从形态学和生态学两个角度分别对河流生境进行了划分。同时,从干扰对生境影响的角度,对水电开发引起的水位变动下的河流生境变化及其生态学效应进行了研究;又从对水利工程干扰下的河流管理角度,探讨了河流生境的生态需水问题。归结起来,本文的各研究部分都属于河流生态学研究范畴。本文的特色是以河流生态学、地貌学、形态学及水利学等学科为知识背景,应用3S技术对溪流结构和山地河流生境进行了划分,并探讨了在水位变化下植被的响应,同时关注河流生境变化对温室气体排放的影响,最后探讨了梯级电站影响下的生境生态需水问题。在这全球关注的重要区域内,河流生境的生态学研究还未见报道。主要研究结果如下:(1)采用Strahler法,同时把比降、两岸植被组成及交接程度、枯水季节水道宽度及能否跨越作为区别河与溪的重要标志,以澎溪河一级支流——东河为例,将东河流域溪流划分为6个等级。通过ArcGIS的计算,可知随着溪流等级的升高,溪流的数量、长度呈现出减少的趋势,一级溪流的数量和长度最大;溪流等级越低,分布的海拔越高,坡度范围越大,植被生长越好和越稳定。(2)河流生境的划分按形态学和生态学进行。从形态学角度进行了物理生境的划分,依据不同尺度结合地貌形态将河流生境分为:宏观尺度的上、中、下游生境;中观尺度对河岸生境、河道生境分别进行划分,河岸生境包括森林河岸、灌丛河岸、草地河岸、农田河岸等5类,河道生境包括险滩、浅滩、深潭、浅流、深流、回流、河滩洼地、河漫滩水凹、沙洲等13类;微观尺度分为巨石、圆石、卵石、水生植物等7种生境。从生态学角度的功能生境分类,依据底质和生物群落组成划分为:露出水面的水生植物床、淹没水下的水生植物床、急流岩石生境等8类。(3)受三峡库区蓄水水位变动影响下的的研究区域,表征河流生境变化的水分格局、土壤养分、植被分布均表现为明显的梯度变化,水分、土壤养分在155m附近为最高;植被空间格局呈四个带垂直分布,即从低海拔到高海拔依次为河漫滩一年生草本植物带、苍耳带、双穗雀稗带和河岸高地高草植物带。水位变动同时也影响了甲烷排放量,其最大的是地表水最深的地方,所以生态学效应也很明显。(4)对山地河流生境影响最大的就是梯级电站的开发,水坝下游形成了大量孤立的减(脱)水断面,使得连续的河流生境发生破碎化。为了维持河流的生态功能,需要加强水库运行的管理。根据计算整个东河的河流生态需水量为1.667亿m3,约占流域年平均径流量的5.7%。通过对每个减(脱)水断面的生态需水量的计算,分析了各电站的实际生态泄流量,考虑到非汛期来水较少,采用多年平均流量的10%进行泄流,汛期则采用近10年最枯月平均流量进行泄流。同时,由于不同的投资主体对梯级水电站进行建设和管理,对于生态泄流的统一管理不利,所以还需要建立有效的监管机制,进行合理管理。更多还原

【Abstract】 One of the most serious problems in regions with the highly-developed economy over the world is the deterioration of river ecosystem. How to effectively do the management and restoration in order to obtain all the key ecological components, river habitat is an important method. As in river ecosystem, a river habitat integrated extending from headwater to estuary at vertical side, is a horizontal combination of floodplain, channel and water body. The habitat study on Mountain River is not only abundance for optimizing river classification system, but also has an important practical significance and application value to the protection of ecological of river habitat and biodiversity.The paper takes Pengxi River in Kaixian County as an example for study. The classification system of river habitat is built up based on the hierarchy classifying of rivers and streams of Mountain River, which tends to elaborate from the perspectives of morphology and ecology. Meanwhile, it studies on the changes of river habitat under water level fluctuation and ecological effect, probes into the problem of the ecological water requirement. To sum up, all the study is focused on the scope of river ecology. The characteristics of this article are basing on the background knowledge of river ecology, geomorphology, morphology and hydraulics, the application of 3S technology to divide mountain river habitat into different spatial scales, the discussion of the response of vegetation under the water level changes, and the concentration on the emissions of greenhouse gases, which haven’t all been reported in the noticed field of ecology aspect of river habitat in the world.The result shows that:(1)With the Strahler method, meanwhile, taking the slope, vegetation construction, combination condition, water channel width in dry season and the ability of river crossing as important indicators to distinguish the river and the stream, a six-order hierarchy is established to classify the river and the stream in the Dong River basin. Having calculated with AcrGIS software, we found that with the increasing order of streams, the quantity and length of streams trend to be decreased; that order 1 has the largest quantity and the longest length; that the lower the stream order is, the higher the elevation is; that the greater the gradient scope is, the better and more stable the vegetation grows.(2) The classification of river is based on the perspective of morphology and ecology. From the point of morphological view, it classifies the physical habitat. Based on the topography condition at different scales, river habitats can be divided into followings: upstream, midstream and downstream habitats in Macro-scale; riparian habitat and river channel habitat respectively divided by the meso-scale. The riparian habitats contain the riparian forest, shrub, grassland, artificial, etc. The river habitats include cascade, riffle, pool, glide, run, backwater, lateral levee lake, floodplain lake, sandbar, etc. Boulder, Cobble, Gravel, Aquatic plants ne and so on, from the micro perspective are classified functionally with the ecological point of view. Based on the substrate type and biological communities, river habitats can be divided into eight types, including emergent macrophyte, submerged macrophyte, rapids rock and so on.(3) As for the study of water level influenced by the impoundment of the Three Gorges Reservoir, soil water content, soil nutrient concentration and distribution of plants are displayed in an obvious grads. The water content and soil nutrient concentration are the highest near the 155-meter height of water level. The vertical distribution of vegetation spatial pattern demonstrates four belts, which respectively include Floodplain annual herb belt, Xanthium sibiricum belt, Paspalum paspaeoides belt and riparian Heights High-grass plants belt. The study shows that the water level change has a significant impact on the methane emission, especially for the deepest surface water. Therefore, there is a distinct domino affect of bionomics.(4)Considering that habitat of Mountain River is seriously affected by the development of hydropower stations, that a large number of isolated reducing water (dehydrated) cross-sections and habitat fragmentation emerge, we must strengthen the management of reservoir operation to maintain the ecological functions of rivers. The ecological water requirement of Dong River is about 166.7 million m3, which takes 5.7% of annual average runoff of the basin. The ecological discharge of each power station is worked out through calculating the ecological water demand of each reducing water (dehydrated) cross-section. Taking into the consideration of the less water input in non-flood season, the 10% of annual average flow rate is adopted as a consult of discharge flow. Whereas the driest monthly mean flow rate in the past 10 years was used as discharge flow at flood period. Meanwhile, because the rundle water and electricity stations are built and managed by different investment, which leads to disadvantages of unified management of zoology discharge, we still need to set up an effective system of supervision for a reasonable management.更多还原