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 78 毫秒
1.
The possibility to use soil-inhabiting rove beetles (Coleoptera, Staphylinidae) as an indicator of disturbed forest areas has been studied. The studies of Staphylinidae succession and changes in beetles’ communities in the couse of demutational successions took place in the dark coniferous forests of the Kuznetsky Alatau. The specific species for all the stages of secondary succession on the clearings of different ages were marked. For instance, Philonthus lepidus Grav. indicates meadow stages of succession in fir forests, while Tachinus marginellus Grav., Tachinus elongatus Gyll and Philonthus setosus Sahlb. are typical for primary forests. In pine forests, Tachyporus obtusus L. may serve as a good indicator for initial stages of succession, while Staphylinus erythropterus L. and Tachinus marginatus Gyll. are typical for old growth forests. A trend of decrease in the level of aggregation during the process of restoration of primary plant communities has been registered for all types of forest ecosystems.  相似文献   

2.
Abstract

Fauna studies in Mongolia have found 275 species of rove beetles belonging to 59 genera and 7 subfamilies. The most varied from the taxonomic point of view are Oxytelinae – 21 genera and 79 species and Staphylininae – 16 genera and 80 species. Landscape distribution and zoo-geography structure of Staphylinidae fauna of Mongolia have been analysed.  相似文献   

3.
The reservoirs of the Ob basin change from a river bed to an additional reservoir and further to flood plain lakes of various flood stages. This process is accompanied by changes in the composition and quantitative development of plankton and benthos communities. In terms of species composition and productivity flood plain lakes at the minor flood stage are the most diverse ones. These reservoirs along with the flood plain inundated during the flood are of fundamental importance for the processes of fattening and reproduction of freshwater fish, which makes up the bulk of fishery. Long-term investigations have revealed certain peculiarities of the dynamics of the state of aquatic community caused by natural factors. Using multivariate statistical analysis methods researchers have discovered that flood plain lakes at the minor flood stage display the repeating pattern of the long-term dynamics of invertebrates’ communities. This is determined by the dynamic combination of the two main limiting factors (hydrologic and temperature behaviour). The analysis shows the influence of these factors on the population dynamics of the fry of the fish spawning in the inundated flood plain and the further formation of the resources.  相似文献   

4.
The biodiversity and distribution of testate amoebae in the Middle Ob flood plain soils have been studied. The biodiversity of Testacea in the soils consists of 83 species and varieties from 12 families. The population of Testacea in flood plain habitats is rich in water forms, especially in the flood plain part of the catena, because of annual floods. The study showed that the density of Testacea in the forest plots is approximately 10 times higher than in the meadow ones. The species diversity of Testacea in the meadows of the flood plain includes 40 species and varieties. It was found that there is an enrichment of the fauna of Testacea in the flood plain meadows with water forms and a decrease in the population of Testacea in the soil according to the depth. The decrease in the diversity and number down the soil profile is related to the decrease in the amount of the oxygen available and general induration of soil. On the whole, the population composition of Testacea in the soils of the pine forest consists of typical representatives of humus substrates with low values of pH, small stock of humus and mineral nutrition. The soils of mature pine forests are rich in Testacea; they have a similar complex of morphological types, mainly because of the moss cover and forest litter thickness.  相似文献   

5.
This paper summarises materials from various sources and the author’s research on the biology of the Siberian sturgeon in the Ob basin. The paper evaluates the significance of various parts of this river system for habitation and formation of sturgeon stock. It has been possible to distinguish semi-diadromous sturgeon and four local (indigenous) schools, according to the difference in morphological characteristics and peculiarities of the Ob basin ecology. Semi-diadromous sturgeon spends most of their life in the lower reach of the Ob and in the Gulf of Ob and migrates to spawn to the upper Ob. These spawning migrations cover a distance of 2500?km or more. Spawners from local schools do not make such long spawning migrations. It is noted that at least two isolated schools have been formed higher up the dams of the hydroelectric power stations on the Ob and the Irtysh. Today, the stock of semi-diadromous sturgeon is extremely low, but this school used to be the most abundant. The population of young fish in the middle-Ob school is of high density. But it has an extremely high mortality rate. The Chulym school of Ob sturgeon is in the best condition. Its population increases from the waters of two sturgeon and nelma reserves.  相似文献   

