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1.
Seventy two taxa of rotifers, belonging to 24 genera, are recorded from Saladillo river basin for the first time. Among them twelve are new for Argentina. These especies are described and illustrated. Ecological and biogeographical information is also given.  相似文献   

2.
This article explores the phenomenon of neighborhood cinema (Cine con vecinos) in Saladillo, Argentina. Since 1995 it has been appropriating screening and production spaces wrested from local television, and more generally challenging the hegemony of national TV and industrial cinema production. Cine con vecinos is analyzed here in terms of social agency, participation and sociality. It has democratized media production through films shot entirely with locals, and has also promoted a revival of local movie theaters. Finally, the prospects of this type of cinema are assessed in contrast to other types of participatory community cinema, and also in view of its recent project of making a future “community set,” or large-scale production site, for community cinema.  相似文献   

3.
Fairy armadillos or pichiciegos (Xenarthra, Dasypodidae) are among the most elusive mammals. Due to their subterranean and nocturnal lifestyle, their basic biology and evolutionary history remain virtually unknown. Two distinct species with allopatric distributions are recognized: Chlamyphorus truncatus is restricted to central Argentina, while Calyptophractus retusus occurs in the Gran Chaco of Argentina, Paraguay, and Bolivia. To test their monophyly and resolve their phylogenetic affinities within armadillos, we obtained sequence data from modern and museum specimens for two mitochondrial genes (12S RNA [MT-RNR1] and NADH dehydrogenase 1 [MT-ND1]) and two nuclear exons (breast cancer 1 early onset exon 11 [BRCA1] and von Willebrand factor exon 28 [VWF]). Phylogenetic analyses provided a reference phylogeny and timescale for living xenarthran genera. Our results reveal monophyletic pichiciegos as members of a major armadillo subfamily (Chlamyphorinae). Their strictly fossorial lifestyle probably evolved as a response to the Oligocene aridification that occurred in South America after their divergence from Tolypeutinae around 32 million years ago (Mya). The ancient divergence date (~17Mya) for separation between the two species supports their taxonomic classification into distinct genera. The synchronicity with Middle Miocene marine incursions along the Paraná river basin suggests a vicariant origin for pichiciegos by the disruption of their ancestral range. Their phylogenetic distinctiveness and rarity in the wild argue in favor of high conservation priority.  相似文献   

4.
The marsh deer is the largest neotropical cervid with morphological and ecological adaptations to wetlands and riparian habitats. Historically, this now endangered species occupied habitats along the major river basins in South America, ranging from southern Amazonia into northern Argentina to the Paraná river delta. This particularly close association with wetlands makes marsh deer an excellent species for studying the effects of Pleistocene climatic changes on their demographic and phylogeographic patterns. We examined mitochondrial DNA variation in 127 marsh deer from 4 areas distributed throughout the Río de la Plata basin. We found 17 haplotypes in marsh deer from Brazil, Bolivia and Argentina that differed by 1–8 substitutions in a 601 bp fragment of mitochondrial control region sequence, and 486 bp of cytochrome b revealed only 3 variable sites that defined 4 haplotypes. Phylogeny and distribution of control region haplotypes suggest that populations close to the Pantanal area in central Brazil underwent a rapid population expansion and that this occurred approximately 28,000–25,000 years BP. Paleoclimatic data from this period suggests that there was a dramatic increase for precipitation in the medium latitudes in South America and these conditions may have fostered marsh deer’s population growth.  相似文献   

