首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 218 毫秒
1.
The state of tree and ground vegetation layers in spruce-fir forests around the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) has been repeatedly evaluated in 25 permanent sampling plots at 5- to 10-year intervals (1989–2013). The results have been used to characterize the dynamics of plant communities in the period of reduction of emissions from the smelter. Although the annual amount of emissions has decreased from 150–225 × 103 t in the 1980s to less than 5 × 103 t after 2010, the vegetation in the impact zone (1 and 2 km from the smelter) remains severely suppressed: the trees continue to die off, and the diversity of ground vegetation layer is very low. In zones with low and moderate levels of industrial pollution (30 and 4–7 km from the smelter), natural factors associated with windfall disturbance after the 1995 windstorm with snow have played a more important role in the dynamics of forest communities than the reduction of emissions itself.  相似文献   

2.
Analysis has been made of changes in the species composition and abundance of epiphytic lichens on fir trees during the first decade after a sharp reduction of emissions from a large copper smelter in the Middle Urals. The results show that lichens have recolonized the area of the former lichen desert and that the abundance of lichen species in the impact and buffer zones has increased. However, a fairly long time is required before lichen communities in the vicinity of the smelter can recover to the background state, since species highly sensitive to pollution still occur only in the background area.  相似文献   

3.
基于最小累积阻力模型的江南水乡河网分区保护研究   总被引:5,自引:0,他引:5  
河网水系是江南水乡重要的自然与历史文化遗产。但近年来,随着城市化进程的快速发展,人类活动对河网的干扰日趋严重,村镇小水体出现大面积填埋,部分地区河网结构趋于简单,非主干河道不断减少。以上海市青浦区为研究区域,采用最小累积阻力模型对河网水系分区保护问题进行探讨,以期为江南水乡风貌保护提供参考。结果显示:(1)河网水系在江南水乡具有明显的廊道效应;(2)青浦区可划分为河网特殊保育区、河网重点保护区、河网风貌保留区、河网生态建设区和河网景观恢复区5个区域,并由此提出具有针对性的水系分区保护方案;(3)最小累积阻力模型在江南水乡河网水系保护方面具有较好的适用性  相似文献   

4.
The area of leaves on birch (Betula pubescens ssp. tortuosa) auxiblasts and brachyblasts and the degree of their damage by the complex of leaf-gnawing and leaf-mining insects were studied in a light birch forest. The results showed that phyllophagous insects, primarily snout beetles, prefer young leaves on the apexes of auxiblasts. Thus, selective damage is inflicted on smaller leaves, both on the auxiblasts and in the entire sample. This phenomenon is widespread and may manifest itself in different ways, depending on the pattern of leaf area distribution along the extended shoot and the feeding preferences of the insects. Thus, it is necessary to reconsider research methods and approaches based on the assumption that insects damage leaves nonselectively, irrespective of their size.  相似文献   

5.
The trophic activity of birch leaf-eating insects in background and impact (highly polluted) sites near the Middle Ural Copper Smelter has been recorded in 2008–2015. Reduction of emissions leads to a significant decrease in the concentration of heavy metals in birch leaves, and the existing differences in the proportion of damaged leaves between the background and impact sites are leveling off. An increasing temporal trend in foliar damage at the impact site confirms that the trophic activity of leaf-eating insects is being recovered following reduction of toxic load, and the remaining differences from the background territory indicate that this process is still continuing.  相似文献   

6.
7.
三峡水库消落区生态环境保护与调控对策研究   总被引:3,自引:2,他引:1  
三峡水库建成后,由于水库调度引起库水位周期性的涨落,在库区两岸形成周期性变化的水陆交错区域即消落区。消落区是水、陆生态系统的交错地带,具有生态脆弱性、变化周期性和人类活动频繁性等特点。随着三峡工程逐步投入使用,人类活动对消落区的影响也逐渐增加,并且消落区自身存在生态脆弱性,如果不采取有效措施,它将影响三峡工程的正常运行和整个库区的可持续发展。因此,针对消落区的水、土环境变化特点,分析了消落区土壤与水环境的相互影响,提出了利用生物缓冲带、复合生态、坡地农业、流域生态学、人工湿地及生态河堤等技术来对消落区生态环境进行保护与调控的措施。  相似文献   

