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- 1. The River Styles® framework is a geomorphic approach to the classification of river types, assessment of the physical condition of rivers, and planning of physical rehabilitation. However, the linkages between River Styles and aquatic biodiversity conservation are still only weakly developed.
- 2. In this study, 41 sites in the Bega River basin in New South Wales, Australia, were classified according to River Style and geomorphic condition, and surveyed for four biological assemblages: diatoms, aquatic and semi‐aquatic macrophytes, aquatic macroinvertebrates and fish.
- 3. Each assemblage differed significantly among River Styles. However, in the case of diatoms and fish, these differences could be accounted for by geographic clustering of sites in the same River Style, and a tendency for River Styles to occupy particular altitudinal zones and sizes of streams. This result was attributed to the overriding influences of water quality on diatoms and of altitude‐related variation in water temperature and distance from the ocean on fish. For macrophytes and macroinvertebrates, geomorphic river type appeared to exert a direct influence, probably via variation in physical habitat characteristics.
- 4. Geomorphic condition, judged as good, moderate or poor by reference to the inferred natural condition of each River Style, was also significantly associated with differences in biological assemblages other than fish. Twice as many taxa appeared to favour sites in good geomorphic condition as favoured sites in poor condition. Many of the taxa associated with sites in poor condition are alien taxa introduced to Australia since European settlement.
- 5. These findings imply that protection of reaches that are in good geomorphic condition is likely to be critical for the maintenance of indigenous biodiversity, and that rehabilitation of geomorphic condition can assist in the rehabilitation of native riverine biota.
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Demography of sea lamprey (Petromyzon marinus) ammocoete populations in relation to potential spawning‐migration obstructions 
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下载免费PDF全文 A. D. Nunn R. J. Taylor I. G. Cowx R. A. A. Noble J. D. Bolland J. P. Harvey 《水产资源保护:海洋与淡水生态系统》2017,27(4):764-772
- Recent advances in the understanding of lamprey migrations have led to concerns over the impacts of obstructions on the demography of many species. This study investigated sea lamprey (Petromyzon marinus) larvae (ammocoetes) in two adjacent but contrasting rivers, both designated Special Areas of Conservation under the EC Habitats Directive (92/43/EEC), one (the River Wye) with a small number of potential migration obstructions in its upper reaches and one (the River Usk) with obstacles along its course. The geographical distributions, densities and age structures of the ammocoete populations were examined in relation to the locations of potential obstructions to the spawning migrations of anadromous adults.
- A minimum of three age classes was recorded as far as 200 km upstream of the mouth of the River Wye (93% of the length of the mainstem), demonstrating that adults regularly migrate to the upper reaches of the catchment (downstream of a natural waterfall). By contrast, sea lamprey ammocoetes appeared to be absent (in suitable habitat) from 20 km (17%) of the River Usk, and there was a reduction in density, prevalence and the number of age classes upstream of two putative spawning‐migration obstructions.
- This study highlights some of the potential impacts of habitat fragmentation by obstructions on the spawning migrations of anadromous species, as inferred from ammocoete demography. When used in combination to compare contiguous reaches, ammocoete densities, prevalence and age structure may be a useful indicator of which structures are likely to be important migration obstructions, and where further studies or mitigation efforts should be focused. It is likely that passage past some obstructions is enhanced if high river levels occur during the spawning migration, but there is a need to facilitate passage during all conditions, to improve access to under‐exploited spawning and nursery areas.
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- 1. Historically, ecological assessment of lakes has depended on open‐water chemical and phytoplankton analysis, with trophic status determined by chlorophyll a and total phosphorus following the general protocol of the OECD lake classification scheme. This has been accompanied by a prevailing opinion that the littoral zone of lakes is too heterogeneous to allow meaningful inter‐lake comparisons.
- 2. Council of the European Communities Directive 2000/60/EC establishing a framework in the field of water policy (the Water Framework Directive) requires a broader approach to ecological assessment, including the need to incorporate a range of biotic variables. This paper describes the results of a monitoring programme designed to determine within‐ and among‐lake variation of macroinvertebrate communities found in defined mesohabitats of 22 lakes incorporating a range of lake types. Three sampling approaches were applied to the study.
- 3. Triplicate macroinvertebrate samples from a cobble/pebble mesohabitat of 11 lakes showed that community composition from a standard habitat was robust.
