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 31 毫秒
1.
Riparian vegetation is an important determinant of the physical, chemical, and biological condition of streams, and odonates are useful indicators of riparian condition. To identify environmental factors that structure Odonata assemblages in tropical forest streams, we collected adult odonate specimens and habitat data from 50 stream sites located in the Brazilian municipality of Paragominas (Pará state). We collected 1769 specimens representing 11 families, 41 genera, and 97 species. Of these species, 56 were Zygoptera, and 41 were Anisoptera. Improved environmental condition was reflected in increased Zygoptera species richness and reduced Anisoptera species richness. Channel shading was strongly and positively related to Zygoptera richness, and negatively to Anisoptera richness. Zygoptera species richness, but not Anisoptera species richness, was related positively to bank angle, quantity of wood in the stream bed, electrical conductivity, and decreased water temperature. Altered riparian vegetation structure was the principal determinant of odonate assemblage structure. Our results indicate that maintaining intact riparian vegetation is fundamental for conserving or re-establishing aquatic odonate assemblage structure.  相似文献   

2.
In Mediterranean ponds, summer drought enhances seasonality whose intensity varies along topographic and climatic gradients. The alternation of wet and dry periods in rain dependent ponds affects their biogeochemistry and differentiates them from ponds fed by more stable water sources, such as groundwater springs. Superimposed onto this, land use is also a very strong factor of variability. In this study we compared nutrients and organic matter concentrations, in water and in sediment, among different types of Mediterranean ponds based on the source of water, hydroperiod and land use. Forty-three ponds were sampled in Eastern Spain corresponding to five pond types: (1) permanent spring ponds in lowlands, (2) permanent spring ponds in mountains, (3) semi-permanent rain ponds, (4) temporary rain ponds with long hydroperiod and (5) temporary rain ponds with short hydroperiod.The results of this study indicate relevant differences among these pond types. The temporary rain ponds with short hydroperiod are characterized by high turbidity due to suspension of sediment particles rich in phosphorous adsorbed onto them (argillotrophic aquatic systems). They are used for watering domestic sheep that enhance sediment suspension by trampling. Total phosphorous (TP) concentrations in the water are high (like those of hypertrophic lakes), but planktonic chlorophyll a is very low and not correlated with TP, because of the low P-bioavailavility in the water. At the other extreme, we have permanent ponds in lowlands fed by groundwater springs. They are heavily loaded with nitrates due to the surrounding intensive agriculture. In these and other permanent/semipermanent ponds chlorophyll is highly correlated with TP. Sediment characteristics provide a good indication of the hydroperiod, since desiccation has important effects on biogeochemical transformations. A threshold of 5% organic matter (OM) in the sediment separates temporary ponds with a short hydroperiod from those with a long hydroperiod, and a threshold of 8% separates the later from the semi-permanent and permanent ponds. Besides OM reduction, important loss of N occurs during desiccation through mineralization, ammonia volatization and the sequential nitrification/denitrification pathway. On the other hand, the increase of organic P mineralization in dry sediments does not represent a loss of P from the system, since o-P remains adsorbed or bound onto the soil. This leads to a low TN/TP ratio in sediments in temporary ponds with short hydroperiod. These characteristics have to be taken into account when establishing pond typologies and ecological thresholds to assess water quality in these unique aquatic habitats.  相似文献   

3.
Partitioning beta diversity into its two components of spatial turnover and nestedness is a more robust method for checking spatial variability in biological communities than calculating the total beta diversity alone. The relative contribution of spatial turnover and nestedness has been used to test the effects of climatic, environmental, spatial and temporal variables on community composition. In this study, we tested the effects of environmental factors and microhabitat features on total beta diversity and its spatial turnover and nestedness components using a comprehensive dataset of aquatic Heteroptera collected from four types of permanent freshwater habitats (i.e. streams, ponds, rock tanks and reservoirs) in the Western Ghats of India. We observed that communities in all four types of habitats were predominantly shaped by dissimilarity caused due to spatial turnover (>85 %). Each type of habitat showed the presence of one or more species uniquely associated with it, which might contribute to the turnover between communities. The abiotic environment (climatic factors, topological factors, soil characteristics and microhabitat features) as well as assemblage structure differed significantly between habitat types. Communities in each type of habitat were affected by different environmental factors, such as precipitation and temperature patterns for streams, altitude and rocky substrate for rock tanks, and soil characteristics and the presence of aquatic macrophytes for ponds and reservoirs. Assemblages observed in the four types of permanent habitats are thus compositionally distinct due to species replacements between local communities, which in turn are strongly influenced by environmental variables. Similar to previous studies, our results show that spatial turnover largely measures the same phenomenon as total beta diversity on a regional scale.  相似文献   