5.
Longitudinal distribution and abundance of macroinvertebrate communities were examined in relation to hydrochemical variables along the Chubut River in the Patagonian Precordillera and Plateau, Argentina. The Chubut River (>1000 km) is the largest river in the area and its basin is subject to multiple uses: agriculture, cattle raising, urbanization and the hydrological regime of the lower section is modified by a reservoir. Quantitative benthic samples were collected at 13 sites in the higher, middle and lower sections of the river basin. Sites were visited four times during 2004 and physicochemical parameters, chlorophyll a and particulate organic matter (POM) were assessed. Ninety-five taxa were collected in the study, with total species richness per site ranging from 5 to 51, and benthos density averaging 299–5024 ind m−2. Altitude and turbidity were implicated as important factors determining macroinvertebrate assemblages along the river system, and an eutrophication gradient was documented in the regulated/urbanized section of the main river. High turbidity (TSS) and sedimentation limited algal productivity in the middle basin. Below the dam, TSS, total phosphorus (TP) and POM decreased, whereas soluble reactive phosphorus (SRP) and chlorophyll a increased. Macroinvertebrate density increased three fold in this area possibly due to habitat improvement and enhanced trophic resources. Mean species richness did not change below the impoundment; however the community was dominated by gastropods, chironomids and flatworms. The Chubut River is complex and its biotic community reflects the landscape attributes. While benthic composition and density was governed by turbidity and flood disturbance in some river segments, a greater environmental heterogeneity resulted in an unexpected high number of species at the main channel upper basin.  相似文献   

6.
Synopsis We report the finding of an established population of exotic Chinook salmon spawning in headwaters of the Santa Cruz River system (Argentina), the first for this species in an Atlantic basin of South America. Spawning takes place in the Caterina River, a small tributary of Lake Argentino, located 488.5 km from the ocean. Anadromy was verified by correspondence of N and C stable isotope ratios with those of fish captured by bottom-trawlers in the ocean and those of anadromous rainbow trout from the same river basin. The scale patterns of most fish examined were consistent with a stream-type life cycle (i.e., seaward migration by juveniles after a full year in fresh water). Two potential origins were identified for this population: in situ introductions of fish imported directly from the USA in the early 20th century or fish from two ranching experiments conducted in southern Chile during the 1980s. In the latter case, colonization would have proceeded through the Strait of Magellan, helped by prevailing eastward currents.  相似文献   

7.
南水北调对海河流域水生态环境影响分析   总被引:21,自引:0,他引:21  
裴源生  王建华  罗琳 《生态学报》2004,24(10):2115-2123
提出可定量分析研究流域水循环变化对水生态环境影响的关联分析方法 ,并对海河流域现状进行了关联分析和和评价。分析研究表明人类对水资源的过度开发利用已改变了海河流域的天然水循环并导致水生态环境全面退化。进一步对未来无南水北调和有南水北调的情况进行定量模拟计算 ,结果表明在无南水北调的情况下 ,未来海河流域将处于无法兼顾发展经济和保护生态环境的困境 ;在实施南水北调的情况下 ,水资源可支撑海河流域经济发展并影响和改善整个流域的水循环状态 ,从整体上遏制海河流域水生态环境恶化的趋势 ,但入海水量仍无法改善  相似文献   

8.
以往研究流域开发战略问题,多从流域内资源的开发利用方面考虑,而衡量其方案的优劣也多以经济效益的大小为准绳。现在,环境污染与生态危机已威胁着人类的生存与发展,因此在研究流域战略问题时,必须开拓思路,  相似文献   

9.
Longitudinal and seasonal distributions of Plecoptera species were examined along the Chubut River in the Patagonian Precordillera and Plateau, Argentina. Chubut River (>1000 km) is the largest river in the area and the hydrological regime is modified in the lower section by an artificial reservoir (Florentino Ameghino Dam). Quantitative samples were collected in 13 sites in the higher, middle, and lower sections of the river basin. Sites were visited four times during 2004, and a total of nine species and 5772 individuals were collected in the study. Plecoptera richness decreased dramatically from the headwaters to the mouth of the river system. Two species, Antarctoperla michaelseni and Potamoperla myrmidon, were able to live below the impoundment but they were not abundant. Notoperlopsis femina and A. michaelseni abundances were higher in summer than in the other seasons, while Limnoperla jaffueli peaked in spring. Species–environmental relationships were examined using Canonical Correspondence Analysis and six independent variables were identified as the major factors structuring stoneflies assemblages. First axis was highly related to environmental variables reflecting the hydro-geological and land use gradients in the basin (conductivity, total suspended solids, periphyton Chlorophyll a). Second axis was more related to variables that changed seasonally (wet width, water temperature and soluble reactive phosphate).  相似文献   