- 4. Twinned samples from contrasting habitats of pebble/cobble and macrophyte dominated mesohabitats of 21 lakes had greater similarity within than among lakes. This showed that even across contrasting habitat structure, macroinvertebrate assemblages can provide a reliable lake‐specific indicator.
- 5. Multivariate analysis of replicate samples from 15 visually distinct mesohabitats in one lake showed that within‐lake variation could, nevertheless, be identified as distinct clusters of invertebrate assemblages.
- 6. Conclusions from the work are that variations within lakes were nested in among‐lake variation across a range of lake types, and that macroinvertebrate assemblages can provide meaningful assessment of ecological differences across lakes. Monitoring can, however, produce a substantial amount of ‘noise’ from the data that reflects the complexity of macroinvertebrate community structure in littoral zones. It is recommended that incorporation of macroinvertebrates in ecological assessment is most useful when confined to well defined mesohabitats rather than attempt to incorporate a complete range of mesohabitats within a single lake.
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《水产资源保护:海洋与淡水生态系统》2003,13(6):507-549
- 1. The European Water Framework Directive requires the determination of ecological status in European fresh and saline waters. This is to be through the establishment of a typology of surface water bodies, the determination of reference (high status) conditions in each element (ecotype) of the typology and of lower grades of status (good, moderate, poor and bad) for each ecotype. It then requires classification of the status of the water bodies and their restoration to at least ‘good status’ in a specified period.
- 2. Though there are many methods for assessing water quality, none has the scope of that defined in the Directive. The provisions of the Directive require a wide range of variables to be measured and give only general guidance as to how systems of classification should be established. This raises issues of comparability across States and of the costs of making the determinations.
- 3. Using expert workshops and subsequent field testing, a practicable pan‐European typology and classification system has been developed for shallow lakes, which can easily be extended to all lakes. It is parsimonious in its choice of determinands, but based on current limnological understanding and therefore as cost‐effective as possible.
- 4. A core typology is described, which can be expanded easily in particular States to meet local conditions. The core includes 48 ecotypes across the entire European climate gradient and incorporates climate, lake area, geology of the catchment and conductivity.
- 5. The classification system is founded on a liberal interpretation of Annexes in the Directive and uses variables that are inexpensive to measure and ecologically relevant. The need for taxonomic expertise is minimized.
- 6. The scheme has been through eight iterations, two of which were tested in the field on tranches of 66 lakes. The final version, Version 8, is offered for operational testing and further refinement by statutory authorities.
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- 1. River restoration is now widely undertaken and may be considered an increasingly important aspect of river management. Recent developments in European legislation (Habitats Directive and the Water Framework Directive) should give further impetus to river restoration across EU member states, as this legislation places greater emphasis on the processes that support river ecology.
- 2. Traditional river restoration approaches have been reach‐focused and opportunistic, capitalizing on flood defence works and the cooperation of sympathetic landowners.
- 3. Furthermore, many schemes have been species‐ or habitat‐driven and, thus, have sought to recreate channel forms believed to be favoured by particular species or associated with particular habitats. Such approaches have not always given due attention to the underlying geomorphological processes that create channel form and, consequently, the schemes have not been self‐sustaining, requiring continued management input.
- 4. Consistent with the ethos of the Water Framework Directive, an eco‐hydromorphic approach to river restoration is proposed here. This approach views spatial and temporal heterogeneity as fundamental characteristics of fluvial systems and advocates recreating a framework within which natural processes, such as sediment transport and nutrient dynamics, can occur.
- 5. Mesoscale habitat approaches are considered as one possible way to plan and achieve this framework, providing the potential to link the wide range of spatial and temporal scales that characterize river systems.
- 6. It is argued that river restoration will only be sustainable if it is undertaken within a process‐driven and strategic framework with inputs from a wide range of specialists. Such an approach needs to be reviewed constantly in light of appraisal and monitoring of previous river restoration schemes.
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- 1. Multivariate analysis of vegetation and water beetles recorded in the abandoned drains and flooded workings of a cut‐over lowland Irish raised bog, Montiaghs Moss, shows that water depth and trophic status are key predictors of plant species composition and that vegetation community structure significantly explains water beetle composition.
- 2. The spatial distribution of secondary and tertiary drains and peat pits influences species composition indirectly, through trophic status, by connecting habitats with primary agricultural drains passing through the bog.