6.
A mercury-cell chlor-alkali plant operated in Pavlodar, Northern Kazakhstan, for 18 years and caused widespread contamination of the surrounding environment. Untreated wastewater from the plant was discharged to Lake Balkyldak, a shallow impounded lake without an outlet. The nearby River Irtysh was also suspected to be impacted by mercury (Hg) via the transport of contaminated groundwater. We took sediment and water samples from both aquatic systems, and also sampled soils along the shoreline of the lake and in the Irtysh flood plain. Sediments from Lake Balkyldak were found to be very heavily contaminated, with Hg concentrations in the surface layer reaching up to approximately 1500 mg kg(-1) near the wastewater outfall pipe. The contaminated lake sediments are prone to wind-driven resuspension and are acting as a strong source of Hg to the water column. Unfiltered lake water samples taken in shallow areas within 10-15 m from the shoreline contained from 0.11 microg Hg L(-1) in the less contaminated northern part of the lake to 1.39 microg L(-1) near the pollutant outfall in the south (up to 7.3 microg L(-1) on windy days). Sediments from the River Irtysh were only slightly impacted, with maximum Hg concentrations of 0.046 mg kg(-1) in the old river channel and 0.36 mg kg(-1) in floodplain oxbow lakes. In water samples from the River Irtysh, Hg was generally not detected, although trace concentrations (3 to 9 ng L(-1)) were found in some samples taken from oxbow lakes. We conclude that the river is not significantly impacted by Hg, but the highly contaminated Lake Balkyldak poses a threat and is in need of remediation. Potential remediation options for the lake are reviewed and are discussed in the context of experiences made at other Hg-contaminated sites.  相似文献   

7.
Abstract

The data show quantitative and qualitative composition of macrozoobenthos of the 12 left-bank confluences of the Middle Ob. The research has documented the presence of various groups, such as Oligohaeta, Diptera, Odonata, Hirudinea, Tabanidae, Trichoptera and Mollusca. The chironomids, molluscs and leeches play a significant role in the generation of biomass in the surveyed streams, and the abundance mostly depends on chironomids, oligochaetes and leeches. In general, zoobenthos abundance ranges from 8.8 (the Shudelka river) to 1839.9 (the Kochebilovka river) ind./m2, biomass is from 0.08 (Tatosh river) to 8.37 (Lozunga river) g/m2. The amount and benthos biomass of the Middle Ob’s second-order tributaries is higher than in the first-order tributaries.  相似文献   

8.
Abstract

The article offers a general view of the graylings (Thymallidae) from the largest Siberian river basins, namely those of the Ob and Yenisei, including the Khantayskoye and Baikal Lakes. It provides data on some of the most important morphological features. It is shown that it is erroneous to consider the graylings only within the subspecies Thymallus arcticus arcticus. The reservoirs of the Altai-Sayan highlands, which drain to the north into the inland waters of Mongolia, should also be considered, as one of the two major centres of speciation and morphogenesis for graylings.  相似文献   

9.
Monitoring of aquatic plant biomass in the Petchburi River, a regulated river system in Thailand, was carried out together with the examination of eco‐hydrological characters and the sedimentary organic content. The surveys were performed during May, August and November of 2010 and 2011. The results indicated temporal variation in water velocity (0.08–2.51 m/s) and medium to low organic levels (0.58–4.68%) of the benthic substrates. Dominant aquatic plants were Hydrilla verticillata (L.F.) Royle and Potamogeton malaianus Miq. with the highest biomass of 70.84 and 182.72 g/m2, respectively. The biomass was substantially decreased during the flood‐induced discharge period. This study indicates that Potamogeton has more adaptive potential to high water velocities than Hydrilla, while Hydrilla prefers lower water velocities. Discharge velocities of less than 0.5 m/s could provide positive growth rates of such submerged plants. Approaching the discharge control from this ecological point of view can further contribute to river habitat conservation.  相似文献   

