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1.
One decade of benthic macroinvertebrate biomonitoring in the River Meuse   总被引:1,自引:0,他引:1  
The benthic macroinvertebrate community of the River Meuse was studied at four locations in Belgium and The Netherlands from 1983–1993. Macroinvertebrates were collected from artificial substrates, placed near the river bottom from June–August. The results were analyzed using autecological information. At an upstream sampling site in the Belgian Ardennes (Hastière) the most diverse fauna was found. One quarter of the taxa found at this site are known to be confined to running waters and none of the dominant or subdominant taxa could be characterized as a specialized riverine taxon. These findings indicate an impoverished riverine fauna. This was especially the case in years with low discharge, indicating a delicately balanced ecosystem, easily susceptible to disturbances in the environment. Further downstream, in the heavily industrialized region of Liège (Hermalle) and just across the Belgian-Dutch border (Borgharen) the macroinvertebrate fauna consisted of taxa tolerating severe organic pollution. The ecosystem at these sites is on the brink of collapse. Recent results indicate an improvement of this situation at Borgharen. The macroinvertebrate fauna in the lowland reach (Keizersveer) indicates ecological recovery. It is concluded that abatement of the severe pollution must be the first step for an ecological rehabilitation of the degraded ecosystem and for the safe drinking water supply for millions of people in Belgium and The Netherlands.This article is dedicated to my friend and colleague Nicole Frantzen, who died in 1992 at the age of 27.  相似文献   

2.
Jamwa Ramgarh reservoir near Jaipur (Rajasthan) is one of the oldest man-made lakes in western India. This paper presents a case study of likely impacts of human activities in freshwater bodies. The history, vegetation and human activities in the catchment area, flora and fauna, physico-chemical characteristics and production in the reservoir are briefly described. The impact of increasing human activities in the last few years is discussed.  相似文献   

3.
Summary Currently in Western Australia (WA) there are no mandated standards for assessing rehabilitation success for the mining industry. We argue a case for focusing on the creation of near‐natural, self‐sustaining, functional ecosystems as the primary objective for rehabilitation programs and where this is not achievable, mines should plan to be ‘environmentally neutral’ by undertaking some improvements to degraded landscapes. We suggest that flora and fauna monitoring are appropriate tools for managers and regulators to obtain information on the extent to which a rehabilitated area has achieved a near natural, self‐sustaining, functional ecosystem similar to that in the adjacent undisturbed area. This monitoring can also be used for completion criteria and closure plans. We report results from a short questionnaire sent to mine site environmental managers to assess the extent of flora and fauna monitoring in rehabilitation areas. Survey results highlighted the need for a more systematic and consistent approach to the monitoring of flora and fauna in rehabilitated mining areas in WA. Of 36 respondents, 23 mines monitored flora, three monitored fauna and two monitored both.  相似文献   

4.
Significant anthropogenic pressure in the Dutch part of the River Rhine is present from the 12th century. River engineering and water pollution were the main stress factors for flora and fauna. From the middle of the 20th century measures were taken to reduce water pollution. Recently, from 1987 onwards, these activities were put into a wider context of ecological river rehabilitation. Effects of improvements on fish and macroinvertebrates in the main distributaries in the Rhine delta are reviewed. The conclusions are that (a) most of the alterations in the Rhine delta are irreversible due to hard socio-economic boundary conditions (e.g. safety, navigation); (b) chances for the development of riverine biotopes have therefore to be found in the forelands and not in the main channels of the Rhine delta; (c) further reduction of pollutants, especially thermal pollution, is needed to help original species to colonise the Rhine delta again; (d) non-indigenous species clearly leave a mark on recolonisation possibilities of original species.  相似文献   