8.
蓝藻水华的拦截和陷阱捕获综合控藻技术研究   总被引:1,自引:0,他引:1  
基于水文气象条件对巢湖蓝藻水华分布的影响,在西北岸万年埠的迎风岸湖段设置蓝藻水华拦截围隔和蓝藻水华捕获陷阱。通过连续监测,比较围隔内外蓝藻生物量和浮游植物多样性的差异,检测水华陷阱的蓝藻捕获效率,从而对蓝藻水华拦截和陷阱处置综合控藻技术的作用进行评估。结果表明:(1)陷阱设置在西半湖万年埠湖段是科学合理的,监测表明蓝藻水华生物量受风力和水流驱使主要聚集在沿岸带区域;(2)水华拦截围隔对蓝藻水华有很好的拦截效果,在水华暴发期间蓝藻围栏可以拦截50%以上的蓝藻水华和50% 以上的Chla浓度,水华拦截区围隔内的生物多样性指数显著高于拦截围栏之外的水域;(3)陷阱对微囊藻水华的聚集捕获效果显著,在适宜气象条件下聚集效率约为2 kg/(m2·d)。这些研究结果说明该综合技术有很好的控藻效果,具有良好的应用前景  相似文献   

9.
It is well known that the structure of leaves plays an important role in adaptation, but there are still no accurate structural criteria to indicate ecological characteristics of the species. We have studied parameters of leaves in 100 herbaceous plant species growing in the southern taiga subzone that belong to different ecological groups in relation to irradiance and moisture supply. The results show that leaf area, thickness, and anatomical type are less correlated with ecological characteristics of the species than structural parameters of photosynthetic tissues. In the series shade-loving mesophytes—light-loving hygromesophytes—mesophytes—xeromesophytes—mesoxerophytes, the concentration of cells and chloroplasts in the leaf gradually increases by a factor of up to 7–10, their size decreases two-to threefold, and the ratio of mesophyll surface area to leaf surface area increases fourto fivefold. It is concluded that characteristics of mesophyll are of adaptive significance. A system of characters is proposed for identification of ecological groups of plants growing in the boreal zone.  相似文献   

10.
为了揭示森林植被水文效应的动态变化过程,将简化的简单生物圈模型与动态植被模型和流域地形指数水文模型相耦合进行长江上游梭磨河流域植被及其水文效应的动态模拟。结果表明:植被覆盖和叶面积指数的增加使植被蒸腾和冠层截留蒸发增加而使土壤蒸发减小,植被的水文效应取决于蒸发分量中这两个相反方向变化的净效应。流域主要由草地和灌木覆盖时流域总蒸发大于裸地和林地。与裸地相比较,当单位叶面积指数截留能力取值0.1 mm时,森林减小了流域总蒸发,但当单位叶面积指数截留能力取值0.2 mm时,森林增加了流域总蒸发。森林的水文效应对冠层截留能力敏感,冠层截留能力存在一个控制森林水文效应从减小总蒸发变为增加总蒸发的转折点。植被的水文效应是随时间变化的,对于给定的植被类型其叶面积指数是决定其水文效应的关键因子。  相似文献   

11.
滨岸潮滩是海岸带的重要组成部分和主要的地理景观 ,具有多种环境功能和生态价值 ,对沿海地区的经济发展起着重要的作用 ;同时滨岸潮滩又是一个环境脆弱带和敏感区 ,极易受人为活动的干扰和破坏。生物多样性是人类生存和经济得以持续发展的基础。滨岸潮滩是生物多样性最为丰富的生态系统之一。通过对上海滨岸潮滩生物多样性影响因素的调查与分析 ,研究了目前人类活动对上海滨岸潮滩生物多样性造成的严重威胁 ,污水的排放使滨岸潮滩水质和底质严重污染 ,对滨岸潮滩的围垦改变了潮滩的自然本底状态 ,造成潮滩生物生长发育和栖息的环境受到破坏 ,影响滨岸潮滩生物多样性。指出滨岸潮滩等方面的社会与环境价值 ,并探讨了上海滨岸带开发与滨岸潮滩生物多样性的保护和利用问题  相似文献   