10.
This article concerns the spatial distribution patterns of small-leaved forests in the Kuznetsk Depression, where these communities are the forest components of zonal vegetation. Two levels of spatial forest heterogeneity are described. Depending on mesorelief, forest communities are organized into topo-ecological series, which differ in sets of components and area covered by different elements. On a larger scale, depending on climatic features in different parts of the depression, the spatial pattern of communities and topo-ecological series reflect the zonal structures. In general, the spatial forest distribution is considered as follows: the central part of the depression is covered by ArtemisioBetuletum communities in combination with CalamagrostioBetuletum forests; approaching the eastern border of the depression, they change to TrollioPopuletum and CampanuloBetuletum combinations; the southern part is occupied by communities of CampanuloBetuletum, together with SaussureoPopuletum forests; in the north-western part the only forest association is PrimuloBetuletum. Throughout the entire region, in places with bad drainage occur communities of CariciBetuletum. Based on climatic parameters, forest-steppe and sub-taiga sub-belts can be distinguished. Forest-steppe in its turn can be divided into an original fragment of plain forest-steppe and typical forest-steppe. In the eastern part of the depression, a sub-taiga sub-belt developed but in the western part, it exists outside the depression.  相似文献   

11.
黄河滩地浅层地下水开发利用研究   总被引:1,自引:0,他引:1  
黄河滩地和河床下蕴藏着较丰富的浅层淡水资源 ,这个淡水资源来源于黄河渗透水 ,经过试验研究 ,初步探明了黄河滩地及河床浅层地下淡水资源的分布规律 ,揭示了这一淡水资源主要接受黄河渗透激发补给 ,评价分析了地下水资源量 ,提出了合理开发利用的取水方式和建议。  相似文献   

12.
The paper presents floristic and geo-botanical characteristics of rare forest ecosystems of the south of Western Siberia – spruce forests on the site of the Ob river ancient bed within the modern Bolshaya Sogra within the boundaries of the state natural reserve ‘Kislukhinsky’ (Altai region). Spruce forests here are at the edge of their spread in the West Siberian Plain conditions. There are over 300 species of vascular plants found in these spruce forests. Among them are plants that are typical of the mountain taiga associations of Russian Altai, as well as orchids, which have high species diversity. Spruce forest set of associations is also varied. The uniqueness of the described communities to the south of Western Siberia, the large number of rare and endangered plant species listed in the Red Books of different ranks, as well as the boreal forest species complex rare to the lowland wooded steppe, which has a relict character, all served as the basis for allocating a special protection area in the ‘Kislukhinsky’ reserve and attributing the studied spruce forests to the forests of high conservation value.  相似文献   

13.
Abstract

This article reports the species richness of vascular plants in the young fluvioglacial landscapes in the Severo-Chuiskiy centre of present-day glaciation using the example of the fluvioglacial deposits of the mountain-glacial basin Aktru. These landscapes are four well distinguished classes of habitats: open pebble fields with minimal vegetation, young larch forests on elevated parts of the relief, shrub thickets on the banks of the Aktru river, and sites with ground-frazil near the valley slopes. There are 132 species of vascular plants in the young fluvioglacial landscapes. These include 36 families and 77 genera. There are 3 species of pteridophytes (only Equisetum), 4 species of gymnosperms, and 125 species of angiosperms. The highest species diversity was recorded for Asteraceae, Poaceae and Salicaceae families, and for Salix, Poa, and Carex genera. The highest species richness – 100 species – were recorded for open pebble fields. There were 76 species in the young larch forests, and 58 species occurred in shrub thickets. The lowest richness is characterised for the sites with ground frazil, where 31 species were recorded.  相似文献   

14.
Abstract

The secondary succession of grass vegetation on the right bank of the river Ob (Altai territory) was investigated. The analysis has shown that the successions go in 3 hypothetical rows, depending on the humidity of ecotopes: ‘xerophytic’, ‘mesophytic’, ‘mesohydrophytic’. It is obvious that the rate of succession slows down in the conditions of more arid ecotopes. The dynamics of the aboveground phytomass are generally subject to this trend. The higher the succession rate, the quicker the phytomass develops.  相似文献   