4.
Our study describes and evaluates environmental influences on assemblages of aquatic Coleoptera and Heteroptera in artificial ponds situated near Lake Steinhude in Lower Saxony (Germany). We determined temporal dynamics and colonization patterns for 14 ponds of different age. In total, we recorded 4941 individuals that represented 87 species of aquatic beetles and bugs. Between 30 and 40 species were found in most of the ponds. Heteropteran species of the families Corixidae and Notonectidae acted as pioneer species in new ponds, while aquatic coleopterans predominated in older ponds. The results of Canonical Correspondence Analyses (CCA) showed that among the key factors affecting community structure were land use, vegetation cover, water chemistry and the age of the ponds. We found that the distribution of adjacent ponds on areas with different land use has a positive influence on the diversity and abundance of the aquatic insect fauna.  相似文献   

5.
Alpine ponds are shallow waterbodies formed in alpine zones characterized by usual pristine conditions, however subject to harsh conditions that enable the emergence of unique communities with high conservational value. Therefore, it is important to gather information about these ecosystems and understand the changes in the biota. This work aimed to use Portugal’s alpine ponds as a case of study in assessed the macroinvertebrates communities in the Mediterranean ecozone. To fulfill this goal, we aimed to understand the alterations on macroinvertebrates community and how are they modulated by environmental variables. Five alpine ponds in Serra da Estrela (Portugal) were studied for one year. Macroinvertebrate communities and physical and chemical water parameters were determined in June/16, October/16, and April/17. Water chemistry values were similar to other studied lentic waterbodies in alpine zones in Europe, with slightly acidic water and low conductivity. Although accentuated macroinvertebrates differences between ponds, no significant differences in diversity were recorded, indeed the main differences recorded were influenced by ponds habitat types and environmental variables. Canonical Correspondence Analysis showed differences in the communities between ponds, namely the high influence of several physical and chemical parameters (conductivity, phosphate content, and pH) in the macroinvertebrates community composition. Indeed, Spearman’s correlation revealed significant interaction in diversity, abundance and richness of macroinvertebrates and several physical and chemical parameters (pH, dissolved oxygen and nitrates concentration).  相似文献   

6.
范少军  周立志  于超 《湖泊科学》2022,34(5):1596-1607
升金湖是长江中下游地区典型的浅水通江湖泊,是东亚-澳大利西亚候鸟迁徙路线上水鸟重要的越冬地. 2017年11月-2018年3月,以该湖泊越冬鸭属(Anas)鸟类为研究对象,对其在芦苇湿地、芡实塘、退耕还湿和水生植被恢复湿地4种湿地生境中的群落结构、行为特征及其环境影响因素进行了研究. 结果表明,升金湖分布有10种越冬鸭属鸟类,斑嘴鸭(Anas poecilorhyncha)、绿翅鸭(A. crecca)和绿头鸭(A. platyrhynchos)为该属鸟类群落的优势种. 鸭属鸟类群落在越冬前期种类和数量最多,在整个越冬期,鸭属鸟类在芦苇湿地中种数、数量、密度和多样性指数最高. 在水生植物盖度高、人为活动弱的芦苇湿地,鸭类的主要行为是休息;在食物资源丰富、人为活动强的芡实塘和退耕还湿湿地,其主要行为是觅食和警戒. 鸭属鸟类群落种数、数量、密度和多样性指数与湿地的面积、水域面积、水生植物盖度呈正相关,与干扰度和水深呈负相关. 觅食时间与气温和沉水植物的盖度呈正相关,与水深和干扰度呈负相关,警戒时间与干扰度呈正相关,与挺水植物的盖度呈负相关. 各种恢复类型的湿地生境成为越冬鸭属鸟类的重要栖息地,因此恢复多种湿地栖息地对于越冬水鸟的保护具有重要意义.  相似文献   