10.
Hydrobiological studies on the Tugela river system   总被引:6,自引:6,他引:0  
Oliff  W. D. 《Hydrobiologia》1960,14(3-4):281-332
Summary A chemical and biological survey of the Tugela river, Natal is described. Some relationships between physical and chemical conditions in the river and the geology and climate of the basin are indicated. The flora and fauna of the main river is described, and the zonation of species in the river, and seasonal variations in the communities at various stations in the zones are delineated.Some relationships between the physical and chemical conditions in the basin, and the distribution and seasonal variations of the biological communities are indicated. Comparisons are made with other rivers. It is concluded that the Tugela river as a type in Southern Africa, falls intermediate between temperate and sub-tropical conditions.  相似文献   

11.
Multimedia fate models have proven to be very useful tools in chemical risk assessment and management. This paper presents BasinBox, a newly developed steady-state generic multimedia fate model for evaluating risks of new and existing chemicals in river basins. The model concepts, as well as the intermedia processes quantified in the model, are outlined, and an overview of the required input parameters is given. To test the BasinBox model, calculations were carried out for predicting the fate of chemicals in the river Rhine basin. This was done for a set of 3175 hypothetical chemicals and three emission scenarios to air, river water and cropland soils. For each of these hypothetical chemicals and emission scenarios the concentration ratio between the downstream area and the upstream area was calculated for all compartments. From these calculations it appeared that BasinBox predicts significant concentration differences between upstream and downstream areas of the Rhine river basin for certain types of chemicals and emission scenarios. There is a clear trend of increasing chemical concentrations in downstream direction of the river basin. The calculations show that taking into account spatial variability between upstream, midstream and downstream areas of large river basins can be useful in the predictions of environmental concentrations by multimedia fate models.  相似文献   

12.
刘晓曼  侯鹏  高吉喜  陈艳梅  吕娜 《生态学报》2024,44(12):4956-4963
流域是最为典型的生态区域,也是我国生态文明建设和山水林田湖草生命共同体的重要载体,流域可持续发展对国家经济社会发展和生态安全都具有十分重要的作用。日趋紧张的人地关系,对流域的生态文明建设和可持续发展提出新的挑战。引入区域生态学的理论及方法,在总结区域生态学的研究对象、研究内容、研究目标和研究尺度基础上,剖析了妨碍我国流域可持续发展的主要区域生态问题,并从流域生态格局-过程-功能协调发展、实现流域间地-地耦合、构建与生态承载力相适宜的人居环境和产业结构、建立生态补偿机制等四个方面提出了基于区域生态学理论和方法的应对策略,以引导我国新时期流域的可持续发展。  相似文献   

13.
In Japan the most heavily cadmium (Cd)-polluted region is the Jinzu river basin, where Itai-itai disease is endemic and the Kakehashi river basin is the second most polluted region.. The village average Cd concentrations in rice were distributed in the range between 0.02 microg/g and 1.06 microg/g in the Jinzu river basin and 0.11 microg g and 0.67 microg g in the Kakehashi river basin. Severe renal damage has occurred widely in the Jinzu river basin. Even after Cd exposure had ceased, renal dysfunction became worse. Dose-response relationships between Cd exposure and health effects were clearly demonstrated in both regions. The allowable limits (according to the present authors' assessment) of Cd concentrations in rice were estimated to be 0.08 microg g to 0.13 microg g and approximately 2 g for total Cd intake. Renal dysfunction caused by exposure to Cd was associated with an increased mortality in both regions. The increased total Cd intake and high concentration of Cd in rice also exerts an adverse influence on life prognosis.  相似文献   