12.
上海滨岸潮滩生物多样性及其利用与保护   总被引:12,自引:3,他引:9  
滨岸潮滩是海岸带的重要组成部分和主要的地理景观,具有多种环境功能和生态价值,对沿海地区的经济发展起着重要的作用;同时滨岸潮滩又是一个环境脆弱带和敏感区,极易受人为活动的干扰和破坏。生物多样性是人类生存和经济得以持续发展的基础。滨岸潮滩是生物多样性最为丰富的生态系统之一。通过对上海滨岸潮滩生物多样性影响因素的调查与分析,研究了目前人类活动对滨岸潮滩生物多样性造成的严重威胁,污水的排放使滨岸潮滩 质和底质严重污染,对滨岸潮滩珠围垦改变 了潮 滩珠自然本底状态,造成潮滩物生长发育和栖息的环境受到破坏,影响滨岸潮滩物多样性。指出滨岸潮滩等方面的社会与环境价值,并探讨了上海滨岸带开发与滨岸潮滩物多样性的保护和利用问题。  相似文献   

13.
Over 2500 species of invertebrate macrofauna and over 177 species of avifauna live in the forest–tundra of the Lower Ob region and adjacent areas of the northern taiga and shrub tundra. About half of the invertebrate species of the study area are northern—mostly hypo- and hemiarctic—tundra species; the rest are boreal and arctomontane-boreal Holarctic and trans-Palearctic species. The anthophilic and aerobiont insect assemblages include many boreal forest forms. A total of 153 species have been observed nesting at the taiga–foresttundra boundary; 81 species have been observed nesting at the tundra–forest-tundra boundary. The avifauna of the forest–tundra becomes enriched with taiga species in floodplain forests and with tundra species on the flat interfluve, in areas of tundra and tundra-like wetlands. The forest–tundra of the Lower Ob region has no avifauna and entomofauna of its own and contains a mixture of taiga and tundra faunas. It has been found that the ecotone effect is not pronounced in the taxonomic composition of birds and insects in the forest–tundra, where only some particular groups (such as amphibiont insects) have increased abundance.  相似文献   

14.
The aim of the present study was to develop a standardised protocol for the use of Lolium perenne cultures to biomonitor the surroundings of an aluminium smelter. Five ecological stations, which corresponded to air quality network monitoring sites pertaining to the smelter, were selected for study. Cultures of L. perenne (one at each site) were exposed for approximately 28 days, at different times between August 1999 and October 2000. At the end of the exposure periods, the fluoride concentrations in the cultures were determined. The concentrations of fluoride determined in the L. perenne cultures varied from 4.32 microg g(-1) to 912.22 microg g(-1) and followed a similar trend to concentrations of atmospheric fluoride. However, a wider range of fluoride concentration was observed in the L. perenne cultures than in the air surrounding the smelter. The background levels of fluoride in L. perenne cultures were also calculated, thereby allowing classification of fluoride air pollution in the area under study.  相似文献   

15.
An analysis is made of the effect of large spruce and birch trees on the spatial pattern of the fields of heavy metal concentrations (Cu, Pb, Cd, Zn) and pH in the forest litter formed in tree stands exposed to long-term pollution with emissions from the copper smelter in Revda, Sverdlovsk oblast. The fields formed by trees growing in the background area have a regular spatial structure: the concentrations of elements decrease with increase in the distance from the tree trunk to the edge of canopy gap, with the position of sampling point relative to the trunk accounting for more than half of total variance. In polluted areas, the regular component of the field structure is very weakly expressed, and the main role is played by higher-order heterogeneity related to the mosaic pollution pattern on the scale of tens to hundreds of meters.  相似文献   