7.
One of the possible consequences of climatic change for streams and rivers in the pampean region of South America is an increment in nutrient loads. To analyze this possible perturbation on a biological scale, the response of oligochaetes to an experimental eutrophication of the La Choza Stream, Argentina was studied. We proposed that the addition of nutrients could increase the abundance, biomass, and species composition of the stream. Two stretches (Control and Treatment sites) were selected, with bimonthly samples being taken (March 2007 through February 2009) in two habitat types: the sediments and the aquatic vegetation. On each sampling occasion the environmental variables were measured. The nutrient addition consisted in the continuous dissolution of a commercial fertilizer. The oligochaete mean density and total biomass, the taxonomic richness, the Shannon diversity (H′), and the evenness (E) were calculated and the BACI ANOVA design used to compare the differences between the sites. Thirty-three species of the families Naididae (Naidinae, Pristininae, Tubificinae, and Rhyacodrilinae), Opistocystidae, Enchytraeidae plus Aphanoneura Aeolosomatidae were collected. The oligochaete abundance and biomass increased significantly in the sediments and on the aquatic vegetation, especially among the Naidinae and Pristininae during their asexual reproductive phase. The diversity and evenness varied significantly in the sediments with the nutrient addition. Significant differences in the species richness and diversity were found on the aquatic vegetation, with both increasing at the treatment site after the fertilization. A significant correlation (Spearman) was observed between the oligochaete density in the sediments and the NO3-N and NH4-N concentration in the water. The increment in the naidines resistant to the fertilizer throughout the experiment could be explained by the greater nutrient availability, their mode of reproduction, and their short life cycles. The results of our study suggested that the incorporation of nutrients modified the composition of the oligochaete assemblage in favor of herbivores and detrivores. The usefulness of these indicator organisms in monitoring freshwater systems is subsequently discussed.  相似文献   

8.
In temporary ponds, reestablishment of zooplankton communities depends on recruitment from the egg bank, the arrival of dispersers from within the region, and on successful establishment of newly arrived species following interaction with local abiotic and biotic factors. When the ponds dry up, zooplankton species may survive as dormant eggs, and since not all eggs hatch in the next season, eggs will accumulate in the sediment over time, representing an archive of the pond's historical biodiversity.To study the effect of “restoration age” (the time since a water body was restored), we studied groups of ponds that were restored in different years (1998, 2003 and 2007). The restoration process involved extensive dredging of sediments which were used to bury the ponds in the 1960s. Our expectation was that the oldest ponds would have the richest zooplankton community, as they have been accumulating biodiversity over a longer time period. We took weekly quantitative samples of zooplankton during four consecutive weeks after flooding to compare taxon richness and zooplankton community composition between ponds of different restoration age during an early stage of zooplankton community re-establishment.Taxon richness was high and similar to regional levels in all the ponds under investigation, suggesting restoration success and unlimited dispersal. Although cumulative richness at the end of the period was not significantly different between ponds, we observed temporal changes within the study period and certain age-related trends in relation to differences in zooplankton composition. These results suggest a difference in the succession of zooplankton communities depending on restoration age (which could be due to historical or local factors) and that this effect becomes evident from the beginning of the pond hydroperiod.  相似文献   

9.
为探明巴音布鲁克高寒沼泽湿地植物群落与环境因子的关系,采用样线与样方结合的方法,于2014-2015年在天鹅湖沼泽湿地进行植物群落调查与环境因子测定.结果显示,巴音布鲁克天鹅湖沼泽湿地植物共有35种,隶属于19科27属.方差分析表明,地表积水条件显著影响植物群落物种多样性,随着地表积水减少,物种丰富度和ShannonWiener指数呈现上升趋势,Pielou指数呈现下降趋势,说明随着地表积水的减少,植物群落的物种多样性逐渐增加.冗余分析与偏冗余分析表明,所有环境因子共解释了植物群落物种组成变异的67.9%.水位与土壤全氮含量对物种组成的总效应达到显著水平,土壤全氮含量的净效应达到极显著水平,但全磷含量和有机碳含量的总效应与净效应均未达到显著水平.研究表明,积水条件和土壤氮含量是巴音布鲁克天鹅湖沼泽湿地植物群落物种组成和分布的主要环境驱动因子.  相似文献   