14.
黄河是中华文明的发源地, 被誉为母亲河, 是两岸社会经济发展的保障, 切实保护好黄河流域湿地生态系统, 事关中华民族伟大复兴的千秋大计。黄河流域湿地总面积为391万ha, 其中80.4%分布在上游, 中游和下游分别仅12.5%和7.1%。黄河流域是东亚-澳大利西亚候鸟迁徙路线和中亚候鸟迁徙路线上水鸟的关键栖息地, 一些迁徙水鸟最关键的栖息地均分布在黄河流域, 如黑颈鹤(Grus nigricollis)、白鹤(G. leucogeranus)、丹顶鹤(G. japonensis)、斑头雁(Anser indicus)、大鸨(Otis tarda)、东方白鹳(Ciconia boyciana)、大天鹅(Cygnus cygnus)、疣鼻天鹅(C. olor)、青头潜鸭(Aythya baeri)等。尽管黄河流域湿地提供的水资源仅占全国的2%, 但维持着全国12%的人口饮水安全和15%的耕地用水, 湿地生态系统的脆弱性较高。截至2017年底, 黄河流域已建立各类湿地自然保护地230处, 其中国家公园2处、国家级自然保护区9处、地方级自然保护区68处、国家湿地公园145处、省级湿地公园6处, 湿地保护率达到65%, 高于我国湿地保护53%的平均水平。然而, 流域尺度现有水鸟生物多样性保护仍然面临不少挑战, 包括全球气候变化、水资源过度利用、水环境污染、栖息地丧失等。为此, 我们提出了建立以国家公园为主体的湿地保护地体系、开展濒危候鸟栖息地修复和强化黄河流域综合管理的体制机制建设等建议。  相似文献   

15.
Significant variations in four biological measures of water quality with stream order and river basin were demonstrated for streams of the Black and Osage river basins of Missouri. Water quality criteria specific for each order and basin were then developed.Benthic macroinvertebrates from springs and stream orders 3–8 in the two river basins were sampled quarterly for one year with riffle nets and artificial substrate samplers. A total of 548 samples were taken at 137 stations. The average annual macroinvertebrate density, index of diversity, number of taxa, and number of mayfly and stonefly taxa were determined for each station. These measures showed significant differences (p < 0.05) across stream order within and between the two river basins. Total taxa, total mayfly and stonefly taxa, and diversity were highest in orders 4 and 5 with decreased values in lower and higher stream orders. Maximum organism densities occurred in intermediate order streams. These differences were attributed to the succession of physical changes from headwaters to mouth within each river and to the unique geomorphology of each catchment basin.Water quality criteria based on three of the four measures described above (with 95% confidence limits) were established for each stream order in each river basin. Criteria for the Osage River basin were then used to identify three streams in the basin affected by environmental disturbances (stream impoundment, channelization and sewage discharge). The use of order- and basin-specific criteria assures that the biological differences between streams caused by environmental disturbance can be distinguished from the natural biological differences between streams of different orders and drainages.  相似文献   

16.
DNA barcode data of the South Asian bagrid catfish genus Sperata indicate the presence of at least five species in the Indian subcontinent. Those results, which are supported by morphological data, show a marked increase in species diversity from the recent taxonomic and fishery literature, although each of the five species had been previously named. Two species are restricted to rivers of peninsular India south of the Godavari: Sperata aorides from the Cauvery river basin and S. seenghala from the Krishna river basin. Most literature records of S. seenghala from the Ganges-Brahmaputra-Meghna river basins likely refer to S. lamarrii, a species which appears to also be present in the Indus river basin. Some genetic data reported as S. seenghala from the Ganges-Brahmaputra-Meghna river basins refer to S. aorella. S. aor is widespread in the Ganges-Brahmaputra-Surma river basins in India and Bangladesh, extending southwards to the Godavari river.  相似文献   