- 3. Habitat isolation and the cessation of drain management promote change in the submerged aquatic vegetation, emergent‐swamp and poor‐fen habitats recorded by facilitating vegetation development and surface acidification.
- 4. The ecological consequences are likely to be a reduction in the area of open‐water habitats, the development of poor‐fen vegetation and the subsequent loss of high conservation value species of plants and beetles.
- 5. Management for biodiversity conservation should initially address water quality, for example, through the European Union (EU) Water Framework Directive, followed by restoration to promote structural and spatial heterogeneity of drain and peat‐pit habitats.
- 6. At a landscape scale, implementing ditch and peat‐pit management across abandoned cut‐over lowland raised bog habitats in the farmed Northern Ireland countryside, through EU Common Agricultural Policy agri‐environment schemes, would give regional gains.
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Francisco García‐Criado Eloy Bcares Camino Fernndez‐Alez Margarita Fernndez‐Alez 《水产资源保护:海洋与淡水生态系统》2005,15(1):31-50
- 1. The EC Water Framework Directive requires that Member States assess the ecological quality of their water bodies on the basis of a wide set of variables, including benthic invertebrates.
- 2. The aim of the study was to find one or more faunistic indices that could be related to ecological status of shallow lakes, independent of different macrophyte types.
- 3. Six invertebrate indices were calculated from abundance and biomass data in 10 Spanish shallow lakes: total abundance and biomass, Shannon's index, percentage of predators, percentage of Ephemeroptera, Plecoptera and Trichoptera, Orthocladiinae as a percentage of the total Chironomidae, and Chironominae as a percentage of the whole macroinvertebrate community. Taxon richness was also calculated.
- 4. Differences in the values of indices across different macrophyte types were explored by means of a one‐way analysis of variance. Significant differences were occasionally found when indices were calculated from biomass data. Total abundance was also significantly different across some architecture types.
- 5. No significant correlations were found between the overall values of the indices for each lake and the environmental variables measured (ecological status, total nitrogen, total phosphorus, chlorophyll a concentrations, dynamics of the water flow, and naturalness of the shore), except in the case of total biomass.
- 6. Values of indices were plotted (box plots) to detect potential differences between lakes of different ecological status. None of the index values was clearly related to ecological status. Thus, the approach used here, requiring relatively little sampling effort and taxonomic expertise, was of little use as a quality indicator for shallow lakes. The implementation of the Directive will therefore require different approaches to be developed and tested.
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Invasive Asian clam distribution pattern reveals minimal constraints to downstream dispersal and imperceptible ecological impacts 下载免费PDF全文
下载免费PDF全文 Joana Luísa Pereira Tânia Vidal Cristiana Mendes Ana Ré Joana Isabel Santos Fernando Gonçalves Bruno Branco Castro 《水产资源保护:海洋与淡水生态系统》2017,27(5):953-964
- The Asian clam Corbicula fluminea is an invasive freshwater species that can cause adverse ecological and economic impacts. Information on its dispersal abilities, ecological preferences and impacts may contribute towards the improvement of management strategies, including those relating to regulatory demands such as the European Water Framework Directive (WFD).
- Both the above perspectives were addressed through inspection of environmental constraints to C. fluminea dispersal and impacts in a semi‐natural drainage catchment (interconnected system of ditches). Forty sites were surveyed in 2014 to describe the species distribution and to characterize benthic macroinvertebrate communities, water column and sediment physico‐chemistry, as well as the hydromorphological conditions.
- Clams were unevenly distributed in the study area and artificial barriers (dikes) did not prevent downstream dispersal of juveniles. Large variation in clam density (0–3077 clams m?2) could not be explained by physico‐chemical or hydromorphological gradients. Although typical clam preference ranges reported in the literature were often exceeded, dense populations were nevertheless observed.
- Macroinvertebrate community structure suggested associations between the Asian clam and some functional feeding groups. However, the impacts of clams on macroinvertebrate assemblages and ecological quality were negligible, suggesting that contemporary methods designed to comply with the WFD bioassessment scheme may fail to detect important drivers of ecological change in freshwater ecosystems.
- This study demonstrated the reduced ecological impacts and broad ecological competence of the Asian clam, but also that its spread depends on human vectors. These findings highlight the need to rethink prediction tools supporting preventive measures against the introduction and spread of this invasive bivalve.