10.
11.
Harpacticoids are an important component of meiofaunal assemblages in springs. No information so far has been available on harpacticoid assemblages of the Western Carpathian spring fens, unique biotopes of high conservation value which cover a very long gradient of mineral content of groundwater, due to the variable geological background setting. Spring fens are isolated habitats of different age which can be assessed by radiocarbon dating of their basal sediment layers. This enables to test a possible effect of habitat age on species composition and species richness. In this study, we examined harpacticoid assemblages in 50 permanent tree-less spring fens (helocrenes) in the Western Carpathians (Slovakia and Czech Republic) in terms of species composition, total abundance, species density, and species richness. We tested mainly the effect of 12 explanatory variables describing water chemistry and temperature, climatic conditions, amount of nutrients, organic carbon, sediment structure, habitat age and size, using Canonical Correspondence Analyses (CCA) with stepwise forward selection. For the computation of species richness rarefaction was used. In total, 20 harpacticoid species were recorded with the total median density of 950 individuals in m−2. Three significant explanatory variables, Ellenberg Indicator Values of plant community for nutrients, in situ measured pH, and average January temperature, explained together 19.0% (adj. 13.7%) of the total variance in the species composition data. The relationships of harpacticoids to these three explanatory variables were species specific and no uniform response of the total assemblage to the environmental variables was found (in terms of total abundance and number of species). The only exception was the influence of overall unfavourable conditions in the mineral-poor acidic Sphagnum-fens. Pilocamptus pilosus was significantly associated with a higher amount of nutrients and warmer climate. Nutrient enrichment was clearly indicated by a decrease or absence of crenophile Bryocamptus cuspidatus, and accompanied by an increase in ubiquitous Attheyella crassa. Moraria brevipes was confined to low pH, B. cuspidatus showed a high tolerance for low pH, whereas Bryocamptus echinatus preferred alkaline conditions. Despite a significant correlation between habitat age and species density we found no clear evidence that any colonisation driven process could influence the number of harpacticoid species within the tested time scale. We hypothesize that rather other habitat characteristics connected with age, i.e. habitat heterogeneity and stability, may be determinant for species richness. The occurrence of some species (e.g. P. pilosus, B. cuspidatus) was clearly geographically limited, but due to the spatial structuring of significant environmental variables no conclusion on dispersal limitations could be made.  相似文献   

12.
Ephemeral aquatic ecosystems have a global distribution being most abundant in semi-arid and arid regions. Due to anthropogenic impacts threatening these environments, there is a need to understand various factors and processes structuring animal communities in these habitats. Macroinvertebrate and zooplankton assemblages were studied in different ephemeral (i.e. flood plain, large endorheic and small endorheic) pans in the south-eastern Lowveld of Zimbabwe in the wet season. Ten Cladoceran species, Calanoids and Cyclopoids taxa and thirty-three macroinvertebrate taxa were identified over the entire hydroperiod. Predator macroinvertebrates were the dominant taxa especially in endorheic pans. The pan categories differed significantly in both zooplankton and macroinvertebrates composition and richness, with zooplankton and macroinvertebrate taxa richness being high in flood plain pans. Conductivity, fish presence, hydroperiod, maximum depth, turbidity and vegetation cover played a major role in shaping both zooplankton and macroinvertebrate communities. The macroinvertebrate community assemblage reveals that small endorheic and flood plain pans represent extremes ends of the environmental gradient in the region while large endorheic pans represent an intermediate end.  相似文献   

13.
泥炭地是一种水-陆过渡型的湿地生态系统。水体沼泽化过程中,植被等生物群落也随之改变,进而影响泥炭地碳埋藏和发育过程。作为泥炭地生态系统重要的次级生产者,摇蚊群落结构变迁可以为追溯泥炭地环境演变和发育历史提供关键线索。泥炭地在发育过程中将经历各种不同阶段,然而,现有的泥炭地摇蚊群落调查仅限于泥炭生境或泥炭地中开阔水域,较短的生境梯度不足以提供更为全面的摇蚊群落变化信息。神农架大九湖湿地包含泥炭地、湖泊、临时性水体等多种生境,本研究选择该湿地公园作为研究区域,通过采集不同生境的表层沉积物及水体样品,提取底泥亚化石摇蚊头壳,分析大九湖湿地中不同生境下的摇蚊群落结构差异,并对其与环境因子间的关系进行探讨。结果表明:1)大九湖湿地不同生境中摇蚊优势种迥异,泥炭藓藓丘生境中Limnophyes、Psilometriocnemus、Pseudosmittia等半陆生种类为主要优势种,湖泊生境中则以典型静水种Polypedilum nubeculosum-type为主要优势种,而过渡性水域(泥炭地洼地、沟渠及水洼生境)中,静水种与半陆生种共存;2)烧失量、水位埋深和pH是塑造不同生境类型下摇蚊群落结构的显著环境因子,水文条件主要通过改变碳积累过程等其他环境条件间接影响生物群落组成;3)沿水生-半陆生生境梯度,有机质含量和类型均发生显著变化,而摇蚊群落也由静水种、静水/半陆生共存转变为以半陆生种为主,摇蚊群落对生境变化表现出良好的响应过程。本研究揭示了不同生境条件下摇蚊群落的结构差异及影响摇蚊群落结构的潜在因子,为未来基于摇蚊的长时间尺度上泥炭地发育过程分析提供参考依据。  相似文献   