15.
现代河漫滩软土固结与压缩微结构探析   总被引:8,自引:0,他引:8       下载免费PDF全文
以长江下游南京市城西曲流段形成的漫滩软土为代表,讨论了现代河漫滩软土的沉积特征、岩土工程性质、物质成分和在固结、压缩作用下微结构的变化,阐述河漫滩相软土的行为,提出了可能的软土地基处理途径。  相似文献   

16.
Conclusion In limited fashion we have been exploring two aspects of man's perception of his environment that contribute to regional differences in flood plain management. In one example we suggest that the perceived frequency of flooding is not a continuous function, but in the cases studied appears to fall within discrete classes. These perceived classes and their related adjustments distinguish areal differences in flood plain management. In the second example, we have speculated on the impact of perceived regional opportunities incorporated in river basin development. Here we suggested that while river basins possess unique opportunities, the importance of these may change adversely through time. These are changes that to some extent are concealed by our favorable perception.The author is an Assistant Professor in the Graduate School of Geography, Clark University, and he gratefully acknowledges the review of an early draft by J.W. Birch, lan Burton, Raymond E. Murphy, and Gilbert F. White.  相似文献   

17.
On the banks of the River Cynon in Aberdare, South Wales, seven designs of flood revetment blocks were tested for resistance to penetration and displacement by R. japonica, an introduced alien now widespread on river banks in some areas. With the subsequent failure of all designs tested, the testing of a new block is described. Its success is attributed to a microporous structure and interlocking/overlapping edges.  相似文献   

18.
Lake Mundshtuchnoye is located in the basin of the Middle Ob, upstream from the influx of its big right-bank tributary, the Tym river. The lake is located within the boundaries of the Tomsk region and is a specially protected natural area of regional importance. Genetic and morphological characteristics of the lake allow us to consider it as a natural monument. It is an important point for conducting scientific research and organizing long-term environmental monitoring. The depth of Lake Mundshtuchnoye reaches 55 m, which is a unique phenomenon for the lowland part of the Ob basin. The shape of the lake basin is also unusual, sectionally resembling a crater. Structural-tectonic features of the area of the lake location allow to link its origin and development to the penetration of reservoir fluids. The lake water is very different from the lake waters of the Ob basin water logged catchment areas. Lake Mundshtuchnoye has low salinity (the amount of basic ions is 7.3 mg/dm3), and a significant concentration of silver. The lake water is clear, and thus very different from the dark-coloured water found in most regional lakes because of inflow from bogs and mires.  相似文献   

19.
This study investigated the environmental impact and level of risk associated with mercury (Hg) contamination near a derelict chlor-alkali plant in Pavlodar, Northern Kazakhstan. Several species of fish were sampled from the highly polluted Lake Balkyldak and the nearby river Irtysh, to assess the extent of Hg bioaccumulation in the aquatic food chain and potential human health risks. A small number of bovine tissue samples, water samples, soil and plant samples from a nearby village were also investigated in order to make a preliminary assessment of potential impacts on the terrestrial food chain. Mercury levels in fish caught from Lake Balkyldak ranged from 0.16 to 2.2 mg kg(-1) and the majority of fish exceeded current human health criteria for Hg. Interspecies comparisons indicated that Hg is accumulated in the order dace>carp>tench. Site-specific bioaccumulation factors (BAF) were calculated for THg, and were estimated for MeHg. Fish from the river Irtysh and floodplain oxbow lakes contained between 0.075 and 0.159 mg kg(-1) of Hg and can be regarded as uncontaminated. Soils were found to be impacted by past atmospheric emissions of Hg. Cattle grazing in the surroundings of the factory are exposed to Hg from contaminated soils, plants and surface water, but the consumption of contaminated fish from the lake appears to be the main route of exposure for humans.  相似文献   

20.
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