5.
Springs are important freshwater habitats that provide refuge for many rare species. In this study, the fauna and abiotic parameters of 20 perennial springs in north-western Switzerland were investigated. Correlation of abiotic and macrozoobenthos data showed that physicochemical parameters had little impact on macrozoobenthic composition, whereas specific substrate parameters strongly influenced the composition of the macrofauna. Surprisingly, nonmetric multidimensional scaling did not reveal a grouping of springs with similar substrate composition or macrozoobenthic assemblages. However, discharge was identified as the factor significantly determining substrate and the composition of macroinvertebrate assemblages. This justifies the hypothesis that, variation in discharge is the disturbance factor governing the macrofaunal composition temporally and spatially within and between patches. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.  相似文献   

6.
This paper describes the Middle Jurassic flora of the Peski locality (Moscow Region), a unique locality for fossil flora and fauna. The systematic composition, age of the flora, and plant taphonomy in context of paleorelief are considered. Plant associations are reconstructed. The paleogeographical significance of the flora is discussed.  相似文献   

7.
Since 1979 the flora and fauna of the artificial rocky shores of the Oosterschelde estuary have been investigated by diving biologists.Spatial and temporal patterns of species diversity and biomass were studied and several groups of species (communities) were distinguished. A west-east gradient in species composition was found. Species distribution proved to be mainly determined by current velocities, silt and plankton concentrations in the water, underwater irradiance, and the nature of the substratum. Some indications of migration between the basin and the North Sea are shown. Biomass of the hard substratum fauna was compared with that of the soft bottom fauna; the ratio appeared to be about 1 : 2, which is surprisingly high considering the small area available for hard substratum fauna.The key to the interactions with the North Sea is found in the water movements and the volume of water passing through the mouth of the basin during each tide. The abiotic and subsequent biotic changes in the basin caused by the building of the storm surge barrier are discussed, and used to illustrate the measure of dependence of the Oosterschelde on the North Sea.  相似文献   

8.
《Comptes rendus biologies》2014,337(12):695-708
Six temporary wetlands in the region of Sejenane (Mogods, NW Tunisia) were studied in order to characterize the aquatic flora and fauna and to quantify their spatio-temporal variability. Samplings of aquatic fauna, phytosociological relevés, and measurements of the physicochemical parameters of water were taken during four different field visits carried out during the four seasons of the year (November 2009–July 2010). Despite the strong anthropic pressures on them, these temporary wetlands are home to rich and diversified biodiversity, including rare and endangered species. Spatial and temporal variations affect fauna and flora differently, as temporal variability influences the fauna rather more than the plants, which are relatively more dependent on spatial factors. These results demonstrate the interest of small water bodies for maintaining biodiversity at the regional level, and thus underscore the conservation issues of Mediterranean temporary wetlands that are declining on an ongoing basis currently.  相似文献   

9.
Trichoptera and substrate stability in the Ochre River,Manitoba   总被引:2,自引:2,他引:0  
A total of 3999 Trichoptera adults, represented by 8 families, 17 genera and 33 species was collected in emergence traps in 1983 and 1984 from five stations on the Ochre River, Manitoba (50° 04 N, 99° 48 W). Species composition for the two years was comparable, but as the result of a summer spate in 1984, abundance was only 40% of that in 1983.Species diversity by station was negatively correlated with substrate instability of the reach, whereas density per trap was negatively correlated with substrate instability and local factors such as sedimentation in some reaches following peak discharges. Analysis of historical peak discharge records indicated that relatively infrequent mid-summer spates had a detrimental effect on subsequent emergence of the Trichoptera fauna. The combination of spates and unstable stream bed substrate resulting from land use practices in the drainage basin have resulted in an impoverished caddisfly fauna in the Ochre River in comparison with other rivers in Manitoba.  相似文献   

10.
Salt and water balance in the Aral Sea are described together with the endemic fauna and flora which were mainly of freshwater origin. During the last thirty years the fauna and flora have undergone dramatic changes due partly to a great increase in salinity as the result of water abstraction from the inflowing rivers and partly as the result of the deliberate and accidental introduction of a wide variety of marine invertebrates and fishes. The increased salinity has eliminated most the species of freshwater origin while many of endemic saline species have been lost as the result of competition with the marine ones. Changes in productivity are described and future prospects for the sea are discussed.  相似文献   