14.
滇池水生植被演替及其与水环境变化关系   总被引:30,自引:7,他引:23  
通过滇池水和植被和水体污染状况的全面高调查(1995-1997年),揭示了水生植被的演替动态与环境质量变化的关系。结果表明,滇池现有水生植物22种,以凤眼莲(Eichhornia crassipes)、喜旱莲子草(AlternanthearPhiloxeroides)、龙须眼子菜(Potamogeton pectinatus)和取草(Myriophyllum spicatum)等为优势种,其水生  相似文献   

15.
Barbara Waldon 《Limnologica》2012,42(4):320-327
This study comprised an inventory of vascular plants in 450 small water reservoirs (up to 1 ha in size). Most water bodies (76%) in the study area (Krajeńskie Lakeland, NW, Poland) were located in an agricultural landscape, typical of the region. A total of 576 species of vascular plants were recorded. Of these, about 76% were native species, 34 taxa were listed as legally protected in Poland and endangered in the region (Western Pomerania) or in Poland. 201 plant communities were identified, including 128 associations.Depending on the surrounding habitat, the following groups of ponds were identified: (1) mid-forest ponds; (2) mid-wetland ponds; ponds between arable fields, including (3) water basins with wide, well developed ecotone zones and (4) ponds with narrow or disturbed contact zones; and (5) ponds in urban areas. 30 ponds of each type were compared in detail. Differentiation and plant species richness of small water reservoirs was dependent on landscape type. The richest ponds were located within fields but isolated from their surroundings by a natural belt of rushes or trees, whilst mid-forest ponds were the poorest. Valorization was based on the presence of valuable flora (e.g. native, rare, and endangered species) and plant communities. This revealed that mid-forest and mid-wetland ponds were the most natural, while ponds in urban areas were the most strongly transformed.Ponds in the study area (n = 450) were also analysed for anthropogenic impacts. Anthropogenic stressors were observed in 51% of ponds. The most serious threats to the ponds of the Krajeńskie Lakeland were deterioration due to drainage and eutrophication. Over 35% of ponds were connected to a network of drainage ditches, with the highest percentage (57.1%) found in mid-forest ponds type.  相似文献   

16.
沉水植物附植生物群落生态学研究进展   总被引:6,自引:4,他引:2  
在高等水生植物表面经常附着生长着藻类、真菌和细菌等,这些有机群体组成附植生物群落,在大中型浅水湖泊中普遍存在.附植生物群落具有特定的物种组成和空间结构,并随季节推移和沉水植物生长表现出一定的动态变化特征.附植生物群落与宿主植物及周围水体环境联系密切,不仅能够表征水体营养盐、光照、温度等环境因子特征,与沉水植物、食草动物、浮游植物等水生生物类群也存在不同的相互作用.水生生态系统中,附植生物群落参与水体营养物质转化,在草-藻型湖泊生态系统的相互转化过程中起重要作用;其较高的初级生产力作为水生动物重要的食物来源,增加了食物网的多样性;同时,附植生物群落因其独特的生理生态特征正逐渐被应用于水质净化和水环境质量监测.本文在综述近年来附植生物群落研究进展的基础上,分析了附植生物群落的组成结构和动态变化特征,阐述了附植生物群落在水生生态系统中的功能,可为湖泊富营养化治理,尤其是沉水植被的生态修复和管理提供科学依据.  相似文献   

17.
富营养化湖泊围隔中重建水生植被及其生态效应   总被引:1,自引:0,他引:1  
胡旭  何亮  曹特  倪乐意  谢平 《湖泊科学》2014,26(3):349-357
水体富营养化导致水生植被衰退、蓝藻水华暴发、水质恶化和水生生态系统崩溃.恢复水生植被被认为是改善受损水体水质和提高其生态系统稳定性的重要手段.本研究通过构建大型围隔,根据水生植物的耐污程度及其对水质和底质等条件的需求,选取几种适宜的水生植物在围隔内进行移栽与群落构建,并以不移栽水生植物的围隔和围隔外水体作为对照.实验期间(2011年4月至2012年6月),围隔内移栽的几种水生植物全部存活,并建立了相对稳定的群落.同时还跟踪监测了3个处理组的水质情况,结果显示,移栽水生植物的围隔内水质明显优于围隔外,与未移栽水生植物围隔相比,也有很大程度的改善,其中移栽水生植物围隔内水体的总氮、铵态氮、总磷、水下消光系数相比于围隔外水体分别低30.55%、44.09%、36.04%和42.13%,相比于未移栽水生植物围隔内水体分别低5.96%、13.40%、6.70%和7.60%,透明度分别比围隔外水体和未移栽水生植物围隔水体高74.59%和8.70%,浮游植物生物量也大大低于围隔外,而浮游动物生物量却明显高于后者.此外,实验后移栽水生植物围隔内沉积物氮、磷含量及其间隙水总氮、总磷、铵态氮浓度明显低于围隔外和未移栽水生植物围隔.研究表明,在富营养化浅水湖泊中通过建立围隔进行合理的群落配置,进而逐步恢复水生植物是完全可行的,而水生植物恢复后加强对其管理和维护至关重要.  相似文献   