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- 1. The ecological status of floodplain areas along the Austrian section of the Danube was assessed by an approach based on dragonfly surveys. Although this river section contains a relatively high portion of the river‐type‐specific alluvial floodplain areas, most of them are influenced by river regulation and damming.
- 2. A key element of the assessment procedure, which is oriented towards the new EC Water Framework Directive, is the Odonate Habitat Index.
- 3. Classification of ecological status is based on the comparison between the status quo and reference conditions derived from a historical situation minimally influenced by human activities.
- 4. Data from 408 sites from 14 investigation areas were used. Ten of the 14 areas were ranked in class II (‘good ecological status’) within the five‐tiered system, which is the level of ecological status targeted in the directive. One area corresponds to the reference condition (class I, ‘high ecological status’), and three areas do not meet the quality objective (class III, ‘moderate ecological status’). A total of 49 species were found along the whole section, which represents 82% of the river‐type‐specific reference list.
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- 1. An index of riparian quality useful for the management of streams and rivers is presented. The purpose of the index is to provide managers with a simple method to evaluate riparian habitat quality. The index is easy to calculate and can be used together with any other index of water quality to assess the ecological status of streams and rivers. It may also be a useful tool for defining ‘high ecological status’ under the EC Water Framework Directive.
- 2. The index, named QBR, is based on four components of riparian habitat: total riparian vegetation cover, cover structure, cover quality and channel alterations. It also takes into account differences in the geomorphology of the river from its headwaters to the lower reaches. These differences are measured in a simple, quantitative way. The index score varies between 0 and 100 points.
- 3. The QBR index is calculated in the field through a two‐sided A4 page form that may be completed in 10 min.
- 4. The development of the QBR index included trials in four Mediterranean stream catchments in Catalonia (NE Spain). Seventy‐two sampling sites were assessed and results were used to test the index.
- 5. No taxonomic expertise is needed to apply the index, although some knowledge of local flora is required to differentiate between native and non‐native tree species.
- 6. These results show that the QBR index may be used despite regional differences in plant communities. The quality ranges obtained when the index is applied are not heavily influenced by observers at the same site.
- 7. At present, the index is being used by different research teams and tested in a comparative study of 12 watersheds along the Mediterranean Spanish coast.
- 8. It is expected that the QBR index may be adapted for use in other geographical areas in temperate and semi‐arid zones without changes in the index rationale.
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A. Basset L. Sabetta A. Fonnesu D. Mouillot T. Do Chi P. Viaroli G. Giordani S. Reizopoulou M. Abbiati G. C. Carrada 《水产资源保护:海洋与淡水生态系统》2006,16(5):441-455
- 1. Transitional waters are ecotones between terrestrial, freshwater and marine ecosystems, being characterized by high spatial heterogeneity and temporal variability.
- 2. The EU Water Framework Directive (WFD) posed to the scientific community the challenge to classify these ecosystems into a small number of types, while retaining a functional classification of ecosystem types.
- 3. A niche theory approach is proposed to identify the limiting forcing factors organizing biological quality elements, i.e. the limiting niche dimensions.
- 4. The analysis of a macro‐invertebrate dataset from published papers on 36 Italian lagoons suggested a two‐level typological classification of Mediterranean lagoons.
- 5. Basic ecological theories, such as niche and island biogeography theories, have fundamental implications for the process of developing a typological classification for all aquatic ecosystems, as required by the WFD.
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- 1. The European Water Framework Directive (WFD) requires that Member States differentiate the transitional water bodies into types.
- 2. WFD assigns coastal lagoons to two different water categories, ‘transitional waters’ and ‘coastal waters’ on the basis of freshwater influence.
- 3. The main physical factors that contribute to the genesis and characterization of coastal lagoons are coastal typology, tidal range and climate.
- 4. Italian lagoons are presented as an example of how these physical factors can be used in coastal lagoon characterization and typology. On this basis, a clear distinction of Italian lagoons into two main groups is possible: Northern Adriatic and Mediterranean.
- 5. Large lagoons can be profitably subdivided into a hierarchical system of sub‐basins facilitating both the comparison of parts of the same lagoon and the comparison between different lagoons.
- 6. The basins are consistent water bodies that can be used as managerial units for environmental conservation, species protection and wise use of resources.
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