17.
Human activities are affecting the environment at continental and global scales. An example of this is the Mississippi basin where there has been a large scale loss of wetlands and water quality deterioration over the past century. Wetland and riparian ecosystems have been isolated from rivers and streams. Wetland loss is due both to drainage and reclamation, mainly for agriculture, and to isolation from the river by levees, as in the Mississippi delta. There has been a decline in water quality due to increasing use of fertilizers, enhanced drainage and the loss of wetlands for cleaning water. Water quality has deteriorated throughout the basin and high nitrogen in the Mississippi river is causing a large area of hypoxia in the Gulf of Mexico adjacent to the Mississippi delta. Since the causes of these problems are distributed over the basin, the solution also needs to be distributed over the basin. Ecotechnology and ecological engineering offer the only ecologically sound and cost-effective method of solving these problems. Wetlands to promote nitrogen removal, mainly through denitrification but also through burial and plant uptake, offer a sound ecotechnological solution. At the level of the Mississippi basin, changes in farming practices and use of wetlands for nitrogen assimilation can reduce nitrogen levels in the River. There are additional benefits of restoration of wetland and riverine ecosystems, flood control, reduction in public health threats, and enhanced wildlife and fisheries. At the local drainage basin level, the use of river diversions in the Mississippi delta can address both problems of coastal land loss and water quality deterioration. Nitrate levels in diverted river water are rapidly reduced as water flows through coastal watersheds. At the local level, wetlands are being used to treat municipal wastewater. This is a cost-effective method, which results in improved water quality, enhanced wetland productivity and increased accretion. The problems in the Mississippi basin serves as an example for other watersheds in the Gulf of Mexico. This is especially important in Mexico, where there is a strong need for economical solutions to ecological problems. The Usumacinta delta-Laguna de Terminos regional ecosystem is an example where ecotechnological approaches offer realistic solutions to environmental problems.  相似文献   

18.
生态需水是河流与湖泊生态系统健康的重要基础。湖泊流域的河流与湖泊生态系统之间存在密切的水量联系,目前对流域内生态用水的研究多为单一生态系统生态需水简单相加,忽略了河流和湖泊之间复杂的水量联系。基于河湖复合生态系统之间的水量联系构建了河湖生态系统生态用水优化模型,并以滇池为例分析了河湖生态系统生态用水规律。结果表明:湖泊流域中单一河流或湖泊生态需水计算结果不能满足复合生态系统的生态用水要求,需要综合考虑河流和湖泊之间的水量联系;在当前水质状况下,牛栏江每年的调水量不能满足滇池流域的生态用水要求;滇池流域水体污染对流域内生态用水影响较大,随着水体污染程度的下降,流域生态用水量和调水量呈指数下降,河流生态用水呈线性下降。  相似文献   

19.
The chemical structure of the oligosaccharide produced from sucrose by an enzyme extracted fromAureobasidium sp. ATCC 20524 was observed. The GC-MS analysis by methylation indicated that this oligosaccharide is composed of 2-linked, 1,2-linked fructose and 1-linked glucose. The [13C]-NMR spectrum indicated that the 1,2-linked glycosidic linkages of fructose of this oligosaccharide are, and the 1-linked glycosidic linkages of fructose are . This investigation suggested that this oligosaccharide is isokestose.  相似文献   

20.
闽江流域生态安全格局及其生态保护修复措施   总被引:2,自引:0,他引:2  
应凌霄  王军  周妍 《生态学报》2019,39(23):8857-8866
流域及其生态环境问题受到国内外的广泛关注,我国面临的流域生态环境问题突出亟待解决,体现流域生态系统完整性的山水林田湖草生命共同体理念对我国流域生态保护修复工作具有重要意义。以福建省山水林田湖草生态保护修复试点的工程区——闽江流域为例,在介绍其生态环境特征的基础上,通过梳理分析,根据区域生态功能的重要性构建“一江一带一区一屏”的闽江流域总体生态安全格局,面临的主要生态环境问题包括闽江水环境污染、流域岸带水土流失、矿区生态破坏、森林屏障和生物多样性退化等一系列威胁;分析提出了闽江水环境综合治理、干支流沿岸带水土流失防治、矿区废弃土地修复、武夷山地等重要生态屏障森林和生物多样性保护等主要任务及相应工程措施,体现了流域整体性、系统性的保护修复需求和内在逻辑;讨论了监测、评价等保障措施,为改善闽江流域生态系统和开展山水林田湖草生态保护修复工程提供科学依据和实践经验。  相似文献   

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