11.
Abstract R iver I nV ertebrate P rediction A nd C lassification S ystem (rivpacs ) is a software package developed by the Institute of Freshwater Ecology (IFE) for assessing the biological quality of rivers in the United Kingdom. The system can be used to generate site-specific predictions of the macroinvertebrate fauna to be expected in the absence of major environmental stress. Each prediction is based on a small number of environmental features that are used to characterize the site. The fauna predicted can then be compared with the fauna observed at the same site. This offers a procedure for evaluating biological quality with application in river management both at the local level and for national surveys. Close collaboration between the IFE team and biologists in the water industry during the project had a beneficial influence on the operational development of the system. A second feature of RIVPACS is the national classification of sites, based on the macro-invertebrate fauna. Although the classification is currently a pre-requisite for the prediction system, it also has intrinsic value because newly sampled sites of high biological quality can be placed within the national framework, based on their macroinvertebrate fauna. This facility is of interest to the statutory nature conservation bodies as an element in their site appraisal procedures. The predictive component of the current version of the system (RIVPACS n) was used in the 1990 River Quality Survey to assess the biological quality of almost 9000 sites throughout the United Kingdom. Further developmental work is now under way to provide a more comprehensive version of the system for the 1995 survey.  相似文献   

12.
Oyster reef restoration has become a principal strategy for ameliorating the loss of natural Crassostrea virginica populations and increasing habitat provision. In 2014, a large‐scale, high‐relief, 23‐ha subtidal C. virginica reef was restored at the historically productive Half Moon Reef in Matagorda Bay, TX, using concrete and limestone substrates. Encrusting and motile fauna were sampled seasonally until 17 months postrestoration at the restored reef and at adjacent unrestored sites. Restored oysters developed rapidly and were most abundant 3 months postrestoration, with subsequent declines possibly due to interacting effects of larval settlement success on new substrate versus post‐settlement mortality due to competitors and predators. Oyster densities were 2× higher than in a restored oyster population in Chesapeake Bay that was reported to be the largest reestablished metapopulation of native oysters in the world. Resident fauna on the restored reef were 62% more diverse, had 433% greater biomass, and comprised a distinct faunal community compared to unrestored sites. The presence of three‐dimensional habitat was the most important factor determining resident faunal community composition, indicating that substrate limitation is a major hindrance for oyster reef community success in Texas and other parts of the Gulf of Mexico. There were only minor differences in density, biomass, and diversity of associated fauna located adjacent (13 m) versus distant (150 m) to the restored reef. The two substrate types compared had little influence on oyster recruitment or faunal habitat provision. Results support the use of reef restoration as a productive means to rebuild habitat and facilitate faunal enhancement.  相似文献   

13.
Spatial and seasonal variation in macrozoobenthic composition, abundance and diversity in Aiba Reservoir were investigated bimonthy between June 2004 and April 2005 using a van Veen grab. A depauperate fauna of nine taxa was recorded. Generally, larger numbers of taxa were recorded during the dry season than in the wet season. Melanoides tuberculata and chironomid larvae dominated the macrozoobenthos and showed wide spatial distribution. Diversity and evenness were lower during the wet season than in the dry season, when densities of the major species were low. Melanoides tuberculata and chironomid larvae were recorded from maximum depths of 3.9 m and 2.6 m, respectively. Both taxa were also recorded from all substrate texture types, regardless of the amount of macrophyte material present. The benthic fauna is characterised as being poor in terms of density, taxonomic richness and diversity  相似文献   

14.
Mongol names and toponyms are most often used by paleontologists for designation of new forms of fossil fauna and flora from the Cenozoic of Central Asia.  相似文献   