16.
Phyllophagous insect assemblages on birch trees have been studied in greeneries of the cities of Labytnangi and Salekhard and natural habitats in the environs of these cities in 2007, 2010, and 2013. The 44 recorded species were dominated by insects of the orders Lepidoptera and Hymenoptera (18 and 12 species, respectively); regarding feeding ecology and mode of life, they were dominated by open-living chewing phyllophages and miners (19 and 10 species). The urban greeneries and sparse birch forests were colonized by the same species, but the density of many species in the cities was considerably higher. The species composition of the communities changed considerably from year to year. The species richness and similarity of insect assemblages at the studied sites were the highest in 2013. The basic pests of birch in the northern cities were chewing phyllophages, especially Tenthredinidae sawflies.  相似文献   

17.
基于多中心网络城市理论和集群网络结构竞争理论,在构建城市群网络空间绩效分析框架和评价指标体系的基础上,采用DEA的BCC模型和Malmquist指数模型,对2008~2010年环鄱阳湖区城市群42个城市空间网络联系效率进行了分析。研究表明:(1)从效率总体比较来看,环鄱阳湖区内的大部分城市处在空间网络联系的生产前沿面上,不在生产前沿面上的城市逐渐向生产前沿面靠近;(2)从效率分解来看,环鄱阳湖城市群空间网络绩效的变化是技术效率和技术水平共同作用的结果,其中,技术水平起的作用更为明显;(3)从效率空间差异分布看,环鄱阳湖区城市群空间网络绩效呈现核心区大于边缘区、边缘区大于外围区的规律,而城市群空间网络发展速度呈现外围区最高,核心区次之,边缘区最低的规律  相似文献   

18.
基于景观格局的盐城海岸带土地利用时空变化分析   总被引:2,自引:0,他引:2  
在GIS和RS技术支持下,以行政区划为评价单元,通过土地利用转移矩阵、景观格局指数对盐城海岸带土地利用变化的主要方式、景观格局特征及时空分异规律进行定量分析。结果表明:2000~2010年,盐城海岸带土地利用类型以耕地、建设用地和水域为主,其中耕地是盐城海岸带的优势类型,虽然近年来呈逐渐下降的趋势,但仍是区域景观基质类型,均占总面积的78%以上;海岸带景观水平趋于破碎化,区域景观格局更加复杂化、分散化和多样化;研究区北部景观水平特征指数较中部、南部为高。自然地理条件、经济发展水平及不同土地利用方式所带来的利益差异是导致盐城海岸带景观格局变化的关键驱动因素。  相似文献   

19.
基于2005~2015年土地利用变更调查数据,结合土地利用变化模型和生态系统服务价值理论,分析了江苏省江淮生态经济区县域单元土地利用结构演化规律及生态系统服务价值变化。结果表明:研究期间建设用地、水域面积增加的最多;土地利用程度指数呈现北高南低的空间格局;生态系统服务价值略有上升,空间上总体为南高北低的格局,呈现市区较低,周边县(市)较高的现象;研究期内水域对于江淮生态经济区生态系统服务价值的贡献和生态环境的调控作用十分显著;结合区域建设开发现状,利用生态系统服务价值敏感性指数,在县域尺度上将研究区划分为以下五种类型:优先保护区、优先开发区、保护均衡区、开发权衡区、开发调整区,并提出建设开发策略,以期为江淮生态经济区开发建设、环境保护提供科学指引。  相似文献   

20.
Fluxes of dissolved organic matter (DOM) in larch biogeocenoses and its export from the drainage basin have been studied in the zone of continuous permafrost. A comparative assessment of DOM input into the soil has been made on slopes of northern and southern exposures (as variants reflecting the current state and warming). The dynamics of DOM export in a creek depending on the increasing depth of the active soil horizon in the drainage area have been revealed. It is concluded that an increase in the depth of the seasonally thawing layer induced by global warming will not have any significant effect on the amount of annual DOM export. Reduction of DOM export may be expected upon a decrease in litter stocks under the effect of their mineralization and forest fires.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号