18.
Widespread loss and degradation of riverine habitats due to dams, diversions, levees, and human development have led to an increase in river habitat enhancement projects in recent decades. These projects typically focus on improving either terrestrial (e.g., riparian vegetation) or aquatic (e.g., fish spawning and rearing) habitats, and do not commonly address the relationship between the two systems. However, there is abundant evidence that fundamental linkages exist between terrestrial and aquatic ecosystems, and anthropogenic impacts such as urban expansion, agricultural activities, and river impoundment can synergistically degrade both systems. This study examines the effects of adult and juvenile salmonid habitat restoration on recruitment, density, and composition of riparian vegetation in an area heavily impacted by mining and flow regulation. For a year following in-channel coarse sediment placement and floodplain construction in an area previously covered with coarse mine tailings, we compared the abundance, richness and diversity of vegetation across four treatments: the newly constructed floodplain, isolated mine tailings, mine tailings near an access road, and a remnant riparian area that was less impacted by mining. Richness and diversity were higher in the floodplain than in any of the other treatments; we identified a total of 15 plant families in the floodplain treatments, as compared to three to five families in the other treatments. We observed significant differences in plant assemblage composition between treatments, with higher richness of primarily obligate or facultative wetland plant taxa in the floodplain treatment. This study demonstrates that restoring hydrological linkages between aquatic and terrestrial habitats, and redistribution of sediment size classes altered by mining, can create conditions that promote rapid wetland plant colonization, enhancing biodiversity and improving ecosystem function.  相似文献   

19.
浅型富营养湖泊的生态恢复——五里湖水生植被重建实验   总被引:30,自引:4,他引:26  
李文朝 《湖泊科学》1996,8(Z1):1-10
依据浅型湖泊生态系统的多稳定态理论,在富营养湖泊治理过程中,当外来污染得到有效控制时,通过人工重建水生植被可以加速湖泊的生态恢复。在五里湖中,挺水植物和浮叶植物都能很好地生长,水底光照不足是沉水植物难以生长的主要原因。在自然条件下建成了永久性挺水植物群落和浮叶植物群落,在人工控制的围隔环境中改善了水底光照条件,建成了沉水植物群落。但这些沉水植物仍不能渡过夏季,主要原因是湖水过深和水温较高,降低水位和建造人工浅滩可为五里湖沉水植被恢复创造有利条件。本研究可为富营养水体的水质控制和植被恢复提供多种实用技术,但在水生植被的结构与环境功能等方面仍需开展深入的定量研究。  相似文献   

20.
The special hydrological situation of temporary streams has a great influence on the abiotic processes and other habitat conditions for organisms. To monitor possible impacts of stream drying on the composition of lotic communities, streamflow measurements and collections of the macrozoobenthos were conducted in a temporary and an adjacent upstream permanent section of the karst stream Sauer (East Westphalia, Germany) in 1996. The Sauer has a summer-dry temporary flow regime. The seasonal dry phase can last from spring to early autumn, so the duration of the dry phase varies from one to several months, increasing with distance downstream from the upstream permanent section. The number of invertebrate taxa and individuals decreases with increasing duration of the dry phase. The permanent section is characterized by taxa typical of montane and submontane streams, whereas the fauna of the temporary section is quite different, composed of representatives of various zonal areas. Limnephilid caddisflies are particularly characteristic of this section. Life cycle strategies and specific adaptations with respect to habitat drying are discussed for several species. It can be concluded that the temporary discharge regime of the karst stream Sauer has a clear effect on the invertebrate communities. They mainly consist of species which can be seen as characteristic faunal elements of temporary streams.  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