15.
In this paper the collection and analysis of a sample of moths made on an altitude transect on Mt. Kinabalu, Sabah, are described. The geological and phytogeographical histories of the mountain are reviewed. Single-link cluster analysis is used to pick out faunal elements in the transect. The geographical affinities of the species composing these elements are investigated and discussed.
As with the flora, species in the lowland elements belong largely to centric groups (with centres of speciation coincident with the locality concerned) of the south-east Asian rain forest regions. Increasingly higher elements have an increasing representation of species from eccentric groups. In the flora these eccentric groups are Himalayan and south temperate in roughly equal proportions. In the moth (and bird) fauna they are almost entirely Himalayan centred.
Distribution of montane habitats during the Pleistocene glaciations favoured the colonization of Kinabalu from sources to the south-east. An explanation is presented for the contrast between flora and moth fauna on Kinabalu in terms of the relative development of these groups in the two source areas.  相似文献   

16.
On the basis of investigations of the diatom flora and the Plecoptera, Ephemeroptera and Trichoptera fauna in two mountain brooks with different chemisms the different effects of the regional factors of the water chemism and the extraregional factors, current and temperature, on the biocoenosis is discussed. The zoocoenotic division of mountain streams is affected by the extraregional factors; the structure of the diatom associations and the distribution of individual species of the insect fauna are dependent on the regional effect of the water chemism. The correlation of the halobic indices as ecological characteristics of the diatom flora with the factors of the water chemism, pH and alkalinity, and their relationship with the distribution of some species of the insect fauna suggest that the halobic index is a useful criterion for the ecological classification of waters. Also for the judgement of the trophic conditions and the self-purification of waters the halobic index can be regarded as an additional criterion.  相似文献   

17.
Have you ever wondered where flora and fauna found their names? Many are named for people--rich and poor, large and small. Even tabletop football is not immune.  相似文献   

18.
In the Mediterranean basin, the yellow-legged gull Larus cachinnans has undergone a widespread demographic increase for the past 30 years. Owing to its high ecological adaptability, its aggressive behaviour and its abundance, this gull is often considered to be a pest. The authors review and analyse the impacts of the expansion of the yellow-legged gull on fauna and flora in the Mediterranean area. Despite the relatively limited number of both intensive and general studies, it clearly appears that the population explosion has had a very diverse and severe effect on the ecosystem as a whole (flora, vertebrates, interspecific competition, extinction–colonization processes). The most serious damage has occurred around the largest breeding colonies to the detriment of fragile, rare or very restricted plant and animal species. Thus, from the point of view of fauna and flora conservation, the yellow-legged gull can, for the moment, be considered to be locally superabun dant. Control measures are often very onerous and necessitate heavy manpower and material resources. Additional extensive investigations will be necessary to assess the future development of yellow-legged gull populations and their impact on natural environments.  相似文献   

19.
Measurements made in fresh water wetland have shown that temperature, pH, dissolved oxygen and bicarbonate alkalinity in the hyacinth infested area were lower, but dissolved free carbon dioxide concentration was excitingly greater than in the open water area. This extreme hypoxic and hypercarbic condition of hyacinth covered areas was caused by the thick coverage of Eichhornia crassipes which was crucial for the composition of the characteristic flora and fauna.  相似文献   

20.
Uranium ore treatment works are responsible for a strong increase in minerals and, to a lesser extent, radio-activity in the rivers receiving their outflows. In certain streams, the fauna and the flora can disappear completely.However, our study has shown that the toxicity does not directly affect fish or crustacea but only algae, the growth of which is either partly or totally inhibited, depending on the dilution provided by the watercourse.This toxicity is not due to the uranium or to the sulphates and chlorides used in the treatment process, but to traces of heavy metals present in the reject, such as copper and zinc.The disappearance of the microalgae, which are the first link of the food chain, has important consequences, provoking the disappearance of the higher trophic levels leading to fish.  相似文献   

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